Closing a Venus Flytrap with electrical and mid-IR photon stimulations

NASA Astrophysics Data System (ADS)

Eisen, David; Janssen, Douglas; Chen, Xing; Choa, Fow-Sen; Kostov, Dan; Fan, Jenyu

2013-03-01

Plants have mechanisms to perceive and transmit information between its organs and tissues. These signals had long been considered as hormonal or hydraulic in nature, but recent studies have shown that electrical signals are also produced causing physiological responses. In this work we show that Venus Flytrap, Dionaea muscipula, can respond to both electrical and optical signals beside mechanical stimulations. While the Venus Flytrap does not have any neurons, it does contain transport cells with very similar characteristics to neurotransmitters and uses ionic mechanisms, as human neurons do, to generate action potentials. In our electrical stimulation study, electrodes made out of soft cloth were soaked in salt water before being placed to the midrib (+) and lobe (-). The flytrap's surface resistance was determined by subtracting out the average electrode resistance from the measured electrode to plant surface resistance, yielding an average contact resistance of around 0.98MΩ. A logarithmic amplifier was used to monitor mechanically generated electrical signals. Two electrical pulses were generated by mechanically touching the trigger hairs in the lobe twice within 20 seconds. By discharging around 600μC charge stored in a capacitor we demonstrated electrically closing of the flytrap. For optical excitation we found in our FTIR study it's tissue contains very similar protein absorption peaks to that of insects. A 7.35μm laser with 50mw power was then used for the stimulation study. Electrical action potential was generated twice by mid-infrared photons before closure of the flytrap.

Novel ultra-wideband (UWB) photonic generation through photodetection and cross-absorption modulation in a single electroabsorption modulator.

PubMed

Wu, Tsu-Hsiu; Wu, Jui-pin; Chiu, Yi-Jen

2010-02-15

We propose and demonstrate, by proof of concept, a novel method of ultra-wide band (UWB) photonic generation using photodetection and cross-absorption modulation (XAM) of multiple quantum wells (MQW) in a single short-terminated electroabsorption modulator (SEAM). As an optical pump pulse excite the MQWs of SEAM waveguide, the probe light pulse with the same polarity can be generated through XAM, simultaneously creating photocurrent pulse propagating along the waveguide. Using the short termination of SEAM accompanied by the delayed microwave line, the photocurrent pulse can be reversed in polarity and re-modulated the waveguide, forming a monocycle UWB optical pulse. An 89 ps cycle of monocycle pulse with 114% fractional bandwidth is obtained, where the electrical power spectrum centered at 4 GHz of frequency ranges from 0.1 GHz to 8 GHz for -10 dB drops. Meanwhile, the generation processing is also confirmed by observing the same cycle of monocycle electrical pulse from the photodetection of SEAM. The whole optical processing is performed inside a compact semiconductor device, suggesting the optoelectronic integration template has a potential for the application of UWB photonic generation.

Efficient and robust quantum random number generation by photon number detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Applegate, M. J.; Cavendish Laboratory, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE; Thomas, O.

2015-08-17

We present an efficient and robust quantum random number generator based upon high-rate room temperature photon number detection. We employ an electric field-modulated silicon avalanche photodiode, a type of device particularly suited to high-rate photon number detection with excellent photon number resolution to detect, without an applied dead-time, up to 4 photons from the optical pulses emitted by a laser. By both measuring and modeling the response of the detector to the incident photons, we are able to determine the illumination conditions that achieve an optimal bit rate that we show is robust against variation in the photon flux. Wemore » extract random bits from the detected photon numbers with an efficiency of 99% corresponding to 1.97 bits per detected photon number yielding a bit rate of 143 Mbit/s, and verify that the extracted bits pass stringent statistical tests for randomness. Our scheme is highly scalable and has the potential of multi-Gbit/s bit rates.« less

Photon harvesting, coloring and polarizing in photovoltaic cell integrated color filters: efficient energy routing strategies for power-saving displays.

PubMed

Wen, Long; Chen, Qin; Song, Shichao; Yu, Yan; Jin, Lin; Hu, Xin

2015-07-03

We describe the integral electro-optical strategies that combine the functionalities of photovoltaic (PV) electricity generation and color filtering as well as polarizing to realize more efficient energy routing in display technology. Unlike the conventional pigment-based filters and polarizers, which absorb substantial amounts of unwanted spectral components and dissipate them in the form of heat, we propose converting the energy of those photons into electricity by constructing PV cell-integrated color filters based on a selectively transmitting aluminum (Al) rear electrode perforated with nanoholes (NHs). Combining with a dielectric-metal-dielectric (DMD) front electrode, the devices were optimized to enable efficient cavity-enhanced photon recycling in the PV functional layers. We perform a comprehensive theoretical and numerical analysis to explore the extraordinary optical transmission (EOT) through the Al NHs and identify basic design rules for achieving structural coloring or polarizing in our PV color filters. We show that the addition of thin photoactive polymer layers on the symmetrically configured Al NH electrode narrows the bandwidth of the EOT-assisted high-pass light filtering due to the strongly damped anti-symmetric coupling of the surface modes excited on the front and rear surface of the Al NHs, which facilitates the whole visible coloring with relatively high purity for the devices. By engineering the cut-off characteristics of the plasmonic waveguide mode supported by the circular or ellipsoidal Al NHs, beyond the photon recycling capacity, PV color filters and PV polarizing color filters that allow polarization-insensitive and strong polarization-anisotropic color filtering were demonstrated. The findings presented here may shed some light on expanding the utilization of PV electricity generation across new-generation energy-saving electrical display devices.

Directly tailoring photon-electron coupling for sensitive photoconductance

NASA Astrophysics Data System (ADS)

Huang, Zhiming; Zhou, Wei; Huang, Jingguo; Wu, Jing; Gao, Yanqing; Qu, Yue; Chu, Junhao

2016-03-01

The coupling between photons and electrons is at the heart of many fundamental phenomena in nature. Despite tremendous advances in controlling electrons by photons in engineered energy-band systems, control over their coupling is still widely lacking. Here we demonstrate an unprecedented ability to couple photon-electron interactions in real space, in which the incident electromagnetic wave directly tailors energy bands of solid to generate carriers for sensitive photoconductance. By spatially coherent manipulation of metal-wrapped material system through anti-symmetric electric field of the irradiated electromagnetic wave, electrons in the metals are injected and accumulated in the induced potential well (EIW) produced in the solid. Respective positive and negative electric conductances are easily observed in n-type and p-type semiconductors into which electrons flow down from the two metallic sides under light irradiation. The photoconductivity is further confirmed by sweeping the injected electrons out of the semiconductor before recombination applied by sufficiently strong electric fields. Our work opens up new perspectives for tailoring energy bands of solids and is especially relevant to develop high effective photon detection, spin injection, and energy harvesting in optoelectronics and electronics.

Electronic tunability of zero dispersion wavelengths in a spiral photonic crystal fiber for supercontinuum generation in the communication window

NASA Astrophysics Data System (ADS)

Hossain, Md. Nazmul; Alam, M. Shah; Mohsin, K. M.; Hasan, Dihan Md. Nuruddin

2011-08-01

A liquid crystal infiltrated spiral photonic crystal fiber (LCSPCF) is presented here for electrical tuning of two zero dispersion wavelengths (ZDWs) in the present communication window. The proposed LCSPCF shows tunability of the ZDWs from 1433 nm to 2136 nm due to the rotation of the infiltrated LC mesogen induced by the external electric field. Therefore, the ZDW can easily be shifted towards the available pump wavelength for effective supercontinuum generation (SCG) over a broad wavelength region. By tuning the bandwidth (BW) in between the two ZDWs the extension of the generated supercontinuum (SC) spectrum can also be electrically controlled. This will help the SCG in our desired band with optimum power budget. Moreover, the index guiding mechanism of the proposed soft glass LCSPCF shows improvement over the narrow operational bandwidth and the low nonlinearity of the band-gap guided silica LCPCF. Additionally, the solid core of the proposed LCSPCF is less lossy than the previously proposed liquid crystal core PCF.

Single photon sources with single semiconductor quantum dots

NASA Astrophysics Data System (ADS)

Shan, Guang-Cun; Yin, Zhang-Qi; Shek, Chan Hung; Huang, Wei

2014-04-01

In this contribution, we briefly recall the basic concepts of quantum optics and properties of semiconductor quantum dot (QD) which are necessary to the understanding of the physics of single-photon generation with single QDs. Firstly, we address the theory of quantum emitter-cavity system, the fluorescence and optical properties of semiconductor QDs, and the photon statistics as well as optical properties of the QDs. We then review the localization of single semiconductor QDs in quantum confined optical microcavity systems to achieve their overall optical properties and performances in terms of strong coupling regime, efficiency, directionality, and polarization control. Furthermore, we will discuss the recent progress on the fabrication of single photon sources, and various approaches for embedding single QDs into microcavities or photonic crystal nanocavities and show how to extend the wavelength range. We focus in particular on new generations of electrically driven QD single photon source leading to high repetition rates, strong coupling regime, and high collection efficiencies at elevated temperature operation. Besides, new developments of room temperature single photon emission in the strong coupling regime are reviewed. The generation of indistinguishable photons and remaining challenges for practical single-photon sources are also discussed.

A Novel Photonic Clock and Carrier Recovery Device

NASA Technical Reports Server (NTRS)

Yao, X. Steve; Lutes, George; Maleki, Lute

1996-01-01

As data communication rates climb toward ten Gb/s, clock recovery and synchronization become more difficult, if not impossible, using conventional electronic circuits. We present in this article experimental results of a high speed clock and carrier recovery using a novel device called a photonic oscillator that we recently developed in our laboratory. This device is capable of recovering clock signals up to 70 GHz. To recover the clock, the incoming data is injected into the photonic oscillator either through the optical injection port or the electrical injection port. The free running photonic oscillator is tuned to oscillate at a nominal frequency equal to the clock frequency of the incoming data. With the injection of the data, the photonic oscillator will be quickly locked to clock frequency of the data stream while rejecting other frequency components associated with the data. Consequently, the output of the locked photonic oscillator is a continuous periodical wave synchronized with the incoming data or simply the recovered clock. We have demonstrated a clock to spur ratio of more than 60 dB of the recovered clock using this technique. Similar to the clock recovery, the photonic oscillator can be used to recover a high frequency carrier degraded by noise and an improvement of about 50 dB in signal-to-noise ratio was demonstrated. The photonic oscillator has both electrical and optical inputs and outputs and can be directly interfaced with a photonic system without signal conversion. In addition to clock and carrier recovery, the photonic oscillator can also be used for (1) stable high frequency clock signal generation, (2) frequency multiplication, (3) square wave and comb frequency generation, and (4) photonic phase locked loop.

Room temperature operation of electro-optical bistability in the edge-emitting tunneling-collector transistor laser

NASA Astrophysics Data System (ADS)

Feng, M.; Holonyak, N.; Wang, C. Y.

2017-09-01

Optical bistable devices are fundamental to digital photonics as building blocks of switches, logic gates, and memories in future computer systems. Here, we demonstrate both optical and electrical bistability and capability for switching in a single transistor operated at room temperature. The electro-optical hysteresis is explained by the interaction of electron-hole (e-h) generation and recombination dynamics with the cavity photon modulation in different switching paths. The switch-UP and switch-DOWN threshold voltages are determined by the rate difference of photon generation at the base quantum-well and the photon absorption via intra-cavity photon-assisted tunneling controlled by the collector voltage. Thus, the transistor laser electro-optical bistable switching is programmable with base current and collector voltage, and the basis for high speed optical logic processors.

Ultrafast single photon emitting quantum photonic structures based on a nano-obelisk.

PubMed

Kim, Je-Hyung; Ko, Young-Ho; Gong, Su-Hyun; Ko, Suk-Min; Cho, Yong-Hoon

2013-01-01

A key issue in a single photon source is fast and efficient generation of a single photon flux with high light extraction efficiency. Significant progress toward high-efficiency single photon sources has been demonstrated by semiconductor quantum dots, especially using narrow bandgap materials. Meanwhile, there are many obstacles, which restrict the use of wide bandgap semiconductor quantum dots as practical single photon sources in ultraviolet-visible region, despite offering free space communication and miniaturized quantum information circuits. Here we demonstrate a single InGaN quantum dot embedded in an obelisk-shaped GaN nanostructure. The nano-obelisk plays an important role in eliminating dislocations, increasing light extraction, and minimizing a built-in electric field. Based on the nano-obelisks, we observed nonconventional narrow quantum dot emission and positive biexciton binding energy, which are signatures of negligible built-in field in single InGaN quantum dots. This results in efficient and ultrafast single photon generation in the violet color region.

Chaotic ultra-wideband radio generator based on an optoelectronic oscillator with a built-in microwave photonic filter.

PubMed

Wang, Li Xian; Zhu, Ning Hua; Zheng, Jian Yu; Liu, Jian Guo; Li, Wei

2012-05-20

We induce a microwave photonic bandpass filter into an optoelectronic oscillator to generate a chaotic ultra-wideband signal in both the optical and electrical domain. The theoretical analysis and numerical simulation indicate that this system is capable of generating band-limited high-dimensional chaos. Experimental results coincide well with the theoretical prediction and show that the power spectrum of the generated chaotic signal basically meets the Federal Communications Commission indoor mask. The generated chaotic carrier is further intensity modulated by a 10 MHz square wave, and the waveform of the output ultra-wideband signal is measured for demonstrating the chaotic on-off keying modulation.

Photon-enhanced thermionic emission for solar concentrator systems.

PubMed

Schwede, Jared W; Bargatin, Igor; Riley, Daniel C; Hardin, Brian E; Rosenthal, Samuel J; Sun, Yun; Schmitt, Felix; Pianetta, Piero; Howe, Roger T; Shen, Zhi-Xun; Melosh, Nicholas A

2010-09-01

Solar-energy conversion usually takes one of two forms: the 'quantum' approach, which uses the large per-photon energy of solar radiation to excite electrons, as in photovoltaic cells, or the 'thermal' approach, which uses concentrated sunlight as a thermal-energy source to indirectly produce electricity using a heat engine. Here we present a new concept for solar electricity generation, photon-enhanced thermionic emission, which combines quantum and thermal mechanisms into a single physical process. The device is based on thermionic emission of photoexcited electrons from a semiconductor cathode at high temperature. Temperature-dependent photoemission-yield measurements from GaN show strong evidence for photon-enhanced thermionic emission, and calculated efficiencies for idealized devices can exceed the theoretical limits of single-junction photovoltaic cells. The proposed solar converter would operate at temperatures exceeding 200 degrees C, enabling its waste heat to be used to power a secondary thermal engine, boosting theoretical combined conversion efficiencies above 50%.

Electrically, chemically, and photonically powered torsional and tensile actuation of hybrid carbon nanotube yarn muscles.

PubMed

Lima, Márcio D; Li, Na; Jung de Andrade, Mônica; Fang, Shaoli; Oh, Jiyoung; Spinks, Geoffrey M; Kozlov, Mikhail E; Haines, Carter S; Suh, Dongseok; Foroughi, Javad; Kim, Seon Jeong; Chen, Yongsheng; Ware, Taylor; Shin, Min Kyoon; Machado, Leonardo D; Fonseca, Alexandre F; Madden, John D W; Voit, Walter E; Galvão, Douglas S; Baughman, Ray H

2012-11-16

Artificial muscles are of practical interest, but few types have been commercially exploited. Typical problems include slow response, low strain and force generation, short cycle life, use of electrolytes, and low energy efficiency. We have designed guest-filled, twist-spun carbon nanotube yarns as electrolyte-free muscles that provide fast, high-force, large-stroke torsional and tensile actuation. More than a million torsional and tensile actuation cycles are demonstrated, wherein a muscle spins a rotor at an average 11,500 revolutions/minute or delivers 3% tensile contraction at 1200 cycles/minute. Electrical, chemical, or photonic excitation of hybrid yarns changes guest dimensions and generates torsional rotation and contraction of the yarn host. Demonstrations include torsional motors, contractile muscles, and sensors that capture the energy of the sensing process to mechanically actuate.

Electrically, Chemically, and Photonically Powered Torsional and Tensile Actuation of Hybrid Carbon Nanotube Yarn Muscles

NASA Astrophysics Data System (ADS)

Lima, Márcio D.; Li, Na; Jung de Andrade, Mônica; Fang, Shaoli; Oh, Jiyoung; Spinks, Geoffrey M.; Kozlov, Mikhail E.; Haines, Carter S.; Suh, Dongseok; Foroughi, Javad; Kim, Seon Jeong; Chen, Yongsheng; Ware, Taylor; Shin, Min Kyoon; Machado, Leonardo D.; Fonseca, Alexandre F.; Madden, John D. W.; Voit, Walter E.; Galvão, Douglas S.; Baughman, Ray H.

2012-11-01

Artificial muscles are of practical interest, but few types have been commercially exploited. Typical problems include slow response, low strain and force generation, short cycle life, use of electrolytes, and low energy efficiency. We have designed guest-filled, twist-spun carbon nanotube yarns as electrolyte-free muscles that provide fast, high-force, large-stroke torsional and tensile actuation. More than a million torsional and tensile actuation cycles are demonstrated, wherein a muscle spins a rotor at an average 11,500 revolutions/minute or delivers 3% tensile contraction at 1200 cycles/minute. Electrical, chemical, or photonic excitation of hybrid yarns changes guest dimensions and generates torsional rotation and contraction of the yarn host. Demonstrations include torsional motors, contractile muscles, and sensors that capture the energy of the sensing process to mechanically actuate.

Opto-electronic microwave oscillator

NASA Astrophysics Data System (ADS)

Yao, X. Steve; Maleki, Lute

1996-12-01

Photonic applications are important in RF communication systems to enhance many functions including remote transfer of antenna signals, carrier frequency up or down conversion, antenna beam steering, and signal filtering. Many of these functions require reference frequency oscillators. However, traditional microwave oscillators cannot meet all the requirements of photonic communication systems that need high frequency and low phase noise signal generation. Because photonic systems involve signals in both optical and electrical domains, an ideal signal source should be able to provide electrical and optical signals. In addition, it should be possible to synchronize or control the signal source by both electrical and optical means. We present such a source1-2 that converts continuous light energy into stable and spectrally pure microwave signals. This Opto-Electronic Oscillator, OEO, consists of a pump laser and a feedback circuit including an intensity modulator, an optical fiber delay line, a photodetector, an amplifier, and a filter, as shown in Figure 1a. Its oscillation frequency, limited only by the speed of the modulator, can be up to 75 GHz.

Towards 5G: A Photonic Based Millimeter Wave Signal Generation for Applying in 5G Access Fronthaul.

PubMed

Alavi, S E; Soltanian, M R K; Amiri, I S; Khalily, M; Supa'at, A S M; Ahmad, H

2016-01-27

5G communications require a multi Gb/s data transmission in its small cells. For this purpose millimeter wave (mm-wave) RF signals are the best solutions to be utilized for high speed data transmission. Generation of these high frequency RF signals is challenging in electrical domain therefore photonic generation of these signals is more studied. In this work, a photonic based simple and robust method for generating millimeter waves applicable in 5G access fronthaul is presented. Besides generating of the mm-wave signal in the 60 GHz frequency band the radio over fiber (RoF) system for transmission of orthogonal frequency division multiplexing (OFDM) with 5 GHz bandwidth is presented. For the purpose of wireless transmission for 5G application the required antenna is designed and developed. The total system performance in one small cell was studied and the error vector magnitude (EVM) of the system was evaluated.

Towards 5G: A Photonic Based Millimeter Wave Signal Generation for Applying in 5G Access Fronthaul

PubMed Central

Alavi, S. E.; Soltanian, M. R. K.; Amiri, I. S.; Khalily, M.; Supa’at, A. S. M.; Ahmad, H.

2016-01-01

5G communications require a multi Gb/s data transmission in its small cells. For this purpose millimeter wave (mm-wave) RF signals are the best solutions to be utilized for high speed data transmission. Generation of these high frequency RF signals is challenging in electrical domain therefore photonic generation of these signals is more studied. In this work, a photonic based simple and robust method for generating millimeter waves applicable in 5G access fronthaul is presented. Besides generating of the mm-wave signal in the 60 GHz frequency band the radio over fiber (RoF) system for transmission of orthogonal frequency division multiplexing (OFDM) with 5 GHz bandwidth is presented. For the purpose of wireless transmission for 5G application the required antenna is designed and developed. The total system performance in one small cell was studied and the error vector magnitude (EVM) of the system was evaluated. PMID:26814621

Towards 5G: A Photonic Based Millimeter Wave Signal Generation for Applying in 5G Access Fronthaul

NASA Astrophysics Data System (ADS)

Alavi, S. E.; Soltanian, M. R. K.; Amiri, I. S.; Khalily, M.; Supa'At, A. S. M.; Ahmad, H.

2016-01-01

5G communications require a multi Gb/s data transmission in its small cells. For this purpose millimeter wave (mm-wave) RF signals are the best solutions to be utilized for high speed data transmission. Generation of these high frequency RF signals is challenging in electrical domain therefore photonic generation of these signals is more studied. In this work, a photonic based simple and robust method for generating millimeter waves applicable in 5G access fronthaul is presented. Besides generating of the mm-wave signal in the 60 GHz frequency band the radio over fiber (RoF) system for transmission of orthogonal frequency division multiplexing (OFDM) with 5 GHz bandwidth is presented. For the purpose of wireless transmission for 5G application the required antenna is designed and developed. The total system performance in one small cell was studied and the error vector magnitude (EVM) of the system was evaluated.

Entropic and near-field improvements of thermoradiative cells

DOE PAGES

Hsu, Wei -Chun; Tong, Jonathan K.; Liao, Bolin; ...

2016-10-13

A p-n junction maintained at above ambient temperature can work as a heat engine, converting some of the supplied heat into electricity and rejecting entropy by interband emission. Such thermoradiative cells have potential to harvest low-grade heat into electricity. By analyzing the entropy content of different spectral components of thermal radiation, we identify an approach to increase the efficiency of thermoradiative cells via spectrally selecting long-wavelength photons for radiative exchange. Furthermore, we predict that the near-field photon extraction by coupling photons generated from interband electronic transition to phonon polariton modes on the surface of a heat sink can increase themore » conversion efficiency as well as the power generation density, providing more opportunities to efficiently utilize terrestrial emission for clean energy. An ideal InSb thermoradiative cell can achieve a maximum efficiency and power density up to 20.4% and 327 Wm -2, respectively, between a hot source at 500 K and a cold sink at 300 K. Furthermore, sub-bandgap and non-radiative losses will significantly degrade the cell performance.« less

Entropic and Near-Field Improvements of Thermoradiative Cells

PubMed Central

Hsu, Wei-Chun; Tong, Jonathan K.; Liao, Bolin; Huang, Yi; Boriskina, Svetlana V.; Chen, Gang

2016-01-01

A p-n junction maintained at above ambient temperature can work as a heat engine, converting some of the supplied heat into electricity and rejecting entropy by interband emission. Such thermoradiative cells have potential to harvest low-grade heat into electricity. By analyzing the entropy content of different spectral components of thermal radiation, we identify an approach to increase the efficiency of thermoradiative cells via spectrally selecting long-wavelength photons for radiative exchange. Furthermore, we predict that the near-field photon extraction by coupling photons generated from interband electronic transition to phonon polariton modes on the surface of a heat sink can increase the conversion efficiency as well as the power generation density, providing more opportunities to efficiently utilize terrestrial emission for clean energy. An ideal InSb thermoradiative cell can achieve a maximum efficiency and power density up to 20.4% and 327 Wm−2, respectively, between a hot source at 500 K and a cold sink at 300 K. However, sub-bandgap and non-radiative losses will significantly degrade the cell performance. PMID:27734902

Terahertz photonic crystals

NASA Astrophysics Data System (ADS)

Jian, Zhongping

This thesis describes the study of two-dimensional photonic crystals slabs with terahertz time domain spectroscopy. In our study we first demonstrate the realization of planar photonic components to manipulate terahertz waves, and then characterize photonic crystals using terahertz pulses. Photonic crystal slabs at the scale of micrometers are first designed and fabricated free of defects. Terahertz time domain spectrometer generates and detects the electric fields of single-cycle terahertz pulses. By putting photonic crystals into waveguide geometry, we successfully demonstrate planar photonic components such as transmission filters, reflection frequency-selective filters, defects modes as well as superprisms. In the characterization study of out-of-plane properties of photonic crystal slabs, we observe very strong dispersion at low frequencies, guided resonance modes at middle frequencies, and a group velocity anomaly at high frequencies. We employ Finite Element Method and Finite-Difference Time-Domain method to simulate the photonic crystals, and excellent agreement is achieved between simulation results and experimental results.

Power Generation from a Radiative Thermal Source Using a Large-Area Infrared Rectenna

NASA Astrophysics Data System (ADS)

Shank, Joshua; Kadlec, Emil A.; Jarecki, Robert L.; Starbuck, Andrew; Howell, Stephen; Peters, David W.; Davids, Paul S.

2018-05-01

Electrical power generation from a moderate-temperature thermal source by means of direct conversion of infrared radiation is important and highly desirable for energy harvesting from waste heat and micropower applications. Here, we demonstrate direct rectified power generation from an unbiased large-area nanoantenna-coupled tunnel diode rectifier called a rectenna. Using a vacuum radiometric measurement technique with irradiation from a temperature-stabilized thermal source, a generated power density of 8 nW /cm2 is observed at a source temperature of 450 °C for the unbiased rectenna across an optimized load resistance. The optimized load resistance for the peak power generation for each temperature coincides with the tunnel diode resistance at zero bias and corresponds to the impedance matching condition for a rectifying antenna. Current-voltage measurements of a thermally illuminated large-area rectenna show current zero crossing shifts into the second quadrant indicating rectification. Photon-assisted tunneling in the unbiased rectenna is modeled as the mechanism for the large short-circuit photocurrents observed where the photon energy serves as an effective bias across the tunnel junction. The measured current and voltage across the load resistor as a function of the thermal source temperature represents direct current electrical power generation.

Fiber-optic delay-line stabilization of heterodyne optical signal generator and method using same

NASA Technical Reports Server (NTRS)

Logan, Ronald T. (Inventor)

1997-01-01

The present invention is a laser heterodyne frequency generator system with a stabilizer for use in the microwave and millimeter-wave frequency ranges utilizing a photonic mixer as a photonic phase detector in a stable optical fiber delay-line. Phase and frequency fluctuations of the heterodyne laser signal generators are stabilized at microwave and millimeter wave frequencies by a delay line system operating as a frequency discriminator. The present invention is free from amplifier and mixer 1/.function. noise at microwave and millimeter-wave frequencies that typically limit phase noise performance in electronic cavity stabilized electronic oscillators. Thus, 1/.function. noise due to conventional mixers is eliminated and stable optical heterodyne generation of electrical signals is achieved.

Highly efficient gate-tunable photocurrent generation in vertical heterostructures of layered materials

PubMed Central

Yu, Woo Jong; Liu, Yuan; Zhou, Hailong; Yin, Anxiang; Li, Zheng; Huang, Yu

2014-01-01

Layered materials of graphene and MoS2, for example, have recently emerged as an exciting material system for future electronics and optoelectronics. Vertical integration of layered materials can enable the design of novel electronic and photonic devices. Here, we report highly efficient photocurrent generation from vertical heterostructures of layered materials. We show that vertically stacked graphene–MoS2–graphene and graphene–MoS2–metal junctions can be created with a broad junction area for efficient photon harvesting. The weak electrostatic screening effect of graphene allows the integration of single or dual gates under and/or above the vertical heterostructure to tune the band slope and photocurrent generation. We demonstrate that the amplitude and polarity of the photocurrent in the gated vertical heterostructures can be readily modulated by the electric field of an external gate to achieve a maximum external quantum efficiency of 55% and internal quantum efficiency up to 85%. Our study establishes a method to control photocarrier generation, separation and transport processes using an external electric field. PMID:24162001

Photon energy upconversion through thermal radiation with the power efficiency reaching 16%.

PubMed

Wang, Junxin; Ming, Tian; Jin, Zhao; Wang, Jianfang; Sun, Ling-Dong; Yan, Chun-Hua

2014-11-28

The efficiency of many solar energy conversion technologies is limited by their poor response to low-energy solar photons. One way for overcoming this limitation is to develop materials and methods that can efficiently convert low-energy photons into high-energy ones. Here we show that thermal radiation is an attractive route for photon energy upconversion, with efficiencies higher than those of state-of-the-art energy transfer upconversion under continuous wave laser excitation. A maximal power upconversion efficiency of 16% is achieved on Yb(3+)-doped ZrO2. By examining various oxide samples doped with lanthanide or transition metal ions, we draw guidelines that materials with high melting points, low thermal conductivities and strong absorption to infrared light deliver high upconversion efficiencies. The feasibility of our upconversion approach is further demonstrated under concentrated sunlight excitation and continuous wave 976-nm laser excitation, where the upconverted white light is absorbed by Si solar cells to generate electricity and drive optical and electrical devices.

Transient Plasma Photonic Crystals for High-Power Lasers.

PubMed

Lehmann, G; Spatschek, K H

2016-06-03

A new type of transient photonic crystals for high-power lasers is presented. The crystal is produced by counterpropagating laser beams in plasma. Trapped electrons and electrically forced ions generate a strong density grating. The lifetime of the transient photonic crystal is determined by the ballistic motion of ions. The robustness of the photonic crystal allows one to manipulate high-intensity laser pulses. The scheme of the crystal is analyzed here by 1D Vlasov simulations. Reflection or transmission of high-power laser pulses are predicted by particle-in-cell simulations. It is shown that a transient plasma photonic crystal may act as a tunable mirror for intense laser pulses. Generalizations to 2D and 3D configurations are possible.

Detection of Nuclear Weapons and Materials: Science, Technologies, Observations

DTIC Science & Technology

2010-06-04

extensive use of photons, packets of energy with no rest mass and no electrical charge. Electromagnetic radiation consists of photons, and may be measured...bulk property, expressed as mass per unit volume. In general, the densest materials are those of high Z. These properties may be used to detect...SNM by detecting the time pattern of neutron generation. A subcritical mass of highly enriched uranium or weapons-grade plutonium can support a

A review on single photon sources in silicon carbide.

PubMed

Lohrmann, A; Johnson, B C; McCallum, J C; Castelletto, S

2017-03-01

This paper summarizes key findings in single-photon generation from deep level defects in silicon carbide (SiC) and highlights the significance of these individually addressable centers for emerging quantum applications. Single photon emission from various defect centers in both bulk and nanostructured SiC are discussed as well as their formation and possible integration into optical and electrical devices. The related measurement protocols, the building blocks of quantum communication and computation network architectures in solid state systems, are also summarized. This includes experimental methodologies developed for spin control of different paramagnetic defects, including the measurement of spin coherence times. Well established doping, and micro- and nanofabrication procedures for SiC may allow the quantum properties of paramagnetic defects to be electrically and mechanically controlled efficiently. The integration of single defects into SiC devices is crucial for applications in quantum technologies and we will review progress in this direction.

Recent Progress in Energy-Driven Water Splitting.

PubMed

Tee, Si Yin; Win, Khin Yin; Teo, Wee Siang; Koh, Leng-Duei; Liu, Shuhua; Teng, Choon Peng; Han, Ming-Yong

2017-05-01

Hydrogen is readily obtained from renewable and non-renewable resources via water splitting by using thermal, electrical, photonic and biochemical energy. The major hydrogen production is generated from thermal energy through steam reforming/gasification of fossil fuel. As the commonly used non-renewable resources will be depleted in the long run, there is great demand to utilize renewable energy resources for hydrogen production. Most of the renewable resources may be used to produce electricity for driving water splitting while challenges remain to improve cost-effectiveness. As the most abundant energy resource, the direct conversion of solar energy to hydrogen is considered the most sustainable energy production method without causing pollutions to the environment. In overall, this review briefly summarizes thermolytic, electrolytic, photolytic and biolytic water splitting. It highlights photonic and electrical driven water splitting together with photovoltaic-integrated solar-driven water electrolysis.

Recent Progress in Energy‐Driven Water Splitting

PubMed Central

Tee, Si Yin; Win, Khin Yin; Teo, Wee Siang; Koh, Leng‐Duei; Liu, Shuhua; Teng, Choon Peng

2017-01-01

Hydrogen is readily obtained from renewable and non‐renewable resources via water splitting by using thermal, electrical, photonic and biochemical energy. The major hydrogen production is generated from thermal energy through steam reforming/gasification of fossil fuel. As the commonly used non‐renewable resources will be depleted in the long run, there is great demand to utilize renewable energy resources for hydrogen production. Most of the renewable resources may be used to produce electricity for driving water splitting while challenges remain to improve cost‐effectiveness. As the most abundant energy resource, the direct conversion of solar energy to hydrogen is considered the most sustainable energy production method without causing pollutions to the environment. In overall, this review briefly summarizes thermolytic, electrolytic, photolytic and biolytic water splitting. It highlights photonic and electrical driven water splitting together with photovoltaic‐integrated solar‐driven water electrolysis. PMID:28546906

Resonantly enhanced multiple exciton generation through below-band-gap multi-photon absorption in perovskite nanocrystals.

PubMed

Manzi, Aurora; Tong, Yu; Feucht, Julius; Yao, En-Ping; Polavarapu, Lakshminarayana; Urban, Alexander S; Feldmann, Jochen

2018-04-17

Multi-photon absorption and multiple exciton generation represent two separate strategies for enhancing the conversion efficiency of light into usable electric power. Targeting below-band-gap and above-band-gap energies, respectively, to date these processes have only been demonstrated independently. Here we report the combined interaction of both nonlinear processes in CsPbBr 3 perovskite nanocrystals. We demonstrate nonlinear absorption over a wide range of below-band-gap excitation energies (0.5-0.8 E g ). Interestingly, we discover high-order absorption processes, deviating from the typical two-photon absorption, at specific energetic positions. These energies are associated with a strong enhancement of the photoluminescence intensity by up to 10 5 . The analysis of the corresponding energy levels reveals that the observed phenomena can be ascribed to the resonant creation of multiple excitons via the absorption of multiple below-band-gap photons. This effect may open new pathways for the efficient conversion of optical energy, potentially also in other semiconducting materials.

Spectral Properties, Generation Order Parameters, and Luminosities for Spin-powered X-Ray Pulsars

NASA Astrophysics Data System (ADS)

Wang, Wei; Zhao, Yongheng

2004-02-01

We show the spectral properties of 15 spin-powered X-ray pulsars, and the correlation between the average power-law photon index and spin-down rate. Generation order parameters (GOPs) based on polar cap models are introduced to characterize the X-ray pulsars. We calculate three definitions of generation order parameters arising from the different effects of magnetic and electric fields on photon absorption during cascade processes, and study the relations between the GOPs and spectral properties of X-ray pulsars. There exists a possible correlation between the photon index and GOP in our pulsar sample. Furthermore, we present a method stemming from the concept of GOPs to estimate the nonthermal X-ray luminosity for spin-powered pulsars. Then X-ray luminosity is calculated in the context of our polar cap accelerator model, which is consistent with most observed X-ray pulsar data. The ratio between the X-ray luminosity estimated by our method and the pulsar's spin-down power is consistent with the LX~10-3Lsd feature.

Reconfigurable radio-frequency arbitrary waveforms synthesized in a silicon photonic chip.

PubMed

Wang, Jian; Shen, Hao; Fan, Li; Wu, Rui; Niu, Ben; Varghese, Leo T; Xuan, Yi; Leaird, Daniel E; Wang, Xi; Gan, Fuwan; Weiner, Andrew M; Qi, Minghao

2015-01-12

Photonic methods of radio-frequency waveform generation and processing can provide performance advantages and flexibility over electronic methods due to the ultrawide bandwidth offered by the optical carriers. However, bulk optics implementations suffer from the lack of integration and slow reconfiguration speed. Here we propose an architecture of integrated photonic radio-frequency generation and processing and implement it on a silicon chip fabricated in a semiconductor manufacturing foundry. Our device can generate programmable radio-frequency bursts or continuous waveforms with only the light source, electrical drives/controls and detectors being off-chip. It modulates an individual pulse in a radio-frequency burst within 4 ns, achieving a reconfiguration speed three orders of magnitude faster than thermal tuning. The on-chip optical delay elements offer an integrated approach to accurately manipulating individual radio-frequency waveform features without constraints set by the speed and timing jitter of electronics, and should find applications ranging from high-speed wireless to defence electronics.

Reconfigurable radio-frequency arbitrary waveforms synthesized in a silicon photonic chip

PubMed Central

Wang, Jian; Shen, Hao; Fan, Li; Wu, Rui; Niu, Ben; Varghese, Leo T.; Xuan, Yi; Leaird, Daniel E.; Wang, Xi; Gan, Fuwan; Weiner, Andrew M.; Qi, Minghao

2015-01-01

Photonic methods of radio-frequency waveform generation and processing can provide performance advantages and flexibility over electronic methods due to the ultrawide bandwidth offered by the optical carriers. However, bulk optics implementations suffer from the lack of integration and slow reconfiguration speed. Here we propose an architecture of integrated photonic radio-frequency generation and processing and implement it on a silicon chip fabricated in a semiconductor manufacturing foundry. Our device can generate programmable radio-frequency bursts or continuous waveforms with only the light source, electrical drives/controls and detectors being off-chip. It modulates an individual pulse in a radio-frequency burst within 4 ns, achieving a reconfiguration speed three orders of magnitude faster than thermal tuning. The on-chip optical delay elements offer an integrated approach to accurately manipulating individual radio-frequency waveform features without constraints set by the speed and timing jitter of electronics, and should find applications ranging from high-speed wireless to defence electronics. PMID:25581847

ALPS: the Dark Matter Generator (coming in 2019)

NASA Astrophysics Data System (ADS)

Barke, Simon; Bush, Zachary; Baum, Claire; Hollis, Hal; Mueller, Guido; Tanner, David

2017-01-01

Very promising dark matter candidates are axion-like particles: sub-eV particles that are expected to (weakly) interact with photons in the presence of a static electric or magnetic field. This interaction can turn photons into axions and back into photons. Hence, in order to generate axions, we will set up a 100 meter long Fabry-Perot cavity that can hold a 150,000 watt laser field and have a 5.3 tesla magnetic field along the entire length. If the theory holds up, a fraction of the photons should transform into relativistic axions. These axions would then propagate through any optical barrier and enter a matched cavity that is situated within an identical magnetic field. Here, some of the axions should turn back into photons of equal energy. Thus these photons resonate in the otherwise empty cavity where they can be detected. It is unknown if axion-like particles exist in the targeted mass range. However, the ALPS detection principle is very convenient because we will know the exact energy of the regenerated photons beforehand thus making a detection much easier.The final stage of the ALPS experiment will be completed by 2019 at the German Electron Synchrotron (DESY) site in Hamburg, Germany. This work is supported by grants from the Heising-Simons Foundation and the National Science Foundation.

Femtosecond Pulse Characterization as Applied to One-Dimensional Photonic Band Edge Structures

NASA Technical Reports Server (NTRS)

Fork, Richard L.; Gamble, Lisa J.; Diffey, William M.

1999-01-01

The ability to control the group velocity and phase of an optical pulse is important to many current active areas of research. Electronically addressable one-dimensional photonic crystals are an attractive candidate to achieve this control. This report details work done toward the characterization of photonic crystals and improvement of the characterization technique. As part of the work, the spectral dependence of the group delay imparted by a GaAs/AlAs photonic crystal was characterized. Also, a first generation an electrically addressable photonic crystal was tested for the ability to electronically control the group delay. The measurement technique, using 100 femtosecond continuum pulses was improved to yield high spectral resolution (1.7 nanometers) and concurrently with high temporal resolution (tens of femtoseconds). Conclusions and recommendations based upon the work done are also presented.

High power beta electron device - Beyond betavoltaics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ayers, William M.; Gentile, Charles A.

Developing watt level power sources with beta emitting radioisotopes has been limited by the inability to utilize high energy (> 100 KeV) beta emitters at high radioisotope loadings without damaging the energy conversion materials. A new type of beta electron power source is described that removes those restrictions. This approach contains the radioisotope in a beta transparent titanium tube and confines beta electrons emitted through the tube wall to spiral trajectories around the tube with an axial magnetic field. The confined beta electrons dissipate energy though multiple interactions with surrounding excimer precursor gas atoms to efficiently generate photons. Photovoltaic cellsmore » convert the photons to electrical power. Since the beta electrons dissipate energy in the excimer precursor gas, the device can be loaded with more than 10 13 Bq of radioisotope to generate 100 milliwatt to watt levels of electrical power without damaging the device materials or degrading its performance. Furthermore, the power source can use a variety of beta radioisotopes and scales by stacking the devices.« less

Plasmon enhanced terahertz emission from single layer graphene.

PubMed

Bahk, Young-Mi; Ramakrishnan, Gopakumar; Choi, Jongho; Song, Hyelynn; Choi, Geunchang; Kim, Yong Hyup; Ahn, Kwang Jun; Kim, Dai-Sik; Planken, Paul C M

2014-09-23

We show that surface plasmons, excited with femtosecond laser pulses on continuous or discontinuous gold substrates, strongly enhance the generation and emission of ultrashort, broadband terahertz pulses from single layer graphene. Without surface plasmon excitation, for graphene on glass, 'nonresonant laser-pulse-induced photon drag currents' appear to be responsible for the relatively weak emission of both s- and p-polarized terahertz pulses. For graphene on a discontinuous layer of gold, only the emission of the p-polarized terahertz electric field is enhanced, whereas the s-polarized component remains largely unaffected, suggesting the presence of an additional terahertz generation mechanism. We argue that in the latter case, 'surface-plasmon-enhanced optical rectification', made possible by the lack of inversion symmetry at the graphene on gold surface, is responsible for the strongly enhanced emission. The enhancement occurs because the electric field of surface plasmons is localized and enhanced where the graphene is located: at the surface of the metal. We believe that our results point the way to small, thin, and more efficient terahertz photonic devices.

High power beta electron device - Beyond betavoltaics

DOE PAGES

Ayers, William M.; Gentile, Charles A.

2017-11-10

Developing watt level power sources with beta emitting radioisotopes has been limited by the inability to utilize high energy (> 100 KeV) beta emitters at high radioisotope loadings without damaging the energy conversion materials. A new type of beta electron power source is described that removes those restrictions. This approach contains the radioisotope in a beta transparent titanium tube and confines beta electrons emitted through the tube wall to spiral trajectories around the tube with an axial magnetic field. The confined beta electrons dissipate energy though multiple interactions with surrounding excimer precursor gas atoms to efficiently generate photons. Photovoltaic cellsmore » convert the photons to electrical power. Since the beta electrons dissipate energy in the excimer precursor gas, the device can be loaded with more than 10 13 Bq of radioisotope to generate 100 milliwatt to watt levels of electrical power without damaging the device materials or degrading its performance. Furthermore, the power source can use a variety of beta radioisotopes and scales by stacking the devices.« less

High power beta electron device - Beyond betavoltaics.

PubMed

Ayers, William M; Gentile, Charles A

2018-01-01

Developing watt level power sources with beta emitting radioisotopes has been limited by the inability to utilize high energy (> 100KeV) beta emitters at high radioisotope loadings without damaging the energy conversion materials. A new type of beta electron power source is described that removes those restrictions. The approach contains the radioisotope in a beta transparent titanium tube and confines beta electrons emitted through the tube wall to spiral trajectories around the tube with an axial magnetic field. The confined beta electrons dissipate energy though multiple interactions with surrounding excimer precursor gas atoms to efficiently generate photons. Photovoltaic cells convert the photons to electrical power. Since the beta electrons dissipate energy in the excimer precursor gas, the device can be loaded with more than 10 13 Bq of radioisotope to generate 100 milliwatt to watt levels of electrical power without damaging the device materials or degrading its performance. The power source can use a variety of beta radioisotopes and scales by stacking the devices. Copyright © 2017. Published by Elsevier Ltd.

Photonic generation of ultra-wide-band doublet pulse through monolithic integration of tapered directional coupler and quantum well waveguide.

PubMed

Kuo, Yu-Zheng; Wu, Jui-Pin; Wu, Tsu-Hsiu; Chiu, Yi-Jen

2012-10-22

We proposed and demonstrated a novel scheme of photonic ultra-wide-band (UWB) doublet pulse based on monolithic integration of tapered optical-direction coupler (TODC) and multiple-quantum-well (MQW) waveguide. TODC is formed by a top tapered MQW waveguide vertically integrating with an underneath passive waveguide. Through simultaneous field-driven optical index- and absorption- change in MQW, the partial optical coupling in TODC can be used to get a valley-shaped of optical transmission against voltage. Therefore, doublet-enveloped optical pulse can be realized by high-speed and high-efficient conversion of input electrical pulse. By just adjusting bias through MQW, 1530 nm photonic UWB doublet optical pulse with 75-ps pulse width, below -41.3 dBm power, 125% fractional bandwidth, and 7.5 GHz of -10 dB bandwidth has been demonstrated, fitted into FCC requirement (3.1 GHz~10.6 GHz). Doublet-pulse data transmission generated in optical fiber is also performed for further characterization, exhibiting a successful 1.25 Gb/s error-free transmission. It suggests such optoelectronic integration template can be applied for photonic UWB generation in fiber-based communications.

Enhancement of ultraweak photon emission with 3 MHz ultrasonic irradiation on transplanted tumor tissues of mice.

PubMed

Kim, Hongbae; Ahn, Saeyoung; Kim, Jungdae; Soh, Kwang-Sup

2008-07-01

We investigated photon emissions of various bio-samples which were induced by ultrasonic stimulation. It has been reported that ultrasonic stimulations induced the thermal excitation of the bio-tissues. After ultrasonic stimulation, any measurement of photon radiation in the visible spectral range has not been carried out yet. The instruments consisted of electronic devices for an ultrasonic generator of the frequency 3 MHz and a photomultiplier tube (PMT) system counting photons from bio-tissues. The transplanted tumor tissues of mice were prepared for the experiments and their liver and spleen tissues were also used for the controls. It was found that the continuous ultrasonic stimulations with the electrical power 2300 mW induced ultraweak photon emissions from the tumor tissues. The number of induced photon was dependent of the type of the tissues and the stimulation time intervals. The level of photon emission was increased from the mouse tumor exposed to the ultrasonic stimulations, and the changes were discriminated from those of the spleens and livers.

Ultra-wideband microwave photonic frequency downconverter based on carrier-suppressed single-sideband modulation

NASA Astrophysics Data System (ADS)

Wang, Yunxin; Li, Jingnan; Wang, Dayong; Zhou, Tao; Xu, Jiahao; Zhong, Xin; Yang, Dengcai; Rong, Lu

2018-03-01

An ultra-wideband microwave photonic frequency downconverter is proposed based on carrier-suppressed single-sideband (CS-SSB) modulation. A radio frequency (RF) signal and a local oscillator (LO) signal are combined to drive a dual-parallel Mach-Zehnder modulator (DPMZM) through the electrical 90°hybrid coupler. To break through the bandwidth limit, an optical bandpass filter (OBPF) is applied simultaneously. Then a photodetector (PD) after OBPF is used to obtain intermediate frequency (IF) signal. Experimental results demonstrate that the proposed frequency downconverter can generate the CS-SSB modulation signal from 2 to 40 GHz in optical spectrum. All the mixing spurs are completely suppressed under the noise floor in electrical spectrum, and the output IF signal possesses high purity with a suppression ratio of the undesired signals (≥40 dB). Furthermore, the multi-octave downconversion can also be implemented to satisfy the bandwidth requirement of multi-channel communication. The proposed frequency downconverter supplies an ultra-wideband and high-purity alternative for the signal processing in microwave photonic applications.

Solar energy conversion with photon-enhanced thermionic emission

NASA Astrophysics Data System (ADS)

Kribus, Abraham; Segev, Gideon

2016-07-01

Photon-enhanced thermionic emission (PETE) converts sunlight to electricity with the combined photonic and thermal excitation of charge carriers in a semiconductor, leading to electron emission over a vacuum gap. Theoretical analyses predict conversion efficiency that can match, or even exceed, the efficiency of traditional solar thermal and photovoltaic converters. Several materials have been examined as candidates for radiation absorbers and electron emitters, with no conclusion yet on the best set of materials to achieve high efficiency. Analyses have shown the complexity of the energy conversion and transport processes, and the significance of several loss mechanisms, requiring careful control of material properties and optimization of the device structure. Here we survey current research on PETE modeling, materials, and device configurations, outline the advances made, and stress the open issues and future research needed. Based on the substantial progress already made in this young topic, and the potential of high conversion efficiency based on theoretical performance limits, continued research in this direction is very promising and may yield a competitive technology for solar electricity generation.

Apparatus for measuring surface movement of an object that is subjected to external vibrations

DOEpatents

Kotidis, Petros A.; Woodroffe, Jaime A.; Rostler, Peter S.

1997-01-01

A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading.

Furnace control apparatus using polarizing interferometer

DOEpatents

Schultz, Thomas J.; Kotidis, Petros A.; Woodroffe, Jaime A.; Rostler, Peter S.

1995-01-01

A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading.

Polarizing optical interferometer having a dual use optical element

DOEpatents

Kotidis, P.A.; Woodroffe, J.A.; Rostler, P.S.

1995-04-04

A system for nondestructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading. 38 figures.

Process control system using polarizing interferometer

DOEpatents

Schultz, T.J.; Kotidis, P.A.; Woodroffe, J.A.; Rostler, P.S.

1994-02-15

A system for nondestructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading. 38 figures.

Polarizing optical interferometer having a dual use optical element

DOEpatents

Kotidis, Petros A.; Woodroffe, Jaime A.; Rostler, Peter S.

1995-01-01

A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading.

Process control system using polarizing interferometer

DOEpatents

Schultz, Thomas J.; Kotidis, Petros A.; Woodroffe, Jaime A.; Rostler, Peter S.

1994-01-01

A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading.

Furnace control apparatus using polarizing interferometer

DOEpatents

Schultz, T.J.; Kotidis, P.A.; Woodroffe, J.A.; Rostler, P.S.

1995-03-28

A system for nondestructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading. 38 figures.

Method and apparatus for measuring surface movement of a solid object that is subjected to external vibrations

DOEpatents

Schultz, Thomas J.; Kotidis, Petros A.; Woodroffe, Jaime A.; Rostler, Peter S.

1995-01-01

A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading.

Method and apparatus for measuring surface movement of an object using a polarizing interfeometer

DOEpatents

Schultz, Thomas J.; Kotidis, Petros A.; Woodroffe, Jaime A.; Rostler, Peter S.

1995-01-01

A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading.

Method and apparatus for measuring surface movement of an object using a polarizing interferometer

DOEpatents

Schultz, T.J.; Kotidis, P.A.; Woodroffe, J.A.; Rostler, P.S.

1995-05-09

A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading. 38 figs.

Method and apparatus for measuring surface movement of a solid object that is subjected to external vibrations

DOEpatents

Schultz, T.J.; Kotidis, P.A.; Woodroffe, J.A.; Rostler, P.S.

1995-04-25

A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading. 38 figs.

Apparatus for measuring surface movement of an object that is subjected to external vibrations

DOEpatents

Kotidis, P.A.; Woodroffe, J.A.; Rostler, P.S.

1997-04-22

A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading. 38 figs.

Thermophotovoltaic power conversion systems: Current performance and future potential

DOE PAGES

Celanovic, Ivan; Bermel, Peter; Soljacic, Marin

2011-01-01

Thermophotovoltaic (TPV) systems offer a unique, solid-state approach to converting heat into electricity based on thermal radiation. TPV is particularly suitable for certain classes of power generation applications that are not well served by standard engines, such as long, remote missions where repairs are difficult, and portable generation where space and weight are at a premium. While standard thermophotovoltaics are limited in their conversion efficiency, photonic crystals can improve performance by an order of magnitude for a number of systems. While there are many potential applications, two exemplary systems are discussed: TPV μreactors for portable power generation in a mm-scalemore » form factor, and solar TPV for long-term off-grid power generation from sunlight. In both cases, photonic crystals can enable potential performance exceeding that of many other well-known technologies, such as single-junction photovoltaics.« less

Broadband photonic single sideband frequency up-converter based on the cross polarization modulation effect in a semiconductor optical amplifier for radio-over-fiber systems.

PubMed

Lee, Seung-Hun; Kim, Hyoung-Jun; Song, Jong-In

2014-01-13

A broadband photonic single sideband (SSB) frequency up-converter based on the cross polarization modulation (XPolM) effect in a semiconductor optical amplifier (SOA) is proposed and experimentally demonstrated. An optical radio frequency (RF) signal in the form of an optical single sideband (OSSB) is generated by the photonic SSB frequency up-converter to solve the power fading problem caused by fiber chromatic dispersion. The generated OSSB RF signal has almost identical optical carrier power and optical sideband power. This SSB frequency up-conversion scheme shows an almost flat electrical RF power response as a function of the RF frequency in a range from 31 GHz to 75 GHz after 40 km single mode fiber (SMF) transmission. The photonic SSB frequency up-conversion technique shows negligible phase noise degradation. The phase noise of the up-converted RF signal at 49 GHz for an offset of 10 kHz is -93.17 dBc/Hz. Linearity analysis shows that the photonic SSB frequency up-converter has a spurious free dynamic range (SFDR) value of 79.51 dB · Hz(2/3).

Terahertz surface plasmon-polaritons in one-dimensional graphene based Fibonacci photonic superlattices

NASA Astrophysics Data System (ADS)

Namdar, Abdolrahman; Feizollahi Onsoroudi, Rana; Khoshsima, Habib; Sahrai, Mostafa

2018-03-01

The surface plasmon-polaritons in one-dimensional graphene-based Fibonacci photonic superlattices in the terahertz frequency range have been theoretically investigated. Our numerical study shows that surface plasmon-polaritons can be realized in both transverse electric and transverse magnetic polarizations. It is shown that these modes are manageable by varying the quasi-periodic generation orders which play a critical role in the occurrence of surface modes. In addition, the effect of thickness of cap layer and chemical potential of graphene sheets on surface plasmon-polaritons and their electric field distribution are studied. We have verified the excitation of surface plasmon-polaritons by using the attenuated total reflection method. This inspection confirms that all the predicted surface modes in the dispersion curves are actually excitable with this method.

Energy-tunable sources of entangled photons: a viable concept for solid-state-based quantum relays.

PubMed

Trotta, Rinaldo; Martín-Sánchez, Javier; Daruka, Istvan; Ortix, Carmine; Rastelli, Armando

2015-04-17

We propose a new method of generating triggered entangled photon pairs with wavelength on demand. The method uses a microstructured semiconductor-piezoelectric device capable of dynamically reshaping the electronic properties of self-assembled quantum dots (QDs) via anisotropic strain engineering. Theoretical models based on k·p theory in combination with finite-element calculations show that the energy of the polarization-entangled photons emitted by QDs can be tuned in a range larger than 100 meV without affecting the degree of entanglement of the quantum source. These results pave the way towards the deterministic implementation of QD entanglement resources in all-electrically-controlled solid-state-based quantum relays.

Energy-Tunable Sources of Entangled Photons: A Viable Concept for Solid-State-Based Quantum Relays

NASA Astrophysics Data System (ADS)

Trotta, Rinaldo; Martín-Sánchez, Javier; Daruka, Istvan; Ortix, Carmine; Rastelli, Armando

2015-04-01

We propose a new method of generating triggered entangled photon pairs with wavelength on demand. The method uses a microstructured semiconductor-piezoelectric device capable of dynamically reshaping the electronic properties of self-assembled quantum dots (QDs) via anisotropic strain engineering. Theoretical models based on k .p theory in combination with finite-element calculations show that the energy of the polarization-entangled photons emitted by QDs can be tuned in a range larger than 100 meV without affecting the degree of entanglement of the quantum source. These results pave the way towards the deterministic implementation of QD entanglement resources in all-electrically-controlled solid-state-based quantum relays.

Assessing Conceptual Knowledge for the Physics of Semiconductors

ERIC Educational Resources Information Center

Ene, Emanuela

2013-01-01

Following the trend in science and engineering education generated by the visible impact created by the Force Concept Inventory (FCI), the investigator developed a Physics of Semiconductors Concept Inventory (PSCI). PSCI fills the need of standardized concept tests for undergraduate education in photonics and electrical engineering. The structure…

Electromagnetic duality and the electric memory effect

NASA Astrophysics Data System (ADS)

Hamada, Yuta; Seo, Min-Seok; Shiu, Gary

2018-02-01

We study large gauge transformations for soft photons in quantum electrodynamics which, together with the helicity operator, form an ISO(2) algebra. We show that the two non-compact generators of the ISO(2) algebra correspond respectively to the residual gauge symmetry and its electromagnetic dual gauge symmetry that emerge at null infinity. The former is helicity universal (electric in nature) while the latter is helicity distinguishing (magnetic in nature). Thus, the conventional large gauge transformation is electric in nature, and is naturally associated with a scalar potential. We suggest that the electric Aharonov-Bohm effect is a direct measure for the electromagnetic memory arising from large gauge transformations.

Space power plants

NASA Astrophysics Data System (ADS)

Khudyakov, S. A.

1985-05-01

Power generators in space are examined. A semiconducting photoelectric converter (FEP) which converts the energy of solar radiation directly into electrical energy is discussed. The operating principle of an FEP is based on the interaction of solar light with a crystal semiconductor, in the process of which the photons produce free electrons, carriers of an electrical charge, in the crystal. Areas with a strong electrical field created specially under the effect of the p-n junction trap the freed electrons and divide them in such a fashion that a current and corresponding electrical power appear in the load circuit. The absorption of light in metals and pure semiconductors is outlined.

Fiber fed x-ray/gamma ray imaging apparatus

DOEpatents

Hailey, C.J.; Ziock, K.P.

1992-06-02

X-ray/gamma ray imaging apparatus is disclosed for detecting the position, energy, and intensity of x-ray/gamma ray radiation comprising scintillation means disposed in the path of such radiation and capable of generating photons in response to such radiation; first photodetection means optically bonded to the scintillation means and capable of generating an electrical signal indicative of the intensity, and energy of the radiation detected by the scintillation means; second photodetection means capable of generating an electrical signal indicative of the position of the radiation in the radiation pattern; and means for optically coupling the scintillation means to the second photodetection means. The photodetection means are electrically connected to control and storage means which may also be used to screen out noise by rejecting a signal from one photodetection means not synchronized to a signal from the other photodetection means; and also to screen out signals from scattered radiation. 6 figs.

Photon Luminescence of the Moon

NASA Technical Reports Server (NTRS)

Wilson, T.L.; Lee, K.T.

2009-01-01

Luminescence is typically described as light emitted by objects at low temperatures, induced by chemical reactions, electrical energy, atomic interactions, or acoustical and mechanical stress. An example is photoluminescence created when photons (electromagnetic radiation) strike a substance and are absorbed, resulting in the emission of a resonant fluorescent or phosphorescent albedo. In planetary science, there exists X-ray fluorescence induced by sunlight absorbed by a regolith a property used to measure some of the chemical composition of the Moon s surface during the Apollo program. However, there exists an equally important phenomenon in planetary science which will be designated here as photon luminescence. It is not conventional photoluminescence because the incoming radiation that strikes the planetary surface is not photons but rather cosmic rays (CRs). Nevertheless, the result is the same: the generation of a photon albedo. In particular, Galactic CRs (GCRs) and solar energetic particles (SEPs) both induce a photon albedo that radiates from the surface of the Moon. Other particle albedos are generated as well, most of which are hazardous (e.g. neutrons). The photon luminescence or albedo of the lunar surface induced by GCRs and SEPs will be derived here, demonstrating that the Moon literally glows in the dark (when there is no sunlight or Earthshine). This extends earlier work on the same subject [1-4]. A side-by-side comparison of these two albedos and related mitigation measures will also be discussed.

Second order optical nonlinearity of graphene due to electric quadrupole and magnetic dipole effects.

PubMed

Cheng, J L; Vermeulen, N; Sipe, J E

2017-03-06

We present a practical scheme to separate the contributions of the electric quadrupole-like and the magnetic dipole-like effects to the forbidden second order optical nonlinear response of graphene, and give analytic expressions for the second order optical conductivities, calculated from the independent particle approximation, with relaxation described in a phenomenological way. We predict strong second order nonlinear effects, including second harmonic generation, photon drag, and difference frequency generation. We discuss in detail the controllability of these effects by tuning the chemical potential, taking advantage of the dominant role played by interband optical transitions in the response.

Waveguiding and bending modes in a plasma photonic crystal bandgap device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, B., E-mail: bwang17@stanford.edu; Cappelli, M. A.

2016-06-15

Waveguiding and bending modes are investigated in a fully tunable plasma photonic crystal. The plasma device actively controls the propagation of free space electromagnetic waves in the S to X band of the microwave spectrum. An array of discharge plasma tubes form a square crystal lattice exhibiting a well-defined bandgap, with individual active switching of the plasma elements to allow for waveguiding and bending modes to be generated dynamically. We show, through simulations and experiments, the existence of transverse electric (TE) mode waveguiding and bending modes.

Enhanced third-harmonic generation in silicon nanoparticles driven by magnetic response.

PubMed

Shcherbakov, Maxim R; Neshev, Dragomir N; Hopkins, Ben; Shorokhov, Alexander S; Staude, Isabelle; Melik-Gaykazyan, Elizaveta V; Decker, Manuel; Ezhov, Alexander A; Miroshnichenko, Andrey E; Brener, Igal; Fedyanin, Andrey A; Kivshar, Yuri S

2014-11-12

We observe enhanced third-harmonic generation from silicon nanodisks exhibiting both electric and magnetic dipolar resonances. Experimental characterization of the nonlinear optical response through third-harmonic microscopy and spectroscopy reveals that the third-harmonic generation is significantly enhanced in the vicinity of the magnetic dipole resonances. The field localization at the magnetic resonance results in two orders of magnitude enhancement of the harmonic intensity with respect to unstructured bulk silicon with the conversion efficiency limited only by the two-photon absorption in the substrate.

Demonstration of glass-based photonic interposer for mid-board-optical engines and electrical-optical circuit board (EOCB) integration strategy

NASA Astrophysics Data System (ADS)

Schröder, H.; Neitz, M.; Schneider-Ramelow, M.

2018-02-01

Due to its optical transparency and superior dielectric properties glass is regarded as a promising candidate for advanced applications as active photonic interposer for mid-board-optics and optical PCB waveguide integration. The concepts for multi-mode and single-mode photonic system integration are discussed and related demonstration project results will be presented. A hybrid integrated photonic glass body interposer with integrated optical lenses for multi-mode data communication wavelength of 850 nm have been realized. The paper summarizes process developments which allow cost efficient metallization of TGV. Electro-optical elements like photodiodes and VCSELs can be directly flip-chip mounted on the glass substrate according to the desired lens positions. Furthermore results for a silicon photonic based single-mode active interposer integration onto a single mode glass made EOCB will be compared in terms of packaging challenges. The board level integration strategy for both of these technological approaches and general next generation board level integration concepts for photonic interposer will be introductorily discussed.

A quantum light-emitting diode for the standard telecom window around 1,550 nm.

PubMed

Müller, T; Skiba-Szymanska, J; Krysa, A B; Huwer, J; Felle, M; Anderson, M; Stevenson, R M; Heffernan, J; Ritchie, D A; Shields, A J

2018-02-28

Single photons and entangled photon pairs are a key resource of many quantum secure communication and quantum computation protocols, and non-Poissonian sources emitting in the low-loss wavelength region around 1,550 nm are essential for the development of fibre-based quantum network infrastructure. However, reaching this wavelength window has been challenging for semiconductor-based quantum light sources. Here we show that quantum dot devices based on indium phosphide are capable of electrically injected single photon emission in this wavelength region. Using the biexciton cascade mechanism, they also produce entangled photons with a fidelity of 87 ± 4%, sufficient for the application of one-way error correction protocols. The material system further allows for entangled photon generation up to an operating temperature of 93 K. Our quantum photon source can be directly integrated with existing long distance quantum communication and cryptography systems, and provides a promising material platform for developing future quantum network hardware.

Pockels effect in strained silicon photonics (Conference Presentation)

NASA Astrophysics Data System (ADS)

Vivien, Laurent; Berciano, Mathias; Damas, Pedro; Marcaud, Guillaume; Le Roux, Xavier; Crozat, Paul; Alonso-Ramos, Carlos A.; Benedikovic, Daniel; Marris-Morini, Delphine; Cassan, Eric

2017-05-01

Silicon photonics has generated a strong interest in recent years, mainly for optical communications and optical interconnects in CMOS circuits. The main motivations for silicon photonics are the reduction of photonic system costs and the increase of the number of functionalities on the same integrated chip by combining photonics and electronics, along with a strong reduction of power consumption. However, one of the constraints of silicon as an active photonic material is its vanishing second order optical susceptibility, the so called χ(2) , due to the centrosymmety of the silicon crystal. To overcome this limitation, strain has been used as a way to deform the crystal and destroy the centrosymmetry which inhibits χ(2). The paper presents the recent advances in the development of second-order nonlinearities including discussions from fundamental origin of Pockels effect in silicon until its implementation in a real device. Carrier effects induced by an electric field leading to an electro-optics behavior will also be discussed.

Engineered Quasi-Phase Matching for Nonlinear Quantum Optics in Waveguides

NASA Astrophysics Data System (ADS)

Van Camp, Mackenzie A.

Entanglement is the hallmark of quantum mechanics. Quantum entanglement--putting two or more identical particles into a non-factorable state--has been leveraged for applications ranging from quantum computation and encryption to high-precision metrology. Entanglement is a practical engineering resource and a tool for sidestepping certain limitations of classical measurement and communication. Engineered nonlinear optical waveguides are an enabling technology for generating entangled photon pairs and manipulating the state of single photons. This dissertation reports on: i) frequency conversion of single photons from the mid-infrared to 843nm as a tool for incorporating quantum memories in quantum networks, ii) the design, fabrication, and test of a prototype broadband source of polarization and frequency entangled photons; and iii) a roadmap for further investigations of this source, including applications in quantum interferometry and high-precision optical metrology. The devices presented herein are quasi-phase-matched lithium niobate waveguides. Lithium niobate is a second-order nonlinear optical material and can mediate optical energy conversion to different wavelengths. This nonlinear effect is the basis of both quantum frequency conversion and entangled photon generation, and is enhanced by i) confining light in waveguides to increase conversion efficiency, and ii) quasi-phase matching, a technique for engineering the second-order nonlinear response by locally altering the direction of a material's polarization vector. Waveguides are formed by diffusing titanium into a lithium niobate wafer. Quasi-phase matching is achieved by electric field poling, with multiple stages of process development and optimization to fabricate the delicate structures necessary for broadband entangled photon generation. The results presented herein update and optimize past fabrication techniques, demonstrate novel optical devices, and propose future avenues for device development. Quantum frequency conversion from 1848nm to 843nm is demonstrated for the first time, with >75% single-photon conversion efficiency. A new electric field poling methodology is presented, combining elements from multiple historical techniques with a new fast-feedback control system. This poling technique is used to fabricate the first chirped-and-apodized Type-II quasi-phase-matched structures in titanium-diffused lithium niobate waveguides, culminating in a measured phasematching spectrum that is predominantly Gaussian ( R2 = 0.80), nearly eight times broader than the unchirped spectrum, and agrees well with simulations.

Simulation of Light Collection for Neutron Electrical Dipole Moment measurement

NASA Astrophysics Data System (ADS)

Ji, Pan; nEDM Collaboration

2017-09-01

nEDM (Neutron Electrical Dipole moment) measurement addresses a critical topic in particle physics and Standard Model, that is CPT violation in neutron electrical dipole moment if detected in which the Time reversal violation is connected to the matter/antimatter imparity of the universe. The neutron electric dipole moment was first measured in 1950 by Smith, Purcell, and Ramsey at the Oak Ridge Reactor - the first intense neutron source. This measurement showed that the neutron was very nearly round (to better than one part in a million). The goal of the nEDM experiment is to further improve the precision of this measurement by another factor of 100. The signal from the experiment is detected by collecting the photons generated when neutron beams were captured by liquid helium 3. The Geant4 simulation project that I participate simulates the process of light collection to improve the design for higher capture efficiency. The simulated geometry includes light source, reflector, wavelength shifting fibers, wavelength shifting TPB and acrylic as in real experiment. The UV photons exiting from Helium go through two wavelength-shifting processes in TPB and fibers to be finally captured. Oak Ridge National Laboratory Neutron Electric Dipole Moment measurement project.

Electrically tunable liquid crystal photonic bandgap fiber laser

NASA Astrophysics Data System (ADS)

Olausson, Christina B.; Scolari, Lara; Wei, Lei; Noordegraaf, Danny; Weirich, Johannes; Alkeskjold, Thomas T.; Hansen, Kim P.; Bjarklev, Anders

2010-02-01

We demonstrate electrical tunability of a fiber laser using a liquid crystal photonic bandgap fiber. Tuning of the laser is achieved by combining the wavelength filtering effect of a liquid crystal photonic bandgap fiber device with an ytterbium-doped photonic crystal fiber. We fabricate an all-spliced laser cavity based on a liquid crystal photonic bandgap fiber mounted on a silicon assembly, a pump/signal combiner with single-mode signal feed-through and an ytterbium-doped photonic crystal fiber. The laser cavity produces a single-mode output and is tuned in the range 1040- 1065 nm by applying an electric field to the silicon assembly.

Propagation of monochromatic light in a hot and dense medium

NASA Astrophysics Data System (ADS)

Masood, Samina S.

2017-12-01

Photons, as quanta of electromagnetic fields, determine the electromagnetic properties of an extremely hot and dense medium. Considering the properties of the photons in the interacting medium of charged particles, we explicitly calculate the electromagnetic properties such as the electric permittivity, magnetic permeability, refractive index and the propagation speed of electromagnetic signals in an extremely hot and dense background. Photons acquire a dynamically generated mass in such a medium. The screening mass of the photon, the Debye shielding length and the plasma frequency are calculated as functions of the statistical parameters of the medium. We study the properties of the propagating particles in astrophysical systems of distinct statistical conditions. The modifications in the properties of the medium lead to the equation of state of the system. We mainly calculate all these parameters for extremely high temperatures of the early universe.

Nonclassical Properties of Pulsed Second-Subharmonic Generation in Photonic-Band-Gap Structures

DTIC Science & Technology

2007-04-01

organized as follows. In Sec. II, a quan- tum model of the nonlinear interaction including both Heisenberg equations for operator electric-field ampli...can then be derived from the Heisenberg equations (for details, see [45, 46]; dX̂ dz = − i h̄ [ Ĝ, X̂ ] ; (13) considering the following momentum...disper- sion, we decompose the electric-field operator amplitudes Êa (a = p, s) using mode operator amplitudes âa in the Heisenberg picture [5, 8

Light emitting diodes as a plant lighting source

NASA Technical Reports Server (NTRS)

Bula, R. J.; Tennessen, D. J.; Morrow, R. C.; Tibbitts, T. W.

1994-01-01

Electroluminescence in solid materials is defined as the generation of light by the passage of an electric current through a body of solid material under an applied electric field. A specific type of electroluminescence, first noted in 1923, involves the generation of photons when electrons are passed through a p-n junction of certain solid materials (junction of a n-type semiconductor, an electron donor, and a p-type semiconductor, an electron acceptor). The development of this light emitting semiconductor technology dates back less than 30 years. During this period of time, the LED has evolved from a rare and expensive light generating device to one of the most widely used electronic components. A number of LED characteristics are of considerable importance in selecting a light source for plant lighting in a controlled environment facility. Of particular importance is the characteristic that light is generated by an LED at a rate far greater than the corresponding thermal radiation predicted by the bulk temperature of the device as defined by Plank's radiation law. This is in sharp contrast to other light sources, such as an incandescent or high intensity discharge lamp. A plant lighting system for controlled environments must provide plants with an adequate flux of photosynthetically active radiation, plus providing photons in the spectral regions that are involved in the photomorphogenic and phototropic responses that result in normal plant growth and development. Use of light sources that emit photons over a broad spectral range generally meet these two lighting requirements. Since the LED's emit over specific spectral regions, they must be carefully selected so that the levels of photsynthetically active and photomorphogenic and phototropic radiation meet these plant requirements.

Fast focus-scanning head in two-photon photoacoustic microscopy with electrically controlled liquid lens

NASA Astrophysics Data System (ADS)

Yamaoka, Yoshihisa; Kimura, Yuka; Harada, Yoshinori; Takamatsu, Tetsuro; Takahashi, Eiji

2018-02-01

Conventional one-photon photoacoustic microscopy (PAM) utilizes high-frequency components of generated photoacoustic waves to improve the depth resolution. However, to obtain optically-high resolution in PAM in the depth direction, the use of high-frequency ultrasonic waves is to be avoided. It is because that the propagation distance is shortened as the frequency of ultrasonic waves becomes high. To overcome this drawback, we have proposed and developed two-photon photoacoustic microscopy (TP-PAM). Two-photon absorption occurs only at the focus point. TPPAM does not need to use the high-frequency components of photoacoustic waves. Thus, TP-PAM can improve the penetration depth while preserving the spatial resolution. However, the image acquisition time of TP-PAM is longer than that of conventional PAM, because TP-PAM needs to scan the laser spot both in the depth and transverse directions to obtain cross-sectional images. In this paper, we have introduced a focus-tunable electrically-controlled liquid lens in TP-PAM. Instead of a mechanical stepping-motor stage, we employed electrically-controlled liquid lens so that the depth of the focus spot can be quickly changed. In our system, the imaging speed of TP-PAM using the liquid lens and one-axis stepping-motor stage was 10 times faster than that using a two-axis stepping-motor stage only. TP-PAM with focus-scanning head consisting of the liquid lens and stepping-motor stage will be a promising method to investigate the inside of living tissues.

Microwave generation with photonic frequency octupling using a DPMZM in a Sagnac loop

NASA Astrophysics Data System (ADS)

Gao, Yongsheng; Wen, Aijun; Li, Ningning; Wu, Xiaohui; Zhang, Huixing

2015-09-01

A photonic microwave signal generation scheme with frequency octupling is proposed and experimentally demonstrated. The scheme is based on bi-directional use of a dual-parallel Mach-Zehnder modulator (DPMZM) in a Sagnac loop. The two sub-modulators in the DPMZM are driven by two low-frequency signals with a π/2 phase difference, and the dc biases of the modulator are all set at the maximum transmission points. Due to the velocity mismatch of the modulator, only the light wave along the clockwise direction is effectively modulated by the drive signals to generate an optical signal with a carrier and ±4th order sidebands, while the modulation of the light wave along the counterclockwise direction is far less effective and can be ignored. By properly adjusting the polarization of the light wave output from the Sagnac loop, the optical carrier can be significantly suppressed at a polarizer, and then an optical signal with only ±4th order sidebands is generated. In the experiment, a pure 24-GHz microwave signal without additional phase noise from the optical system is generated using a 3-GHz local oscillator signal. As no electrical or optical filter is used, the photonic frequency octupler is of good frequency tunability.

Simulating TGF and gamma ray emission above and within stormclouds due to the interaction of TeV cosmic ray shower electrons/positrons/photons with plausible electric field geometries generated in stormclouds.

NASA Astrophysics Data System (ADS)

Connell, P. H.

2017-12-01

The University of Valencia has developed a software simulator LEPTRACK to simulate lepton and photon scattering in any kind of media with a variable density, and permeated by electric/magnetic fields of any geometry, and which can handle an exponential runaway avalanche. Here we show results of simulating the interaction of electrons/positrons/photons in an incoming TeV cosmic ray shower with the kind of electric fields expected in a stormcloud after a CG discharge which removes much of the positive charge build up at the centre of the cloud. The point is to show not just a Relativistic Runaway Electron Avalanche (RREA) above the upper negative shielding layer at 12 km but other gamma ray emission due to electron/positron interaction in the remaining positive charge around 9km and the lower negative charge at 6km altitude. We present here images, lightcurves, altitude profiles, spectra and videos showing the different ionization, excitation and photon density fields produced, their time evolution, and how they depend critically on where the cosmic ray shower beam intercepts the electric field geometry. We also show a new effect of incoming positrons, which make up a significant fraction of the shower, where they appear to "orbit" within the high altitude negative shielding layer, and which has been conjectured to produce significant microwave emission, as well as a short range 511 keV annihilation line. The interesting question is if this conjectured emission can be observed and correlated with TGF orbital observations to prove that a TGF originates in the macro-fields of stormclouds or the micro-fields of light leaders and streamers where this "positron orbiting" is not likely to occur.

NREL Researchers Capture Excess Photon Energy to Produce Solar Fuels | News

Science.gov Websites

applied to produce extra chemical reactions or stored energy in chemical bonds." The maximum generation for photoelectrochemical hydrogen evolution reactions with quantum yields exceeding 100%, co that MEG enhancement in a chemical bond rather than just in the electrical current," Beard said

Quantum optics with nanowires (Conference Presentation)

NASA Astrophysics Data System (ADS)

Zwiller, Val

2017-02-01

Nanowires offer new opportunities for nanoscale quantum optics; the quantum dot geometry in semiconducting nanowires as well as the material composition and environment can be engineered with unprecedented freedom to improve the light extraction efficiency. Quantum dots in nanowires are shown to be efficient single photon sources, in addition because of the very small fine structure splitting, we demonstrate the generation of entangled pairs of photons from a nanowire. By doping a nanowire and making ohmic contacts on both sides, a nanowire light emitting diode can be obtained with a single quantum dot as the active region. Under forward bias, this will act as an electrically pumped source of single photons. Under reverse bias, an avalanche effect can multiply photocurrent and enables the detection of single photons. Another type of nanowire under study in our group is superconducting nanowires for single photon detection, reaching efficiencies, time resolution and dark counts beyond currently available detectors. We will discuss our first attempts at combining semiconducting nanowire based single photon emitters and superconducting nanowire single photon detectors on a chip to realize integrated quantum circuits.

Absorption of gamma-ray photons in a vacuum neutron star magnetosphere: II. The formation of "lightnings"

NASA Astrophysics Data System (ADS)

Istomin, Ya. N.; Sob'yanin, D. N.

2011-10-01

The absorption of a high-energy photon from the external cosmic gamma-ray background in the inner neutron star magnetosphere triggers the generation of a secondary electron-positron plasma and gives rise to a lightning—a lengthening and simultaneously expanding plasma tube. It propagates along magnetic fields lines with a velocity close to the speed of light. The high electron-positron plasma generation rate leads to dynamical screening of the longitudinal electric field that is provided not by charge separation but by electric current growth in the lightning. The lightning radius is comparable to the polar cap radius of a radio pulsar. The number of electron-positron pairs produced in the lightning in its lifetime reaches 1028. The density of the forming plasma is comparable to or even higher than that in the polar cap regions of ordinary pulsars. This suggests that the radio emission from individual lightnings can be observed. Since the formation time of the radio emission is limited by the lightning lifetime, the possible single short radio bursts may be associated with rotating radio transients (RRATs).

Nanogap near-field thermophotovoltaics.

PubMed

Fiorino, Anthony; Zhu, Linxiao; Thompson, Dakotah; Mittapally, Rohith; Reddy, Pramod; Meyhofer, Edgar

2018-06-18

Conversion of heat to electricity via solid-state devices is of great interest and has led to intense research of thermoelectric materials 1,2 . Alternative approaches for solid-state heat-to-electricity conversion include thermophotovoltaic (TPV) systems where photons from a hot emitter traverse a vacuum gap and are absorbed by a photovoltaic (PV) cell to generate electrical power. In principle, such systems may also achieve higher efficiencies and offer more versatility in use. However, the typical temperature of the hot emitter remains too low (<1,000 K) to achieve a sufficient photon flux to the PV cell, limiting practical applications. Theoretical proposals 3-12 suggest that near-field (NF) effects 13-18 that arise in nanoscale gaps may be leveraged to increase the photon flux to the PV cell and significantly enhance the power output. Here, we describe functional NFTPV devices consisting of a microfabricated system and a custom-built nanopositioner and demonstrate an ~40-fold enhancement in the power output at nominally 60 nm gaps relative to the far field. We systematically characterize this enhancement over a range of gap sizes and emitter temperatures, and for PV cells with two different bandgap energies. We anticipate that this technology, once optimized, will be viable for waste heat recovery applications.

Asymmetric Invisibility Cloaking Theory Based on the Concept of Effective Electromagnetic Fields for Photons

NASA Astrophysics Data System (ADS)

Amemiya, Tomo; Taki, Masato; Kanazawa, Toru; Arai, Shigehisa

2014-03-01

The asymmetric invisibility cloak is a special cloak with unidirectional transparency; that is, a person in the cloak should not be seen from the outside but should be able to see the outside. Existing theories of designing invisibility cloaks cannot be used for asymmetric cloaking because they are based on the transformation optics that uses Riemannian metric tensor independent of direction. To overcome this problem, we propose introducing directionality into invisibility cloaking. Our theory is based on ``the theory of effective magnetic field for photons'' proposed by Stanford University.[2] To realize asymmetric cloaking, we have extended the Stanford's theory to add the concept of ``effective electric field for photons.'' The effective electric and the magnetic field can be generated using a photonc resonator lattice, which is a kind of metamaterial. The Hamiltonian for photons in these fields has a similar form to that of the Hamiltonian for a charged particle in an electromagnetic field. An incident photon therefore experiences a ``Lorentz-like'' and a ``Coulomb-like'' force and shows asymmetric movement depending of its travelling direction.We show the procedure of designing actual invisibility cloaks using the photonc resonator lattice and confirm their operation with the aid of computer simulation. This work was supported in part by the MEXT; JSPS KAKENHI Grant Numbers #24246061, #24656046, #25420321, #25420322.

Polarization resolved electric field measurements on plasma bullets in N2 using four-wave mixing

NASA Astrophysics Data System (ADS)

van der Schans, Marc; Boehm, Patrick; Nijdam, Sander; Ijzerman, Wilbert; Czarnetzki, Uwe

2016-09-01

Atmospheric pressure plasma jets generated by kHz AC or pulsed DC voltages typically consist of discrete guided ionization waves called plasma bullets. In this work, the electric field of plasma bullets generated in a pulsed DC jet with N2 as feed gas is investigated using the four-wave mixing method. In this diagnostic two laser beams, where one is Stokes shifted from the other, non-linearly interact with the N2 molecules and the bullet's electric field. As a result of the interaction a coherent anti-Stokes Raman scattered (CARS) beam and an infrared beam are generated from which the electric field can be determined. Compared to emission-based methods, this technique has the advantage of being able to also probe the electric field in regions around the plasma bullet where no photons are emitted. The four-wave mixing method and its analysis have been adapted to work with the non-uniform electric field of plasma bullets. In addition, an ex-situ calibration procedure using an electrode geometry different from the discharge geometry has been developed. An experimentally obtained radial profile of the axial electric field component of a plasma bullet in N2 is presented. The position of this profile is related to the location of the propagating bullet from temporally resolved images.

Intracavity Rydberg-atom electromagnetically induced transparency using a high-finesse optical cavity

NASA Astrophysics Data System (ADS)

Sheng, Jiteng; Chao, Yuanxi; Kumar, Santosh; Fan, Haoquan; Sedlacek, Jonathon; Shaffer, James P.

2017-09-01

We present an experimental study of cavity-assisted Rydberg-atom electromagnetically induced transparency (EIT) using a high-finesse optical cavity (F ˜28 000 ). Rydberg atoms are excited via a two-photon transition in a ladder-type EIT configuration. A three-peak structure of the cavity transmission spectrum is observed when Rydberg EIT is generated inside the cavity. The two symmetrically spaced side peaks are caused by bright-state polaritons, while the central peak corresponds to a dark-state polariton. Anticrossing phenomena and the effects of mirror adsorbate electric fields are studied under different experimental conditions. We determine a lower bound on the coherence time for the system of 7.26 ±0.06 μ s , most likely limited by laser dephasing. The cavity-Rydberg EIT system can be useful for single-photon generation using the Rydberg blockade effect, studying many-body physics, and generating novel quantum states among many other applications.

Dual-tone optical vector millimeter wave signal generated by frequency-nonupling the radio frequency 16-star quadrature-amplitude-modulation signal

NASA Astrophysics Data System (ADS)

Wu, Tonggen; Ma, Jianxin

2017-12-01

This paper proposes an original scheme to generate the photonic dual-tone optical millimeter wave (MMW) carrying the 16-star quadrature-amplitude-modulation (QAM) signal via an optical phase modulator (PM) and an interleaver with adaptive photonic frequency-nonupling without phase precoding. To enable the generated optical vector MMW signal to resist the power fading effect caused by the fiber chromatic dispersion, the modulated -5th- and +4th-order sidebands are selected from the output of the PM, which is driven by the precoding 16-star QAM signal. The modulation index of the PM is optimized to gain the maximum opto-electrical conversion efficiency. A radio over fiber link is built by simulation, and the simulated constellations and the bit error rate graph demonstrate that the frequency-nonupling 16-star QAM MMW signal has good transmission performance. The simulation results agree well with our theoretical results.

Excitability and optical pulse generation in semiconductor lasers driven by resonant tunneling diode photo-detectors.

PubMed

Romeira, Bruno; Javaloyes, Julien; Ironside, Charles N; Figueiredo, José M L; Balle, Salvador; Piro, Oreste

2013-09-09

We demonstrate, experimentally and theoretically, excitable nanosecond optical pulses in optoelectronic integrated circuits operating at telecommunication wavelengths (1550 nm) comprising a nanoscale double barrier quantum well resonant tunneling diode (RTD) photo-detector driving a laser diode (LD). When perturbed either electrically or optically by an input signal above a certain threshold, the optoelectronic circuit generates short electrical and optical excitable pulses mimicking the spiking behavior of biological neurons. Interestingly, the asymmetric nonlinear characteristic of the RTD-LD allows for two different regimes where one obtain either single pulses or a burst of multiple pulses. The high-speed excitable response capabilities are promising for neurally inspired information applications in photonics.

THz photonic wireless links with 16-QAM modulation in the 375-450 GHz band.

PubMed

Jia, Shi; Yu, Xianbin; Hu, Hao; Yu, Jinlong; Guan, Pengyu; Da Ros, Francesco; Galili, Michael; Morioka, Toshio; Oxenløwe, Leif K

2016-10-17

We propose and experimentally demonstrate THz photonic wireless communication systems with 16-QAM modulation in the 375-450 GHz band. The overall throughput reaches as high as 80 Gbit/s by exploiting four THz channels with 5 Gbaud 16-QAM baseband modulation per channel. We create a coherent optical frequency comb (OFC) for photonic generation of multiple THz carriers based on photo-mixing in a uni-travelling carrier photodiode (UTC-PD). The OFC configuration also allows us to generate reconfigurable THz carriers with low phase noise. The multiple-channel THz radiation is received by using a Schottky mixer based electrical receiver after 0.5 m free-space wireless propagation. 2-channel (40 Gbit/s) and 4-channel (80 Gbit/s) THz photonic wireless links with 16-QAM modulation are reported in this paper, and the bit error rate (BER) performance for all channels in both cases is below the hard decision forward error correction (HD-FEC) threshold of 3.8e-3 with 7% overhead. In addition, we also successfully demonstrate hybrid photonic wireless transmission of 40 Gbit/s 16-QAM signal at carrier frequencies of 400 GHz and 425 GHz over 30 km standard single mode fiber (SSMF) between the optical baseband signal transmitter and the THz wireless transmitter with negligible induced power penalty.

Dirac and non-Dirac conditions in the two-potential theory of magnetic charge

NASA Astrophysics Data System (ADS)

Scott, John; Evans, Timothy J.; Singleton, Douglas; Dzhunushaliev, Vladimir; Folomeev, Vladimir

2018-05-01

We investigate the Cabbibo-Ferrari, two-potential approach to magnetic charge coupled to two different complex scalar fields, Φ _1 and Φ _2, each having different electric and magnetic charges. The scalar field, Φ _1, is assumed to have a spontaneous symmetry breaking self-interaction potential which gives a mass to the "magnetic" gauge potential and "magnetic" photon, while the other "electric" gauge potential and "electric" photon remain massless. The magnetic photon is hidden until one reaches energies of the order of the magnetic photon rest mass. The second scalar field, Φ _2, is required in order to make the theory non-trivial. With only one field one can always use a duality rotation to rotate away either the electric or magnetic charge, and thus decouple either the associated electric or magnetic photon. In analyzing this system of two scalar fields in the Cabbibo-Ferrari approach we perform several duality and gauge transformations, which require introducing non-Dirac conditions on the initial electric and magnetic charges. We also find that due to the symmetry breaking the usual Dirac condition is altered to include the mass of the magnetic photon. We discuss the implications of these various conditions on the charges.

Light emitting diodes as a plant lighting source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bula, R.J.; Tennessen, D.J.; Morrow, R.C.

1994-12-31

Electroluminescence in solid materials is defined as the generation of light by the passage of an electric current through a body of solid material under an applied electric field. A specific type of electroluminescence, first noted by Lossew in 1923, involves the generation of photons when electrons are passed through a p-n junction of certain solid materials (junction of a n-type semiconductor, an electron donor, and a p-type semiconductor, an electron acceptor). Development efforts to translate these observations into visible light emitting devices, however, was not undertaken until the 1950s. The term, light emitting diode (LEDs), was first used inmore » a report by Wolfe, et al., in 1955. The development of this light emitting semiconductor technology dates back less than 30 years. During this period of time, the LED has evolved from a rare and expensive light generating device to one of the most widely used electronic components. The most popular applications of the LED are as indicators or as optoelectronic switches. However, several recent advances in LED technology have made possible the utilization of LEDs for applications that require a high photon flux, such as for plant lighting in controlled environments. The new generation of LEDs based on a gallium aluminum arsenide (GaAlAS) semiconductor material fabricated as a double heterostructure on a transparent substrate has opened up many new applications for these LEDs.« less

Quantum Optics with Near-Lifetime-Limited Quantum-Dot Transitions in a Nanophotonic Waveguide.

PubMed

Thyrrestrup, Henri; Kiršanskė, Gabija; Le Jeannic, Hanna; Pregnolato, Tommaso; Zhai, Liang; Raahauge, Laust; Midolo, Leonardo; Rotenberg, Nir; Javadi, Alisa; Schott, Rüdiger; Wieck, Andreas D; Ludwig, Arne; Löbl, Matthias C; Söllner, Immo; Warburton, Richard J; Lodahl, Peter

2018-03-14

Establishing a highly efficient photon-emitter interface where the intrinsic linewidth broadening is limited solely by spontaneous emission is a key step in quantum optics. It opens a pathway to coherent light-matter interaction for, e.g., the generation of highly indistinguishable photons, few-photon optical nonlinearities, and photon-emitter quantum gates. However, residual broadening mechanisms are ubiquitous and need to be combated. For solid-state emitters charge and nuclear spin noise are of importance, and the influence of photonic nanostructures on the broadening has not been clarified. We present near-lifetime-limited linewidths for quantum dots embedded in nanophotonic waveguides through a resonant transmission experiment. It is found that the scattering of single photons from the quantum dot can be obtained with an extinction of 66 ± 4%, which is limited by the coupling of the quantum dot to the nanostructure rather than the linewidth broadening. This is obtained by embedding the quantum dot in an electrically contacted nanophotonic membrane. A clear pathway to obtaining even larger single-photon extinction is laid out; i.e., the approach enables a fully deterministic and coherent photon-emitter interface in the solid state that is operated at optical frequencies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Damtie, Fikeraddis A., E-mail: Fikeraddis.Damtie@teorfys.lu.se; Wacker, Andreas, E-mail: Andreas.Wacker@fysik.lu.se; Karki, Khadga J., E-mail: Khadga.Karki@chemphys.lu.se

Multiple exciton generation (MEG) is a process in which more than one electron hole pair is generated per absorbed photon. It allows us to increase the efficiency of solar energy harvesting. Experimental studies have shown the multiple exciton generation yield of 1.2 in isolated colloidal quantum dots. However real photoelectric devices require the extraction of electron hole pairs to electric contacts. We provide a systematic study of the corresponding quantum coherent processes including extraction and injection and show that a proper design of extraction and injection rates enhances the yield significantly up to values around 1.6.

Surface Plasmon Enhanced Strong Exciton-Photon Coupling in Hybrid Inorganic-Organic Perovskite Nanowires.

PubMed

Shang, Qiuyu; Zhang, Shuai; Liu, Zhen; Chen, Jie; Yang, Pengfei; Li, Chun; Li, Wei; Zhang, Yanfeng; Xiong, Qihua; Liu, Xinfeng; Zhang, Qing

2018-06-13

Manipulating strong light-matter interaction in semiconductor microcavities is crucial for developing high-performance exciton polariton devices with great potential in next-generation all-solid state quantum technologies. In this work, we report surface plasmon enhanced strong exciton-photon interaction in CH 3 NH 3 PbBr 3 perovskite nanowires. Characteristic anticrossing behaviors, indicating a Rabi splitting energy up to ∼564 meV, are observed near exciton resonance in hybrid perovskite nanowire/SiO 2 /Ag cavity at room temperature. The exciton-photon coupling strength is enhanced by ∼35% on average, which is mainly attributed to surface plasmon induced localized excitation field redistribution. Further, systematic studies on SiO 2 thickness and nanowire dimension dependence of exciton-photon interaction are presented. These results provide new avenues to achieve extremely high coupling strengths and push forward the development of electrically pumped and ultralow threshold small lasers.

Strong coupling of a single electron in silicon to a microwave photon

NASA Astrophysics Data System (ADS)

Mi, Xiao; Cady, Jeffrey; Zajac, David; Petta, Jason

We demonstrate a hybrid circuit quantum electrodynamics (cQED) architecture in which a single electron in a Si/SiGe double quantum dot is dipole-coupled to the electric field of microwave photons in a superconducting cavity. Vacuum Rabi splitting is observed in the cavity transmission when the transition energy of the single-electron charge qubit matches that of a cavity photon, demonstrating that our device is in the strong coupling regime. The achievement of strong coupling is largely facilitated by an exceptionally low charge decoherence rate of 5 MHz and paves the way toward a wide range of cQED experiments with quantum dots, such as non-local qubit interactions, strong spin-cavity coupling and single photon generation . Research sponsored by ARO Grant No. W911NF-15-1-0149, the Gordon and Betty Moore Foundation's EPiQS Initiative through Grant GBMF4535, and the NSF (DMR-1409556 and DMR-1420541).

Photonic-powered cable assembly

DOEpatents

Sanderson, Stephen N.; Appel, Titus James; Wrye, IV, Walter C.

2013-01-22

A photonic-cable assembly includes a power source cable connector ("PSCC") coupled to a power receive cable connector ("PRCC") via a fiber cable. The PSCC electrically connects to a first electronic device and houses a photonic power source and an optical data transmitter. The fiber cable includes an optical transmit data path coupled to the optical data transmitter, an optical power path coupled to the photonic power source, and an optical feedback path coupled to provide feedback control to the photonic power source. The PRCC electrically connects to a second electronic device and houses an optical data receiver coupled to the optical transmit data path, a feedback controller coupled to the optical feedback path to control the photonic power source, and a photonic power converter coupled to the optical power path to convert photonic energy received over the optical power path to electrical energy to power components of the PRCC.

Photonic-powered cable assembly

DOEpatents

Sanderson, Stephen N; Appel, Titus James; Wrye, IV, Walter C

2014-06-24

A photonic-cable assembly includes a power source cable connector ("PSCC") coupled to a power receive cable connector ("PRCC") via a fiber cable. The PSCC electrically connects to a first electronic device and houses a photonic power source and an optical data transmitter. The fiber cable includes an optical transmit data path coupled to the optical data transmitter, an optical power path coupled to the photonic power source, and an optical feedback path coupled to provide feedback control to the photonic power source. The PRCC electrically connects to a second electronic device and houses an optical data receiver coupled to the optical transmit data path, a feedback controller coupled to the optical feedback path to control the photonic power source, and a photonic power converter coupled to the optical power path to convert photonic energy received over the optical power path to electrical energy to power components of the PRCC.

A photonic circuit for complementary frequency shifting, in-phase quadrature/single sideband modulation and frequency multiplication: analysis and integration feasibility

NASA Astrophysics Data System (ADS)

Hasan, Mehedi; Hu, Jianqi; Nikkhah, Hamdam; Hall, Trevor

2017-08-01

A novel photonic integrated circuit architecture for implementing orthogonal frequency division multiplexing by means of photonic generation of phase-correlated sub-carriers is proposed. The circuit can also be used for implementing complex modulation, frequency up-conversion of the electrical signal to the optical domain and frequency multiplication. The principles of operation of the circuit are expounded using transmission matrices and the predictions of the analysis are verified by computer simulation using an industry-standard software tool. Non-ideal scenarios that may affect the correct function of the circuit are taken into consideration and quantified. The discussion of integration feasibility is illustrated by a photonic integrated circuit that has been fabricated using 'library' components and which features most of the elements of the proposed circuit architecture. The circuit is found to be practical and may be fabricated in any material platform that offers a linear electro-optic modulator such as organic or ferroelectric thin films hybridized with silicon photonics.

Direct Dark Matter Detection through the use of a Xenon Based TPC Detector

NASA Astrophysics Data System (ADS)

Daniel, Jonathan; Akerib, Daniel; LZ group at SLAC

2018-01-01

The vast majority of matter in the universe is unaccounted for. Only 15% of the universe's mass density is visible matter, while the other 85% is Dark Matter (DM). The Weakly Interacting Massive Particle (WIMP) is currently the frontrunner of the DM candidates. The Large Underground Xenon (LUX) and next generation LUX-ZEPLIN (LZ) experiments are designed to directly detect WIMPs. Both experiments are xenon-based Time Projection Chambers (TPC) used to observe possible WIMP interactions. These interactions produce photons and electrons with the photons being collected in a set of two photomultiplier tube (PMT) arrays and the electrons drifted upwards in the detector by a strong electric field to create a secondary production of photons in gaseous xenon. These two populations of photons are classified as S1 and S2 signals, respectively. Using these signals we reconstruct the energy and position of the interaction and in doing so we can eliminate background events that would otherwise “light up” the detector. My participation in the experiment, while at SLAC, was the creation of the grids that produce the large electric field, along with additional lab activities aimed at testing the grids. While at Stan State, I work on background modeling in order to distinguish a possible WIMP signal from ambient backgrounds.

Band gap control using electric field of photonic gel cells fabricated with block copolymer and hydrogel.

PubMed

Lee, Sung Nam; Baek, Young Bin; Shin, Dong Myung

2014-08-01

Optical and electrical characteristics of the devices using photonic gel film and hydrogel electrolyte were studied. Poly(styrene-b-2-vinylpyridine) (PS-b-P2VP) lamellar film with alternating hydrophobic block and hydrophilic polyelectrolyte block polymers (52 kg/mol-b-57 kg/mol) were prepared for the photonic gel. Poly(isobutylene-co-maleic acid) sodium salts were prepared for the hydrogel. This hydrogel fiber is common water swelling material and it owned ions for a device has conductivity. Photonic gel and hydrogel was spin coating onto Indium-tin-oxide (ITO) glass for make electric fields. The reflectance maximum wavelength of photonic crystal device shifted from 538 nm and reached to 557 nm, 585 nm and 604 nm during 30 min voltage applying time. The bandwidth variation was very limited. Loss of electrolyte was much less with hydrogel compared to the pure water. We can control color of hydrogel used photonic device by electric field with reasonable time range under moderate electric field by applying 2 V between two facing electrodes.

On-chip electrically controlled routing of photons from a single quantum dot

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bentham, C.; Coles, R. J.; Royall, B.

2015-06-01

Electrical control of on-chip routing of photons emitted by a single InAs/GaAs self-assembled quantum dot (SAQD) is demonstrated in a photonic crystal cavity-waveguide system. The SAQD is located inside an H1 cavity, which is coupled to two photonic crystal waveguides. The SAQD emission wavelength is electrically tunable by the quantum-confined Stark effect. When the SAQD emission is brought into resonance with one of two H1 cavity modes, it is preferentially routed to the waveguide to which that mode is selectively coupled. This proof of concept provides the basis for scalable, low-power, high-speed operation of single-photon routers for use in integratedmore » quantum photonic circuits.« less

Multipolar second-harmonic generation by Mie-resonant dielectric nanoparticles

NASA Astrophysics Data System (ADS)

Smirnova, Daria; Smirnov, Alexander I.; Kivshar, Yuri S.

2018-01-01

By combining analytical and numerical approaches, we study resonantly enhanced second-harmonic generation by individual high-index dielectric nanoparticles made of centrosymmetric materials. Considering both bulk and surface nonlinearities, we describe second-harmonic nonlinear scattering from a silicon nanoparticle optically excited in the vicinity of the magnetic and electric dipolar resonances. We discuss the contributions of different nonlinear sources and the effect of the low-order optical Mie modes on the characteristics of the generated far field. We demonstrate that the multipolar expansion of the radiated field is dominated by dipolar and quadrupolar modes (two axially symmetric electric quadrupoles, an electric dipole, and a magnetic quadrupole) and the interference of these modes can ensure directivity of the nonlinear scattering. The developed multipolar analysis can be instructive for interpreting the far-field measurements of the nonlinear scattering and it provides prospective insights into a design of complementary metal-oxide-semiconductor compatible nonlinear nanoantennas fully integrated with silicon-based photonic circuits, as well as methods of nonlinear diagnostics.

Micro spectrometer for parallel light and method of use

NASA Technical Reports Server (NTRS)

Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

2011-01-01

A spectrometer system includes an optical assembly for collimating light, a micro-ring grating assembly having a plurality of coaxially-aligned ring gratings, an aperture device defining an aperture circumscribing a target focal point, and a photon detector. An electro-optical layer of the grating assembly may be electrically connected to an energy supply to change the refractive index of the electro-optical layer. Alternately, the gratings may be electrically connected to the energy supply and energized, e.g., with alternating voltages, to change the refractive index. A data recorder may record the predetermined spectral characteristic. A method of detecting a spectral characteristic of a predetermined wavelength of source light includes generating collimated light using an optical assembly, directing the collimated light onto the micro-ring grating assembly, and selectively energizing the micro-ring grating assembly to diffract the predetermined wavelength onto the target focal point, and detecting the spectral characteristic using a photon detector.

Graphene-based photovoltaic cells for near-field thermal energy conversion

PubMed Central

Messina, Riccardo; Ben-Abdallah, Philippe

2013-01-01

Thermophotovoltaic devices are energy-conversion systems generating an electric current from the thermal photons radiated by a hot body. While their efficiency is limited in far field by the Schockley-Queisser limit, in near field the heat flux transferred to a photovoltaic cell can be largely enhanced because of the contribution of evanescent photons, in particular for a source supporting a surface mode. Unfortunately, in the infrared where these systems operate, the mismatch between the surface-mode frequency and the semiconductor gap reduces drastically the potential of this technology. In this paper we propose a modified thermophotovoltaic device in which the cell is covered by a graphene sheet. By discussing the transmission coefficient and the spectral properties of the flux, we show that both the cell efficiency and the produced current can be enhanced, paving the way to promising developments for the production of electricity from waste heat. PMID:23474891

Integrating a dual-silicon photoelectrochemical cell into a redox flow battery for unassisted photocharging.

PubMed

Liao, Shichao; Zong, Xu; Seger, Brian; Pedersen, Thomas; Yao, Tingting; Ding, Chunmei; Shi, Jingying; Chen, Jian; Li, Can

2016-05-04

Solar rechargeable flow cells (SRFCs) provide an attractive approach for in situ capture and storage of intermittent solar energy via photoelectrochemical regeneration of discharged redox species for electricity generation. However, overall SFRC performance is restricted by inefficient photoelectrochemical reactions. Here we report an efficient SRFC based on a dual-silicon photoelectrochemical cell and a quinone/bromine redox flow battery for in situ solar energy conversion and storage. Using narrow bandgap silicon for efficient photon collection and fast redox couples for rapid interface charge injection, our device shows an optimal solar-to-chemical conversion efficiency of ∼5.9% and an overall photon-chemical-electricity energy conversion efficiency of ∼3.2%, which, to our knowledge, outperforms previously reported SRFCs. The proposed SRFC can be self-photocharged to 0.8 V and delivers a discharge capacity of 730 mAh l(-1). Our work may guide future designs for highly efficient solar rechargeable devices.

Graphene-based photovoltaic cells for near-field thermal energy conversion.

PubMed

Messina, Riccardo; Ben-Abdallah, Philippe

2013-01-01

Thermophotovoltaic devices are energy-conversion systems generating an electric current from the thermal photons radiated by a hot body. While their efficiency is limited in far field by the Schockley-Queisser limit, in near field the heat flux transferred to a photovoltaic cell can be largely enhanced because of the contribution of evanescent photons, in particular for a source supporting a surface mode. Unfortunately, in the infrared where these systems operate, the mismatch between the surface-mode frequency and the semiconductor gap reduces drastically the potential of this technology. In this paper we propose a modified thermophotovoltaic device in which the cell is covered by a graphene sheet. By discussing the transmission coefficient and the spectral properties of the flux, we show that both the cell efficiency and the produced current can be enhanced, paving the way to promising developments for the production of electricity from waste heat.

Novel microwave photonic fractional Hilbert transformer using a ring resonator-based optical all-pass filter.

PubMed

Zhuang, Leimeng; Khan, Muhammad Rezaul; Beeker, Willem; Leinse, Arne; Heideman, René; Roeloffzen, Chris

2012-11-19

We propose and demonstrate a novel wideband microwave photonic fractional Hilbert transformer implemented using a ring resonator-based optical all-pass filter. The full programmability of the ring resonator allows variable and arbitrary fractional order of the Hilbert transformer. The performance analysis in both frequency and time domain validates that the proposed implementation provides a good approximation to an ideal fractional Hilbert transformer. This is also experimentally verified by an electrical S₂₁ response characterization performed on a waveguide realization of a ring resonator. The waveguide-based structure allows the proposed Hilbert transformer to be integrated together with other building blocks on a photonic integrated circuit to create various system-level functionalities for on-chip microwave photonic signal processors. As an example, a circuit consisting of a splitter and a ring resonator has been realized which can perform on-chip phase control of microwave signals generated by means of optical heterodyning, and simultaneous generation of in-phase and quadrature microwave signals for a wide frequency range. For these functionalities, this simple and on-chip solution is considered to be practical, particularly when operating together with a dual-frequency laser. To our best knowledge, this is the first-time on-chip demonstration where ring resonators are employed to perform phase control functionalities for optical generation of microwave signals by means of optical heterodyning.

Gain modulation by graphene plasmons in aperiodic lattice lasers

NASA Astrophysics Data System (ADS)

Chakraborty, S.; Marshall, O. P.; Folland, T. G.; Kim, Y.-J.; Grigorenko, A. N.; Novoselov, K. S.

2016-01-01

Two-dimensional graphene plasmon-based technologies will enable the development of fast, compact, and inexpensive active photonic elements because, unlike plasmons in other materials, graphene plasmons can be tuned via the doping level. Such tuning is harnessed within terahertz quantum cascade lasers to reversibly alter their emission. This is achieved in two key steps: first, by exciting graphene plasmons within an aperiodic lattice laser and, second, by engineering photon lifetimes, linking graphene’s Fermi energy with the round-trip gain. Modal gain and hence laser spectra are highly sensitive to the doping of an integrated, electrically controllable, graphene layer. Demonstration of the integrated graphene plasmon laser principle lays the foundation for a new generation of active, programmable plasmonic metamaterials with major implications across photonics, material sciences, and nanotechnology.

Electric currents induced by twisted light in Quantum Rings.

PubMed

Quinteiro, G F; Berakdar, J

2009-10-26

We theoretically investigate the generation of electric currents in quantum rings resulting from the optical excitation with twisted light. Our model describes the kinetics of electrons in a two-band model of a semiconductor-based mesoscopic quantum ring coupled to light having orbital angular momentum (twisted light). We find the analytical solution, which exhibits a "circular" photon-drag effect and an induced magnetization, suggesting that this system is the circular analog of that of a bulk semiconductor excited by plane waves. For realistic values of the electric field and material parameters, the computed electric current can be as large as microA; from an applied perspective, this opens new possibilities to the optical control of the magnetization in semiconductors.

Voltage-matched, monolithic, multi-band-gap devices

DOEpatents

Wanlass, Mark W.; Mascarenhas, Angelo

2006-08-22

Monolithic, tandem, photonic cells include at least a first semiconductor layer and a second semiconductor layer, wherein each semiconductor layer includes an n-type region, a p-type region, and a given band-gap energy. Formed within each semiconductor layer is a sting of electrically connected photonic sub-cells. By carefully selecting the numbers of photonic sub-cells in the first and second layer photonic sub-cell string(s), and by carefully selecting the manner in which the sub-cells in a first and second layer photonic sub-cell string(s) are electrically connected, each of the first and second layer sub-cell strings may be made to achieve one or more substantially identical electrical characteristics.

Voltage-Matched, Monolithic, Multi-Band-Gap Devices

DOEpatents

Wanlass, M. W.; Mascarenhas, A.

2006-08-22

Monolithic, tandem, photonic cells include at least a first semiconductor layer and a second semiconductor layer, wherein each semiconductor layer includes an n-type region, a p-type region, and a given band-gap energy. Formed within each semiconductor layer is a string of electrically connected photonic sub-cells. By carefully selecting the numbers of photonic sub-cells in the first and second layer photonic sub-cell string(s), and by carefully selecting the manner in which the sub-cells in a first and second layer photonic sub-cell string(s) are electrically connected, each of the first and second layer sub-cell strings may be made to achieve one or more substantially identical electrical characteristics.

A Population Synthesis Study of Terrestrial Gamma-ray Flashes

NASA Astrophysics Data System (ADS)

Cramer, E. S.; Briggs, M. S.; Stanbro, M.; Dwyer, J. R.; Mailyan, B. G.; Roberts, O.

2017-12-01

In astrophysics, population synthesis models are tools used to determine what mix of stars could be consistent with the observations, e.g. how the intrinsic mass-to-light ratio changes by the measurement process. A similar technique could be used to understand the production of TGFs. The models used for this type of population study probe the conditions of electron acceleration inside the high electric field regions of thunderstorms, i.e. acceleration length, electric field strength, and beaming angles. In this work, we use a Monte Carlo code to generate bremsstrahlung photons from relativistic electrons that are accelerated by a large-scale RREA thunderstorm electric field. The code simulates the propagation of photons through the atmosphere at various source altitudes, where they interact with air via Compton scattering, pair production, and photoelectric absorption. We then show the differences in the hardness ratio at spacecraft altitude between these different simulations and compare them with TGF data from Fermi-GBM. Such comparisons can lead to constraints that can be applied to popular TGF beaming models, and help determine whether the population presented in this study is consistent or not with reality.

Second generation measurement of the electric dipole moment of the electron using trapped ThF+ ions

NASA Astrophysics Data System (ADS)

Ng, Kia Boon; Zhou, Yan; Gresh, Daniel; Cairncross, William; Grau, Matthew; Ni, Yiqi; Ye, Jun; Cornell, Eric

2016-05-01

ThF+ has been chosen as the candidate for a second generation measurement of the electric dipole moment of the electron (eEDM). Compared to the current HfF+ eEDM experiment, ThF+ has several advantages: (i) the eEDM-sensitive state (3Δ1) is the ground state, which facilitates a long coherence time; (ii) its effective electric field (38 GV/cm) is 50% larger than that of HfF+, which promises a direct increase of the eEDM sensitivity; and (iii) the ionization energy of neutral ThF is lower than its dissociation energy, which introduces greater flexibility in rotational state-selective photoionization via core-nonpenetrating Rydberg states. Here, we present progress of our experimental setup, preliminary spectroscopic data of multi-photon ionization, and discussions of new features in ion trapping, state preparation and population readout.

Dynamics of Single-Photon Emission from Electrically Pumped Color Centers

NASA Astrophysics Data System (ADS)

Khramtsov, Igor A.; Agio, Mario; Fedyanin, Dmitry Yu.

2017-08-01

Low-power, high-speed, and bright electrically driven true single-photon sources, which are able to operate at room temperature, are vital for the practical realization of quantum-communication networks and optical quantum computations. Color centers in semiconductors are currently the best candidates; however, in spite of their intensive study in the past decade, the behavior of color centers in electrically controlled systems is poorly understood. Here we present a physical model and establish a theoretical approach to address single-photon emission dynamics of electrically pumped color centers, which interprets experimental results. We support our analysis with self-consistent numerical simulations of a single-photon emitting diode based on a single nitrogen-vacancy center in diamond and predict the second-order autocorrelation function and other emission characteristics. Our theoretical findings demonstrate remarkable agreement with the experimental results and pave the way to the understanding of single-electron and single-photon processes in semiconductors.

Absorption of gamma-ray photons in a vacuum neutron star magnetosphere: II. The formation of 'lightnings'

DOE Office of Scientific and Technical Information (OSTI.GOV)

Istomin, Ya. N., E-mail: istomin@lpi.ru; Sob'yanin, D. N., E-mail: sobyanin@lpi.ru

2011-10-15

The absorption of a high-energy photon from the external cosmic gamma-ray background in the inner neutron star magnetosphere triggers the generation of a secondary electron-positron plasma and gives rise to a lightning-a lengthening and simultaneously expanding plasma tube. It propagates along magnetic fields lines with a velocity close to the speed of light. The high electron-positron plasma generation rate leads to dynamical screening of the longitudinal electric field that is provided not by charge separation but by electric current growth in the lightning. The lightning radius is comparable to the polar cap radius of a radio pulsar. The number ofmore » electron-positron pairs produced in the lightning in its lifetime reaches 10{sup 28}. The density of the forming plasma is comparable to or even higher than that in the polar cap regions of ordinary pulsars. This suggests that the radio emission from individual lightnings can be observed. Since the formation time of the radio emission is limited by the lightning lifetime, the possible single short radio bursts may be associated with rotating radio transients (RRATs).« less

Quantum random number generator

DOEpatents

Pooser, Raphael C.

2016-05-10

A quantum random number generator (QRNG) and a photon generator for a QRNG are provided. The photon generator may be operated in a spontaneous mode below a lasing threshold to emit photons. Photons emitted from the photon generator may have at least one random characteristic, which may be monitored by the QRNG to generate a random number. In one embodiment, the photon generator may include a photon emitter and an amplifier coupled to the photon emitter. The amplifier may enable the photon generator to be used in the QRNG without introducing significant bias in the random number and may enable multiplexing of multiple random numbers. The amplifier may also desensitize the photon generator to fluctuations in power supplied thereto while operating in the spontaneous mode. In one embodiment, the photon emitter and amplifier may be a tapered diode amplifier.

Efficient electroluminescent cooling with a light-emitting diode coupled to a photovoltaic cell (Conference Presentation)

NASA Astrophysics Data System (ADS)

Xiao, Tianyao P.; Chen, Kaifeng; Santhanam, Parthiban; Fan, Shanhui; Yablonovitch, Eli

2017-02-01

The new breakthrough in photovoltaics, exemplified by the slogan "A great solar cell has to be a great light-emitting diode (LED)", has led to all the major new solar cell records, while also leading to extraordinary LED efficiency. As an LED becomes very efficient in converting its electrical input into light, the device cools as it operates because the photons carry away entropy as well as energy. If these photons are absorbed in a photovoltaic (PV) cell, the generated electricity can be used to provide part of the electrical input that drives the LED. Indeed, the LED/PV cell combination forms a new type of heat engine with light as the working fluid. The electroluminescent refrigerator requires only a small amount of external electricity to provide cooling, leading to a high coefficient of performance. We present the theoretical performance of such a refrigerator, in which the cool side (LED) is radiatively coupled to the hot side (PV) across a vacuum gap. The coefficient of performance is maximized by using a highly luminescent material, such as GaAs, together with device structures that optimize extraction of the luminescence. We consider both a macroscopic vacuum gap and a sub-wavelength gap; the latter allows for evanescent coupling of photons between the devices, potentially providing a further enhancement to the efficiency of light extraction. Using device assumptions based on the current record-efficiency solar cells, we show that electroluminescent cooling can, in certain regimes of cooling power, achieve a higher coefficient of performance than thermoelectric cooling.

2d axisymmetric "beam-bulk" modelling of the generation of runaway electrons by streamers.

NASA Astrophysics Data System (ADS)

Chanrion, Olivier; Bonaventura, Zdenek; Bourdon, Anne; Neubert, Torsten

2017-04-01

We present results from a 2d axisymmetric numerical model of streamers based on a "beam-bulk" approach which describes cold electrons with a fluid model and high energy electrons with a particle model. The interest is motivated by the generation of runaway electrons by streamers which may participate in the recently observed TGFs and which challenge the modelling. Runaway electrons are known to be generated from streamers when the electric field in its negative tip is of sufficient magnitude. After overtaking the streamer tip, runaways can affect the streamer propagation ahead and may produce high energy photons through the bremsstrahlung process. In conventional model of streamers, the evolution of the streamer discharge is mostly governed by cold electrons. By including runaway electrons, we model their production, their impact on the discharge propagation and can address their role in TGFs. Results of streamer propagation in leader electric field show that the runaway electrons accelerate the streamers, reduce the electric field in its tip and enlarge its radius by pre-ionizing the gas ahead. We observed that if we increase the electric field, the discharge is getting more diffuse, with a pattern driven by the increase in runaway induced ionisation.

Electric-Field-Induced Energy Tuning of On-Demand Entangled-Photon Emission from Self-Assembled Quantum Dots.

PubMed

Zhang, Jiaxiang; Zallo, Eugenio; Höfer, Bianca; Chen, Yan; Keil, Robert; Zopf, Michael; Böttner, Stefan; Ding, Fei; Schmidt, Oliver G

2017-01-11

We explore a method to achieve electrical control over the energy of on-demand entangled-photon emission from self-assembled quantum dots (QDs). The device used in our work consists of an electrically tunable diode-like membrane integrated onto a piezoactuator, which is capable of exerting a uniaxial stress on QDs. We theoretically reveal that, through application of the quantum-confined Stark effect to QDs by a vertical electric field, the critical uniaxial stress used to eliminate the fine structure splitting of QDs can be linearly tuned. This feature allows experimental realization of a triggered source of energy-tunable entangled-photon emission. Our demonstration represents an important step toward realization of a solid-state quantum repeater using indistinguishable entangled photons in Bell state measurements.

Applied optics. Gain modulation by graphene plasmons in aperiodic lattice lasers.

PubMed

Chakraborty, S; Marshall, O P; Folland, T G; Kim, Y-J; Grigorenko, A N; Novoselov, K S

2016-01-15

Two-dimensional graphene plasmon-based technologies will enable the development of fast, compact, and inexpensive active photonic elements because, unlike plasmons in other materials, graphene plasmons can be tuned via the doping level. Such tuning is harnessed within terahertz quantum cascade lasers to reversibly alter their emission. This is achieved in two key steps: first, by exciting graphene plasmons within an aperiodic lattice laser and, second, by engineering photon lifetimes, linking graphene's Fermi energy with the round-trip gain. Modal gain and hence laser spectra are highly sensitive to the doping of an integrated, electrically controllable, graphene layer. Demonstration of the integrated graphene plasmon laser principle lays the foundation for a new generation of active, programmable plasmonic metamaterials with major implications across photonics, material sciences, and nanotechnology. Copyright © 2016, American Association for the Advancement of Science.

Two-Photon Absorption in Organometallic Bromide Perovskites.

PubMed

Walters, Grant; Sutherland, Brandon R; Hoogland, Sjoerd; Shi, Dong; Comin, Riccardo; Sellan, Daniel P; Bakr, Osman M; Sargent, Edward H

2015-09-22

Organometallic trihalide perovskites are solution-processed semiconductors that have made great strides in third-generation thin film light-harvesting and light-emitting optoelectronic devices. Recently, it has been demonstrated that large, high-purity single crystals of these perovskites can be synthesized from the solution phase. These crystals' large dimensions, clean bandgap, and solid-state order have provided us with a suitable medium to observe and quantify two-photon absorption in perovskites. When CH3NH3PbBr3 single crystals are pumped with intense 800 nm light, we observe band-to-band photoluminescence at 572 nm, indicative of two-photon absorption. We report the nonlinear absorption coefficient of CH3NH3PbBr3 perovskites to be 8.6 cm GW(-1) at 800 nm, comparable to epitaxial single-crystal semiconductors of similar bandgap. We have leveraged this nonlinear process to electrically autocorrelate a 100 fs pulsed laser using a two-photon perovskite photodetector. This work demonstrates the viability of organometallic trihalide perovskites as a convenient and low-cost nonlinear absorber for applications in ultrafast photonics.

Photonic quasi-crystal terahertz lasers

PubMed Central

Vitiello, Miriam Serena; Nobile, Michele; Ronzani, Alberto; Tredicucci, Alessandro; Castellano, Fabrizio; Talora, Valerio; Li, Lianhe; Linfield, Edmund H.; Davies, A. Giles

2014-01-01

Quasi-crystal structures do not present a full spatial periodicity but are nevertheless constructed starting from deterministic generation rules. When made of different dielectric materials, they often possess fascinating optical properties, which lie between those of periodic photonic crystals and those of a random arrangement of scatterers. Indeed, they can support extended band-like states with pseudogaps in the energy spectrum, but lacking translational invariance, they also intrinsically feature a pattern of ‘defects’, which can give rise to critically localized modes confined in space, similar to Anderson modes in random structures. If used as laser resonators, photonic quasi-crystals open up design possibilities that are simply not possible in a conventional periodic photonic crystal. In this letter, we exploit the concept of a 2D photonic quasi crystal in an electrically injected laser; specifically, we pattern the top surface of a terahertz quantum-cascade laser with a Penrose tiling of pentagonal rotational symmetry, reaching 0.1–0.2% wall-plug efficiencies and 65 mW peak output powers with characteristic surface-emitting conical beam profiles, result of the rich quasi-crystal Fourier spectrum. PMID:25523102

Photonic quasi-crystal terahertz lasers

NASA Astrophysics Data System (ADS)

Vitiello, Miriam Serena; Nobile, Michele; Ronzani, Alberto; Tredicucci, Alessandro; Castellano, Fabrizio; Talora, Valerio; Li, Lianhe; Linfield, Edmund H.; Davies, A. Giles

2014-12-01

Quasi-crystal structures do not present a full spatial periodicity but are nevertheless constructed starting from deterministic generation rules. When made of different dielectric materials, they often possess fascinating optical properties, which lie between those of periodic photonic crystals and those of a random arrangement of scatterers. Indeed, they can support extended band-like states with pseudogaps in the energy spectrum, but lacking translational invariance, they also intrinsically feature a pattern of ‘defects’, which can give rise to critically localized modes confined in space, similar to Anderson modes in random structures. If used as laser resonators, photonic quasi-crystals open up design possibilities that are simply not possible in a conventional periodic photonic crystal. In this letter, we exploit the concept of a 2D photonic quasi crystal in an electrically injected laser; specifically, we pattern the top surface of a terahertz quantum-cascade laser with a Penrose tiling of pentagonal rotational symmetry, reaching 0.1-0.2% wall-plug efficiencies and 65 mW peak output powers with characteristic surface-emitting conical beam profiles, result of the rich quasi-crystal Fourier spectrum.

Photonic quasi-crystal terahertz lasers.

PubMed

Vitiello, Miriam Serena; Nobile, Michele; Ronzani, Alberto; Tredicucci, Alessandro; Castellano, Fabrizio; Talora, Valerio; Li, Lianhe; Linfield, Edmund H; Davies, A Giles

2014-12-19

Quasi-crystal structures do not present a full spatial periodicity but are nevertheless constructed starting from deterministic generation rules. When made of different dielectric materials, they often possess fascinating optical properties, which lie between those of periodic photonic crystals and those of a random arrangement of scatterers. Indeed, they can support extended band-like states with pseudogaps in the energy spectrum, but lacking translational invariance, they also intrinsically feature a pattern of 'defects', which can give rise to critically localized modes confined in space, similar to Anderson modes in random structures. If used as laser resonators, photonic quasi-crystals open up design possibilities that are simply not possible in a conventional periodic photonic crystal. In this letter, we exploit the concept of a 2D photonic quasi crystal in an electrically injected laser; specifically, we pattern the top surface of a terahertz quantum-cascade laser with a Penrose tiling of pentagonal rotational symmetry, reaching 0.1-0.2% wall-plug efficiencies and 65 mW peak output powers with characteristic surface-emitting conical beam profiles, result of the rich quasi-crystal Fourier spectrum.

Imaging of pure spin-valley diffusion current in WS2-WSe2 heterostructures

NASA Astrophysics Data System (ADS)

Jin, Chenhao; Kim, Jonghwan; Utama, M. Iqbal Bakti; Regan, Emma C.; Kleemann, Hans; Cai, Hui; Shen, Yuxia; Shinner, Matthew James; Sengupta, Arjun; Watanabe, Kenji; Taniguchi, Takashi; Tongay, Sefaattin; Zettl, Alex; Wang, Feng

2018-05-01

Transition metal dichalcogenide (TMDC) materials are promising for spintronic and valleytronic applications because valley-polarized excitations can be generated and manipulated with circularly polarized photons and the valley and spin degrees of freedom are locked by strong spin-orbital interactions. In this study we demonstrate efficient generation of a pure and locked spin-valley diffusion current in tungsten disulfide (WS2)–tungsten diselenide (WSe2) heterostructures without any driving electric field. We imaged the propagation of valley current in real time and space by pump-probe spectroscopy. The valley current in the heterostructures can live for more than 20 microseconds and propagate over 20 micrometers; both the lifetime and the diffusion length can be controlled through electrostatic gating. The high-efficiency and electric-field–free generation of a locked spin-valley current in TMDC heterostructures holds promise for applications in spin and valley devices.

Metal photonics and plasmonics for energy generation

NASA Astrophysics Data System (ADS)

Nagpal, Prashant

Energy generation from renewable sources and conservation of energy are important goals for reducing our carbon footprint on the environment. Important sources of renewable energy like sun and geothermal energy are difficult to harness because of their energetically broad radiation. Most of our current energy requirements are met through consumption of fossil fuels, and more than 60% of this energy is released to the environment as "waste heat". Thus, converting heat from sun, or inefficient furnaces and automobiles can provide an important source of energy generation. In the present work, I describe design, fabrication, and characterization two and three dimensional patterned metals. These nanofabricated structures can be used as selective emitters to tailor the glow of hot objects. The tailored radiation can then be converted efficiently into electricity using an infrared photocell. This thermophotovoltaic conversion can be very efficient, and useful for converting heat-to-electricity from a wide variety of sources.

Brain plasticity and functionality explored by nonlinear optical microscopy

NASA Astrophysics Data System (ADS)

Sacconi, L.; Allegra, L.; Buffelli, M.; Cesare, P.; D'Angelo, E.; Gandolfi, D.; Grasselli, G.; Lotti, J.; Mapelli, J.; Strata, P.; Pavone, F. S.

2010-02-01

In combination with fluorescent protein (XFP) expression techniques, two-photon microscopy has become an indispensable tool to image cortical plasticity in living mice. In parallel to its application in imaging, multi-photon absorption has also been used as a tool for the dissection of single neurites with submicrometric precision without causing any visible collateral damage to the surrounding neuronal structures. In this work, multi-photon nanosurgery is applied to dissect single climbing fibers expressing GFP in the cerebellar cortex. The morphological consequences are then characterized with time lapse 3-dimensional two-photon imaging over a period of minutes to days after the procedure. Preliminary investigations show that the laser induced fiber dissection recalls a regenerative process in the fiber itself over a period of days. These results show the possibility of this innovative technique to investigate regenerative processes in adult brain. In parallel with imaging and manipulation technique, non-linear microscopy offers the opportunity to optically record electrical activity in intact neuronal networks. In this work, we combined the advantages of second-harmonic generation (SHG) with a random access (RA) excitation scheme to realize a new microscope (RASH) capable of optically recording fast membrane potential events occurring in a wide-field of view. The RASH microscope, in combination with bulk loading of tissue with FM4-64 dye, was used to simultaneously record electrical activity from clusters of Purkinje cells in acute cerebellar slices. Complex spikes, both synchronous and asynchronous, were optically recorded simultaneously across a given population of neurons. Spontaneous electrical activity was also monitored simultaneously in pairs of neurons, where action potentials were recorded without averaging across trials. These results show the strength of this technique in describing the temporal dynamics of neuronal assemblies, opening promising perspectives in understanding the computations of neuronal networks.

Integrating photonic crystals in thin film silicon photovoltaics

NASA Astrophysics Data System (ADS)

O'Brien, P. G.; Chutinan, A.; Ozin, G. A.; Kherani, N. P.; Zukotynski, S.

2010-06-01

Wave-optics analysis is performed to investigate the benefits of integrating photonic crystals into micromorph cells. Specifically, we theoretically investigate two novel micromorph cells which integrate photonic crystals and compare their optical performance with that of conventional micromorph cells. In the first innovative micromorph cell configuration the intermediate reflector is a selectively transparent and conducting photonic crystal (STCPC). In the second micromorph cell its bottom μc-Si:H cell is structured in the form of an inverted opal. Our results show that with the AM1.5 solar spectrum at normal incidence the current generated in a conventional micromorph cell is increased from 12.1 mA/cm2 to 13.0 mA/cm2 when the bottom μc-Si:H cell is structured in the form of an inverted opal. However, the current generated in the micromorph cell can be increased to as much as 13.7 mA/cm2 when an STCPC is utilized as the intermediate reflector. Furthermore, the thickness of the μc-Si:H opal must be relatively large in order to absorb a sufficient amount of the solar irradiance, which is expected to degrade the electrical performance of the device. In contrast, our results suggest that STCPC intermediate reflectors are a viable technology that could potentially enhance the performance of micromorph cells.

Communication Limits Due to Photon-Detector Jitter

NASA Technical Reports Server (NTRS)

Moision, Bruce E.; Farr, William H.

2008-01-01

A theoretical and experimental study was conducted of the limit imposed by photon-detector jitter on the capacity of a pulse-position-modulated optical communication system in which the receiver operates in a photon-counting (weak-signal) regime. Photon-detector jitter is a random delay between impingement of a photon and generation of an electrical pulse by the detector. In the study, jitter statistics were computed from jitter measurements made on several photon detectors. The probability density of jitter was mathematically modeled by use of a weighted sum of Gaussian functions. Parameters of the model were adjusted to fit histograms representing the measured-jitter statistics. Likelihoods of assigning detector-output pulses to correct pulse time slots in the presence of jitter were derived and used to compute channel capacities and corresponding losses due to jitter. It was found that the loss, expressed as the ratio between the signal power needed to achieve a specified capacity in the presence of jitter and that needed to obtain the same capacity in the absence of jitter, is well approximated as a quadratic function of the standard deviation of the jitter in units of pulse-time-slot duration.

Exciton dynamics of C60-based single-photon emitters explored by Hanbury Brown-Twiss scanning tunnelling microscopy.

PubMed

Merino, P; Große, C; Rosławska, A; Kuhnke, K; Kern, K

2015-09-29

Exciton creation and annihilation by charges are crucial processes for technologies relying on charge-exciton-photon conversion. Improvement of organic light sources or dye-sensitized solar cells requires methods to address exciton dynamics at the molecular scale. Near-field techniques have been instrumental for this purpose; however, characterizing exciton recombination with molecular resolution remained a challenge. Here, we study exciton dynamics by using scanning tunnelling microscopy to inject current with sub-molecular precision and Hanbury Brown-Twiss interferometry to measure photon correlations in the far-field electroluminescence. Controlled injection allows us to generate excitons in solid C60 and let them interact with charges during their lifetime. We demonstrate electrically driven single-photon emission from localized structural defects and determine exciton lifetimes in the picosecond range. Monitoring lifetime shortening and luminescence saturation for increasing carrier injection rates provides access to charge-exciton annihilation dynamics. Our approach introduces a unique way to study single quasi-particle dynamics on the ultimate molecular scale.

Compact tunable and reconfigurable microwave photonic filter for satellite payloads

NASA Astrophysics Data System (ADS)

Santos, M. C.; Yoosefi, O.

2017-11-01

The trend towards the photonic processing of electrical signals at microwave frequencies for satellite payloads is increasing at a breathtaking pace, mainly spurred by prospects of wide electrical bandwidth operation, low mass and volume, reduced electrical noise levels, immunity to electromagnetic interferences and resistance to both temperature and radiation.

Variable waveband infrared imager

DOEpatents

Hunter, Scott R.

2013-06-11

A waveband imager includes an imaging pixel that utilizes photon tunneling with a thermally actuated bimorph structure to convert infrared radiation to visible radiation. Infrared radiation passes through a transparent substrate and is absorbed by a bimorph structure formed with a pixel plate. The absorption generates heat which deflects the bimorph structure and pixel plate towards the substrate and into an evanescent electric field generated by light propagating through the substrate. Penetration of the bimorph structure and pixel plate into the evanescent electric field allows a portion of the visible wavelengths propagating through the substrate to tunnel through the substrate, bimorph structure, and/or pixel plate as visible radiation that is proportional to the intensity of the incident infrared radiation. This converted visible radiation may be superimposed over visible wavelengths passed through the imaging pixel.

Photonic crystal wave guide for non-cryogenic cooled carbon nanotube based middle wave infrared sensors

NASA Astrophysics Data System (ADS)

Fung, Carmen Kar Man; Xi, Ning; Lou, Jianyong; Lai, King Wai Chiu; Chen, Hongzhi

2010-10-01

We report high sensitivity carbon nanotube (CNT) based middle wave infrared (MWIR) sensors with a two-dimensional photonic crystal waveguide. MWIR sensors are of great importance in a variety of current military applications including ballistic missile defense, surveillance and target detection. Unlike other existing MWIR sensing materials, CNTs exhibit low noise level and can be used as new nano sensing materials for MWIR detection where cryogenic cooling is not required. However, the quantum efficiency of the CNT based infrared sensor is still limited by the small sensing area and low incoming electric field. Here, a photonic nanostructure is used as a resonant cavity for boosting the electric field intensity at the position of the CNT sensing element. A two-dimensional photonic crystal with periodic holes in a polymer thin film is fabricated and a resonant cavity is formed by removing holes from the array of the photonic crystal. Based on the design of the photonic crystal topologies, we theoretically study the electric field distribution to predict the resonant behavior of the structure. Numerical simulations reveal the field is enhanced and almost fully confined to the defect region of the photonic crystal. To verify the electric field enhancement effect, experiments are also performed to measure the photocurrent response of the sensor with and without the photonic crystal resonant cavity. Experimental results show that the photocurrent increases ~3 times after adding the photonic crystal resonant cavity.

Photonic ultrawideband impulse radio generation and modulation over a fiber link using a phase modulator and a delay interferometer.

PubMed

Shao, Jing; Sun, Junqiang

2012-08-15

We propose and experimentally demonstrate a simple and flexible photonic scheme for generation and modulation of ultrawideband (UWB) using a phase modulator and a fiber delay interferometer (DI)-based multichannel frequency discrimination. By introducing a Gaussian signal to the phase modulator, the UWB polarity-switchable doublet pulses can be achieved by combining the pair of UWB monocycle pulses with inverted polarities at the DI outputs under proper time delay. Furthermore, the pulse shape modulation, pulse position modulation, and on-off keying can be performed by coding the electrical data patterns and adjusting the time delay between the two monocycle pulses. Only a laser source introduced in the architecture guarantees the excellent dispersion tolerance over 75 km optical fiber link for UWB pulse sequence, which has potential application in future high-speed UWB impulse radio over optical fiber access networks.

Silicon Photomultiplier Performance in High ELectric Field

NASA Astrophysics Data System (ADS)

Montoya, J.; Morad, J.

2016-12-01

Roughly 27% of the universe is thought to be composed of dark matter. The Large Underground Xenon (LUX) relies on the emission of light from xenon atoms after a collision with a dark matter particle. After a particle interaction in the detector, two things can happen: the xenon will emit light and charge. The charge (electrons), in the liquid xenon needs to be pulled into the gas section so that it can interact with gas and emit light. This allows LUX to convert a single electron into many photons. This is done by applying a high voltage across the liquid and gas regions, effectively ripping electrons out of the liquid xenon and into the gas. The current device used to detect photons is the photomultiplier tube (PMT). These devices are large and costly. In recent years, a new technology that is capable of detecting single photons has emerged, the silicon photomultiplier (SiPM). These devices are cheaper and smaller than PMTs. Their performance in a high electric fields, such as those found in LUX, are unknown. It is possible that a large electric field could introduce noise on the SiPM signal, drowning the single photon detection capability. My hypothesis is that SiPMs will not observe a significant increase is noise at an electric field of roughly 10kV/cm (an electric field within the range used in detectors like LUX). I plan to test this hypothesis by first rotating the SiPMs with no applied electric field between two metal plates roughly 2 cm apart, providing a control data set. Then using the same angles test the dark counts with the constant electric field applied. Possibly the most important aspect of LUX, is the photon detector because it's what detects the signals. Dark matter is detected in the experiment by looking at the ratio of photons to electrons emitted for a given interaction in the detector. Interactions with a low electron to photon ratio are more like to be dark matter events than those with a high electron to photon ratio. The ability to distinguish these ratios relies on the high sensitivity to single photons. To achieve a similar sensitivity to dark matter interactions as LUX, the new SiPM devices need to operate in the same conditions without any loss in sensitivity to single photons. Knowing that this new type of technology operates in high electric field without issues, could save hundreds of thousands of dollars and valuable space.

Combined calculi for photon orbital and spin angular momenta

NASA Astrophysics Data System (ADS)

Elias, N. M.

2014-08-01

Context. Wavelength, photon spin angular momentum (PSAM), and photon orbital angular momentum (POAM), completely describe the state of a photon or an electric field (an ensemble of photons). Wavelength relates directly to energy and linear momentum, the corresponding kinetic quantities. PSAM and POAM, themselves kinetic quantities, are colloquially known as polarization and optical vortices, respectively. Astrophysical sources emit photons that carry this information. Aims: PSAM characteristics of an electric field (intensity) are compactly described by the Jones (Stokes/Mueller) calculus. Similarly, I created calculi to represent POAM characteristics of electric fields and intensities in an astrophysical context. Adding wavelength dependence to all of these calculi is trivial. The next logical steps are to 1) form photon total angular momentum (PTAM = POAM + PSAM) calculi; 2) prove their validity using operators and expectation values; and 3) show that instrumental PSAM can affect measured POAM values for certain types of electric fields. Methods: I derive the PTAM calculi of electric fields and intensities by combining the POAM and PSAM calculi. I show how these quantities propagate from celestial sphere to image plane. I also form the PTAM operator (the sum of the POAM and PSAM operators), with and without instrumental PSAM, and calculate the corresponding expectation values. Results: Apart from the vector, matrix, dot product, and direct product symbols, the PTAM and POAM calculi appear superficially identical. I provide tables with all possible forms of PTAM calculi. I prove that PTAM expectation values are correct for instruments with and without instrumental PSAM. I also show that POAM measurements of "unfactored" PTAM electric fields passing through non-zero instrumental circular PSAM can be biased. Conclusions: The combined PTAM calculi provide insight into mathematically modeling PTAM sources and calibrating POAM- and PSAM-induced measurement errors.

Single-photon emitting diode in silicon carbide.

PubMed

Lohrmann, A; Iwamoto, N; Bodrog, Z; Castelletto, S; Ohshima, T; Karle, T J; Gali, A; Prawer, S; McCallum, J C; Johnson, B C

2015-07-23

Electrically driven single-photon emitting devices have immediate applications in quantum cryptography, quantum computation and single-photon metrology. Mature device fabrication protocols and the recent observations of single defect systems with quantum functionalities make silicon carbide an ideal material to build such devices. Here, we demonstrate the fabrication of bright single-photon emitting diodes. The electrically driven emitters display fully polarized output, superior photon statistics (with a count rate of >300 kHz) and stability in both continuous and pulsed modes, all at room temperature. The atomic origin of the single-photon source is proposed. These results provide a foundation for the large scale integration of single-photon sources into a broad range of applications, such as quantum cryptography or linear optics quantum computing.

Theoretical analysis and modeling of a photonic integrated circuit for frequency 8-tupled and 24-tupled millimeter wave signal generation.

PubMed

Hasan, Mehedi; Guemri, Rabiaa; Maldonado-Basilio, Ramón; Lucarz, Frédéric; de Bougrenet de la Tocnaye, Jean-Louis; Hall, Trevor

2014-12-15

A photonic circuit design for implementing frequency 8-tupling and 24-tupling is proposed. The front- and back-end of the circuit comprises 4×4 MMI couplers enclosing an array of four pairs of phase modulators and 2×2 MMI couplers. The proposed design for frequency multiplication requires no optical or electrical filters, the operation is not limited to carefully adjusted modulation indexes, and the drift originated from static DC bias is mitigated by making use of the intrinsic phase relations of multi-mode interference couplers. A transfer matrix approach is used to represent the main building blocks of the design and hence to describe the operation of the frequency 8-tupling and 24-tupling. The concept is theoretically developed and demonstrated by simulations. Ideal and imperfect power imbalances in the multi-mode interference couplers, as well as ideal and imperfect phases of the electric drives to the phase modulators, are analyzed.

Visualization of frequency-modulated electric field based on photonic frequency tracking in asynchronous electro-optic measurement system

NASA Astrophysics Data System (ADS)

Hisatake, Shintaro; Yamaguchi, Koki; Uchida, Hirohisa; Tojyo, Makoto; Oikawa, Yoichi; Miyaji, Kunio; Nagatsuma, Tadao

2018-04-01

We propose a new asynchronous measurement system to visualize the amplitude and phase distribution of a frequency-modulated electromagnetic wave. The system consists of three parts: a nonpolarimetric electro-optic frequency down-conversion part, a phase-noise-canceling part, and a frequency-tracking part. The photonic local oscillator signal generated by electro-optic phase modulation is controlled to track the frequency of the radio frequency (RF) signal to significantly enhance the measurable RF bandwidth. We demonstrate amplitude and phase measurement of a quasi-millimeter-wave frequency-modulated continuous-wave signal (24 GHz ± 80 MHz with a 2.5 ms period) as a proof-of-concept experiment.

Enhancing the brightness of electrically driven single-photon sources using color centers in silicon carbide

NASA Astrophysics Data System (ADS)

Khramtsov, Igor A.; Vyshnevyy, Andrey A.; Fedyanin, Dmitry Yu.

2018-03-01

Practical applications of quantum information technologies exploiting the quantum nature of light require efficient and bright true single-photon sources which operate under ambient conditions. Currently, point defects in the crystal lattice of diamond known as color centers have taken the lead in the race for the most promising quantum system for practical non-classical light sources. This work is focused on a different quantum optoelectronic material, namely a color center in silicon carbide, and reveals the physics behind the process of single-photon emission from color centers in SiC under electrical pumping. We show that color centers in silicon carbide can be far superior to any other quantum light emitter under electrical control at room temperature. Using a comprehensive theoretical approach and rigorous numerical simulations, we demonstrate that at room temperature, the photon emission rate from a p-i-n silicon carbide single-photon emitting diode can exceed 5 Gcounts/s, which is higher than what can be achieved with electrically driven color centers in diamond or epitaxial quantum dots. These findings lay the foundation for the development of practical photonic quantum devices which can be produced in a well-developed CMOS compatible process flow.

Radioisotopic energy conversion system (RECS): A new radioisotopic power cell, based on nuclear, atomic, and radiation transport principles

NASA Astrophysics Data System (ADS)

Steinfelds, Eric Victor

The topic of this thesis is the development of the Radioisotope Energy Conversion System (RECS) in a project which is utilizing analytical computational assisted design and some experimental Research in the investigation of fluorescers and effective transducers with the appropriate energy range choice for the conversion of energy. It is desirable to increase the efficiency in electrical power from the raw kinetic power available from the radioactive material within radioisotope power generators. A major step in this direction is the development and use of Radioisotope Energy Conversion Systems to supplement and ideally replace Radioactive Thermal Generators (RTG). It is possible to achieve electrical conversion efficiencies exceeding 25% for RECS power devices compared to only 9 percent efficiency for RTG's. The theoretical basis with existent materials for the potential achievability of efficiencies above 25% is documented within this thesis. The fundamental RECS consists of a radioisotope radiative source (C1), a mediating fluorescent gas (C2) which readily absorbs energy from the beta particles (or alpha's) and subsequently emits blue or UV photons, photovoltaic cells (C3) to convert the blue and UV photons into electrical energy [2], and electrical circuitry (C4). Solid State inspired component (C3), due to its theoretical (and attainable) high efficiency, is a large step ahead of the RTG design concept. The radioisotope flux source produces the beta(-) particles or alpha particles. Geometrically, presently, we prefer to have the ambient fluorescent gas surround the radioisotope flux source. Our fluorescer shall be a gas such as Krypton. Our specifically wide band-gap photovoltaic cells shall have gap energies which are slightly less than that of UV photons produced by the fluorescing gas. Diamond and Aluminum Nitride sample materials are good potential choices for photovoltaic cells, as is explained here in. Out of the material examples discussed, the highest electric power to mass ratio is found to be readily attainable with strontium-90 as the radiative source. Krypton-85 is indisputably the most efficient in RECS devices. In the conclusion in chapter VI, suggestions are given on acceptable ways of containing krypton-85 and providing sufficient shielding on deep space probes destined to use krypton-85 powered 'batteries'.

Dynamically tunable interface states in 1D graphene-embedded photonic crystal heterostructure

NASA Astrophysics Data System (ADS)

Huang, Zhao; Li, Shuaifeng; Liu, Xin; Zhao, Degang; Ye, Lei; Zhu, Xuefeng; Zang, Jianfeng

2018-03-01

Optical interface states exhibit promising applications in nonlinear photonics, low-threshold lasing, and surface-wave assisted sensing. However, the further application of interface states in configurable optics is hindered by their limited tunability. Here, we demonstrate a new approach to generate dynamically tunable and angle-resolved interface states using graphene-embedded photonic crystal (GPC) heterostructure device. By combining the GPC structure design with in situ electric doping of graphene, a continuously tunable interface state can be obtained and its tuning range is as wide as the full bandgap. Moreover, the exhibited tunable interface states offer a possibility to study the correspondence between space and time characteristics of light, which is beyond normal incident conditions. Our strategy provides a new way to design configurable devices with tunable optical states for various advanced optical applications such as beam splitter and dynamically tunable laser.

Photonic band gap spectra in Octonacci metamaterial quasicrystals

NASA Astrophysics Data System (ADS)

Brandão, E. R.; Vasconcelos, M. S.; Albuquerque, E. L.; Fulco, U. L.

2017-02-01

In this work we study theoretically the photonic band gap spectra for a one-dimensional quasicrystal made up of SiO2 (layer A) and a metamaterial (layer B) organized following the Octonacci sequence, where its nth-stage Sn is given by the inflation rule Sn =Sn - 1Sn - 2Sn - 1 for n ≥ 3 , with initial conditions S1 = A and S2 = B . The metamaterial is characterized by a frequency dependent electric permittivity ε(ω) and magnetic permeability μ(ω) . The polariton dispersion relation is obtained analytically by employing a theoretical calculation based on a transfer-matrix approach. A quantitative analysis of the spectra is then discussed, stressing the distribution of the allowed photonic band widths for high generations of the Octonacci structure, which depict a self-similar scaling property behavior, with a power law depending on the common in-plane wavevector kx .

Electrically driven polarized single-photon emission from an InGaN quantum dot in a GaN nanowire.

PubMed

Deshpande, Saniya; Heo, Junseok; Das, Ayan; Bhattacharya, Pallab

2013-01-01

In a classical light source, such as a laser, the photon number follows a Poissonian distribution. For quantum information processing and metrology applications, a non-classical emitter of single photons is required. A single quantum dot is an ideal source of single photons and such single-photon sources in the visible spectral range have been demonstrated with III-nitride and II-VI-based single quantum dots. It has been suggested that short-wavelength blue single-photon emitters would be useful for free-space quantum cryptography, with the availability of high-speed single-photon detectors in this spectral region. Here we demonstrate blue single-photon emission with electrical injection from an In0.25Ga0.75N quantum dot in a single nanowire. The emitted single photons are linearly polarized along the c axis of the nanowire with a degree of linear polarization of ~70%.

OSA Trends in Optics and Photonics Series. Volume 13: Ultrafast Electronics and Optoelectronics

DTIC Science & Technology

1997-01-01

David DiGiovanni, Uziel Koren, and Kevin Dreyer Multiwavelength , 10 GHz Picosecond Pulse Generation from a Single-Stripe Semiconductor Traveling...community. The change in slope in the experimental results that led to more rapid progress was due to the invention of an experimental trick which...feed-forward channel equalization for chirped pulse wavelength division multiplexing," Electr. Lett., vol. 33, p. 10-11,(1997). Multiwavelength

Background-free millimeter-wave ultra-wideband signal generation based on a dual-parallel Mach-Zehnder modulator.

PubMed

Zhang, Fangzheng; Pan, Shilong

2013-11-04

A novel scheme for photonic generation of a millimeter-wave ultra-wideband (MMW-UWB) signal is proposed and experimentally demonstrated based on a dual-parallel Mach-Zehnder modulator (DPMZM). In the proposed scheme, a single-frequency radio frequency (RF) signal is applied to one sub-MZM of the DPMZM to achieve optical suppressed-carrier modulation, and an electrical control pulse train is applied to the other sub-MZM biased at the minimum transmission point, to get an on/off switchable optical carrier. By filtering out the optical carrier with one of the first-order sidebands, and properly setting the amplitude of the control pulse, an MMW-UWB pulse train without the residual local oscillation is generated after photo-detection. The generated MMW-UWB signal is background-free, because the low-frequency components in the electrical spectrum are effectively suppressed. In the experiment, an MMW-UWB pulse train centered at 25 GHz with a 10-dB bandwidth of 5.5 GHz is successfully generated. The low frequency components are suppressed by 22 dB.

Electrically tunable zero dispersion wavelengths in photonic crystal fibers filled with a dual frequency addressable liquid crystal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wahle, Markus, E-mail: markus.wahle@uni-paderborn.de; Kitzerow, Heinz-Siegfried

2015-11-16

We present a liquid crystal (LC) infiltrated photonic crystal fiber, which enables the electrical tuning of the position of zero dispersion wavelengths (ZDWs). A dual frequency addressable liquid crystal is aligned perpendicular on the inclusion walls of a photonic crystal fiber, which results in an escaped radial director field. The orientation of the LC is controlled by applying an external electric field. Due to the high index of the liquid crystal the fiber guides light by the photonic band gap effect. Multiple ZDWs exist in the visible and near infrared. The positions of the ZDWs can be either blue ormore » red shifted depending on the frequency of the applied voltage.« less

Non-Geiger-Mode Single-Photon Avalanche Detector with Low Excess Noise

NASA Technical Reports Server (NTRS)

Zhao, Kai; Lo, YuHwa; Farr, William

2010-01-01

This design constitutes a self-resetting (gain quenching), room-temperature operational semiconductor single-photon-sensitive detector that is sensitive to telecommunications optical wavelengths and is scalable to large areas (millimeter diameter) with high bandwidth and efficiencies. The device can detect single photons at a 1,550-nm wavelength at a gain of 1 x 10(exp 6). Unlike conventional single photon avalanche detectors (SPADs), where gain is an extremely sensitive function to the bias voltage, the multiplication gain of this device is stable at 1 x 10(exp 6) over a wide range of bias from 30.2 to 30.9 V. Here, the multiplication gain is defined as the total number of charge carriers contained in one output pulse that is triggered by the absorption of a single photon. The statistics of magnitude of output signals also shows that the device has a very narrow pulse height distribution, which demonstrates a greatly suppressed gain fluctuation. From the histograms of both pulse height and pulse charge, the equivalent gain variance (excess noise) is between 1.001 and 1.007 at a gain of 1 x 10(exp 6). With these advantages, the device holds promise to function as a PMT-like photon counter at a 1,550- nm wavelength. The epitaxial layer structure of the device allows photons to be absorbed in the InGaAs layer, generating electron/hole (e-h) pairs. Driven by an electrical field in InGaAs, electrons are collected at the anode while holes reach the multiplication region (InAlAs p-i-n structure) and trigger the avalanche process. As a result, a large number of e-h pairs are created, and the holes move toward the cathode. Holes created by the avalanche process gain large kinetic energy through the electric field, and are considered hot. These hot holes are cooled as they travel across a p -InAlAs low field region, and are eventually blocked by energy barriers formed by the InGaAsP/ InAlAs heterojunctions. The composition of the InGaAsP alloy was chosen to have an 80 meV valance band offset with InAlAs, which is high enough to hinder the transport of the already cooled holes. Being stopped by the energy barrier, holes are accumulated at the junctions to shield the electric field, resulting in a decrease of the electric field in the multiplication region. Because the impact ionization rate is extremely sensitive to the magnitude of the electric field, the field-screening effect drastically reduces the impact ionization rate and quenches the output signals. After the avalanche pulse signal is self-quenched, the accumulated holes at the InGaAsP/ InAlAs interface escape the energy barrier through thermal excitation and tunneling and finally leave the device. The device is thus reset and ready for subsequent photon detection. This recovery time is controlled by the height of the energy barrier and the hole-cooling rate.

Solar Pumped Lasers and Their Applications

NASA Technical Reports Server (NTRS)

Lee, Ja H.

1991-01-01

Since 1980, NASA has been pursuing high power solar lasers as part of the space power beaming program. Materials in liquid, solid, and gas phases have been evaluated against the requirements for solar pumping. Two basic characteristics of solar insolation, namely its diffuse irradiance and 5800 K blackbody-like spectrum, impose rather stringent requirements for laser excitation. However, meeting these requirements is not insurmountable as solar thermal energy technology has progressed today, and taking advantage of solar pumping lasers is becoming increasingly attractive. The high density photons of concentrated solar energy have been used for mainly electric power generation and thermal processing of materials by the DOE Solar Thermal Technologies Program. However, the photons can interact with materials through many other direct kinetic paths, and applications of the concentrated photons could be extended to processes requiring photolysis, photosynthesis, and photoexcitation. The use of solar pumped lasers on Earth seems constrained by economics and sociopolitics. Therefore, prospective applications may be limited to those that require use of quantum effects and coherency of the laser in order to generate extremely high value products and services when conventional and inexpensive means are ineffective or impossible. The new applications already proposed for concentrated solar photons, such as destruction of hazardous waste, production of renewable fuel, production of fertilizer, and air/water pollution controls, may benefit from the use of inexpensive solar pumped laser matched with the photochemical kinetics of these processes.

Optical studies of current-induced magnetization switching and photonic quantum states

NASA Astrophysics Data System (ADS)

Lorenz, Virginia

2017-04-01

The ever-decreasing size of electronic components is leading to a fundamental change in the way computers operate, as at the few-nanometer scale, resistive heating and quantum mechanics prohibit efficient and stable operation. One of the most promising next-generation computing paradigms is Spintronics, which uses the spin of the electron to manipulate and store information in the form of magnetic thin films. I will present our optical studies of the fundamental mechanisms by which we can efficiently manipulate magnetization using electrical current. Although electron spin is a quantum-mechanical property, Spintronics relies on macroscopic magnetization and thus does not take advantage of quantum mechanics in the algorithms used to encode and transmit information. For the second part of my talk, I will present our work under the umbrella of new computing and communication technologies based on the quantum mechanical properties of photons. Quantum technologies often require the carriers of information, or qubits, to have specific properties. Photonic quantum states are good information carriers because they travel fast and are robust to environmental fluctuations, but characterizing and controlling photonic sources so the photons have just the right properties is still a challenge. I will describe our work towards enabling quantum-physics-based secure long-distance communication using photons.

Generating photon pairs from a silicon microring resonator using an electronic step recovery diode for pump pulse generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savanier, Marc, E-mail: msavanier@eng.ucsd.edu; Mookherjea, Shayan, E-mail: smookherjea@eng.ucsd.edu

Generation of photon pairs from compact, manufacturable, and inexpensive silicon (Si) photonic devices at room temperature may help develop practical applications of quantum photonics. An important characteristic of photon-pair generation is the two-photon joint spectral intensity, which describes the frequency correlations of the photon pair. Recent attempts to generate a factorizable photon-pair state suitable for heralding have used short optical pump pulses from mode-locked lasers, which are much more expensive and bigger table-top or rack-sized instruments compared with the Si microchip used for generating photon pairs, and thus dominate the cost and inhibit the miniaturization of the source. Here, wemore » generate photon pairs from an Si microring resonator by using an electronic step-recovery diode to drive an electro-optic modulator which carves the pump light from a continuous-wave laser diode into pulses of the appropriate width, thus potentially eliminating the need for optical mode-locked lasers.« less

Generating photon pairs from a silicon microring resonator using an electronic step recovery diode for pump pulse generation

NASA Astrophysics Data System (ADS)

Savanier, Marc; Mookherjea, Shayan

2016-06-01

Generation of photon pairs from compact, manufacturable, and inexpensive silicon (Si) photonic devices at room temperature may help develop practical applications of quantum photonics. An important characteristic of photon-pair generation is the two-photon joint spectral intensity, which describes the frequency correlations of the photon pair. Recent attempts to generate a factorizable photon-pair state suitable for heralding have used short optical pump pulses from mode-locked lasers, which are much more expensive and bigger table-top or rack-sized instruments compared with the Si microchip used for generating photon pairs, and thus dominate the cost and inhibit the miniaturization of the source. Here, we generate photon pairs from an Si microring resonator by using an electronic step-recovery diode to drive an electro-optic modulator which carves the pump light from a continuous-wave laser diode into pulses of the appropriate width, thus potentially eliminating the need for optical mode-locked lasers.

Three-photon N00N states generated by photon subtraction from double photon pairs.

PubMed

Kim, Heonoh; Park, Hee Su; Choi, Sang-Kyung

2009-10-26

We describe an experimental demonstration of a novel three-photon N00N state generation scheme using a single source of photons based on spontaneous parametric down-conversion (SPDC). The three-photon entangled state is generated when a photon is subtracted from a double pair of photons and detected by a heralding counter. Interference fringes measured with an emulated three-photon detector reveal the three-photon de Broglie wavelength and exhibit visibility > 70% without background subtraction.

Electrically and mechanically induced long period gratings in liquid crystal photonic bandgap fibers

NASA Astrophysics Data System (ADS)

Noordegraaf, Danny; Scolari, Lara; Lægsgaard, Jesper; Rindorf, Lars; Tanggaard Alkeskjold, Thomas

2007-06-01

We demonstrate electrically and mechanically induced long period gratings (LPGs) in a photonic crystal fiber (PCF) filled with a high-index liquid crystal. The presence of the liquid crystal changes the guiding properties of the fiber from an index guiding fiber to a photonic bandgap guiding fiber - a so called liquid crystal photonic bandgap (LCPBG) fiber. Both the strength and resonance wavelength of the gratings are highly tunable. By adjusting the amplitude of the applied electric field, the grating strength can be tuned and by changing the temperature, the resonance wavelength can be tuned as well. Numerical calculations of the higher order modes of the fiber cladding are presented, allowing the resonance wavelengths to be calculated. A high polarization dependent loss of the induced gratings is also observed.

Quantum mechanics of a photon

NASA Astrophysics Data System (ADS)

Babaei, Hassan; Mostafazadeh, Ali

2017-08-01

A first-quantized free photon is a complex massless vector field A =(Aμ ) whose field strength satisfies Maxwell's equations in vacuum. We construct the Hilbert space H of the photon by endowing the vector space of the fields A in the temporal-Coulomb gauge with a positive-definite and relativistically invariant inner product. We give an explicit expression for this inner product, identify the Hamiltonian for the photon with the generator of time translations in H , determine the operators representing the momentum and the helicity of the photon, and introduce a chirality operator whose eigenfunctions correspond to fields having a definite sign of energy. We also construct a position operator for the photon whose components commute with each other and with the chirality and helicity operators. This allows for the construction of the localized states of the photon with a definite sign of energy and helicity. We derive an explicit formula for the latter and compute the corresponding electric and magnetic fields. These turn out to diverge not just at the point where the photon is localized but on a plane containing this point. We identify the axis normal to this plane with an associated symmetry axis and show that each choice of this axis specifies a particular position operator, a corresponding position basis, and a position representation of the quantum mechanics of a photon. In particular, we examine the position wave functions determined by such a position basis, elucidate their relationship with the Riemann-Silberstein and Landau-Peierls wave functions, and give an explicit formula for the probability density of the spatial localization of the photon.

Beamlike photon pairs entangled by a 2x2 fiber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lo, Hsin-Pin; Department of Electrophysics, National Chiao-Tung University, Hsinchu, 300, Taiwan; Yabushita, Atsushi

Polarization-entangled photon pairs have been widely used as a light source of quantum communication. The polarization-entangled photon pairs are generally obtained at the crossing points of the light cones that are generated from a type-II nonlinear crystal. However, it is hard to pick up the photon pairs coming out from the crossing points because of their invisible wavelength and low intensity. In our previous work, we succeeded in generating polarization-entangled photon pairs by overlapping two light paths for the photon-pair generation. The photon pairs could be entangled in all of the generated photon pairs without clipping the crossing points, evenmore » with some difficulty in its alignment to overlap the two light paths. In this paper, we have developed an optical system which generates polarization-entangled photon pairs using a beamlike photon pair, without the difficulty in alignment. The measured results show that the photon pairs generated in the system are entangled in their polarizations.« less

Novel Nuclear Powered Photocatalytic Energy Conversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

White,John R.; Kinsmen,Douglas; Regan,Thomas M.

2005-08-29

The University of Massachusetts Lowell Radiation Laboratory (UMLRL) is involved in a comprehensive project to investigate a unique radiation sensing and energy conversion technology with applications for in-situ monitoring of spent nuclear fuel (SNF) during cask transport and storage. The technology makes use of the gamma photons emitted from the SNF as an inherent power source for driving a GPS-class transceiver that has the ability to verify the position and contents of the SNF cask. The power conversion process, which converts the gamma photon energy into electrical power, is based on a variation of the successful dye-sensitized solar cell (DSSC)more » design developed by Konarka Technologies, Inc. (KTI). In particular, the focus of the current research is to make direct use of the high-energy gamma photons emitted from SNF, coupled with a scintillator material to convert some of the incident gamma photons into photons having wavelengths within the visible region of the electromagnetic spectrum. The high-energy gammas from the SNF will generate some power directly via Compton scattering and the photoelectric effect, and the generated visible photons output from the scintillator material can also be converted to electrical power in a manner similar to that of a standard solar cell. Upon successful implementation of an energy conversion device based on this new gammavoltaic principle, this inherent power source could then be utilized within SNF storage casks to drive a tamper-proof, low-power, electronic detection/security monitoring system for the spent fuel. The current project has addressed several aspects associated with this new energy conversion concept, including the development of a base conceptual design for an inherent gamma-induced power conversion unit for SNF monitoring, the characterization of the radiation environment that can be expected within a typical SNF storage system, the initial evaluation of Konarka's base solar cell design, the design and fabrication of a range of new cell materials and geometries at Konarka's manufacturing facilities, and the irradiation testing and evaluation of these new cell designs within the UML Radiation Laboratory. The primary focus of all this work was to establish the proof of concept of the basic gammavoltaic principle using a new class of dye-sensitized photon converter (DSPC) materials based on KTI's original DSSC design. In achieving this goal, this report clearly establishes the viability of the basic gammavoltaic energy conversion concept, yet it also identifies a set of challenges that must be met for practical implementation of this new technology.« less

Photon Shot Noise Limited Radio Frequency Electric Field Sensing Using Rydberg Atoms in Vapor Cells

NASA Astrophysics Data System (ADS)

Kumar, Santosh; Jahangiri, Akbar J.; Fan, Haoquan; Kuebler, Harald; Shaffer, James P.

2017-04-01

We report Rydberg atom-based radio frequency (RF) electrometry measurements at a sensitivity limited by probe laser photon shot noise. By utilizing the phenomena of electromagnetically induced transparency (EIT) in room temperature atomic vapor cells, Rydberg atoms can be used for absolute electric field measurements that significantly surpass conventional methods in utility, sensitivity and accuracy. We show that by using a Mach-Zehnder interferometer with homodyne detection or using frequency modulation spectroscopy with active control of residual amplitude modulation we can achieve a RF electric field detection sensitivity of 3 μVcm-1Hz/2. The sensitivity is limited by photon shot noise on the detector used to readout the probe laser of the EIT scheme. We suggest a new multi-photon scheme that can mitigate the effect of photon shot noise. The multi-photon approach allows an increase in probe laser power without decreasing atomic coherence times that result from collisions caused by an increase in Rydberg atom excitation. The multi-photon scheme also reduces Residual Doppler broadening enabling more accurate measurements to be carried out. This work is supported by DARPA, and NRO.

Photoluminescence from oxygen-doped single-walled carbon nanotubes modified by dielectric metasurfaces

NASA Astrophysics Data System (ADS)

Ma, Xuedan; Doorn, Stephen; Htoon, Han; Brener, Igal

Oxygen dopants in single-walled carbon nanotubes (SWCNTs) have recently been discovered as a novel single photon source enabling single photon generation up to room temperature in the telecom wavelength range. While they are promising for quantum information processing, it is fundamentally important to be able to manipulate their photoluminescence (PL) properties. All-dielectric metasurfaces made from arrays of high index nanoparticles have emerged as an attractive alternative to plasmonic metasurfaces due to their support of both electric and magnetic modes. Their low intrinsic losses at optical frequencies compared to that of plasmonic nanostructures provide a novel setting for tailoring emission from quantum emitters. We couple PL from single oxygen dopants in SWCNTs to the magnetic mode of silicon metasurfaces. Aside from the observation of a PL enhancement due to the Purcell effect, more interestingly, we find that the presence of the silicon metasurfaces significantly modifies the PL polarization of the dopants, which we attribute to near-field polarization modification caused by the silicon metasurfaces. Our finding presents dielectric metasurfaces as potential building blocks of photonic circuits for controlling PL intensity and polarization of single photon sources.

Principle of the electrically induced Transient Current Technique

NASA Astrophysics Data System (ADS)

Bronuzzi, J.; Moll, M.; Bouvet, D.; Mapelli, A.; Sallese, J. M.

2018-05-01

In the field of detector development for High Energy Physics, the so-called Transient Current Technique (TCT) is used to characterize the electric field profile and the charge trapping inside silicon radiation detectors where particles or photons create electron-hole pairs in the bulk of a semiconductor device, as PiN diodes. In the standard approach, the TCT signal originates from the free carriers generated close to the surface of a silicon detector, by short pulses of light or by alpha particles. This work proposes a new principle of charge injection by means of lateral PN junctions implemented in one of the detector electrodes, called the electrical TCT (el-TCT). This technique is fully compatible with CMOS technology and therefore opens new perspectives for assessment of radiation detectors performances.

Imaging of pure spin-valley diffusion current in WS2-WSe2 heterostructures.

PubMed

Jin, Chenhao; Kim, Jonghwan; Utama, M Iqbal Bakti; Regan, Emma C; Kleemann, Hans; Cai, Hui; Shen, Yuxia; Shinner, Matthew James; Sengupta, Arjun; Watanabe, Kenji; Taniguchi, Takashi; Tongay, Sefaattin; Zettl, Alex; Wang, Feng

2018-05-25

Transition metal dichalcogenide (TMDC) materials are promising for spintronic and valleytronic applications because valley-polarized excitations can be generated and manipulated with circularly polarized photons and the valley and spin degrees of freedom are locked by strong spin-orbital interactions. In this study we demonstrate efficient generation of a pure and locked spin-valley diffusion current in tungsten disulfide (WS 2 )-tungsten diselenide (WSe 2 ) heterostructures without any driving electric field. We imaged the propagation of valley current in real time and space by pump-probe spectroscopy. The valley current in the heterostructures can live for more than 20 microseconds and propagate over 20 micrometers; both the lifetime and the diffusion length can be controlled through electrostatic gating. The high-efficiency and electric-field-free generation of a locked spin-valley current in TMDC heterostructures holds promise for applications in spin and valley devices. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Electric field induced structural colour tuning of a silver/titanium dioxide nanoparticle one-dimensional photonic crystal

PubMed Central

Aluicio-Sarduy, Eduardo; Callegari, Simone; Figueroa del Valle, Diana Gisell; Desii, Andrea; Kriegel, Ilka

2016-01-01

Summary An electric field is employed for the active tuning of the structural colour in photonic crystals, which acts as an effective external stimulus with an impact on light transmission manipulation. In this work, we demonstrate structural colour in a photonic crystal device comprised of alternating layers of silver nanoparticles and titanium dioxide nanoparticles, exhibiting spectral shifts of around 10 nm for an applied voltage of only 10 V. The accumulation of charge at the metal/dielectric interface with an applied electric field leads to an effective increase of the charges contributing to the plasma frequency in silver. This initiates a blue shift of the silver plasmon band with a simultaneous blue shift of the photonic band gap as a result of the change in the silver dielectric function (i.e. decrease of the effective refractive index). These results are the first demonstration of active colour tuning in silver/titanium dioxide nanoparticle-based photonic crystals and open the route to metal/dielectric-based photonic crystals as electro-optic switches. PMID:27826514

Electric field induced structural colour tuning of a silver/titanium dioxide nanoparticle one-dimensional photonic crystal.

PubMed

Aluicio-Sarduy, Eduardo; Callegari, Simone; Figueroa Del Valle, Diana Gisell; Desii, Andrea; Kriegel, Ilka; Scotognella, Francesco

2016-01-01

An electric field is employed for the active tuning of the structural colour in photonic crystals, which acts as an effective external stimulus with an impact on light transmission manipulation. In this work, we demonstrate structural colour in a photonic crystal device comprised of alternating layers of silver nanoparticles and titanium dioxide nanoparticles, exhibiting spectral shifts of around 10 nm for an applied voltage of only 10 V. The accumulation of charge at the metal/dielectric interface with an applied electric field leads to an effective increase of the charges contributing to the plasma frequency in silver. This initiates a blue shift of the silver plasmon band with a simultaneous blue shift of the photonic band gap as a result of the change in the silver dielectric function (i.e. decrease of the effective refractive index). These results are the first demonstration of active colour tuning in silver/titanium dioxide nanoparticle-based photonic crystals and open the route to metal/dielectric-based photonic crystals as electro-optic switches.

System for detecting special nuclear materials

DOEpatents

Jandel, Marian; Rusev, Gencho Yordanov; Taddeucci, Terry Nicholas

2015-07-14

The present disclosure includes a radiological material detector having a convertor material that emits one or more photons in response to a capture of a neutron emitted by a radiological material; a photon detector arranged around the convertor material and that produces an electrical signal in response to a receipt of a photon; and a processor connected to the photon detector, the processor configured to determine the presence of a radiological material in response to a predetermined signature of the electrical signal produced at the photon detector. One or more detectors described herein can be integrated into a detection system that is suited for use in port monitoring, treaty compliance, and radiological material management activities.

Photonics education development for electrical engineering students

NASA Astrophysics Data System (ADS)

Cao, Yang; Luo, Yuan; Liu, Yu; Hu, ZhangFang; Cai, Xuemei

2017-08-01

We describe the contents of an advanced undergraduate course on photonics at School of Electrical Engineering, Chongqing University of Posts and Telecommunications. The main goal of the course is to equip the student with the necessary theoretical and practical knowledge to participate in photonics-related industry and further graduate level study and research if they choose. The prerequisites include college-level physics and higher mathematics which a general engineering student has already had in his/her first and second year college study. Although applications of photonics are ubiquitous such as telecommunications, photonic computing, spectroscopy, military technology, and biophotonics etc. Telecommunication information system application is more emphasized in our course considering about the potential job chances for our students.

Electrical and optical 3D modelling of light-trapping single-photon avalanche diode

NASA Astrophysics Data System (ADS)

Zheng, Tianzhe; Zang, Kai; Morea, Matthew; Xue, Muyu; Lu, Ching-Ying; Jiang, Xiao; Zhang, Qiang; Kamins, Theodore I.; Harris, James S.

2018-02-01

Single-photon avalanche diodes (SPADs) have been widely used to push the frontier of scientific research (e.g., quantum science and single-molecule fluorescence) and practical applications (e.g., Lidar). However, there is a typical compromise between photon detection efficiency and jitter distribution. The light-trapping SPAD has been proposed to break this trade-off by coupling the vertically incoming photons into a laterally propagating mode while maintaining a small jitter and a thin Si device layer. In this work, we provide a 3D-based optical and electrical model based on practical fabrication conditions and discuss about design parameters, which include surface texturing, photon injection position, device area, and other features.

Electrically controllable photonic molecule laser.

PubMed

Fasching, G; Deutsch, Ch; Benz, A; Andrews, A M; Klang, P; Zobl, R; Schrenk, W; Strasser, G; Ragulis, P; Tamosiūnas, V; Unterrainer, K

2009-10-26

We have studied the coherent intercavity coupling of the evanescent fields of two microdisk terahertz quantum-cascade lasers. The electrically controllable optical coupling of the single-mode operating lasers has been observed for cavity spacings up to 30 mum. The strongest coupled photonic molecule with 2 mum intercavity spacing allows to conditionally switch the optical emission by the electrical modulation of only one microdisk. The lasing threshold characteristics demonstrate the linear dependence of the gain of a quantum-cascade laser on the applied electric field.

Detecting photons in the dark region of Laguerre-Gauss beams.

PubMed

Klimov, Vasily; Bloch, Daniel; Ducloy, Martial; Rios Leite, Jose R

2009-06-08

We show that a photon detector, sensitive to the magnetic field or to the gradient of electric field, can help to characterize the quantum properties of spatially-dependent optical fields. We discuss the excitation of an atom through magnetic dipole or electric quadrupole transitions with the photons of a Bessel beam or a Laguerre-Gauss (LG) beams. These spiral beams are shown to be not true hollow beams, due to the presence of magnetic fields and gradients of electric fields on beam axis. This approach paves the way to an analysis at the quantum level of the propagating light beams having a complicated spatial structure.

Electrothermal energy conversion using electron gas volumetric change inside semiconductors

NASA Astrophysics Data System (ADS)

Yazawa, K.; Shakouri, A.

2016-07-01

We propose and analyze an electrothermal energy converter using volumetric changes in non-equilibrium electron gas inside semiconductors. The geometric concentration of electron gas under an electric field increases the effective pressure of the electrons, and then a barrier filters out cold electrons, acting like a valve. Nano- and micro-scale features enable hot electrons to arrive at the contact in a short enough time to avoid thermalization with the lattice. Key length and time scales, preliminary device geometry, and anticipated efficiency are estimated for electronic analogs of Otto and Brayton power generators and Joule-Thomson micro refrigerators on a chip. The power generators convert the energy of incident photons from the heat source to electrical current, and the refrigerator can reduce the temperature of electrons in a semiconductor device. The analytic calculations show that a large energy conversion efficiency or coefficient of performance may be possible.

Electrothermal energy conversion using electron gas volumetric change inside semiconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yazawa, K.; Shakouri, A.

2016-07-25

We propose and analyze an electrothermal energy converter using volumetric changes in non-equilibrium electron gas inside semiconductors. The geometric concentration of electron gas under an electric field increases the effective pressure of the electrons, and then a barrier filters out cold electrons, acting like a valve. Nano- and micro-scale features enable hot electrons to arrive at the contact in a short enough time to avoid thermalization with the lattice. Key length and time scales, preliminary device geometry, and anticipated efficiency are estimated for electronic analogs of Otto and Brayton power generators and Joule-Thomson micro refrigerators on a chip. The powermore » generators convert the energy of incident photons from the heat source to electrical current, and the refrigerator can reduce the temperature of electrons in a semiconductor device. The analytic calculations show that a large energy conversion efficiency or coefficient of performance may be possible.« less

Giant Linear Nonreciprocity, Zero Reflection, and Zero Band Gap in Equilibrated Space-Time-Varying Media

NASA Astrophysics Data System (ADS)

Taravati, Sajjad

2018-06-01

This article presents a class of space-time-varying media with giant linear nonreciprocity, zero space-time local reflections, and zero photonic band gap. This is achieved via equilibrium in the electric and magnetic properties of unidirectionally space-time-modulated media. The enhanced nonreciprocity is accompanied by a larger sonic regime interval which provides extra design freedom for achieving strong nonreciprocity by a weak pumping strength. We show that the width of photonic band gaps in general periodic space-time permittivity- and permeability-modulated media is proportional to the absolute difference between the electric and magnetic pumping strengths. We derive a rigorous analytical solution for investigation of wave propagation and scattering from general periodic space-time permittivity- and permeability-modulated media. In contrast with weak photonic transitions, from the excited mode to its two adjacent modes, in conventional space-time permittivity-modulated media, in an equilibrated space-time-varying medium, strong photonic transitions occur from the excited mode to its four adjacent modes. We study the enhanced nonreciprocity and zero band gap in equilibrated space-time-modulated media by analysis of their dispersion diagrams. In contrast to conventional space-time permittivity-modulated media, equilibrated space-time media exhibit different phase and group velocities for forward and backward harmonics. Furthermore, the numerical simulation scheme of general space-time permittivity- and permeability-modulated media is presented, which is based on the finite-difference time-domain technique. Our analytical and numerical results provide insights into general space-time refractive-index-modulated media, paving the way toward optimal isolators, nonreciprocal integrated systems, and subharmonic frequency generators.

MOS Circuitry Would Detect Low-Energy Charged Particles

NASA Technical Reports Server (NTRS)

Sinha, Mahadeva; Wadsworth, Mark

2003-01-01

Metal oxide semiconductor (MOS) circuits for measuring spatially varying intensities of beams of low-energy charged particles have been developed. These circuits are intended especially for use in measuring fluxes of ions with spatial resolution along the focal planes of mass spectrometers. Unlike prior mass spectrometer focal-plane detectors, these MOS circuits would not be based on ion-induced generation of electrons, and photons; instead, they would be based on direct detection of the electric charges of the ions. Hence, there would be no need for microchannel plates (for ion-to-electron conversion), phosphors (for electron-to-photon conversion), and photodetectors (for final detection) -- components that degrade spatial resolution and contribute to complexity and size. The developmental circuits are based on linear arrays of charge-coupled devices (CCDs) with associated readout circuitry (see figure). They resemble linear CCD photodetector arrays, except that instead of a photodetector, each pixel contains a capacitive charge sensor. The capacitor in each sensor comprises two electrodes (typically made of aluminum) separated by a layer of insulating material. The exposed electrode captures ions and accumulates their electric charges during signal-integration periods.

Photon pair generation with tailored frequency correlations in graded-index multimode fibers.

PubMed

Pourbeyram, Hamed; Mafi, Arash

2018-05-01

We study theoretically the generation of photon pairs with controlled spectral correlations via the four-wave mixing process in graded-index multimode optical fibers (GIMFs). We show that the quantum correlations of the generated photons in GIMFs can be preserved over a wide spectral range for a tunable pump source. Therefore, GIMFs can be utilized as quantum-state-preserving tunable sources of photons. In particular, we have shown that it is possible to generate factorable two-photon states, which allow for heralding of pure-state single photons without the need for narrowband spectral post filtering. We also elaborate on the possibility of simultaneously generating correlated and uncorrelated photon pairs in the same optical fiber.

Second NASA Conference on Laser Energy Conversion

NASA Technical Reports Server (NTRS)

Billman, K. W. (Editor)

1976-01-01

The possible transmission of high power laser beams over long distances and their conversion to thrust, electricity, or other useful forms of energy is considered. Specific topics discussed include: laser induced chemistry; developments in photovoltaics, including modification of the Schottky barrier devices and generation of high voltage emf'sby laser radiation of piezoelectric ceramics; the thermo electronic laser energy converter and the laser plasmadynamics converters; harmonic conversion of infrared laser radiation in molecular gases; and photon engines.

Absolute atomic oxygen density measurements for nanosecond-pulsed atmospheric-pressure plasma jets using two-photon absorption laser-induced fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Jiang, C.; Carter, C.

2014-12-01

Nanosecond-pulsed plasma jets that are generated under ambient air conditions and free from confinement of electrodes have become of great interest in recent years due to their promising applications in medicine and dentistry. Reactive oxygen species that are generated by nanosecond-pulsed, room-temperature non-equilibrium He-O2 plasma jets among others are believed to play an important role during the bactericidal or sterilization processes. We report here absolute measurements of atomic oxygen density in a 1 mm-diameter He/(1%)O2 plasma jet at atmospheric pressure using two-photon absorption laser-induced fluorescence spectroscopy. Oxygen number density on the order of 1013 cm-3 was obtained in a 150 ns, 6 kV single-pulsed plasma jet for an axial distance up to 5 mm above the device nozzle. Temporally resolved O density measurements showed that there are two maxima, separated in time by 60-70 µs, and a total pulse duration of 260-300 µs. Electrostatic modeling indicated that there are high-electric-field regions near the nozzle exit that may be responsible for the observed temporal behavior of the O production. Both the field-distribution-based estimation of the time interval for the O number density profile and a pulse-energy-dependence study confirmed that electric-field-dependent, direct and indirect electron-induced processes play important roles for O production.

49.6 Gb/s direct detection DMT transmission over 40 km single mode fibre using an electrically packaged silicon photonic modulator.

PubMed

Lacava, C; Cardea, I; Demirtzioglou, I; Khoja, A E; Ke, Li; Thomson, D J; Ruan, X; Zhang, F; Reed, G T; Richardson, D J; Petropoulos, P

2017-11-27

We present the characterization of a silicon Mach-Zehnder modulator with electrical packaging and show that it exhibits a large third-order intermodulation spurious-free dynamic range (> 100 dB Hz 2/3 ). This characteristic renders the modulator particularly suitable for the generation of high spectral efficiency discrete multi-tone signals and we experimentally demonstrate a single-channel, direct detection transmission system operating at 49.6 Gb/s, exhibiting a baseband spectral efficiency of 5 b/s/Hz. Successful transmission is demonstrated over various lengths of single mode fibre up to 40 km, without the need of any amplification or dispersion compensation.

Fabrication of nanofibers reinforced polymer microstructures using femtosecond laser material processing

NASA Astrophysics Data System (ADS)

Alubaidy, Mohammed-Amin

A new method has been introduced for the formation of microfeatures made of nanofibers reinforced polymer, using femtosecond laser material processing. The Femtosecond laser is used for the generation of three-dimensional interweaved nanofibers and the construction of microfeatures, like microchannels and voxels, through multi photon polymerization of nanofiber dispersed polymer resin. A new phenomenon of multiphoton polymerization induced by dual wavelength irradiation was reported for the first time. A significant improvement in the spatial resolution, compared to the two photon absorption (2PA) and the three photon absorption (3PA) processes has been achieved. Conductive polymer microstructures and magnetic polymer microstructures have been fabricated through this method. The mechanical properties of nanofiber reinforced polymer microstructures has been investigated by means of nanoindentation and the volume fraction of the generated nanofibers in the nanocomposite was calculated by using nanoindentation analysis. The results showed significant improvement in strength of the material. The electrical conductivity of the two photon polymerization (TPP) generated microfeatures was measured by a two-probe system at room temperature and the conductivity-temperature relationship was measured at a certain temperature range. The results suggest that the conductive polymer microstructure is reproducible and has a consistent conductivity-temperature relation. The magnetic strength has been characterized using Guassmeter. To demonstrate the potential application of the new fabrication method, a novel class of DNA-functionalized three-dimensional (3D), stand-free, and nanostructured electrodes were fabricated. The developed nanofibrous DNA biosensor has been characterized by cyclic voltammetry with the use of ferrocyanide as an electrochemical redox indicator. Results showed that the probe--target recognition has been improved. This research demonstrated that femtosecond laser materials processing is a viable tool of the construction of naomaterial- reinforced polymer microfeatures with tailored properties.

The formation of ozone and UV radiation from high-power pulsed electric discharges

NASA Astrophysics Data System (ADS)

Piskarev, I. M.; Ushkanov, V. A.; Selemir, V. D.; Spirov, G. M.; Malevannaya Pikar', I. A.; Zuimach, E. A.

2008-09-01

High-power electric discharges with pulse energies of from 0.15 J to 4 kJ were studied. The yields of UV photons and ozone were found to be approximately equal, which led us to conclude that discharge conditions under which UV radiation and ozone fully destroyed each other were possible. If ozone formation was suppressed, as when a negative volume charge was created in the spark gap region, the flux of UV photons reached 3 × 1023 photons/(cm2 s).

Systems analysis of the single photon response in invertebrate photoreceptors.

PubMed

Pumir, Alain; Graves, Jennifer; Ranganathan, Rama; Shraiman, Boris I

2008-07-29

Photoreceptors of Drosophila compound eye employ a G protein-mediated signaling pathway that transduces single photons into transient electrical responses called "quantum bumps" (QB). Although most of the molecular components of this pathway are already known, the system-level understanding of the mechanism of QB generation has remained elusive. Here, we present a quantitative model explaining how QBs emerge from stochastic nonlinear dynamics of the signaling cascade. The model shows that the cascade acts as an "integrate and fire" device and explains how photoreceptors achieve reliable responses to light although keeping low background in the dark. The model predicts the nontrivial behavior of mutants that enhance or suppress signaling and explains the dependence on external calcium, which controls feedback regulation. The results provide insight into physiological questions such as single-photon response efficiency and the adaptation of response to high incident-light level. The system-level analysis enabled by modeling phototransduction provides a foundation for understanding G protein signaling pathways less amenable to quantitative approaches.

New solar cell and clean unit system platform (CUSP) for earth and environmental science

NASA Astrophysics Data System (ADS)

Ishibashi, A.; Matsuoka, T.; Enomoto, R.; Yasutake, M.

2017-11-01

We have investigated InGaN-based multi-striped orthogonal photon-photocarrier propagation solar cell (MOP3SC) in which sunlight propagates in a direction being orthogonal to that of photocarriers generated by the sunlight. Thanks to the orthogonality, in MOP3SC, absorption of the sunlight and collection of the photocarriers can be simultaneously and independently optimized with no trade-off. Furthermore, by exploiting the degree of freedom along the photon propagation and using multi-semiconductor stripes in which the incoming photons first encounter the widest gap semiconductor, and the narrowest at last, we can convert the whole solar spectrum into electricity resulting in the high conversion efficiency. For processing MOP3SC, we have developed Clean Unit System Platform (CUSP), which turns out to be able to serve as clean versatile environment having low power-consumption and high cost-performance. CUSP is suitable not only for processing devices, but also for cross-disciplinary fields, including medical/hygienic applications.

Nanowire-based detector

DOEpatents

Berggren, Karl K; Hu, Xiaolong; Masciarelli, Daniele

2014-06-24

Systems, articles, and methods are provided related to nanowire-based detectors, which can be used for light detection in, for example, single-photon detectors. In one aspect, a variety of detectors are provided, for example one including an electrically superconductive nanowire or nanowires constructed and arranged to interact with photons to produce a detectable signal. In another aspect, fabrication methods are provided, including techniques to precisely reproduce patterns in subsequently formed layers of material using a relatively small number of fabrication steps. By precisely reproducing patterns in multiple material layers, one can form electrically insulating materials and electrically conductive materials in shapes such that incoming photons are redirected toward a nearby electrically superconductive materials (e.g., electrically superconductive nanowire(s)). For example, one or more resonance structures (e.g., comprising an electrically insulating material), which can trap electromagnetic radiation within its boundaries, can be positioned proximate the nanowire(s). The resonance structure can include, at its boundaries, electrically conductive material positioned proximate the electrically superconductive nanowire such that light that would otherwise be transmitted through the sensor is redirected toward the nanowire(s) and detected. In addition, electrically conductive material can be positioned proximate the electrically superconductive nanowire (e.g. at the aperture of the resonant structure), such that light is directed by scattering from this structure into the nanowire.

Comprehensive photonics-electronics convergent simulation and its application to high-speed electronic circuit integration on a Si/Ge photonic chip

NASA Astrophysics Data System (ADS)

Takeda, Kotaro; Honda, Kentaro; Takeya, Tsutomu; Okazaki, Kota; Hiraki, Tatsurou; Tsuchizawa, Tai; Nishi, Hidetaka; Kou, Rai; Fukuda, Hiroshi; Usui, Mitsuo; Nosaka, Hideyuki; Yamamoto, Tsuyoshi; Yamada, Koji

2015-01-01

We developed a design technique for a photonics-electronics convergence system by using an equivalent circuit of optical devices in an electrical circuit simulator. We used the transfer matrix method to calculate the response of an optical device. This method used physical parameters and dimensions of optical devices as calculation parameters to design a device in the electrical circuit simulator. It also used an intermediate frequency to express the wavelength dependence of optical devices. By using both techniques, we simulated bit error rates and eye diagrams of optical and electrical integrated circuits and calculated influences of device structure change and wavelength shift penalty.

Electrical and chemical properties of XeCl*(308 nm) exciplex lamp created by a dielectric barrier discharge

NASA Astrophysics Data System (ADS)

Baadj, S.; Harrache, Z.; Belasri, A.

2013-12-01

The aim of this work is to highlight, through numerical modeling, the chemical and the electrical characteristics of xenon chloride mixture in XeCl* (308 nm) excimer lamp created by a dielectric barrier discharge. A temporal model, based on the Xe/Cl2 mixture chemistry, the circuit and the Boltzmann equations, is constructed. The effects of operating voltage, Cl2 percentage in the Xe/Cl2 gas mixture, dielectric capacitance, as well as gas pressure on the 308-nm photon generation, under typical experimental operating conditions, have been investigated and discussed. The importance of charged and excited species, including the major electronic and ionic processes, is also demonstrated. The present calculations show clearly that the model predicts the optimal operating conditions and describes the electrical and chemical properties of the XeCl* exciplex lamp.

Characterization of anthocyanin based dye-sensitized organic solar cells (DSSC) and modifications based on bio-inspired ion mobility improvements

NASA Astrophysics Data System (ADS)

Mawyin, Jose Amador

The worldwide electrical energy consumption will increase from currently 10 terawatts to 30 terawatts by 2050. To decrease the current atmospheric CO2 would require our civilization to develop a 20 terawatts non-greenhouse emitting (renewable) electrical power generation capability. Solar photovoltaic electric power generation is thought to be a major component of proposed renewable energy-based economy. One approach to less costly, easily manufactured solar cells is the Dye-sensitized solar cells (DSSC) introduced by Greatzel and others. This dissertation describes the work focused on improving the performance of DSSC type solar cells. In particular parameters affecting dye-sensitized solar cells (DSSC) based on anthocyanin pigments extracted from California blackberries (Rubus ursinus) and bio-inspired modifications were analyzed and solar cell designs optimized. Using off-the-shelf materials DSSC were constructed and tested using a custom made solar spectrum simulator and photoelectric property characterization. This equipment facilitated the taking of automated I-V curve plots and the experimental determination of parameters such as open circuit voltage (V OC), short circuit current (JSC), fill factor (FF), etc. This equipment was used to probe the effect of various modifications such as changes in the annealing time and composition of the of the electrode counter-electrode. Solar cell optimization schemes included novel schemes such as solar spectrum manipulation to increase the percentage of the solar spectrum capable of generating power in the DSSC. Solar manipulation included light scattering and photon upconversion. Techniques examined here focused on affordable materials such as silica nanoparticles embedded inside a TiO2 matrix. Such materials were examined for controlled scattering of visible light and optimize light trapping within the matrix as well as a means to achieve photon up-energy-conversion using the Raman effect in silica nano-particles (due to a strong Raman anti-Stoke scattering probability). Finally, solutions to the mobility problem of organic photovoltaics were explored. The solutions examined here were based on the bio-inspired neural ionic conduction were nature has overcome the poor ionic mobility in solutions (D ˜ 10-5cm2/ s) to achieve amazingly fast ionic conduction using non-electric field energy gradients. Electric-permeability-graded layers with possibility to create an energy gradient that helps the diffusion DSSC electrolyte diffusion were explored in this work.

Integrated pillar scatterers for speeding up classification of cell holograms.

PubMed

Lugnan, Alessio; Dambre, Joni; Bienstman, Peter

2017-11-27

The computational power required to classify cell holograms is a major limit to the throughput of label-free cell sorting based on digital holographic microscopy. In this work, a simple integrated photonic stage comprising a collection of silica pillar scatterers is proposed as an effective nonlinear mixing interface between the light scattered by a cell and an image sensor. The light processing provided by the photonic stage allows for the use of a simple linear classifier implemented in the electric domain and applied on a limited number of pixels. A proof-of-concept of the presented machine learning technique, which is based on the extreme learning machine (ELM) paradigm, is provided by the classification results on samples generated by 2D FDTD simulations of cells in a microfluidic channel.

Electro-optofluidics: achieving dynamic control on-chip

PubMed Central

Soltani, Mohammad; Inman, James T.; Lipson, Michal; Wang, Michelle D.

2012-01-01

A vital element in integrated optofluidics is dynamic tuning and precise control of photonic devices, especially when employing electronic techniques which are challenging to utilize in an aqueous environment. We overcome this challenge by introducing a new platform in which the photonic device is controlled using electro-optical phase tuning. The phase tuning is generated by the thermo-optic effect using an on-chip electric microheater located outside the fluidic channel, and is transmitted to the optofluidic device through optical waveguides. The microheater is compact, high-speed (> 18 kHz), and consumes low power (~mW). We demonstrate dynamic optical trapping control of nanoparticles by an optofluidic resonator. This novel electro-optofluidic platform allows the realization of high throughput optofluidic devices with switching, tuning, and reconfiguration capability, and promises new directions in optofluidics. PMID:23037380

Competition between second harmonic generation and two-photon-induced luminescence in single, double and multiple ZnO nanorods.

PubMed

Dai, Jun; Zeng, Jian-Hua; Lan, Sheng; Wan, Xia; Tie, Shao-Long

2013-04-22

The nonlinear optical properties of single, double and multiple ZnO nanorods (NRs) were investigated by using a focused femtosecond (fs) laser beam. The excitation wavelength of the fs laser was intentionally chosen to be 754 nm at which the energy of two photons is slightly larger than that of the exciton ground state but smaller than the bandgap energy of ZnO. Second harmonic generation (SHG) or/and two-photon-induced luminescence (TPL) were observed and their dependences on excitation density were examined. For single ZnO NRs, only SHG was observed even at the highest excitation density we used in the experiments. The situation was changed when the joint point of two ZnO NRs perpendicular to each other was excited. In this case, TPL could be detected at low excitation densities and it increased rapidly with increasing excitation density. At the highest excitation density of ~15 MW/cm(2), the intensity of the TPL became comparable to that of the SHG. For an ensemble of ZnO NRs packed closely, a rapid increase of TPL with a slope of more than 7.0 and a gradual saturation of SHG with a slope of ~0.34 were found at high excitation densities. Consequently, the nonlinear response spectrum was eventually dominated by the TPL at high excitation densities and the SHG appeared to be very weak. We interpret this phenomenon by considering both the difference in electric field distribution and the effect of heat accumulation. It is suggested that the electric field enhancement in double and multiple NRs plays a crucial role in determining the nonlinear response of the NRs. In addition, the reduction in the bandgap energy induced by the heat accumulation effect also leads to the significant change in nonlinear response. This explanation is supported by the calculation of the electric field distribution using the discrete dipole approximation method and the simulation of temperature rise in different ZnO NRs based on the finite element method.

Active temporal multiplexing of indistinguishable heralded single photons

PubMed Central

Xiong, C.; Zhang, X.; Liu, Z.; Collins, M. J.; Mahendra, A.; Helt, L. G.; Steel, M. J.; Choi, D. -Y.; Chae, C. J.; Leong, P. H. W.; Eggleton, B. J.

2016-01-01

It is a fundamental challenge in quantum optics to deterministically generate indistinguishable single photons through non-deterministic nonlinear optical processes, due to the intrinsic coupling of single- and multi-photon-generation probabilities in these processes. Actively multiplexing photons generated in many temporal modes can decouple these probabilities, but key issues are to minimize resource requirements to allow scalability, and to ensure indistinguishability of the generated photons. Here we demonstrate the multiplexing of photons from four temporal modes solely using fibre-integrated optics and off-the-shelf electronic components. We show a 100% enhancement to the single-photon output probability without introducing additional multi-photon noise. Photon indistinguishability is confirmed by a fourfold Hong–Ou–Mandel quantum interference with a 91±16% visibility after subtracting multi-photon noise due to high pump power. Our demonstration paves the way for scalable multiplexing of many non-deterministic photon sources to a single near-deterministic source, which will be of benefit to future quantum photonic technologies. PMID:26996317

Observation of the doubly strange b-Baryon Ω b -

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jose de Jesus Hernandez Orduna

2011-02-01

This thesis reports the first experimental evidence of the doubly strange b-baryon Ω b - (ssb) following the decay channel Ω b - → J/Ψ(1S) μ +μ - Ω - Λ K - p π - in pmore » $$\\bar{p}$$ collisions at √s = 1.96 Tev. Using approximately 1.3 fb -1 of data collected with the D0 detector at the Fermilab Tevatron Collider, they observe 17.8 ± 4.9(stat) ± 0.8(syst) Ω b - signal events at 6.165 ± 0.010(stat) ± 0.013(syst) GeV/c 2 with a corresponding significance of 5.4 σ, meaning that the probability of the signal coming from a fluctuation in the background is 6.7 x 10 -8. The theoretical model we have to describe what we believe are the building blocks of nature and the interactions between them, is known as Standard Model. The Standard Model is the combination of Electroweak Theory and Quantum Chromodynamics into a single core in the attempt to include all interactions of subatomic particles except those due to gravity in a simple framework. This model has proved highly accurate in predicting certain interactions, but it does not explain all aspects of subatomic particles. For example, it cannot say how many particles there should be or what their masses are. The search goes on for a more complete theory, and in particular an unified field theory describing the strong, weak, and electromagnetic forces. Twelve elementary particles are known in the Standard Model: the Fermions. They have spin -1/2 and obey the Pauli Exclusion Principle. Fermions are divided into six Quarks: up u, down d, charm c, strange s, top t and, bottom b; and six Leptons: electron e, muon μ, ττ, electron neutrino v e, muon neutrino v μ and, τ neutrino v τ. Quarks interact via the strong force because they carry color charge, electromagnetically because of their electric charge and via the weak nuclear interaction because of the weak isospin. Quarks form color-neutral composite particles known as Hadrons which are divided in Mesons, containing a quark and an antiquark and Baryons, made up three quarks. Leptons have no color charge and can not interact via the strong force. Only three of them have electric charge, hence interact electromagnetically. The motion of non-electrically charged leptons, the neutrinos, is influenced only by the weak nuclear interaction. Every fermion have an associated antiparticle. For quarks, the antiparticle carry opposite electric charge, color charge and baryon number. For leptons, the antiparticle carry opposite electric charge and lepton number. Fermions are suitably grouped together considering their properties and three generations of them are defined. A higher generation fermion have greater mass than those in lower generations. Charged members of the first generation do not decay and form the ultimate building blocks for all the baryonic matter we know about. Charged members of higher generations have very short half lives and are found normally in high-energy environments. Non-electrically charged fermions do not decay and rarely interact with baryonic matter. The way particles interact and influence each other in the Standard Model is result from matter particles exchanging other particles, known as Force Mediating Particles. They are believed to be the reason of the existence of the forces and interactions between particles observed in the laboratory and the universe. Force mediating particles have spin 1, i.e., they are Bosons, and do not follow the Pauli Exclusion Principle. The types of force mediating particles are: the photon γ, three gauge bosons W ± and Z and, eight gluons g. Photons have no mass, the theory of Quantum Electrodynamics describe them very well and are responsible for mediation of the electromagnetic force between electrically charged particles. Gauge bosons are massive, being Z heavier than W ±. They are responsible for the mediation of the weak interactions between particles of different flavors but W ± act only on left-handed particles and right-handed antiparticles while Z with both left-handed particles and antiparticles. Due to the electric charge of W ±, they couple also to electromagnetic interactions. Photons and the three gauge bosons are grouped together and collectively mediate the electroweak interactions. Finally, gluons have no mass, the theory of Quantum Chromodynamics describe them and are responsible for the mediation of the strong interactions between particles with color charge. Having an effective color charge, gluons can interact among themselves. The Higgs Boson is the only particle in the SM without direct experimental evidence. Its detection would help in the explanation of the difference between massive bosons mediating the weak force and the massless photon mediating the electromagnetism.« less

On-chip microwave signal generation based on a silicon microring modulator.

PubMed

Shao, Haifeng; Yu, Hui; Li, Xia; Li, Yan; Jiang, Jianfei; Wei, Huan; Wang, Gencheng; Dai, Tingge; Chen, Qimei; Yang, Jianyi; Jiang, Xiaoqing

2015-07-15

A photonic-assisted microwave signal generator based on a silicon microring modulator is demonstrated. The microring cavity incorporates an embedded PN junction that enables a microwave signal to modulate the lightwave circling inside. The DC component of the modulated light is trapped in the cavity, while the high-order sideband components are able to exit the cavity and then generate microwave signals at new frequencies in a photodetector. In our proof-of-concept experiment, a 10 GHz microwave signal is converted to a 20 GHz signal in the optical domain with an electrical harmonic suppression ratio of 22 dB. An analytic model is also established to explain the operation mechanism, which agrees well with the measured data.

Electric and magnetic target polarization in quantum radar

NASA Astrophysics Data System (ADS)

Brandsema, Matthew J.; Narayanan, Ram M.; Lanzagorta, Marco

2017-05-01

In this paper, we discuss the effect that photon polarization has on the quantum radar cross section (QRCS) during the special case scenario of when the target is enveloped in either a uniform electric field or magnetic field and all of its atomic electric/magnetic dipole moments become aligned (target polarization). This target polarization causes the coupling between the photon and the matter to change and alter the scattering characteristics of the target. Most notably, it causes scattering to be very near zero at a specified angle. We also investigate the relationship between electric and magnetic types of coupling and find that the electric contribution dominates the QRCS response.

Practical photon number detection with electric field-modulated silicon avalanche photodiodes.

PubMed

Thomas, O; Yuan, Z L; Shields, A J

2012-01-24

Low-noise single-photon detection is a prerequisite for quantum information processing using photonic qubits. In particular, detectors that are able to accurately resolve the number of photons in an incident light pulse will find application in functions such as quantum teleportation and linear optics quantum computing. More generally, such a detector will allow the advantages of quantum light detection to be extended to stronger optical signals, permitting optical measurements limited only by fluctuations in the photon number of the source. Here we demonstrate a practical high-speed device, which allows the signals arising from multiple photon-induced avalanches to be precisely discriminated. We use a type of silicon avalanche photodiode in which the lateral electric field profile is strongly modulated in order to realize a spatially multiplexed detector. Clearly discerned multiphoton signals are obtained by applying sub-nanosecond voltage gates in order to restrict the detector current.

Tuneable photonic device including an array of metamaterial resonators

DOEpatents

Brener, Igal; Wanke, Michael; Benz, Alexander

2017-03-14

A photonic apparatus includes a metamaterial resonator array overlying and electromagnetically coupled to a vertically stacked plurality of quantum wells defined in a semiconductor body. An arrangement of electrical contact layers is provided for facilitating the application of a bias voltage across the quantum well stack. Those portions of the semiconductor body that lie between the electrical contact layers are conformed to provide an electrically conductive path between the contact layers and through the quantum well stack.

Evidence of Light-by-Light Scattering with Real Photons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boege, J.

2003-12-19

In a new experiment at the Stanford Linear Accelerator Center, heretofore untested aspects of high field strength Quantum Electrodynamics were probed. Bunches of 46.6 GeV electrons available in the Final Focus Test Beam line were brought into collision with terawatt pulses of either 1.17 eV or 2.34 eV photons from a Nd:Glass laser system. Several physical process were investigated. This thesis describes the production of electron-positron pairs in photon-photon collisions. This is particularly interesting since it represents the generation of massive particles from massless particles. The bunch/pulse trajectories are approximately antiparallel. Due to the head-on nature of the collisions, themore » electrons see, in their rest frame, a transformed laser pulse electric field amplitude {bar {var_epsilon}}{sub 0} = 2{gamma}{var_epsilon}{sub 0}, and so a lab frame field {var_epsilon} {approx} 1.0 x 10{sup 11} V/cm corresponds to a 46.6 GeV electron rest frame field {bar {var_epsilon}}{sub 0} {approx} 1.8 x 10{sup 16} V/cm. For electric field amplitudes of this magnitude, perturbative QED is of limited validity. Multiphoton processes dominate collision results. The geometry of the experiments was such that any pairs produced came into existence in the midst of the electron/photon collision region. The electron from a produced pair was indistinguishable from the recoil electrons generated via other processes in collisions. Detecting the positron, then, was the only way to observe pair production. In data accumulated during the September 1994 Final Focus Test Beam run, positrons in excess of background were detected. Positron signals were extracted from an ensemble of data collected during electron bunch/laser pulse collisions. Calorimeter readings were used to measure the energy, and reconstruct the transverse displacement of positrons propagating downstream from the bunch/pulse collision region. Field maps of permanent magnets located downstream of the collision region but upstream of the calorimeter were used in implementing a cut of off-momentum background positrons. Effects of various cuts and the characteristics of the detected positrons are presented. Statistically significant positron production above background is reported. The rate for e{sup +} production is calculated, and the energy spectrum of the candidates is shown. The agreement of simulation results with these observations is described.« less

The physics of heterodyne detection in the far-infrared: Transition from electric-field to photon-absorption detection in a simple system

NASA Technical Reports Server (NTRS)

Teich, M. C.

1980-01-01

The history of heterodyne detection is reviewed from the radiowave to the optical regions of the electromagnetic spectrum with emphasion the submillimeter/far infrared. The transition from electric field to photon absorption detection in a simple system is investigated. The response of an isolated two level detector to a coherent source of incident radiation is calculated for both heterodyne and video detection. When the processes of photon absorption and photon emission cannot be distinguished, the relative detected power at double- and sum-frequencies is found to be multiplied by a coefficient, which is less than or equal to unity, and which depends on the incident photon energy and on the effective temperature of the system.

Lux in obscuro II: photon orbits of extremal AdS black holes revisited

NASA Astrophysics Data System (ADS)

Tang, Zi-Yu; Ong, Yen Chin; Wang, Bin

2017-12-01

A large class of spherically symmetric static extremal black hole spacetimes possesses a stable null photon sphere on their horizons. For the extremal Kerr-Newman family, the photon sphere only really coincides with the horizon in the sense clarified by Doran. The condition under which a photon orbit is stable on an asymptotically flat extremal Kerr-Newman black hole horizon has recently been clarified; it is found that a sufficiently large angular momentum destabilizes the photon orbit, whereas an electrical charge tends to stabilize it. We investigated the effect of a negative cosmological constant on this observation, and found the same behavior in the case of extremal asymptotically Kerr-Newman-AdS black holes in (3+1) -dimensions. In (2+1) -dimensions, in the presence of an electrical charge, the angular momentum never becomes large enough to destabilize the photon orbit. We comment on the instabilities of black hole spacetimes with a stable photon orbit.

Continuously tunable devices based on electrical control of dual-frequency liquid crystal filled photonic bandgap fibers

NASA Astrophysics Data System (ADS)

Scolari, Lara; Tanggaard Alkeskjold, Thomas; Riishede, Jesper; Bjarklev, Anders; Sparre Hermann, David; Anawati, Anawati; Dybendal Nielsen, Martin; Bassi, Paolo

2005-09-01

We present an electrically controlled photonic bandgap fiber device obtained by infiltrating the air holes of a photonic crystal fiber (PCF) with a dual-frequency liquid crystal (LC) with pre-tilted molecules. Compared to previously demonstrated devices of this kind, the main new feature of this one is its continuous tunability due to the fact that the used LC does not exhibit reverse tilt domain defects and threshold effects. Furthermore, the dual-frequency features of the LC enables electrical control of the spectral position of the bandgaps towards both shorter and longer wavelengths in the same device. We investigate the dynamics of this device and demonstrate a birefringence controller based on this principle.

Electrically pumped edge-emitting photonic bandgap semiconductor laser

DOEpatents

Lin, Shawn-Yu; Zubrzycki, Walter J.

2004-01-06

A highly efficient, electrically pumped edge-emitting semiconductor laser based on a one- or two-dimensional photonic bandgap (PBG) structure is described. The laser optical cavity is formed using a pair of PBG mirrors operating in the photonic band gap regime. Transverse confinement is achieved by surrounding an active semiconductor layer of high refractive index with lower-index cladding layers. The cladding layers can be electrically insulating in the passive PBG mirror and waveguide regions with a small conducting aperture for efficient channeling of the injection pump current into the active region. The active layer can comprise a quantum well structure. The quantum well structure can be relaxed in the passive regions to provide efficient extraction of laser light from the active region.

CMOS-compatible photonic devices for single-photon generation

NASA Astrophysics Data System (ADS)

Xiong, Chunle; Bell, Bryn; Eggleton, Benjamin J.

2016-09-01

Sources of single photons are one of the key building blocks for quantum photonic technologies such as quantum secure communication and powerful quantum computing. To bring the proof-of-principle demonstration of these technologies from the laboratory to the real world, complementary metal-oxide-semiconductor (CMOS)-compatible photonic chips are highly desirable for photon generation, manipulation, processing and even detection because of their compactness, scalability, robustness, and the potential for integration with electronics. In this paper, we review the development of photonic devices made from materials (e.g., silicon) and processes that are compatible with CMOS fabrication facilities for the generation of single photons.

Tuning subwavelength-structured focus in the hyperbolic metamaterials

NASA Astrophysics Data System (ADS)

Pan, Rong; Tang, Zhixiang; Pan, Jin; Peng, Runwu

2016-10-01

In this paper, we have systematically investigated light propagating in the hyperbolic metamaterials (HMMs) covered by a subwavelength grating. Based on the equal-frequency contour analyses, light in the HMM is predicted to propagate along a defined direction because of its hyperbolic dispersion, which is similar to the self-collimating effects in photonic crystals. By using the finite-difference time-domain, numerical simulations demonstrate a subwavelength bright spot at the intersection of the adjacent directional beams. Different from the images in homogeneous media, the magnetic fields and electric fields at the spot are layered, especially for the electric fields Ez that is polarized to the propagating direction, i.e., the layer normal direction. Moreover, the Ez is hollow in the layer plane and is stronger than the other electric field component Ex. Therefore, the whole electric field is structured and its pattern can be tuned by the HMM's effective anisotropic electromagnetic parameters. Our results may be useful for generating subwavelength structured light.

Coherent phonon optics in a chip with an electrically controlled active device.

PubMed

Poyser, Caroline L; Akimov, Andrey V; Campion, Richard P; Kent, Anthony J

2015-02-05

Phonon optics concerns operations with high-frequency acoustic waves in solid media in a similar way to how traditional optics operates with the light beams (i.e. photons). Phonon optics experiments with coherent terahertz and sub-terahertz phonons promise a revolution in various technical applications related to high-frequency acoustics, imaging, and heat transport. Previously, phonon optics used passive methods for manipulations with propagating phonon beams that did not enable their external control. Here we fabricate a phononic chip, which includes a generator of coherent monochromatic phonons with frequency 378 GHz, a sensitive coherent phonon detector, and an active layer: a doped semiconductor superlattice, with electrical contacts, inserted into the phonon propagation path. In the experiments, we demonstrate the modulation of the coherent phonon flux by an external electrical bias applied to the active layer. Phonon optics using external control broadens the spectrum of prospective applications of phononics on the nanometer scale.

Electrical and chemical properties of XeCl*(308 nm) exciplex lamp created by a dielectric barrier discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baadj, S.; Harrache, Z., E-mail: zharrache@yahoo.com; Belasri, A.

2013-12-15

The aim of this work is to highlight, through numerical modeling, the chemical and the electrical characteristics of xenon chloride mixture in XeCl* (308 nm) excimer lamp created by a dielectric barrier discharge. A temporal model, based on the Xe/Cl{sub 2} mixture chemistry, the circuit and the Boltzmann equations, is constructed. The effects of operating voltage, Cl{sub 2} percentage in the Xe/Cl{sub 2} gas mixture, dielectric capacitance, as well as gas pressure on the 308-nm photon generation, under typical experimental operating conditions, have been investigated and discussed. The importance of charged and excited species, including the major electronic and ionicmore » processes, is also demonstrated. The present calculations show clearly that the model predicts the optimal operating conditions and describes the electrical and chemical properties of the XeCl* exciplex lamp.« less

National Photonics Skills Standard for Technicians.

ERIC Educational Resources Information Center

Center for Occupational Research and Development, Inc., Waco, TX.

This document defines "photonics" as the generation, manipulation, transport, detection, and use of light information and energy whose quantum unit is the photon. The range of applications of photonics extends from energy generation to detection to communication and information processing. Photonics is at the heart of today's…

Photonic liquid crystal fibers — a new challenge for fiber optics and liquid crystals photonics

NASA Astrophysics Data System (ADS)

Woliński, T. R.; Ertman, S.; Lesiak, P.; Domański, A. W.; Czapla, A.; Dąbrowski, R.; Nowinowski-Kruszelnicki, E.; Wójcik, J.

2006-12-01

The paper reviews and discusses the latest developments in the field of the photonic liquid crystal fibers that have occurred for the last three years in view of new challenges for both fiber optics and liquid crystal photonics. In particular, we present the latest experimental results on electrically induced birefringence in photonic liquid crystal fibers and discuss possibilities and directions of future developments.

Practical application of a bidirectional microwave photonic filter: simultaneous transmission of analog TV signals

NASA Astrophysics Data System (ADS)

Correa-Mena, Ana Gabriela; Zaldívar-Huerta, Ignacio E.; Abril García, Jose Humberto; García-Juárez, Alejandro; Vera-Marquina, Alicia

2016-10-01

A practical application of a bidirectional microwave photonic filter (MPF) to transmit simultaneous analog TV signals coded on microwave carriers is experimentally demonstrated. The frequency response of the bidirectional MPF is obtained by the interaction of an externally modulated multimode laser diode emitting at 1.55 μm associated to the free-spectral range of the optical source, the chromatic dispersion parameter of the optical fiber, as well as the length of the optical link. The filtered microwave bandpass window generated around 2 GHz is used as electrical carrier in order to simultaneously transmit TV signals of 67.25 and 61.25 MHz in both directions. The obtained signal-to-noise ratios for the transmitted signals of 67.25 and 61.25 MHz are 37.62 and 44.77 dB, respectively.

Wide field video-rate two-photon imaging by using spinning disk beam scanner

NASA Astrophysics Data System (ADS)

Maeda, Yasuhiro; Kurokawa, Kazuo; Ito, Yoko; Wada, Satoshi; Nakano, Akihiko

2018-02-01

The microscope technology with wider view field, deeper penetration depth, higher spatial resolution and higher imaging speed are required to investigate the intercellular dynamics or interactions of molecules and organs in cells or a tissue in more detail. The two-photon microscope with a near infrared (NIR) femtosecond laser is one of the technique to improve the penetration depth and spatial resolution. However, the video-rate or high-speed imaging with wide view field is difficult to perform with the conventional two-photon microscope. Because point-to-point scanning method is used in conventional one, so it's difficult to achieve video-rate imaging. In this study, we developed a two-photon microscope with spinning disk beam scanner and femtosecond NIR fiber laser with around 10 W average power for the microscope system to achieve above requirements. The laser is consisted of an oscillator based on mode-locked Yb fiber laser, a two-stage pre-amplifier, a main amplifier based on a Yb-doped photonic crystal fiber (PCF), and a pulse compressor with a pair of gratings. The laser generates a beam with maximally 10 W average power, 300 fs pulse width and 72 MHz repetition rate. And the beam incident to a spinning beam scanner (Yokogawa Electric) optimized for two-photon imaging. By using this system, we achieved to obtain the 3D images with over 1mm-penetration depth and video-rate image with 350 x 350 um view field from the root of Arabidopsis thaliana.

Observation of microwave absorption and emission from incoherent electron tunneling through a normal-metal-insulator-superconductor junction.

PubMed

Masuda, Shumpei; Tan, Kuan Y; Partanen, Matti; Lake, Russell E; Govenius, Joonas; Silveri, Matti; Grabert, Hermann; Möttönen, Mikko

2018-03-02

We experimentally study nanoscale normal-metal-insulator-superconductor junctions coupled to a superconducting microwave resonator. We observe that bias-voltage-controllable single-electron tunneling through the junctions gives rise to a direct conversion between the electrostatic energy and that of microwave photons. The measured power spectral density of the microwave radiation emitted by the resonator exceeds at high bias voltages that of an equivalent single-mode radiation source at 2.5 K although the phonon and electron reservoirs are at subkelvin temperatures. Measurements of the generated power quantitatively agree with a theoretical model in a wide range of bias voltages. Thus, we have developed a microwave source which is compatible with low-temperature electronics and offers convenient in-situ electrical control of the incoherent photon emission rate with a predetermined frequency, without relying on intrinsic voltage fluctuations of heated normal-metal components or suffering from unwanted losses in room temperature cables. Importantly, our observation of negative generated power at relatively low bias voltages provides a novel type of verification of the working principles of the recently discovered quantum-circuit refrigerator.

Effects of substrate voltage on noise characteristics and hole lifetime in SOI metal-oxide-semiconductor field-effect transistor photon detector.

PubMed

Putranto, Dedy Septono Catur; Priambodo, Purnomo Sidi; Hartanto, Djoko; Du, Wei; Satoh, Hiroaki; Ono, Atsushi; Inokawa, Hiroshi

2014-09-08

Low-frequency noise and hole lifetime in silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistors (MOSFETs) are analyzed, considering their use in photon detection based on single-hole counting. The noise becomes minimum at around the transition point between front- and back-channel operations when the substrate voltage is varied, and increases largely on both negative and positive sides of the substrate voltage showing peculiar Lorentzian (generation-recombination) noise spectra. Hole lifetime is evaluated by the analysis of drain current histogram at different substrate voltages. It is found that the peaks in the histogram corresponding to the larger number of stored holes become higher as the substrate bias becomes larger. This can be attributed to the prolonged lifetime caused by the higher electric field inside the body of SOI MOSFET. It can be concluded that, once the inversion channel is induced for detection of the photo-generated holes, the small absolute substrate bias is favorable for short lifetime and low noise, leading to high-speed operation.

Methods and apparatus for producing and storing positrons and protons

DOEpatents

Akers, Douglas W [Idaho Falls, ID

2010-07-06

Apparatus for producing and storing positrons may include a trap that defines an interior chamber therein and that contains an electric field and a magnetic field. The trap may further include a source material that includes atoms that, when activated by photon bombardment, become positron emitters to produce positrons. The trap may also include a moderator positioned adjacent the source material. A photon source is positioned adjacent the trap so that photons produced by the photon source bombard the source material to produce the positron emitters. Positrons from the positron emitters and moderated positrons from the moderator are confined within the interior chamber of the trap by the electric and magnetic fields. Apparatus for producing and storing protons are also disclosed.

Imaging fluorescent nanoparticles to probe photoinduced charging of a semiconductor-solution interface.

PubMed

Peterson, Eric M; Harris, Joel M

2013-09-24

Optically transparent semiconductors allow simultaneous control of interfacial electrical potential and spectroscopic observation of chemistry near the electrode surface. Care must be taken, however, to avoid unwanted photoexcitation-induced charging of the semiconductor electrode that could influence the results. In this work, we investigate the in situ surface charging by photoexcitation well below the band gap of an optically transparent semiconductor, indium-tin oxide (ITO) electrode. Using total-internal-reflection fluorescence microscopy, the population of ~100-nm negatively charged carboxylate-polystyrene fluorescent nanoparticles at an ITO-aqueous solution interface could be monitored in situ. At positive applied potentials (~0.7 V versus Ag/AgCl), nanoparticles accumulate reversibly in the electrical double-layer of the ITO surface, and the interfacial nanoparticle populations increase with 488-nm excitation intensity. The potential sensitivity of nanoparticle population exhibited no dependence on excitation intensity, varied from 0.1 to 10 W cm(-2), while the onset potential for particle accumulation shifted by as much as 0.3 V. This shift in surface potential appears to be due to photoexcitation-induced charging of the ITO, even though the excitation radiation photon energy, ~2.4 eV, is well below the primary band gap of ITO, >3.5 eV. A kinetic model was developed to determine the photon order of electron-hole generation relative to the electron-hole recombination. The photoexcitation process was found to be first-order in photon flux, suggesting one-photon excitation of an indirect band gap or defect sites, rather than two-photon excitation into the direct band gap. A control experiment was conducted with red-fluorescent carboxylate-polystyrene particles that were counted using 647-nm excitation, where the photon energy is below the indirect band gap or defect site energy and where the optical absorption of the film vanishes. Red illumination between 1 and 15 W cm(-2) produced no detectable shifts in the onset accumulation potential, which is consistent with the negligible optical absorption of the ITO film at this longer wavelength.

Effect of background dielectric on TE-polarized photonic bandgap of metallodielectric photonic crystals using Dirichlet-to-Neumann map method.

PubMed

Sedghi, Aliasghar; Rezaei, Behrooz

2016-11-20

Using the Dirichlet-to-Neumann map method, we have calculated the photonic band structure of two-dimensional metallodielectric photonic crystals having the square and triangular lattices of circular metal rods in a dielectric background. We have selected the transverse electric mode of electromagnetic waves, and the resulting band structures showed the existence of photonic bandgap in these structures. We theoretically study the effect of background dielectric on the photonic bandgap.

Monte Carlo code G3sim for simulation of plastic scintillator detectors with wavelength shifter fiber readout.

PubMed

Mohanty, P K; Dugad, S R; Gupta, S K

2012-04-01

A detailed description of a compact Monte Carlo simulation code "G3sim" for studying the performance of a plastic scintillator detector with wavelength shifter (WLS) fiber readout is presented. G3sim was developed for optimizing the design of new scintillator detectors used in the GRAPES-3 extensive air shower experiment. Propagation of the blue photons produced by the passage of relativistic charged particles in the scintillator is treated by incorporating the absorption, total internal, and diffuse reflections. Capture of blue photons by the WLS fibers and subsequent re-emission of longer wavelength green photons is appropriately treated. The trapping and propagation of green photons inside the WLS fiber is treated using the laws of optics for meridional and skew rays. Propagation time of each photon is taken into account for the generation of the electrical signal at the photomultiplier. A comparison of the results from G3sim with the performance of a prototype scintillator detector showed an excellent agreement between the simulated and measured properties. The simulation results can be parametrized in terms of exponential functions providing a deeper insight into the functioning of these versatile detectors. G3sim can be used to aid the design and optimize the performance of scintillator detectors prior to actual fabrication that may result in a considerable saving of time, labor, and money spent. © 2012 American Institute of Physics

If EM waves don't interfere, what causes interferograms?

NASA Astrophysics Data System (ADS)

Wellard, Stanley J.

2012-10-01

Photonics engineers involved in designing and operating Fourier transform spectrometers (FTS) often rely on Maxwell's wave equations and time-frequency (distance-wavenumber) Fourier theory as models to understand and predict the conversion of optical energy to electrical signals in their instruments. Dr. Chandrasekhar Roychoudhuri and his colleagues, at last year's conference, presented three significant concepts that might completely change the way we comprehend the interaction of light and matter and the way interference information is generated. The first concept is his non-interaction of waves (NIW) formulation, which puts in place an optical wave description that more accurately describe the properties of the finite time and spatial signals of an optical system. The second is a new description for the cosmic EM environment that recognizes that space is really filled with the ether of classical electromagnetics. The third concept is a new metaphysics or metaphotonics that compares the photon as a particle in a void against the photon as a wave in a medium to see which best explain the twelve different aspects of light. Dr. Henry Lindner presents a compelling case that photons are waves in a medium and particles (electrons, protons, atoms) are wave-structures embedded in the new ether. Discussion of the three new principles is intended to increase the curiosity of photonics engineers to investigate these changes in the nature of light and matter.

Change of electric dipole moment in charge transfer transitions of ferrocene oligomers studied by ultrafast two-photon absorption

NASA Astrophysics Data System (ADS)

Mikhaylov, Alexander; Arias, Eduardo; Moggio, Ivana; Ziolo, Ronald; Uudsemaa, Merle; Trummal, Aleksander; Cooper, Thomas; Rebane, Aleksander

2017-02-01

Change of permanent electric dipole moment in the lower-energy charge transfer transitions for a series of symmetrical and non-symmetrical ferrocene-phenyleneethynylene oligomers were studied by measuring the corresponding femtosecond two-photon absorption cross section spectra, and were determined to be in the range Δμ = 3 - 10 D. Quantum-chemical calculations of Δμ for the non-symmetrical oligomers show good quantitative agreement with the experimental results, thus validating two-photon absorption spectroscopy as a viable experimental approach to study electrostatic properties of organometallics and other charge transfer systems.

Controlling the Properties of Matter with Quantum Dots

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klimov, Victor

2017-03-22

Solar cells and photodetectors could soon be made from new types of materials based on semiconductor quantum dots, thanks to new insights based on ultrafast measurements capturing real-time photoconversion processes. Photoconversion is a process wherein the energy of a photon, or quantum of light, is converted into other forms of energy, for example, chemical or electrical. Semiconductor quantum dots are chemically synthesized crystalline nanoparticles that have been studied for more than three decades in the context of various photoconversion schemes including photovoltaics (generation of photo-electricity) and photo-catalysis (generation of “solar fuels”). The appeal of quantum dots comes from the unmatchedmore » tunability of their physical properties, which can be adjusted by controlling the size, shape and composition of the dots. At Los Alamos, the research connects to the institutional mission of solving national security challenges through scientific excellence, in this case focusing on novel physical principles for highly efficient photoconversion, charge manipulation in exploratory device structures and novel nanomaterials.« less

Photon-triggered nanowire transistors

NASA Astrophysics Data System (ADS)

Kim, Jungkil; Lee, Hoo-Cheol; Kim, Kyoung-Ho; Hwang, Min-Soo; Park, Jin-Sung; Lee, Jung Min; So, Jae-Pil; Choi, Jae-Hyuck; Kwon, Soon-Hong; Barrelet, Carl J.; Park, Hong-Gyu

2017-10-01

Photon-triggered electronic circuits have been a long-standing goal of photonics. Recent demonstrations include either all-optical transistors in which photons control other photons or phototransistors with the gate response tuned or enhanced by photons. However, only a few studies report on devices in which electronic currents are optically switched and amplified without an electrical gate. Here we show photon-triggered nanowire (NW) transistors, photon-triggered NW logic gates and a single NW photodetection system. NWs are synthesized with long crystalline silicon (CSi) segments connected by short porous silicon (PSi) segments. In a fabricated device, the electrical contacts on both ends of the NW are connected to a single PSi segment in the middle. Exposing the PSi segment to light triggers a current in the NW with a high on/off ratio of >8 × 106. A device that contains two PSi segments along the NW can be triggered using two independent optical input signals. Using localized pump lasers, we demonstrate photon-triggered logic gates including AND, OR and NAND gates. A photon-triggered NW transistor of diameter 25 nm with a single 100 nm PSi segment requires less than 300 pW of power. Furthermore, we take advantage of the high photosensitivity and fabricate a submicrometre-resolution photodetection system. Photon-triggered transistors offer a new venue towards multifunctional device applications such as programmable logic elements and ultrasensitive photodetectors.

Photon-triggered nanowire transistors.

PubMed

Kim, Jungkil; Lee, Hoo-Cheol; Kim, Kyoung-Ho; Hwang, Min-Soo; Park, Jin-Sung; Lee, Jung Min; So, Jae-Pil; Choi, Jae-Hyuck; Kwon, Soon-Hong; Barrelet, Carl J; Park, Hong-Gyu

2017-10-01

Photon-triggered electronic circuits have been a long-standing goal of photonics. Recent demonstrations include either all-optical transistors in which photons control other photons or phototransistors with the gate response tuned or enhanced by photons. However, only a few studies report on devices in which electronic currents are optically switched and amplified without an electrical gate. Here we show photon-triggered nanowire (NW) transistors, photon-triggered NW logic gates and a single NW photodetection system. NWs are synthesized with long crystalline silicon (CSi) segments connected by short porous silicon (PSi) segments. In a fabricated device, the electrical contacts on both ends of the NW are connected to a single PSi segment in the middle. Exposing the PSi segment to light triggers a current in the NW with a high on/off ratio of >8 × 10 6 . A device that contains two PSi segments along the NW can be triggered using two independent optical input signals. Using localized pump lasers, we demonstrate photon-triggered logic gates including AND, OR and NAND gates. A photon-triggered NW transistor of diameter 25 nm with a single 100 nm PSi segment requires less than 300 pW of power. Furthermore, we take advantage of the high photosensitivity and fabricate a submicrometre-resolution photodetection system. Photon-triggered transistors offer a new venue towards multifunctional device applications such as programmable logic elements and ultrasensitive photodetectors.

Dynamical Casimir effect in stochastic systems: Photon harvesting through noise

NASA Astrophysics Data System (ADS)

Román-Ancheyta, Ricardo; Ramos-Prieto, Irán; Perez-Leija, Armando; Busch, Kurt; León-Montiel, Roberto de J.

2017-09-01

We theoretically investigate the dynamical Casimir effect in a single-mode cavity endowed with a driven off-resonant mirror. We explore the dynamics of photon generation as a function of the ratio between the cavity mode and the mirror's driving frequency. Interestingly, we find that this ratio defines a threshold—which we referred to as a metal-insulator phase transition—between exponential growth and low photon production. The low photon production is due to Bloch-like oscillations that produce a strong localization of the initial vacuum state, thus preventing higher generation of photons. To break localization of the vacuum state and enhance the photon generation, we impose a dephasing mechanism, based on dynamic disorder, into the driving frequency of the mirror. Additionally, we explore the effects of finite temperature on the photon production. Concurrently, we propose a classical analog of the dynamical Casimir effect in engineered photonic lattices, where the propagation of classical light emulates the photon generation from the quantum vacuum of a single-mode tunable cavity.

Electro-optical modulator in a polymerinfiltrated silicon slotted photonic crystal waveguide heterostructure resonator.

PubMed

Wülbern, Jan Hendrik; Petrov, Alexander; Eich, Manfred

2009-01-05

We present a novel concept of a compact, ultra fast electro-optic modulator, based on photonic crystal resonator structures that can be realized in two dimensional photonic crystal slabs of silicon as core material employing a nonlinear optical polymer as infiltration and cladding material. The novel concept is to combine a photonic crystal heterostructure cavity with a slotted defect waveguide. The photonic crystal lattice can be used as a distributed electrode for the application of a modulation signal. An electrical contact is hence provided while the optical wave is kept isolated from the lossy metal electrodes. Thereby, well known disadvantages of segmented electrode designs such as excessive scattering are avoided. The optical field enhancement in the slotted region increases the nonlinear interaction with an external electric field resulting in an envisaged switching voltage of approximately 1 V at modulation speeds up to 100 GHz.

Electrically switchable organo–inorganic hybrid for a white-light laser source

PubMed Central

Huang, Jui-Chieh; Hsiao, Yu-Cheng; Lin, Yu-Ting; Lee, Chia-Rong; Lee, Wei

2016-01-01

We demonstrate a spectrally discrete white-light laser device based on a photonic bandgap hybrid, which is composed of a soft photonic crystal; i.e., a layer of dye-doped cholesteric liquid crystal (CLC), sandwiched between two imperfect but identical, inorganic multilayer photonic crystals. With a sole optical pump, a mono-, bi-, or tri-chromatic laser can be obtained and, through the soft photonic crystal regulated by an applied voltage, the hybrid possesses electrical tunability in laser wavelength. The three emitted spectral peaks originate from two bandedges of the CLC reflection band as well as one of the photonic defect modes in dual-mode lasing. Thanks to the optically bistable nature of CLC, such a white-light laser device can operate in quite an energy-saving fashion. This technique has potential to fulfill the present mainstream in the coherent white-light source. PMID:27324219

Surface/Interface Carrier-Transport Modulation for Constructing Photon-Alternative Ultraviolet Detectors Based on Self-Bending-Assembled ZnO Nanowires.

PubMed

Guo, Zhen; Zhou, Lianqun; Tang, Yuguo; Li, Lin; Zhang, Zhiqi; Yang, Hongbo; Ma, Hanbin; Nathan, Arokia; Zhao, Dongxu

2017-09-13

Surface/interface charge-carrier generation, diffusion, and recombination/transport modulation are especially important in the construction of photodetectors with high efficiency in the field of nanoscience. In the paper, a kind of ultraviolet (UV) detector is designed based on ZnO nanostructures considering photon-trapping, surface plasmonic resonance (SPR), piezophototronic effects, interface carrier-trapping/transport control, and collection. Through carefully optimized surface/interface carrier-transport modulation, a designed device with detectivity as high as 1.69 × 10 16 /1.71 × 10 16 cm·Hz 1/2 /W irradiating with 380 nm photons under ultralow bias of 0.2 V is realized by alternating nanoparticle/nanowire active layers, respectively, and the designed UV photodetectors show fast and slow recovery processes of 0.27 and 4.52 ms, respectively, which well-satisfy practical needs. Further, it is observed that UV photodetection could be performed within an alternative response by varying correlated key parameters, through efficient surface/interface carrier-transport modulation, spectrally resolved photoresponse of the detector revealing controlled detection in the UV region based on the ZnO nanomaterial, photodetection allowed or limited by varying the active layers, irradiation distance from one of the electrodes, standing states, or electric field. The detailed carrier generation, diffusion, and recombination/transport processes are well illustrated to explain charge-carrier dynamics contributing to the photoresponse behavior.

Three-dimensional hot electron photovoltaic device with vertically aligned TiO2 nanotubes.

PubMed

Goddeti, Kalyan C; Lee, Changhwan; Lee, Young Keun; Park, Jeong Young

2018-05-09

Titanium dioxide (TiO 2 ) nanotubes with vertically aligned array structures show substantial advantages in solar cells as an electron transport material that offers a large surface area where charges travel linearly along the nanotubes. Integrating this one-dimensional semiconductor material with plasmonic metals to create a three-dimensional plasmonic nanodiode can influence solar energy conversion by utilizing the generated hot electrons. Here, we devised plasmonic Au/TiO 2 and Ag/TiO 2 nanodiode architectures composed of TiO 2 nanotube arrays for enhanced photon absorption, and for the subsequent generation and capture of hot carriers. The photocurrents and incident photon to current conversion efficiencies (IPCE) were obtained as a function of photon energy for hot electron detection. We observed enhanced photocurrents and IPCE using the Ag/TiO 2 nanodiode. The strong plasmonic peaks of the Au and Ag from the IPCE clearly indicate an enhancement of the hot electron flux resulting from the presence of surface plasmons. The calculated electric fields and the corresponding absorbances of the nanodiode using finite-difference time-domain simulation methods are also in good agreement with the experimental results. These results show a unique strategy of combining a hot electron photovoltaic device with a three-dimensional architecture, which has the clear advantages of maximizing light absorption and a metal-semiconductor interface area.

Back-irradiation photonic sintering for defect-free high-conductivity metal patterns on transparent plastic

NASA Astrophysics Data System (ADS)

Kwak, Ji Hye; Chun, Su Jin; Shon, Chae-Hwa; Jung, Sunshin

2018-04-01

Photonic sintering has attracted considerable attention for printed electronics. It irradiates high-intensity light onto the front surface of metal nanoparticle patterns, which often causes defects such as delamination, cavities, and cracks in the patterns. Here, a back-irradiation photonic sintering method is developed for obtaining defect-free high-conductivity metal patterns on a transparent plastic substrate, through which high-intensity light is irradiated onto the back surface of the patterns for a few milliseconds. Ag patterns back-irradiated with ˜10.0 J cm-2 are defect-free in contrast to front-irradiated patterns and exhibited an electrical conductivity of ˜2.3 × 107 S m-1. Furthermore, real-time high-speed observation reveals that the mechanisms that generate defects in the front-irradiated patterns and prevent defects in the back-irradiated patterns are closely related to vapor trapping. In contrast to the latter, in the former, vapor is trapped and delaminates the patterns from the substrate because the front of the patterns acts as a barrier to vapor venting.

Single photon imaging and timing array sensor apparatus and method

DOEpatents

Smith, R. Clayton

2003-06-24

An apparatus and method are disclosed for generating a three-dimension image of an object or target. The apparatus is comprised of a photon source for emitting a photon at a target. The emitted photons are received by a photon receiver for receiving the photon when reflected from the target. The photon receiver determines a reflection time of the photon and further determines an arrival position of the photon on the photon receiver. An analyzer is communicatively coupled to the photon receiver, wherein the analyzer generates a three-dimensional image of the object based upon the reflection time and the arrival position.

Dual CARS and SHG image acquisition scheme that combines single central fiber and multimode fiber bundle to collect and differentiate backward and forward generated photons

PubMed Central

Weng, Sheng; Chen, Xu; Xu, Xiaoyun; Wong, Kelvin K.; Wong, Stephen T. C.

2016-01-01

In coherent anti-Stokes Raman scattering (CARS) and second harmonic generation (SHG) imaging, backward and forward generated photons exhibit different image patterns and thus capture salient intrinsic information of tissues from different perspectives. However, they are often mixed in collection using traditional image acquisition methods and thus are hard to interpret. We developed a multimodal scheme using a single central fiber and multimode fiber bundle to simultaneously collect and differentiate images formed by these two types of photons and evaluated the scheme in an endomicroscopy prototype. The ratio of these photons collected was calculated for the characterization of tissue regions with strong or weak epi-photon generation while different image patterns of these photons at different tissue depths were revealed. This scheme provides a new approach to extract and integrate information captured by backward and forward generated photons in dual CARS/SHG imaging synergistically for biomedical applications. PMID:27375938

Cavity Mediated Manipulation of Distant Spin Currents Using a Cavity-Magnon-Polariton.

PubMed

Bai, Lihui; Harder, Michael; Hyde, Paul; Zhang, Zhaohui; Hu, Can-Ming; Chen, Y P; Xiao, John Q

2017-05-26

Using electrical detection of a strongly coupled spin-photon system comprised of a microwave cavity mode and two magnetic samples, we demonstrate the long distance manipulation of spin currents. This distant control is not limited by the spin diffusion length, instead depending on the interplay between the local and global properties of the coupled system, enabling systematic spin current control over large distance scales (several centimeters in this work). This flexibility opens the door to improved spin current generation and manipulation for cavity spintronic devices.

Chiral surface waves for enhanced circular dichroism

NASA Astrophysics Data System (ADS)

Pellegrini, Giovanni; Finazzi, Marco; Celebrano, Michele; Duò, Lamberto; Biagioni, Paolo

2017-06-01

We present a novel chiral sensing platform that combines a one-dimensional photonic crystal design with a birefringent surface defect. The platform sustains simultaneous transverse electric and transverse magnetic surface modes, which are exploited to generate chiral surface waves. The present design provides homogeneous and superchiral fields of both handednesses over arbitrarily large areas in a wide spectral range, resulting in the enhancement of the circular dichroism signal by more than two orders of magnitude, thus paving the road toward the successful combination of surface-enhanced spectroscopies and electromagnetic superchirality.

Optical XOR gate

DOEpatents

Vawter, G. Allen

2013-11-12

An optical XOR gate is formed as a photonic integrated circuit (PIC) from two sets of optical waveguide devices on a substrate, with each set of the optical waveguide devices including an electroabsorption modulator electrically connected in series with a waveguide photodetector. The optical XOR gate utilizes two digital optical inputs to generate an XOR function digital optical output. The optical XOR gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.

Design of photonic crystal surface emitting lasers with indium-tin-oxide top claddings

NASA Astrophysics Data System (ADS)

Huang, Shen-Che; Hong, Kuo-Bin; Chiu, Han-Lun; Lan, Shao-Wun; Chang, Tsu-Chi; Li, Heng; Lu, Tien-Chang

2018-02-01

Electrically pumped GaAs-based photonic crystal surface emitting lasers were fabricated using a simple fabrication process by directly capping the indium-tin-oxide transparent conducting thin film as the top cladding layer upon a photonic crystal layer. Optimization of the separate-confinement heterostructures of a laser structure is crucial to improving characteristics by providing advantageous optical confinements. The turn-on voltage, series resistance, threshold current, and slope efficiency of the laser with a 100 × 100 μm2 photonic crystal area operated at room temperature were 1.3 V, 1.5 Ω, 121 mA, and 0.2 W/A, respectively. Furthermore, we demonstrated a single-lobed lasing wavelength of 928.6 nm at 200 mA and a wavelength redshift rate of 0.05 nm/K in temperature-dependent measurements. The device exhibited the maximum output power of approximately 400 mW at an injection current of 2 A; moreover, divergence angles of less than 1° for the unpolarized circular-shaped laser beam were measured at various injection currents. Overall, the low threshold current, excellent beam quality, small divergence, high output power, and high-operating-temperature (up to 343 K) of our devices indicate that they can potentially fill the requirements for next-generation light sources and optoelectronic devices.

QED effects induced harmonics generation in extreme intense laser foil interaction

NASA Astrophysics Data System (ADS)

Yu, J. Y.; Yuan, T.; Liu, W. Y.; Chen, M.; Luo, W.; Weng, S. M.; Sheng, Z. M.

2018-04-01

A new mechanism of harmonics generation (HG) induced by quantum electrodynamics (QED) effects in extreme intense laser foil interaction is found and investigated by particle-in-cell (PIC) simulations. When two laser pulses with identical intensities of 1.6× {10}24 {{W}} {{{cm}}}-2 are counter-incident on a thin foil target, harmonics emission is observed in their reflected electromagnetic waves. Such harmonics radiation is excited due to transversely oscillating electric currents coming from the vibration of QED effect generated {e}-{e}+ pairs. The effects of laser intensity and polarization were studied. By distinguishing the cascade depth of generated photons and pairs, the influence of QED cascades on HG was analyzed. Although the current HG is not an efficient way for radiation source applications, it may provide a unique way to detect the QED processes in the near future ultra-relativistic laser solid interactions.

Generation of single photons with highly tunable wave shape from a cold atomic ensemble

PubMed Central

Farrera, Pau; Heinze, Georg; Albrecht, Boris; Ho, Melvyn; Chávez, Matías; Teo, Colin; Sangouard, Nicolas; de Riedmatten, Hugues

2016-01-01

The generation of ultra-narrowband, pure and storable single photons with widely tunable wave shape is an enabling step toward hybrid quantum networks requiring interconnection of remote disparate quantum systems. It allows interaction of quantum light with several material systems, including photonic quantum memories, single trapped ions and opto-mechanical systems. Previous approaches have offered a limited tuning range of the photon duration of at most one order of magnitude. Here we report on a heralded single photon source with controllable emission time based on a cold atomic ensemble, which can generate photons with temporal durations varying over three orders of magnitude up to 10 μs without a significant change of the readout efficiency. We prove the nonclassicality of the emitted photons, show that they are emitted in a pure state, and demonstrate that ultra-long photons with nonstandard wave shape can be generated, which are ideally suited for several quantum information tasks. PMID:27886166

Multiharmonic Frequency-Chirped Transducers for Surface-Acoustic-Wave Optomechanics

NASA Astrophysics Data System (ADS)

Weiß, Matthias; Hörner, Andreas L.; Zallo, Eugenio; Atkinson, Paola; Rastelli, Armando; Schmidt, Oliver G.; Wixforth, Achim; Krenner, Hubert J.

2018-01-01

Wide-passband interdigital transducers are employed to establish a stable phase lock between a train of laser pulses emitted by a mode-locked laser and a surface acoustic wave generated electrically by the transducer. The transducer design is based on a multiharmonic split-finger architecture for the excitation of a fundamental surface acoustic wave and a discrete number of its overtones. Simply by introducing a variation of the transducer's periodicity p , a frequency chirp is added. This combination results in wide frequency bands for each harmonic. The transducer's conversion efficiency from the electrical to the acoustic domain is characterized optomechanically using single quantum dots acting as nanoscale pressure sensors. The ability to generate surface acoustic waves over a wide band of frequencies enables advanced acousto-optic spectroscopy using mode-locked lasers with fixed repetition rate. Stable phase locking between the electrically generated acoustic wave and the train of laser pulses is confirmed by performing stroboscopic spectroscopy on a single quantum dot at a frequency of 320 MHz. Finally, the dynamic spectral modulation of the quantum dot is directly monitored in the time domain combining stable phase-locked optical excitation and time-correlated single-photon counting. The demonstrated scheme will be particularly useful for the experimental implementation of surface-acoustic-wave-driven quantum gates of optically addressable qubits or collective quantum states or for multicomponent Fourier synthesis of tailored nanomechanical waveforms.

Adiabatic Nanofocusing in Hybrid Gap Plasmon Waveguides on the Silicon-on-Insulator Platform.

PubMed

Nielsen, Michael P; Lafone, Lucas; Rakovich, Aliaksandra; Sidiropoulos, Themistoklis P H; Rahmani, Mohsen; Maier, Stefan A; Oulton, Rupert F

2016-02-10

We present an experimental demonstration of a new class of hybrid gap plasmon waveguides on the silicon-on-insulator (SOI) platform. Created by the hybridization of the plasmonic mode of a gap in a thin metal sheet and the transverse-electric (TE) photonic mode of an SOI slab, this waveguide is designed for efficient adiabatic nanofocusing simply by varying the gap width. For gap widths greater than 100 nm, the mode is primarily photonic in character and propagation lengths can be many tens of micrometers. For gap widths below 100 nm, the mode becomes plasmonic in character with field confinement predominantly within the gap region and with propagation lengths of a few microns. We estimate the electric field intensity enhancement in hybrid gap plasmon waveguide tapers at 1550 nm by three-photon absorption of selectively deposited CdSe/ZnS quantum dots within the gap. Here, we show electric field intensity enhancements of up to 167 ± 26 for a 24 nm gap, proving the viability of low loss adiabatic nanofocusing on a commercially relevant photonics platform.

Photonic Sorting of Aligned, Crystalline Carbon Nanotube Textiles.

PubMed

Bulmer, John S; Gspann, Thurid S; Orozco, Francisco; Sparkes, Martin; Koerner, Hilmar; Di Bernardo, A; Niemiec, Arkadiusz; Robinson, J W A; Koziol, Krzysztof K; Elliott, James A; O'Neill, William

2017-10-11

Floating catalyst chemical vapor deposition uniquely generates aligned carbon nanotube (CNT) textiles with individual CNT lengths magnitudes longer than competing processes, though hindered by impurities and intrinsic/extrinsic defects. We present a photonic-based post-process, particularly suited for these textiles, that selectively removes defective CNTs and other carbons not forming a threshold thermal pathway. In this method, a large diameter laser beam rasters across the surface of a partly aligned CNT textile in air, suspended from its ends. This results in brilliant, localized oxidation, where remaining material is an optically transparent film comprised of few-walled CNTs with profound and unique improvement in microstructure alignment and crystallinity. Raman spectroscopy shows substantial D peak suppression while preserving radial breathing modes. This increases the undoped, specific electrical conductivity at least an order of magnitude to beyond that of single-crystal graphite. Cryogenic conductivity measurements indicate intrinsic transport enhancement, opposed to simply removing nonconductive carbons/residual catalyst.

Camera Concepts for the Advanced Gamma-Ray Imaging System (AGIS)

NASA Astrophysics Data System (ADS)

Nepomuk Otte, Adam

2009-05-01

The Advanced Gamma-Ray Imaging System (AGIS) is a concept for the next generation observatory in ground-based very high energy gamma-ray astronomy. Design goals are ten times better sensitivity, higher angular resolution, and a lower energy threshold than existing Cherenkov telescopes. Each telescope is equipped with a camera that detects and records the Cherenkov-light flashes from air showers. The camera is comprised of a pixelated focal plane of blue sensitive and fast (nanosecond) photon detectors that detect the photon signal and convert it into an electrical one. The incorporation of trigger electronics and signal digitization into the camera are under study. Given the size of AGIS, the camera must be reliable, robust, and cost effective. We are investigating several directions that include innovative technologies such as Geiger-mode avalanche-photodiodes as a possible detector and switched capacitor arrays for the digitization.

Photodetectors for the Advanced Gamma-ray Imaging System (AGIS)

NASA Astrophysics Data System (ADS)

Wagner, Robert G.; Advanced Gamma-ray Imaging System AGIS Collaboration

2010-03-01

The Advanced Gamma-Ray Imaging System (AGIS) is a concept for the next generation very high energy gamma-ray observatory. Design goals include an order of magnitude better sensitivity, better angular resolution, and a lower energy threshold than existing Cherenkov telescopes. Each telescope is equipped with a camera that detects and records the Cherenkov-light flashes from air showers. The camera is comprised of a pixelated focal plane of blue sensitive and fast (nanosecond) photon detectors that detect the photon signal and convert it into an electrical one. Given the scale of AGIS, the camera must be reliable and cost effective. The Schwarzschild-Couder optical design yields a smaller plate scale than present-day Cherenkov telescopes, enabling the use of more compact, multi-pixel devices, including multianode photomultipliers or Geiger avalanche photodiodes. We present the conceptual design of the focal plane for the camera and results from testing candidate! focal plane sensors.

Time encoded radiation imaging

DOEpatents

Marleau, Peter; Brubaker, Erik; Kiff, Scott

2014-10-21

The various technologies presented herein relate to detecting nuclear material at a large stand-off distance. An imaging system is presented which can detect nuclear material by utilizing time encoded imaging relating to maximum and minimum radiation particle counts rates. The imaging system is integrated with a data acquisition system that can utilize variations in photon pulse shape to discriminate between neutron and gamma-ray interactions. Modulation in the detected neutron count rates as a function of the angular orientation of the detector due to attenuation of neighboring detectors is utilized to reconstruct the neutron source distribution over 360 degrees around the imaging system. Neutrons (e.g., fast neutrons) and/or gamma-rays are incident upon scintillation material in the imager, the photons generated by the scintillation material are converted to electrical energy from which the respective neutrons/gamma rays can be determined and, accordingly, a direction to, and the location of, a radiation source identified.

Heterodyne mixing of millimetre electromagnetic waves and sub-THz sound in a semiconductor device

PubMed Central

Heywood, Sarah L.; Glavin, Boris A.; Beardsley, Ryan P.; Akimov, Andrey V.; Carr, Michael W.; Norman, James; Norton, Philip C.; Prime, Brian; Priestley, Nigel; Kent, Anthony J.

2016-01-01

We demonstrate heterodyne mixing of a 94 GHz millimetre wave photonic signal, supplied by a Gunn diode oscillator, with coherent acoustic waves of frequency ~100 GHz, generated by pulsed laser excitation of a semiconductor surface. The mixing takes place in a millimetre wave Schottky diode, and the intermediate frequency electrical signal is in the 1–12 GHz range. The mixing process preserves all the spectral content in the acoustic signal that falls within the intermediate frequency bandwidth. Therefore this technique may find application in high-frequency acoustic spectroscopy measurements, exploiting the nanometre wavelength of sub-THz sound. The result also points the way to exploiting acoustoelectric effects in photonic devices working at sub-THz and THz frequencies, which could provide functionalities at these frequencies, e.g. acoustic wave filtering, that are currently in widespread use at lower (GHz) frequencies. PMID:27477841

On-Shore Central Hydraulic Power Generation for Wind and Tidal Energy

NASA Technical Reports Server (NTRS)

Jones, Jack A.; Bruce, Allan; Lim, Steven; Murray, Luke; Armstrong, Richard; Kimbrall, Richard; Cook-Chenault, Kimberly; DeGennaro, Sean

2012-01-01

Tidal energy, offshore wind energy, and onshore wind energy can be converted to electricity at a central ground location by means of converting their respective energies into high-pressure hydraulic flows that are transmitted to a system of generators by high-pressure pipelines. The high-pressure flows are then efficiently converted to electricity by a central power plant, and the low-pressure outlet flow is returned. The Department of Energy (DOE) is presently supporting a project led by Sunlight Photonics to demonstrate a 15 kW tidal hydraulic power generation system in the laboratory and possibly later submerged in the ocean. All gears and submerged electronics are completely eliminated. A second portion of this DOE project involves sizing and costing a 15 MW tidal energy system for a commercial tidal energy plant. For this task, Atlantis Resources Corporation s 18-m diameter demonstrated tidal blades are rated to operate in a nominal 2.6 m/sec tidal flow to produce approximately one MW per set of tidal blades. Fifteen units would be submerged in a deep tidal area, such as in Maine s Western Passage. All would be connected to a high-pressure (20 MPa, 2900 psi) line that is 35 cm ID. The high-pressure HEPG fluid flow is transported 500-m to on-shore hydraulic generators. HEPG is an environmentally-friendly, biodegradable, watermiscible fluid. Hydraulic adaptations to ORPC s cross-flow turbines are also discussed. For 15 MW of wind energy that is onshore or offshore, a gearless, high efficiency, radial piston pump can replace each set of top-mounted gear-generators. The fluid is then pumped to a central, easily serviceable generator location. Total hydraulic/electrical efficiency is 0.81 at full rated wind or tidal velocities and increases to 0.86 at 1/3 rated velocities.

On-Shore Central Hydraulic Power Generation for Wind and Tidal Energy

NASA Technical Reports Server (NTRS)

Jones, Jack A.; Bruce, Allan; Lim, Steven; Murray, Luke; Armstrong, Richard; Kimball, Richard; Cook-Chenault, Kimberly; DeGennaro, Sean

2012-01-01

Tidal energy, offshore wind energy, and onshore wind energy can be converted to electricity at a central ground location by means of converting their respective energies into high-pressure hydraulic flows that are transmitted to a system of generators by high-pressure pipelines. The high-pressure flows are then efficiently converted to electricity by a central power plant, and the low-pressure outlet flow is returned. The Department of Energy (DOE) is presently supporting a project led by Sunlight Photonics to demonstrate a 15 kilowatt tidal hydraulic power generation system in the laboratory and possibly later submerged in the ocean. All gears and submerged electronics are completely eliminated.A second portion of this DOE project involves sizing and costing a 15 megawatt tidal energy system for a commercial tidal energy plant. For this task, Atlantis Resources Corporation's 18-m diameter demonstrated tidal blades are rated to operate in a nominal 2.6 m/sec tidal flow to produce approximately one megawatt per set of tidal blades. Fifteen units would be submerged in a deep tidal area, such as in Maine's Western Passage. All would be connected to a high-pressure (20 megapascals, 2900 pounds per square inch) line that is 35 cm ID. The high-pressure HEPG fluid flow is transported 500-m to on-shore hydraulic generators. HEPG is an environmentally-friendly, biodegradable, water-miscible fluid. Hydraulic adaptations to ORPC's cross-flow turbines are also discussed.For 15 megawatt of wind energy that is onshore or offshore, a gearless, high efficiency, radial piston pump can replace each set of top-mounted gear-generators. The fluid is then pumped to a central, easily serviceable generator location. Total hydraulic/electrical efficiency is 0.81 at full rated wind or tidal velocities and increases to 0.86 at 1/3 rated velocities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grice, Warren P; Bennink, Ryan S; Evans, Philip G

A growing number of experiments make use of multiple pairs of photons generated in the process of spontaneous parametric down-conversion. We show that entanglement in unwanted degrees of freedom can adversely affect the results of these experiments. We also discuss techniques to reduce or eliminate spectral and spatial entanglement, and we present results from two-photon polarization-entangled source with almost no entanglement in these degrees of freedom. Finally, we present two methods for the generation of four-photon polarization- entangled states. In one of these methods, four-photon can be generated without the need for intermediate two-photon entanglement.

Complementary metal-oxide semiconductor compatible source of single photons at near-visible wavelengths

NASA Astrophysics Data System (ADS)

Cernansky, Robert; Martini, Francesco; Politi, Alberto

2018-02-01

We demonstrate on chip generation of correlated pairs of photons in the near-visible spectrum using a CMOS compatible PECVD Silicon Nitride photonic device. Photons are generated via spontaneous four wave mixing enhanced by a ring resonator with high quality Q-factor of 320,000 resulting in a generation rate of 950,000 $\\frac{pairs}{mW}$. The high brightness of this source offers the opportunity to expand photonic quantum technologies over a broad wavelength range and provides a path to develop fully integrated quantum chips working at room temperature.

Two-photon sensitized recording materials for multilayer optical disk

NASA Astrophysics Data System (ADS)

Akiba, M.; Goto-Takahashi, E.; Takizawa, H.; Sasaki, T.; Mochizuki, H.; Mikami, T.; Kitahara, T.

2010-06-01

Two types of novel two-photon sensitized recording material writable at 405 nm and 522nm were developed. The fluorescent dye generation type (F-type) material consists of at least two-photon absorption dye (TPAD) and fluorescent dye precursor (FDP), which is non-fluorescent before two-photon recording and fluorescent after two-photon recording due to fluorescent dye generation. The fluorescence quench type (Q-type) material, on the other hand, consists of at least TPAD, fluorescent dye (FD) and fluorescent quencher precursor (QP), which is fluorescent before two-photon recording and the fluorescence intensity is reduced after two-photon recording at the recorded spot due to fluorescent quencher generation. Both types of material showed quadratic dependency of recording light intensity at 522 and 405 nm. A twenty-layer two-photon recording media was fabricated with the Q-type material, and two-photon recording and onephoton fluorescent signal readout was successfully conducted.

Thickness dependent optical and electrical properties of CdSe thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Purohit, A., E-mail: anuradha.purohit34@gmail.com; Chander, S.; Nehra, S. P.

2016-05-06

The effect of thickness on the optical and electrical properties of CdSe thin films is investigated in this paper. The films of thickness 445 nm, 631 nm and 810 nm were deposited on glass and ITO coated glass substrates using thermal evaporation technique. The deposited thin films were thermally annealed in air atmosphere at temperature 100°C and were subjected to UV-Vis spectrophotometer and source meter for optical and electrical analysis respectively. The absorption coefficient is observed to increase with photon energy and found maximum in higher photon energy region. The extinction coefficient and refractive index are also calculated. The electrical analysis shows thatmore » the electrical resistivity is observed to be decreased with thickness.« less

Consistent simulation of direct-photon production in hadron collisions including associated two-jet production

NASA Astrophysics Data System (ADS)

Odaka, Shigeru; Kurihara, Yoshimasa

2016-05-01

We have developed an event generator for direct-photon production in hadron collisions, including associated 2-jet production in the framework of the GR@PPA event generator. The event generator consistently combines γ + 2-jet production processes with the lowest-order γ + jet and photon-radiation (fragmentation) processes from quantum chromodynamics (QCD) 2-jet production using a subtraction method. The generated events can be fed to general-purpose event generators to facilitate the addition of hadronization and decay simulations. Using the obtained event information, we can simulate photon isolation and hadron-jet reconstruction at the particle (hadron) level. The simulation reasonably reproduces measurement data obtained at the large hadron collider (LHC) concerning not only the inclusive photon spectrum, but also the correlation between the photon and jet. The simulation implies that the contribution of the γ + 2-jet is very large, especially in low photon-pT ( ≲ 50 GeV) regions. Discrepancies observed at low pT, although marginal, may indicate the necessity for the consideration of further higher-order processes. Unambiguous particle-level definition of the photon-isolation condition for the signal events is desired to be given explicitly in future measurements.

Analysis and Design of Manycore Processor-to-DRAM Opto-Electrical Networks with Integrated Silicon Photonics

DTIC Science & Technology

2009-12-24

Networks Silicon-Photonic Clos Networks for Global On-Chip Communication Ajay Joshi* Christopher Batten? Yong-Jin Kwon! Scott Beamer! Imran Shamim ...4th edition, 2007. •A\\ [13] A Joshi, C Batten, Y Kwon, S Beamer, Imran Shamim , Krste Asanovic, and Vladimir Sto- janovic. Silicon-photonic clos

Integrated Photonic Neural Probes for Patterned Brain Stimulation

DTIC Science & Technology

2017-08-14

two -photon imaging Task 3.2: In vivo demonstration of remote optical stimulation using photonic probes and multi -site electrical recording...have patterned nine e-pixels. We can individually address each e-pixel by tuning the color of the input light to the AWG. Figure (8) shows two ...Report: Integrated Photonic Neural Probes for Patterned Brain Stimulation The views , opinions and/or findings contained in this report are those of the

Modeling the frequency-dependent detective quantum efficiency of photon-counting x-ray detectors.

PubMed

Stierstorfer, Karl

2018-01-01

To find a simple model for the frequency-dependent detective quantum efficiency (DQE) of photon-counting detectors in the low flux limit. Formula for the spatial cross-talk, the noise power spectrum and the DQE of a photon-counting detector working at a given threshold are derived. Parameters are probabilities for types of events like single counts in the central pixel, double counts in the central pixel and a neighboring pixel or single count in a neighboring pixel only. These probabilities can be derived in a simple model by extensive use of Monte Carlo techniques: The Monte Carlo x-ray propagation program MOCASSIM is used to simulate the energy deposition from the x-rays in the detector material. A simple charge cloud model using Gaussian clouds of fixed width is used for the propagation of the electric charge generated by the primary interactions. Both stages are combined in a Monte Carlo simulation randomizing the location of impact which finally produces the required probabilities. The parameters of the charge cloud model are fitted to the spectral response to a polychromatic spectrum measured with our prototype detector. Based on the Monte Carlo model, the DQE of photon-counting detectors as a function of spatial frequency is calculated for various pixel sizes, photon energies, and thresholds. The frequency-dependent DQE of a photon-counting detector in the low flux limit can be described with an equation containing only a small set of probabilities as input. Estimates for the probabilities can be derived from a simple model of the detector physics. © 2017 American Association of Physicists in Medicine.

Deterministic and robust generation of single photons from a single quantum dot with 99.5% indistinguishability using adiabatic rapid passage.

PubMed

Wei, Yu-Jia; He, Yu-Ming; Chen, Ming-Cheng; Hu, Yi-Nan; He, Yu; Wu, Dian; Schneider, Christian; Kamp, Martin; Höfling, Sven; Lu, Chao-Yang; Pan, Jian-Wei

2014-11-12

Single photons are attractive candidates of quantum bits (qubits) for quantum computation and are the best messengers in quantum networks. Future scalable, fault-tolerant photonic quantum technologies demand both stringently high levels of photon indistinguishability and generation efficiency. Here, we demonstrate deterministic and robust generation of pulsed resonance fluorescence single photons from a single semiconductor quantum dot using adiabatic rapid passage, a method robust against fluctuation of driving pulse area and dipole moments of solid-state emitters. The emitted photons are background-free, have a vanishing two-photon emission probability of 0.3% and a raw (corrected) two-photon Hong-Ou-Mandel interference visibility of 97.9% (99.5%), reaching a precision that places single photons at the threshold for fault-tolerant surface-code quantum computing. This single-photon source can be readily scaled up to multiphoton entanglement and used for quantum metrology, boson sampling, and linear optical quantum computing.

Electrically Driven Photonic Crystal Nanocavity Devices

DTIC Science & Technology

2012-01-01

material, here gallium arsenide and indium arsenide self- assembled quantum dots (QDs). QDs are preferred for the gain medium because they can have...blue points ) and 150 K (green points ). The black lines are linear fits to the above threshold output power of the lasers, which are used to find the...SHAMBAT et al.: ELECTRICALLY DRIVEN PHOTONIC CRYSTAL NANOCAVITY DEVICES 1707 Fig. 13. (a) Tilted SEM picture of a fabricated triple cavity device. The in

Toward high-energy-density, high-efficiency, and moderate-temperature chip-scale thermophotovoltaics

PubMed Central

Chan, Walker R.; Bermel, Peter; Pilawa-Podgurski, Robert C. N.; Marton, Christopher H.; Jensen, Klavs F.; Senkevich, Jay J.; Joannopoulos, John D.; Soljačić, Marin; Celanovic, Ivan

2013-01-01

The challenging problem of ultra-high-energy-density, high-efficiency, and small-scale portable power generation is addressed here using a distinctive thermophotovoltaic energy conversion mechanism and chip-based system design, which we name the microthermophotovoltaic (μTPV) generator. The approach is predicted to be capable of up to 32% efficient heat-to-electricity conversion within a millimeter-scale form factor. Although considerable technological barriers need to be overcome to reach full performance, we have performed a robust experimental demonstration that validates the theoretical framework and the key system components. Even with a much-simplified μTPV system design with theoretical efficiency prediction of 2.7%, we experimentally demonstrate 2.5% efficiency. The μTPV experimental system that was built and tested comprises a silicon propane microcombustor, an integrated high-temperature photonic crystal selective thermal emitter, four 0.55-eV GaInAsSb thermophotovoltaic diodes, and an ultra-high-efficiency maximum power-point tracking power electronics converter. The system was demonstrated to operate up to 800 °C (silicon microcombustor temperature) with an input thermal power of 13.7 W, generating 344 mW of electric power over a 1-cm2 area. PMID:23440220

Apparatus and method for heterodyne-generated two-dimensional detector array using a single element detector

DOEpatents

Strauss, Charlie E.

1997-01-01

Apparatus and method for heterodyne-generated, two-dimensional detector array using a single detector. Synthetic-array heterodyne detection, permits a single-element optical detector to behave as though it were divided into an array of separate heterodyne detector elements. A fifteen-element synthetic array has successfully been experimentally realized on a single-element detector, permitting all of the array elements to be read out continuously and in parallel from one electrical connection. A CO.sub.2 laser and a single-element HgCdTe photodiode are employed. A different heterodyne local oscillator frequency is incident upon the spatially resolvable regions of the detector surface. Thus, different regions are mapped to different heterodyne beat frequencies. One can determine where the photons were incident on the detector surface even though a single electrical connection to the detector is used. This also prevents the destructive interference that occurs when multiple speckles are imaged (similar to spatial diversity), In coherent LIDAR this permits a larger field of view. An acoustooptic modulator generates the local oscillator frequencies and can achieve adequate spatial separation of optical frequencies of the order of a megahertz apart.

Apparatus and method for heterodyne-generated two-dimensional detector array using a single element detector

DOEpatents

Strauss, C.E.

1997-11-18

Apparatus and method are disclosed for heterodyne-generated, two-dimensional detector array using a single detector. Synthetic-array heterodyne detection, permits a single-element optical detector to behave as though it were divided into an array of separate heterodyne detector elements. A fifteen-element synthetic array has successfully been experimentally realized on a single-element detector, permitting all of the array elements to be read out continuously and in parallel from one electrical connection. A CO{sub 2} laser and a single-element HgCdTe photodiode are employed. A different heterodyne local oscillator frequency is incident upon the spatially resolvable regions of the detector surface. Thus, different regions are mapped to different heterodyne beat frequencies. One can determine where the photons were incident on the detector surface even though a single electrical connection to the detector is used. This also prevents the destructive interference that occurs when multiple speckles are imaged (similar to spatial diversity), In coherent LIDAR this permits a larger field of view. An acoustooptic modulator generates the local oscillator frequencies and can achieve adequate spatial separation of optical frequencies of the order of a megahertz apart. 4 figs.

Ultra-wideband microwave photonic link based on single-sideband modulation

NASA Astrophysics Data System (ADS)

Li, Jingnan; Wang, Yunxin; Wang, Dayong; Zhou, Tao; Zhong, Xin; Xu, Jiahao; Yang, Dengcai; Rong, Lu

2017-10-01

Comparing with the conventional double-sideband (DSB) modulation in communication system, single-sideband (SSB) modulation only demands half bandwidth of DSB in transmission. Two common ways are employed to implement SSB modulation by using optical filter (OF) or electrical 90° phase shift, respectively. However, the bandwidth of above methods is limited by characteristics of current OF and electrical phase shift. To overcome this problem, an ultra-wideband microwave photonic link based on SSB modulation is proposed and demonstrated. The radio frequency (RF) signal modulates a single-drive dual-parallel Mach-Zehnder modulator, and the SSB modulation is realized by combining an electrical 90° hybrid coupler and an optical bandpass filter. The experimental results indicate that the system can achieve SSB modulation for RF signal from 2 to 40 GHz. The proposed microwave photonic link provides an ultra-wideband approach based on SSB modulation for radio-over-fiber system.

Photonic crystal active and passive device components in III-V semiconductors

NASA Astrophysics Data System (ADS)

Sabarinathan, Jayshri

Photonic crystals (PC's) are emerging as potentially important candidates in propelling the development in planar photonic integrated circuits, high capacity optical fibers and nanoscopic lasers. Photonic crystals are expected to play a role analogous to that played by crystalline semiconductors in the development of electronic circuits. What makes these photonic crystals more interesting is that introducing "defects"---a missing period or phase slip, in the PC lattice introduces defect modes that lie within the bandgap of the PC. In this investigation, both two dimensional and three dimensional photonic crystals have been fabricated and studied using III-V compound semiconductors which are presently the most useful material systems for integrating with existing optoelectronic technology. A novel single step epitaxial technique to fabricate GaAs-based 3D photonic crystals with sub-micron feature size has been developed employing MBE growth on patterned substrates, ebeam and optical lithography, and lateral wet oxidation of AlGaAs. Transmission characteristics of the fabricated 3D PCs have been measured revealing a 10dB stopband centered at 1 mum for the smallest feature sizes. Electrically injected 2D photonic crystal defect microcavities were designed and fabricated to realize low threshold vertically emitting light sources. The electroluminescent devices were fabricated with GaAs- and InP-based quantum wells heterostructures with emission wavelengths at 0.94mum and 1.55 mum respectively. The light-current, spectral, near- and far-field characteristics of these devices have been studied in detail. The processing and high-aspect ratio etch techniques were carefully developed to create the 2D PCs embedded in the electrically injected apertures. Quantum dots with emission wavelength of 1.04 mum were incorporated into electrically injected 2D PC microcavities to study the electrical and optical confinement simultaneously provided in this configuration. Weak microcavity effects were observed in the fabricated devices. Passive 2D PC's with linear defects, which act as efficient waveguides to confine and channel light even around very sharp bends, have also been investigated. A novel microfluidic sensor using 2D GaAs-based photonic crystal waveguides to detect one or more fluids on the basis of their refractive index properties have been designed, fabricated and demonstrated for the first time.

Subcycle quantum physics (Conference Presentation)

NASA Astrophysics Data System (ADS)

Leitenstorfer, Alfred

2017-02-01

A time-domain approach to quantum electrodynamics is presented, covering the entire mid-infrared and terahertz frequency ranges. Ultrabroadband electro-optic sampling with few-femtosecond laser pulses allows direct detection of the vacuum fluctuations of the electric field in free space [1,2]. Besides the Planck and electric field fundamental constants, the variance of the ground state is determined solely by the inverse of the four-dimensional space-time volume over which a measurement or physical process integrates. Therefore, we can vary the contribution of multi-terahertz vacuum fluctuations and discriminate against the trivial shot noise due to the constant flux of near-infrared probe photons. Subcycle temporal resolution based on a nonlinear phase shift provides signals from purely virtual photons for accessing the ground-state wave function without amplification to finite intensity. Recently, we have succeeded in generation and analysis of mid-infrared squeezed transients with quantum noise patterns that are time-locked to the intensity envelope of the probe pulses. We find subcycle temporal positions with a noise level distinctly below the bare vacuum which serves as a direct reference. Delay times with increased differential noise indicate generation of highly correlated quantum fields by spontaneous parametric fluorescence. Our time-domain approach offers a generalized understanding of spontaneous emission processes as a consequence of local anomalies in the co-propagating reference frame modulating the quantum vacuum, in combination with the boundary conditions set by Heisenberg's uncertainty principle. [1] C. Riek et al., Science 350, 420 (2015) [2] A. S. Moskalenko et al., Phys. Rev. Lett. 115, 263601 (2015)

Dual-function photonic integrated circuit for frequency octo-tupling or single-side-band modulation.

PubMed

Hasan, Mehedi; Maldonado-Basilio, Ramón; Hall, Trevor J

2015-06-01

A dual-function photonic integrated circuit for microwave photonic applications is proposed. The circuit consists of four linear electro-optic phase modulators connected optically in parallel within a generalized Mach-Zehnder interferometer architecture. The photonic circuit is arranged to have two separate output ports. A first port provides frequency up-conversion of a microwave signal from the electrical to the optical domain; equivalently single-side-band modulation. A second port provides tunable millimeter wave carriers by frequency octo-tupling of an appropriate amplitude RF carrier. The circuit exploits the intrinsic relative phases between the ports of multi-mode interference couplers to provide substantially all the static optical phases needed. The operation of the proposed dual-function photonic integrated circuit is verified by computer simulations. The performance of the frequency octo-tupling and up-conversion functions is analyzed in terms of the electrical signal to harmonic distortion ratio and the optical single side band to unwanted harmonics ratio, respectively.

Generation, storage, and retrieval of nonclassical states of light using atomic ensembles

NASA Astrophysics Data System (ADS)

Eisaman, Matthew D.

This thesis presents the experimental demonstration of several novel methods for generating, storing, and retrieving nonclassical states of light using atomic ensembles, and describes applications of these methods to frequency-tunable single-photon generation, single-photon memory, quantum networks, and long-distance quantum communication. We first demonstrate emission of quantum-mechanically correlated pulses of light with a time delay between the pulses that is coherently controlled by utilizing 87Rb atoms. The experiment is based on Raman scattering, which produces correlated pairs of excited atoms and photons, followed by coherent conversion of the atomic states into a different photon field after a controllable delay. We then describe experiments demonstrating a novel approach for conditionally generating nonclassical pulses of light with controllable photon numbers, propagation direction, timing, and pulse shapes. We observe nonclassical correlations in relative photon number between correlated pairs of photons, and create few-photon light pulses with sub-Poissonian photon-number statistics via conditional detection on one field of the pair. Spatio-temporal control over the pulses is obtained by exploiting long-lived coherent memory for photon states and electromagnetically induced transparency (EIT) in an optically dense atomic medium. Finally, we demonstrate the use of EIT for the controllable generation, transmission, and storage of single photons with tunable frequency, timing, and bandwidth. To this end, we study the interaction of single photons produced in a "source" ensemble of 87Rb atoms at room temperature with another "target" ensemble. This allows us to simultaneously probe the spectral and quantum statistical properties of narrow-bandwidth single-photon pulses, revealing that their quantum nature is preserved under EIT propagation and storage. We measure the time delay associated with the reduced group velocity of the single-photon pulses and report observations of their storage and retrieval. Together these experiments utilize atomic ensembles to realize a narrow-bandwidth single-photon source, single-photon memory that preserves the quantum nature of the single photons, and a primitive quantum network comprised of two atomic-ensemble quantum memories connected by a single photon in an optical fiber. Each of these experimental demonstrations represents an essential element for the realization of long-distance quantum communication.

Fabrication of micro- and nanometre-scale polymer structures in liquid crystal devices for next generation photonics applications

NASA Astrophysics Data System (ADS)

Tartan, Chloe C.; Salter, Patrick S.; Booth, Martin J.; Morris, Stephen M.; Elston, Steve J.

2016-09-01

Direct Laser Writing (DLW) by two-photon photopolymerization (TPP) enables the fabrication of micron-scale polymeric structures in soft matter systems. The technique has implications in a broad range of optics and photonics; in particular fast-switching liquid crystal (LC) modes for the development of next generation display technologies. In this paper, we report two different methodologies using our TPP-based fabrication technique. Two explicit examples are provided of voltage-dependent LC director profiles that are inherently unstable, but which appear to be promising candidates for fast-switching photonics applications. In the first instance, 1 μm-thick periodic walls of polymer network are written into a planar aligned (parallel rubbed) nematic pi-cell device containing a nematic LC-monomer mixture. The structures are fabricated when the device is electrically driven into a fast-switching nematic LC state and aberrations induced by the device substrates are corrected for by virtue of the adaptive optics elements included within the DLW setup. Optical polarizing microscopy images taken post-fabrication reveal that polymer walls oriented perpendicular to the rubbing direction promote the stability of the so-called optically compensated bend mode upon removal of the externally applied field. In the second case, polymer walls are written in a nematic LC-optically adhesive glue mixture. A polymer- LCs-polymer-slices or `POLICRYPS' template is formed by immersing the device in acetone post-fabrication to remove any remaining non-crosslinked material. Injecting the resultant series of polymer microchannels ( 1 μm-thick) with a short-pitch, chiral nematic LC mixture leads to the spontaneous alignment of a fast-switching chiral nematic mode, where the helical axis lies parallel to the glass substrates. Optimal contrast between the bright and dark states of the uniform lying helix alignment is achieved when the structures are spaced at the order of the device thickness, which was also found to be the case for the achiral system. The high resolution DLW technique limits structures to the focal spot size of the beam, 1 μm in diameter, such that the transmittance is expected to be significantly enhanced relative to other stabilization techniques. Moreover, both devices remain stable under electrical and thermal cycling.

Signatures of two-photon pulses from a quantum two-level system

NASA Astrophysics Data System (ADS)

Fischer, Kevin A.; Hanschke, Lukas; Wierzbowski, Jakob; Simmet, Tobias; Dory, Constantin; Finley, Jonathan J.; Vučković, Jelena; Müller, Kai

2017-07-01

A two-level atom can generate a strong many-body interaction with light under pulsed excitation. The best known effect is single-photon generation, where a short Gaussian laser pulse is converted into a Lorentzian single-photon wavepacket. However, recent studies suggested that scattering of intense laser fields off a two-level atom may generate oscillations in two-photon emission that come out of phase with the Rabi oscillations, as the power of the pulse increases. Here, we provide an intuitive explanation for these oscillations using a quantum trajectory approach and show how they may preferentially result in emission of two-photon pulses. Experimentally, we observe the signatures of these oscillations by measuring the bunching of photon pulses scattered off a two-level quantum system. Our theory and measurements provide insight into the re-excitation process that plagues on-demand single-photon sources while suggesting the possibility of producing new multi-photon states.

Laser-Bioplasma Interaction: The Epilepsy-Topion-Bioplasma, (the Seizure Onset Area) Upon the Action of the Optical-Fiber-Guided Multi-Ultraviolet-Photon Beams

NASA Astrophysics Data System (ADS)

Stefan, V. Alexander

2016-10-01

The ultraviolet photons may control the imbalance of sodium and potassium ions in the brain bioplasma and, consequently, may prove to be efficient in the prevention of epileptic seizures. A novel method is based on the multi-ultraviolet-photon beam interaction with the epilepsy-topion-bioplasma, (nonlinear coupling of an ultra high frequency mode to the brain beta phonons). It is hypothesized that epilepsy is a chaotic-dynamics phenomenon: small electrical changes in the epilepsy-topion-bioplasma lead, (within the 10s of milliseconds), to the onset of chaos, (seizure-excessive electrical discharge), and subsequent cascading into adjacent areas.

Generation of Single Photons and Entangled Photon Pairs from a Quantum Dot

NASA Astrophysics Data System (ADS)

Yamamoto, Y.; Pelton, M.; Santori, C.; Solomon, G. S.

2002-10-01

Current quantum cryptography systems are limited by the Poissonian photon statistics of a standard light source: a security loophole is opened up by the possibility of multiple-photon pulses. By replacing the source with a single-photon emitter, transmission rates of secure information can be improved. A single photon source is also essential to implement a linear optics quantum computer. We have investigated the use of single self-assembled InAs/GaAs quantum dots as such single-photon sources, and have seen a hundred-fold reduction in the multi-photon probability as compared to Poissonian pulses. An extension of our experiment should also allow for the generation of triggered, polarizationentangled photon pairs.

Targeted intracellular voltage recordings from dendritic spines using quantum-dot-coated nanopipettes

NASA Astrophysics Data System (ADS)

Jayant, Krishna; Hirtz, Jan J.; Plante, Ilan Jen-La; Tsai, David M.; de Boer, Wieteke D. A. M.; Semonche, Alexa; Peterka, Darcy S.; Owen, Jonathan S.; Sahin, Ozgur; Shepard, Kenneth L.; Yuste, Rafael

2017-05-01

Dendritic spines are the primary site of excitatory synaptic input onto neurons, and are biochemically isolated from the parent dendritic shaft by their thin neck. However, due to the lack of direct electrical recordings from spines, the influence that the neck resistance has on synaptic transmission, and the extent to which spines compartmentalize voltage, specifically excitatory postsynaptic potentials, albeit critical, remains controversial. Here, we use quantum-dot-coated nanopipette electrodes (tip diameters ∼15-30 nm) to establish the first intracellular recordings from targeted spine heads under two-photon visualization. Using simultaneous somato-spine electrical recordings, we find that back propagating action potentials fully invade spines, that excitatory postsynaptic potentials are large in the spine head (mean 26 mV) but are strongly attenuated at the soma (0.5-1 mV) and that the estimated neck resistance (mean 420 MΩ) is large enough to generate significant voltage compartmentalization. Nanopipettes can thus be used to electrically probe biological nanostructures.

Targeted intracellular voltage recordings from dendritic spines using quantum-dot-coated nanopipettes

PubMed Central

Jayant, Krishna; Hirtz, Jan J.; Plante, Ilan Jen-La; Tsai, David M.; De Boer, Wieteke D. A. M.; Semonche, Alexa; Peterka, Darcy S.; Owen, Jonathan S.; Sahin, Ozgur; Shepard, Kenneth L.; Yuste, Rafael

2017-01-01

Dendritic spines are the primary site of excitatory synaptic input onto neurons, and are biochemically isolated from the parent dendritic shaft by their thin neck. However, due to the lack of direct electrical recordings from spines, the influence that the neck resistance has on synaptic transmission, and the extent to which spines compartmentalize voltage, specifically excitatory postsynaptic potentials, albeit critical, remains controversial. Here, we use quantum-dot-coated nanopipette electrodes (tip diameters ~15–30 nm) to establish the first intracellular recordings from targeted spine heads under two-photon visualization. Using simultaneous somato-spine electrical recordings, we find that back propagating action potentials fully invade spines, that excitatory postsynaptic potentials are large in the spine head (mean 26 mV) but are strongly attenuated at the soma (0.5–1 mV) and that the estimated neck resistance (mean 420 MΩ) is large enough to generate significant voltage compartmentalization. Nanopipettes can thus be used to electrically probe biological nanostructures. PMID:27941898

Targeted intracellular voltage recordings from dendritic spines using quantum-dot-coated nanopipettes.

PubMed

Jayant, Krishna; Hirtz, Jan J; Plante, Ilan Jen-La; Tsai, David M; De Boer, Wieteke D A M; Semonche, Alexa; Peterka, Darcy S; Owen, Jonathan S; Sahin, Ozgur; Shepard, Kenneth L; Yuste, Rafael

2017-05-01

Dendritic spines are the primary site of excitatory synaptic input onto neurons, and are biochemically isolated from the parent dendritic shaft by their thin neck. However, due to the lack of direct electrical recordings from spines, the influence that the neck resistance has on synaptic transmission, and the extent to which spines compartmentalize voltage, specifically excitatory postsynaptic potentials, albeit critical, remains controversial. Here, we use quantum-dot-coated nanopipette electrodes (tip diameters ∼15-30 nm) to establish the first intracellular recordings from targeted spine heads under two-photon visualization. Using simultaneous somato-spine electrical recordings, we find that back propagating action potentials fully invade spines, that excitatory postsynaptic potentials are large in the spine head (mean 26 mV) but are strongly attenuated at the soma (0.5-1 mV) and that the estimated neck resistance (mean 420 MΩ) is large enough to generate significant voltage compartmentalization. Nanopipettes can thus be used to electrically probe biological nanostructures.

Preliminary Breakdown: Physical Mechanisms and Potential for Energetic Emissions

NASA Astrophysics Data System (ADS)

Petersen, D.; Beasley, W. H.

2014-12-01

Observations and analysis of the preliminary breakdown phase of virgin negative cloud-to-ground (-CG) lightning strokes will be presented. Of primary interest are the physical processes responsible for the fast electric field "characteristic" pulses that are often observed during this phase. The pulse widths of characteristic pulses are shown to occur as a superposed bimodal distribution, with the short and long modes having characteristic timescales on the order of 1 microsecond and 10 microseconds, respectively. Analysis of these pulses is based on comparison with laboratory observations of long spark discharge processes and with recently acquired high-speed video observations of a single -CG event. It will be argued that the fast electric field bimodal distribution is the result of conventional discharge processes operating in an extensive strong ambient electric field environment. An important related topic will also be discussed, where it will be argued that preliminary breakdown discharges are capable of generating energetic electrons and may therefore seed relativistic electron avalanches that go on to produce pulsed energetic photon emissions.

The Effect of the Electron Tunneling on the Photoelectric Hot Electrons Generation in Metallic-Semiconductor Nanostructures

NASA Astrophysics Data System (ADS)

Elsharif, Asma M.

2018-01-01

Semiconductor photonic crystals (MSPhC) were used to convert solar energy into hot electrons. An experimental model was designed by using metallic semiconductor photonic crystals (MSPhC). The designed MSPhC is based on TiO2/Au schottky contact. The model has similar nanocavity structure for broad gold absorption, but the materials on top of the cavity were changed to a metal and a semiconductor in order to collect the hot electrons. Detailed design steps and characterization have shown a broadband sub-bandgap photoresponse at a wavelength of 590 nm. This is due to the surface plasmon absorption by the wafer-scale Au/TiO2 metallic-semiconductor photonic crystal. Analytical calculation of the hot electron transport from the Au thin layer to the TiO2 conduction band is discussed. This theoretical study is based on the quantum tunneling effect. The photo generation of the hot electrons was undertaken at different wavelengths in Au absorber followed by tunneling through a schottky barrier into a TiO2 collector. The presence of a tunnel current from the absorber to the collector under illumination, offers a method to extract carriers from a hot-electron distribution at few bias voltages is presented in this study. The effects of doping different concentrations of the semiconductor on the evolution of the current characteristics were also investigated and discussed. The electrical characteristics were found to be sensitive to any change in the thickness of the barrier.

Deterministic Generation of All-Photonic Quantum Repeaters from Solid-State Emitters

NASA Astrophysics Data System (ADS)

Buterakos, Donovan; Barnes, Edwin; Economou, Sophia E.

2017-10-01

Quantum repeaters are nodes in a quantum communication network that allow reliable transmission of entanglement over large distances. It was recently shown that highly entangled photons in so-called graph states can be used for all-photonic quantum repeaters, which require substantially fewer resources compared to atomic-memory-based repeaters. However, standard approaches to building multiphoton entangled states through pairwise probabilistic entanglement generation severely limit the size of the state that can be created. Here, we present a protocol for the deterministic generation of large photonic repeater states using quantum emitters such as semiconductor quantum dots and defect centers in solids. We show that arbitrarily large repeater states can be generated using only one emitter coupled to a single qubit, potentially reducing the necessary number of photon sources by many orders of magnitude. Our protocol includes a built-in redundancy, which makes it resilient to photon loss.

Probing photoresponse of aligned single-walled carbon nanotube doped ultrathin MoS2.

PubMed

Wang, Rui; Wang, Tianjiao; Hong, Tu; Xu, Ya-Qiong

2018-08-24

We report a facile method to produce ultrathin molybdenum disulfide (MoS 2 ) hybrids with polarized near-infrared (NIR) photoresponses, in which horizontally-aligned single-walled carbon nanotubes (SWNTs) are integrated with single- and few-layer MoS 2 through a two-step chemical vapor deposition process. The photocurrent generation mechanisms in SWNT-MoS 2 hybrids are systematically investigated through wavelength- and polarization-dependent scanning photocurrent measurements. When the incident photon energy is above the direct bandgap of MoS 2 , isotropic photocurrent signals are observed, which can be primarily attributed to the direct bandgap transition in MoS 2 . In contrast, if the incident photon energy in the NIR region is below the direct bandgap of MoS 2 , the maximum photocurrent response occurs when the incident light is polarized in the direction along the SWNTs, indicating that photocurrent signals mainly result from the anisotropic absorption of SWNTs. More importantly, these two-dimensional (2D) hybrid structures inherit the electrical transport properties from MoS 2 , displaying n-type characteristics at a zero gate voltage. These fundamental studies provide a new way to produce ultrathin MoS 2 hybrids with inherited electrical properties and polarized NIR photoresponses, opening doors for engineering various 2D hybrid materials for future broadband optoelectronic applications.

Hybrid Lead Halide Perovskites for Ultrasensitive Photoactive Switching in Terahertz Metamaterial Devices.

PubMed

Manjappa, Manukumara; Srivastava, Yogesh Kumar; Solanki, Ankur; Kumar, Abhishek; Sum, Tze Chien; Singh, Ranjan

2017-08-01

The recent meteoric rise in the field of photovoltaics with the discovery of highly efficient solar-cell devices is inspired by solution-processed organic-inorganic lead halide perovskites that exhibit unprecedented light-to-electricity conversion efficiencies. The stunning performance of perovskites is attributed to their strong photoresponsive properties that are thoroughly utilized in designing excellent perovskite solar cells, light-emitting diodes, infrared lasers, and ultrafast photodetectors. However, optoelectronic application of halide perovskites in realizing highly efficient subwavelength photonic devices has remained a challenge. Here, the remarkable photoconductivity of organic-inorganic lead halide perovskites is exploited to demonstrate a hybrid perovskite-metamaterial device that shows extremely low power photoswitching of the metamaterial resonances in the terahertz part of the electromagnetic spectrum. Furthermore, a signature of a coupled phonon-metamaterial resonance is observed at higher pump powers, where the Fano resonance amplitude is extremely weak. In addition, a low threshold, dynamic control of the highly confined electric field intensity is also observed in the system, which could tremendously benefit the new generation of subwavelength photonic devices as active sensors, low threshold optically controlled lasers, and active nonlinear devices with enhanced functionalities in the infrared, optical, and the terahertz parts of the electromagnetic spectrum. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of the local environment on CNT-based nanoelectronics: development of a microenvironment probe station.

PubMed

McClain, Devon; Thomas, Nicole; Nguyen, Tri; O'Brien, Kevin P; Jiao, Jun

2010-11-01

In this study, we report the development of a microenvironment probe station capable of detecting the effect of small changes to the local environment around a carbon nanotube conduction channel. The microenvironment probe station is highly versatile and is used to characterize alterations in carbon nanotube field effect transistor electrical behavior in response to changes in temperature, gas species, infrared and ultraviolet light. All devices were electrically characterized in atmospheric, ultrahigh vacuum and oxygen-rich environments. The results suggest that devices could be changed from n-type at 1 x 10(-8) torr through an intermediate ambipolar state at 1 x 10(-4) torr to p-type at atmosphere solely by increasing the oxygen concentration. The average resistance of these carbon nanotube field effect transistors after annealing was observed to decrease by approximately 54% from their initial value under ultrahigh vacuum to their final value in the presence of pure oxygen while corresponding threshold voltages shifts were also observed. Illumination with infrared light resulted in a approximately 10% increase in drain current with an estimated response time <1 fs due to photon-induced electron-hole pair generation. Illumination with ultraviolet light resulted in approximately 5-15% reduction in drain current due to photon-induced desorption of oxygen adsorbate.

Quantum Confined Semiconductors for High Efficiency Photovoltaics

NASA Astrophysics Data System (ADS)

Beard, Matthew

2014-03-01

Semiconductor nanostructures, where at least one dimension is small enough to produce quantum confinement effects, provide new pathways for controlling energy flow and therefore have the potential to increase the efficiency of the primary photon-to-free energy conversion step. In this discussion, I will present the current status of research efforts towards utilizing the unique properties of colloidal quantum dots (NCs confined in three dimensions) in prototype solar cells and demonstrate that these unique systems have the potential to bypass the Shockley-Queisser single-junction limit for solar photon conversion. The solar cells are constructed using a low temperature solution based deposition of PbS or PbSe QDs as the absorber layer. Different chemical treatments of the QD layer are employed in order to obtain good electrical communication while maintaining the quantum-confined properties of the QDs. We have characterized the transport and carrier dynamics using a transient absorption, time-resolved THz, and temperature-dependent photoluminescence. I will discuss the interplay between carrier generation, recombination, and mobility within the QD layers. A unique aspect of our devices is that the QDs exhibit multiple exciton generation with an efficiency that is ~ 2 to 3 times greater than the parental bulk semiconductor.

A method for unique identification of relativistic /greater than 0.5/ magnetic monopoles with a fast film Cerenkov detector

NASA Technical Reports Server (NTRS)

Pinsky, L. S.; Hagstrom, R.

1975-01-01

A magnetic monopole traversing a dielectric medium at a velocity greater than the phase velocity of light in that medium, will give rise to Cerenkov radiation with the electric field tangent to the cone generated by the photon wave propagation vector, and the magnetic field normal to that surface. This is the opposite polarization to that encountered with an electric charge. It is proposed that either by inserting a linearly polarizing layer between the radiator and the photographic emulsion, or by selecting a linearly polarizing material as the radiator, one could directly observe the field polarization by examining the photographic image and thus uniquely identify a magnetic monopole. The ability of the detector is further enhanced by the index of refraction dependence of the Cerenkov output from a magnetic monopole.

Laser generation in opal-like single-crystal and heterostructure photonic crystals

NASA Astrophysics Data System (ADS)

Kuchyanov, A. S.; Plekhanov, A. I.

2016-11-01

This study describes the laser generation of a 6Zh rhodamine in artificial opals representing single-crystal and heterostructure films. The spectral and angular properties of emission and the threshold characteristics of generation are investigated. In the case where the 6Zh rhodamine was in a bulk opal, the so-called random laser generation was observed. In contrast to this, the laser generation caused by a distributed feedback inside the structure of the photonic bandgap was observed in photonic-crystal opal films.

Improved Photon-Emission-Microscope System

NASA Technical Reports Server (NTRS)

Vu, Duc

2006-01-01

An improved photon-emission-microscope (PEM) instrumentation system has been developed for use in diagnosing failure conditions in semiconductor devices, including complex integrated circuits. This system is designed primarily to image areas that emit photons, at wavelengths from 400 to 1,100 nm, associated with device failures caused by leakage of electric current through SiO2 and other dielectric materials used in multilayer semiconductor structures. In addition, the system is sensitive enough to image areas that emit photons during normal operation.

Quantum Dot-Photonic Crystal Cavity QED Based Quantum Information Processing

DTIC Science & Technology

2012-08-14

Majumdar, A. Faraon, M . Toishi, N. Stolz, P. Petroff, J. Vuckovic. Resonant Excitation of a Quantum Dot Strongly Coupled to a Photonic Crystal...11 J. O’Brien, A. Furusawa , J. Vuckovic. Photonic Quantum Technologies, Nature Photonics, (12 2009): . doi: 2010/08/30 15:11:17 10 D. Englund, A...devices via micron-scale electrical heaters, Applied Physics Letters, ( 2009): . doi: 2009/08/19 13:18:36 7 M . Toishi, D. Englund, A. Faraon, J

Generation of laser-induced periodic surface structures in indium-tin-oxide thin films and two-photon lithography of ma-N photoresist by sub-15 femtosecond laser microscopy for liquid crystal cell application

NASA Astrophysics Data System (ADS)

Klötzer, Madlen; Afshar, Maziar; Feili, Dara; Seidel, Helmut; König, Karsten; Straub, Martin

2015-03-01

Indium-tin-oxide (ITO) is a widely used electrode material for liquid crystal cell applications because of its transparency in the visible spectral range and its high electrical conductivity. Important examples of applications are displays and optical phase modulators. We report on subwavelength periodic structuring and precise laser cutting of 150 nm thick indium-tin-oxide films on glass substrates, which were deposited by magnetron reactive DC-sputtering from an indiumtin target in a low-pressure oxygen atmosphere. In order to obtain nanostructured electrodes laser-induced periodic surface structures with a period of approximately 100 nm were generated using tightly focused high-repetition rate sub-15 femtosecond pulsed Ti:sapphire laser light, which was scanned across the sample by galvanometric mirrors. Three-dimensional spacers were produced by multiphoton photopolymerization in ma-N 2410 negative-tone photoresist spin-coated on top of the ITO layers. The nanostructured electrodes were aligned in parallel to set up an electrically switchable nematic liquid crystal cell.

Resource-efficient generation of linear cluster states by linear optics with postselection

DOE PAGES

Uskov, D. B.; Alsing, P. M.; Fanto, M. L.; ...

2015-01-30

Here we report on theoretical research in photonic cluster-state computing. Finding optimal schemes of generating non-classical photonic states is of critical importance for this field as physically implementable photon-photon entangling operations are currently limited to measurement-assisted stochastic transformations. A critical parameter for assessing the efficiency of such transformations is the success probability of a desired measurement outcome. At present there are several experimental groups that are capable of generating multi-photon cluster states carrying more than eight qubits. Separate photonic qubits or small clusters can be fused into a single cluster state by a probabilistic optical CZ gate conditioned on simultaneousmore » detection of all photons with 1/9 success probability for each gate. This design mechanically follows the original theoretical scheme of cluster state generation proposed more than a decade ago by Raussendorf, Browne, and Briegel. The optimality of the destructive CZ gate in application to linear optical cluster state generation has not been analyzed previously. Our results reveal that this method is far from the optimal one. Employing numerical optimization we have identified that the maximal success probability of fusing n unentangled dual-rail optical qubits into a linear cluster state is equal to 1/2 n-1; an m-tuple of photonic Bell pair states, commonly generated via spontaneous parametric down-conversion, can be fused into a single cluster with the maximal success probability of 1/4 m-1.« less

A giant enhancement of multiphoton absorption in single-layer molybdenum disulfide

NASA Astrophysics Data System (ADS)

Zhou, Feng; Ji, Wei

Identifying light absorption mechanisms in nanoscale materials, which are more efficient than those observed in bulk semiconductors, are of paramount importance to next-generation, infrared photo-detection. Here, we report considerable enhancement of degenerate two-photon absorption (2PA) and three-photon absorption (3PA) through two-dimensional (2D) excitonic effects in single-layer molybdenum disulfide (1L-MoS2) . We theoretically predict that both degenerate 2PA and 3PA coefficients of 1L-MoS2 are enhanced by 10-1000 times in the near-infrared (NIR), as compared with those of bulk semiconductors. Our theoretical prediction is validated by measuring photocurrents induced by 2PA or 3PA in a 1L-MoS2 photo-detector at room temperature where excitons in the immediate vicinity of the bandgap are transferred to the conduction band by a very small amount of thermal energy and dissociated under an external electric field. Our finding lays theoretical foundation and provides experimental evidence for developing sensitive infrared multiphoton detectors for nano-photonics. This work was supported by National University of Singapore through a research Grant: R144-000-327-112.

PICSiP: new system-in-package technology using a high bandwidth photonic interconnection layer for converged microsystems

NASA Astrophysics Data System (ADS)

Tekin, Tolga; Töpper, Michael; Reichl, Herbert

2009-05-01

Technological frontiers between semiconductor technology, packaging, and system design are disappearing. Scaling down geometries [1] alone does not provide improvement of performance, less power, smaller size, and lower cost. It will require "More than Moore" [2] through the tighter integration of system level components at the package level. System-in-Package (SiP) will deliver the efficient use of three dimensions (3D) through innovation in packaging and interconnect technology. A key bottleneck to the implementation of high-performance microelectronic systems, including SiP, is the lack of lowlatency, high-bandwidth, and high density off-chip interconnects. Some of the challenges in achieving high-bandwidth chip-to-chip communication using electrical interconnects include the high losses in the substrate dielectric, reflections and impedance discontinuities, and susceptibility to crosstalk [3]. Obviously, the incentive for the use of photonics to overcome the challenges and leverage low-latency and highbandwidth communication will enable the vision of optical computing within next generation architectures. Supercomputers of today offer sustained performance of more than petaflops, which can be increased by utilizing optical interconnects. Next generation computing architectures are needed with ultra low power consumption; ultra high performance with novel interconnection technologies. In this paper we will discuss a CMOS compatible underlying technology to enable next generation optical computing architectures. By introducing a new optical layer within the 3D SiP, the development of converged microsystems, deployment for next generation optical computing architecture will be leveraged.

Ultrafast Plasmon-Enhanced Hot Electron Generation at Ag Nanocluster/Graphite Heterojunctions.

PubMed

Tan, Shijing; Liu, Liming; Dai, Yanan; Ren, Jindong; Zhao, Jin; Petek, Hrvoje

2017-05-03

Hot electron processes at metallic heterojunctions are central to optical-to-chemical or electrical energy transduction. Ultrafast nonlinear photoexcitation of graphite (Gr) has been shown to create hot thermalized electrons at temperatures corresponding to the solar photosphere in less than 25 fs. Plasmonic resonances in metallic nanoparticles are also known to efficiently generate hot electrons. Here we deposit Ag nanoclusters (NC) on Gr to study the ultrafast hot electron generation and dynamics in their plasmonic heterojunctions by means of time-resolved two-photon photoemission (2PP) spectroscopy. By tuning the wavelength of p-polarized femtosecond excitation pulses, we find an enhancement of 2PP yields by 2 orders of magnitude, which we attribute to excitation of a surface-normal Mie plasmon mode of Ag/Gr heterojunctions at 3.6 eV. The 2PP spectra include contributions from (i) coherent two-photon absorption of an occupied interface state (IFS) 0.2 eV below the Fermi level, which electronic structure calculations assign to chemisorption-induced charge transfer, and (ii) hot electrons in the π*-band of Gr, which are excited through the coherent screening response of the substrate. Ultrafast pump-probe measurements show that the IFS photoemission occurs via virtual intermediate states, whereas the characteristic lifetimes attribute the hot electrons to population of the π*-band of Gr via the plasmon dephasing. Our study directly probes the mechanisms for enhanced hot electron generation and decay in a model plasmonic heterojunction.

Switching of Photonic Crystal Lasers by Graphene.

PubMed

Hwang, Min-Soo; Kim, Ha-Reem; Kim, Kyoung-Ho; Jeong, Kwang-Yong; Park, Jin-Sung; Choi, Jae-Hyuck; Kang, Ju-Hyung; Lee, Jung Min; Park, Won Il; Song, Jung-Hwan; Seo, Min-Kyo; Park, Hong-Gyu

2017-03-08

Unique features of graphene have motivated the development of graphene-integrated photonic devices. In particular, the electrical tunability of graphene loss enables high-speed modulation of light and tuning of cavity resonances in graphene-integrated waveguides and cavities. However, efficient control of light emission such as lasing, using graphene, remains a challenge. In this work, we demonstrate on/off switching of single- and double-cavity photonic crystal lasers by electrical gating of a monolayer graphene sheet on top of photonic crystal cavities. The optical loss of graphene was controlled by varying the gate voltage V g , with the ion gel atop the graphene sheet. First, the fundamental properties of graphene were investigated through the transmittance measurement and numerical simulations. Next, optically pumped lasing was demonstrated for a graphene-integrated single photonic crystal cavity at V g below -0.6 V, exhibiting a low lasing threshold of ∼480 μW, whereas lasing was not observed at V g above -0.6 V owing to the intrinsic optical loss of graphene. Changing quality factor of the graphene-integrated photonic crystal cavity enables or disables the lasing operation. Moreover, in the double-cavity photonic crystal lasers with graphene, switching of individual cavities with separate graphene sheets was achieved, and these two lasing actions were controlled independently despite the close distance of ∼2.2 μm between adjacent cavities. We believe that our simple and practical approach for switching in graphene-integrated active photonic devices will pave the way toward designing high-contrast and ultracompact photonic integrated circuits.

Nonlinear silicon photonics

NASA Astrophysics Data System (ADS)

Borghi, M.; Castellan, C.; Signorini, S.; Trenti, A.; Pavesi, L.

2017-09-01

Silicon photonics is a technology based on fabricating integrated optical circuits by using the same paradigms as the dominant electronics industry. After twenty years of fervid development, silicon photonics is entering the market with low cost, high performance and mass-manufacturable optical devices. Until now, most silicon photonic devices have been based on linear optical effects, despite the many phenomenologies associated with nonlinear optics in both bulk materials and integrated waveguides. Silicon and silicon-based materials have strong optical nonlinearities which are enhanced in integrated devices by the small cross-section of the high-index contrast silicon waveguides or photonic crystals. Here the photons are made to strongly interact with the medium where they propagate. This is the central argument of nonlinear silicon photonics. It is the aim of this review to describe the state-of-the-art in the field. Starting from the basic nonlinearities in a silicon waveguide or in optical resonator geometries, many phenomena and applications are described—including frequency generation, frequency conversion, frequency-comb generation, supercontinuum generation, soliton formation, temporal imaging and time lensing, Raman lasing, and comb spectroscopy. Emerging quantum photonics applications, such as entangled photon sources, heralded single-photon sources and integrated quantum photonic circuits are also addressed at the end of this review.

Electric sail, photonic sail and deorbiting applications of the freely guided photonic blade

NASA Astrophysics Data System (ADS)

Janhunen, Pekka

2014-01-01

We consider a freely guided photonic blade (FGPB) which is a centrifugally stretched sheet of photonic sail membrane that can be tilted by changing the centre of mass or by other means. The FGPB can be installed at the tip of each main tether of an electric solar wind sail (E-sail) so that one can actively manage the tethers to avoid their mutual collisions and to modify the spin rate of the sail if needed. This enables a more scalable and modular E-sail than the baseline approach where auxiliary tethers are used for collision avoidance. For purely photonic sail applications one can remove the tethers and increase the size of the blades to obtain a novel variant of the heliogyro that can have a significantly higher packing density than the traditional heliogyro. For satellite deorbiting in low Earth orbit (LEO) conditions, analogous designs exist where the E-sail effect is replaced by the negative polarity plasma brake effect and the photonic pressure by atmospheric drag. We conclude that the FGPB appears to be an enabling technique for diverse applications. We also outline a way of demonstrating it on ground and in LEO at low cost.

Characterization of photonic colloidal crystals in real and reciprocal space

NASA Astrophysics Data System (ADS)

Thijssen, J. H. J.

2007-05-01

In this thesis, we present experimental work on the characterization of photonic colloidal crystals in real and reciprocal space. Photonic crystals are structures in which the refractive index varies periodically in space on the length scale of the wavelength of light. Self-assembly of colloidal particles is a promising route towards three-dimensional (3-D) photonic crystals. However, fabrication of photonic band-gap materials remains challenging, so calculations that predict their optical properties are indispensable. Our photonic band-structure calculations on binary Laves phases have led to a proposed route towards photonic colloidal crystals with a band gap in the visible region. Furthermore, contrary to results in literature, we found that there is no photonic band gap for inverse BCT crystals. Finally, optical spectra of colloidal crystals were analyzed using band-structure calculations. Self-assembled photonic crystals are fabricated in multiple steps. Each of these steps can significantly affect the 3-D structure of the resulting crystal. X-rays are an excellent probe of the internal structure of photonic crystals, even if the refractive-index contrast is large. In Chapter 3, we demonstrate that an angular resolution of 0.002 mrad is achievable at a third-generation synchrotron using compound refractive optics. As a result, the position and the width of Bragg reflections in 2D diffraction patterns can be resolved, even for lattice spacings larger than a micrometer (corresponding to approximately 0.1 mrad). X-ray diffraction patterns and electron-microscopy images are used in Chapter 4 to determine the orientation of hexagonal layers in convective-assembly colloidal crystals. Quantitative analysis revealed that, in our samples, the layers were not exactly hexagonal and the stacking sequence was that of face-centered cubic (FCC) crystals, though stacking faults may have been present. In Chapter 5, binary colloidal crystals of organic spheres (polystyrene, PMMA) and/or inorganic spheres (silica) are introduced as promising templates for strongly photonic crystals. To prevent melting of the template, we used atomic layer deposition (ALD) to infiltrate polystyrene and PMMA templates with alumina, after which chemical vapor deposition (CVD) was used to further enhance the refractive-index contrast. Binary colloidal crystals of silica spheres can be infiltrated by CVD directly, but they often have a layer of colloidal fluid on top. Preliminary etching experiments demonstrated that it may be possible to etch silica templates with plasmas or with adhesive tape. As described in Chapter 6, sedimentation of colloidal silica spheres in an external, high-frequency electric field lead to mm-scale BCT crystals with up to 25 layers. In addition, electric fields were used as an external control to switch between BCT and close-packed (CP) crystal structures within seconds. We also developed two procedures to invert BCT crystals without loss of structure - colloidal particles were immobilized by diffusion-polymerization or photo-induced polymerization of the surrounding solvent. Some BCT crystals were even infiltrated with silicon using CVD. We demonstrate in Chapter 7 that X-ray diffraction can be used to determine the 3-D structure of such photonic colloidal crystals at the various stages of their fabrication. Excellent agreement was found with confocal and electron-microscopy images.

Molding resonant energy transfer by colloidal crystal: Dexter transfer and electroluminescence

NASA Astrophysics Data System (ADS)

González-Urbina, Luis; Kolaric, Branko; Libaers, Wim; Clays, Koen

2010-05-01

Building photonic crystals by combination of colloidal ordering and metal sputtering we were able to construct a system sensitive to an electrical field. In corresponding crystals we embedded the Dexter pair (Ir(ppy3) and BAlq) and investigated the influence of the band gap on the resonant energy transfer when the system is excited by light and by an electric field respectively. Our investigations extend applications of photonic crystals into the field of electroluminescence and LED technologies.

Photon counting detector for the personal radiography inspection system "SIBSCAN"

NASA Astrophysics Data System (ADS)

Babichev, E. A.; Baru, S. E.; Grigoriev, D. N.; Leonov, V. V.; Oleynikov, V. P.; Porosev, V. V.; Savinov, G. A.

2017-02-01

X-ray detectors operating in the energy integrating mode are successfully used in many different applications. Nevertheless the direct photon counting detectors, having the superior parameters in comparison with the integrating ones, are rarely used yet. One of the reasons for this is the low value of the electrical signal generated by a detected photon. Silicon photomultiplier (SiPM) based scintillation counters have a high detection efficiency, high electronic gain and compact dimensions. This makes them a very attractive candidate to replace routinely used detectors in many fields. More than 10 years ago the digital scanning radiography system based on multistrip ionization chamber (MIC) was suggested at Budker Institute of Nuclear Physics. The detector demonstrates excellent radiation resistance and parameter stability after 5 year operations and an imaging of up to 1000 persons per day. Currently, the installations operate at several Russian airports and at subway stations in some cities. At the present time we design a new detector operating in the photon counting mode, having superior parameters than the gas one, based on scintillator - SiPM assemblies. This detector has close to zero noise, higher quantum efficiency and a count rate capability of more than 5 MHz per channel (20% losses), which leads to better image quality and improved detection capability. The suggested detector technology could be expanded to medical applications.

Mechanism and modulation of terahertz generation from a semimetal - graphite

PubMed Central

Ye, Tong; Meng, Sheng; Zhang, Jin; E, Yiwen; Yang, Yuping; Liu, Wuming; Yin, Yan; Wang, Li

2016-01-01

Semi-metals might offer a stronger interaction and a better confinement for terahertz wave than semiconductors, while preserve tunability. Particularly, graphene-based materials are envisioned as terahertz modulators, filters and ultra-broadband sources. However, the understanding of terahertz generation from those materials is still not clear, thus limits us recognizing the potential and improving device performances. Graphite, the mother material of graphene and a typical bulk semi-metal, is a good system to study semi-metals and graphene-based materials. Here we experimentally modulate and maximize the terahertz signal from graphite surface, thus reveal the mechanism - surface field driving photon induced carriers into transient current to radiate terahertz wave. We also discuss the differences between graphite and semiconductors; particularly graphite shows very weak temperature dependency from room temperature to 80 °C. Above knowledge will help us understand terahertz generations, achieve maximum output and electric modulation, in semi-metal or graphene based devices. PMID:26972818

Mechanism and modulation of terahertz generation from a semimetal--graphite.

PubMed

Ye, Tong; Meng, Sheng; Zhang, Jin; E, Yiwen; Yang, Yuping; Liu, Wuming; Yin, Yan; Wang, Li

2016-03-14

Semi-metals might offer a stronger interaction and a better confinement for terahertz wave than semiconductors, while preserve tunability. Particularly, graphene-based materials are envisioned as terahertz modulators, filters and ultra-broadband sources. However, the understanding of terahertz generation from those materials is still not clear, thus limits us recognizing the potential and improving device performances. Graphite, the mother material of graphene and a typical bulk semi-metal, is a good system to study semi-metals and graphene-based materials. Here we experimentally modulate and maximize the terahertz signal from graphite surface, thus reveal the mechanism--surface field driving photon induced carriers into transient current to radiate terahertz wave. We also discuss the differences between graphite and semiconductors; particularly graphite shows very weak temperature dependency from room temperature to 80 °C. Above knowledge will help us understand terahertz generations, achieve maximum output and electric modulation, in semi-metal or graphene based devices.

Experimental realization of narrowband four-photon Greenberger-Horne-Zeilinger state in a single cold atomic ensemble.

PubMed

Dong, Ming-Xin; Zhang, Wei; Hou, Zhi-Bo; Yu, Yi-Chen; Shi, Shuai; Ding, Dong-Sheng; Shi, Bao-Sen

2017-11-15

Multi-photon entangled states not only play a crucial role in research on quantum physics but also have many applications in quantum information fields such as quantum computation, quantum communication, and quantum metrology. To fully exploit the multi-photon entangled states, it is important to establish the interaction between entangled photons and matter, which requires that photons have narrow bandwidth. Here, we report on the experimental generation of a narrowband four-photon Greenberger-Horne-Zeilinger state with a fidelity of 64.9% through multiplexing two spontaneous four-wave mixings in a cold Rb85 atomic ensemble. The full bandwidth of the generated GHZ state is about 19.5 MHz. Thus, the generated photons can effectively match the atoms, which are very suitable for building a quantum computation and quantum communication network based on atomic ensembles.

High-fidelity entanglement swapping and generation of three-qubit GHZ state using asynchronous telecom photon pair sources.

PubMed

Tsujimoto, Yoshiaki; Tanaka, Motoki; Iwasaki, Nobuo; Ikuta, Rikizo; Miki, Shigehito; Yamashita, Taro; Terai, Hirotaka; Yamamoto, Takashi; Koashi, Masato; Imoto, Nobuyuki

2018-01-23

We experimentally demonstrate a high-fidelity entanglement swapping and a generation of the Greenberger-Horne-Zeilinger (GHZ) state using polarization-entangled photon pairs at telecommunication wavelength produced by spontaneous parametric down conversion with continuous-wave pump light. While spatially separated sources asynchronously emit photon pairs, the time-resolved photon detection guarantees the temporal indistinguishability of photons without active timing synchronizations of pump lasers and/or adjustment of optical paths. In the experiment, photons are sufficiently narrowed by fiber-based Bragg gratings with the central wavelengths of 1541 nm & 1580 nm, and detected by superconducting nanowire single-photon detectors with low timing jitters. The observed fidelities of the final states for entanglement swapping and the generated three-qubit state were 0.84 ± 0.04 and 0.70 ± 0.05, respectively.

Optical Limiting Using the Two-Photon Absorption Electrical Modulation Effect in HgCdTe Photodiode

PubMed Central

Cui, Haoyang; Yang, Junjie; Zeng, Jundong; Tang, Zhong

2013-01-01

The electrical modulation properties of the output intensity of two-photon absorption (TPA) pumping were analyzed in this paper. The frequency dispersion dependence of TPA and the electric field dependence of TPA were calculated using Wherrett theory model and Garcia theory model, respectively. Both predicted a dramatic variation of TPA coefficient which was attributed into the increasing of the transition rate. The output intensity of the laser pulse propagation in the pn junction device was calculated by using function-transfer method. It shows that the output intensity increases nonlinearly with increasing intensity of incident light and eventually reaches saturation. The output saturation intensity depends on the electric field strength; the greater the electric field, the smaller the output intensity. Consequently, the clamped saturation intensity can be controlled by the electric field. The prior advantage of electrical modulation is that the TPA can be varied extremely continuously, thus adjusting the output intensity in a wide range. This large change provides a manipulate method to control steady output intensity of TPA by adjusting electric field. PMID:24198721

Free-space quantum key distribution with a high generation rate potassium titanyl phosphate waveguide photon-pair source

NASA Astrophysics Data System (ADS)

Wilson, Jeffrey D.; Chaffee, Dalton W.; Wilson, Nathaniel C.; Lekki, John D.; Tokars, Roger P.; Pouch, John J.; Roberts, Tony D.; Battle, Philip R.; Floyd, Bertram; Lind, Alexander J.; Cavin, John D.; Helmick, Spencer R.

2016-09-01

A high generation rate photon-pair source using a dual element periodically-poled potassium titanyl phosphate (PP KTP) waveguide is described. The fully integrated photon-pair source consists of a 1064-nm pump diode laser, fiber-coupled to a dual element waveguide within which a pair of 1064-nm photons are up-converted to a single 532-nm photon in the first stage. In the second stage, the 532-nm photon is down-converted to an entangled photon-pair at 800 nm and 1600 nm which are fiber-coupled at the waveguide output. The photon-pair source features a high pair generation rate, a compact power-efficient package, and continuous wave (CW) or pulsed operation. This is a significant step towards the long term goal of developing sources for high-rate Quantum Key Distribution (QKD) to enable Earth-space secure communications. Characterization and test results are presented. Details and preliminary results of a laboratory free space QKD experiment with the B92 protocol are also presented.

Free-Space Quantum Key Distribution with a High Generation Rate Potassium Titanyl Phosphate Waveguide Photon-Pair Source

NASA Technical Reports Server (NTRS)

Wilson, Jeffrey D.; Chaffee, Dalton W.; Wilson, Nathaniel C.; Lekki, John D.; Tokars, Roger P.; Pouch, John J.; Roberts, Tony D.; Battle, Philip; Floyd, Bertram M.; Lind, Alexander J.;

Enhanced Ultrafast Nonlinear Optics With Microstructure Fibers And Photonic Crystals

DTIC Science & Technology

2004-07-01

NANOHOLES FREQUENCY-TUNABLE ANTI-STOKES LINE EMISSION BY EIGENMODES OF A BIREFRINGENT MICROSTRUCTURE FIBER GENERATION OF FEMTOSECOND ANTI-STOKES PULSES...laser technologies, and ultrafast photonics. ANTI-STOKES GENERATION IN GUIDED MODES OF PHOTONIC-CRYSTAL FIBERS MODIFIED WITH AN ARRAY OF NANOHOLES

Design concepts for hot carrier-based detectors and energy converters in the near ultraviolet and infrared

NASA Astrophysics Data System (ADS)

Gong, Tao; Krayer, Lisa; Munday, Jeremy N.

2016-10-01

Semiconductor materials are well suited for power conversion when the incident photon energy is slightly larger than the bandgap energy of the semiconductor. However, for photons with energy significantly greater than the bandgap energy, power conversion efficiencies are low. Further, for photons with energy below the bandgap energy, the absence of absorption results in no power generation. Here, we describe photon detection and power conversion of both high- and low-energy photons using hot carrier effects. For the absorption of high-energy photons, excited electrons and holes have excess kinetic energy that is typically lost through thermalization processes between the carriers and the lattice. However, collection of hot carriers before thermalization allows for reduced power loss. Devices utilizing plasmonic nanostructures or simple three-layer stacks (transparent conductor-insulator-metal) can be used to generate and collect these hot carriers. Alternatively, hot carrier collection from sub-bandgap photons can be possible by forming a Schottky junction with an absorbing metal so that hot carriers generated in the metal can be injected across the semiconductor-metal interface. Such structures enable near-IR detection based on sub-bandgap photon absorption. Further, utilization and optimization of localized surface plasmon resonances can increase optical absorption and hot carrier generation (through plasmon decay). Combining these concepts, hot carrier generation and collection can be exploited over a large range of incident wavelengths spanning the UV, visible, and IR.

Physics of the Brain: Interaction of the Optical-Fiber-Guided Multi-Ultraviolet-Photon Beams with the Epilepsy Topion, (the Seizure Onset Area)

NASA Astrophysics Data System (ADS)

Stefan, V. Alexander

A novel method for the possible prevention of epileptic seizures is proposed, based on the multi-ultraviolet-photon beam interaction with the epilepsy topion, (nonlinear coupling of an ultra high frequency mode to the brain beta phonons). It is hypothesized that epilepsy is a chaotic-dynamics phenomenon: small electrical changes in the epilepsy-topion lead, (within the 10s of milliseconds), to the onset of chaos, (seizure--excessive electrical discharge), and subsequent cascading into adjacent areas. The ultraviolet photons may control the imbalance of sodium and potassium ions and, consequently, may prove to be efficient in the prevention of epileptic seizures. Supported by Nikola Tesla Labs, Stefan University.

SiNOI and AlGaAs-on-SOI nonlinear circuits for continuum generation in Si photonics

NASA Astrophysics Data System (ADS)

El Dirani, Houssein; Monat, Christelle; Brision, Stéphane; Olivier, Nicolas; Jany, Christophe; Letartre, Xavier; Pu, Minhao; Girouard, Peter D.; Hagedorn Frandsen, Lars; Semenova, Elizaveta; Katsuo Oxenløwe, Leif; Yvind, Kresten; Sciancalepore, Corrado

2018-02-01

In this communication, we report on the design, fabrication, and testing of Silicon Nitride on Insulator (SiNOI) and Aluminum-Gallium-Arsenide (AlGaAs) on silicon-on-insulator (SOI) nonlinear photonic circuits for continuum generation in Silicon (Si) photonics. As recently demonstrated, the generation of frequency continua and supercontinua can be used to overcome the intrinsic limitations of nowadays silicon photonics notably concerning the heterogeneous integration of III-V on SOI lasers for datacom and telecom applications. By using the Kerr nonlinearity of monolithic silicon nitride and heterointegrated GaAs-based alloys on SOI, the generation of tens or even hundreds of new optical frequencies can be obtained in dispersion tailored waveguides, thus providing an all-optical alternative to the heterointegration of hundreds of standalone III-V on Si lasers. In our work, we present paths to energy-efficient continua generation on silicon photonics circuits. Notably, we demonstrate spectral broadening covering the full C-band via Kerrbased self-phase modulation in SiNOI nanowires featuring full process compatibility with Si photonic devices. Moreover, AlGaAs waveguides are heterointegrated on SOI in order to dramatically reduce (x1/10) thresholds in optical parametric oscillation and in the power required for supercontinuum generation under pulsed pumping. The manufacturing techniques allowing the monolithic co-integration of nonlinear functionalities on existing CMOS-compatible Si photonics for both active and passive components will be shown. Experimental evidence based on self-phase modulation show SiNOI and AlGaAs nanowires capable of generating wide-spanning frequency continua in the C-Band. This will pave the way for low-threshold power-efficient Kerr-based comb- and continuum- sources featuring compatibility with Si photonic integrated circuits (Si-PICs).

Continuous generation and stabilization of mesoscopic field superposition states in a quantum circuit

NASA Astrophysics Data System (ADS)

Roy, Ananda; Leghtas, Zaki; Stone, A. Douglas; Devoret, Michel; Mirrahimi, Mazyar

2015-01-01

While dissipation is widely considered to be harmful for quantum coherence, it can, when properly engineered, lead to the stabilization of nontrivial pure quantum states. We propose a scheme for continuous generation and stabilization of Schrödinger cat states in a cavity using dissipation engineering. We first generate nonclassical photon states with definite parity by means of a two-photon drive and dissipation, and then stabilize these transient states against single-photon decay. The single-photon stabilization is autonomous, and is implemented through a second engineered bath, which exploits the photon-number-dependent frequency splitting due to Kerr interactions in the strongly dispersive regime of circuit QED. Starting with the Hamiltonian of the baths plus cavity, we derive an effective model of only the cavity photon states along with analytic expressions for relevant physical quantities, such as the stabilization rate. The deterministic generation of such cat states is one of the key ingredients in performing universal quantum computation.

Pulsed source of spectrally uncorrelated and indistinguishable photons at telecom wavelengths.

PubMed

Bruno, N; Martin, A; Guerreiro, T; Sanguinetti, B; Thew, R T

2014-07-14

We report on the generation of indistinguishable photon pairs at telecom wavelengths based on a type-II parametric down conversion process in a periodically poled potassium titanyl phosphate (PPKTP) crystal. The phase matching, pump laser characteristics and coupling geometry are optimised to obtain spectrally uncorrelated photons with high coupling efficiencies. Four photons are generated by a counter-propagating pump in the same crystal and anlysed via two photon interference experiments between photons from each pair source as well as joint spectral and g((2)) measurements. We obtain a spectral purity of 0.91 and coupling efficiencies around 90% for all four photons without any filtering. These pure indistinguishable photon sources at telecom wavelengths are perfectly adapted for quantum network demonstrations and other multi-photon protocols.

EDITORIAL: Photonic Crystal Devices

NASA Astrophysics Data System (ADS)

Bhattacharya, Pallab K.

2007-05-01

The engineering of electromagnetic modes at optical frequencies in artificial dielectric structures with periodic and random variation of the refractive index, enabling control of the radiative properties of the materials and photon localization, was first proposed independently by Yablonovitch and John in 1987. It is possible to control the flow of light in the periodic dielectric structures, known as photonic crystals (PC). As light waves scatter within the photonic crystal, destructive interference cancels out light of certain wavelengths, thereby forming a photonic bandgap, similar to the energy bandgap for electron waves in a semiconductor. Photons whose energies lie within the gap cannot propagate through the periodic structure. This property can be used to make a low-loss cavity. If a point defect, such as one or more missing periods, is introduced into the periodic structure a region is obtained within which the otherwise forbidden wavelengths can be locally trapped. This property can be used to realize photonic microcavities. Similarly, a line of defects can serve as a waveguide. While the realization of three-dimensional (3D) photonic crystals received considerable attention initially, planar two-dimensional (2D) structures are currently favoured because of their relative ease of fabrication. 2D photonic crystal structures provide most of the functionality of 3D structures. These attributes have generated worldwide research and development of sub-μm and μm size active and passive photonic devices such as single-mode and non- classical light sources, guided wave devices, resonant cavity detection, and components for optical communication. More recently, photonic crystal guided wave devices are being investigated for application in microfludic and biochemical sensing. Photonic crystal devices have been realized with bulk, quantum well and quantum dot active regions. The Cluster of articles in this issue of Journal of Physics D: Applied Physics provides a glimpse of some of the most recent advances in the application of photonic crystals. The modelling of PC defect-mode cavities are described by Zhou et al. Ye and co-authors describe the concept and realization of a novel 3D silicon-based spiral PC. It is, in fact, the only article on 3D PCs. The design and realization of ultra-high Q heterostructure PC nanocavities are described by Song and co-authors. The concept of self-collimation of light in PCs and its applications are presented by Prather and co-workers. Experimental and numerical studies on the negative refraction related phenomenon in 2D PCs are the subject of the next article by Ozbay and co-authors. The emerging subject of slow light generation, control and propagation in PCs is presented in the next two articles by Baba and Mori and by Krauss. Finally, the progress made in the development of PC microcavity lasers and electrically injected microcavity light emitters and arrays is described, respectively, by O'Brien et al and by Chakravarty et al. It is hoped that readers will get a sense of the exciting developments and the possibilities presented by heterostructure photonic crystals and their devices from reading the articles in this Cluster.

Ultra-fast photon counting with a passive quenching silicon photomultiplier in the charge integration regime

NASA Astrophysics Data System (ADS)

Zhang, Guoqing; Lina, Liu

2018-02-01

An ultra-fast photon counting method is proposed based on the charge integration of output electrical pulses of passive quenching silicon photomultipliers (SiPMs). The results of the numerical analysis with actual parameters of SiPMs show that the maximum photon counting rate of a state-of-art passive quenching SiPM can reach ~THz levels which is much larger than that of the existing photon counting devices. The experimental procedure is proposed based on this method. This photon counting regime of SiPMs is promising in many fields such as large dynamic light power detection.

Site-controlled InGaN/GaN single-photon-emitting diode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Lei; Deng, Hui, E-mail: dengh@umich.edu; Teng, Chu-Hsiang

2016-04-11

We report single-photon emission from electrically driven site-controlled InGaN/GaN quantum dots. The device is fabricated from a planar light-emitting diode structure containing a single InGaN quantum well, using a top-down approach. The location, dimension, and height of each single-photon-emitting diode are controlled lithographically, providing great flexibility for chip-scale integration.

Influence of the photon orbital angular momentum on electric dipole transitions: negative experimental evidence.

PubMed

Giammanco, F; Perona, A; Marsili, P; Conti, F; Fidecaro, F; Gozzini, S; Lucchesini, A

2017-01-15

We describe an experiment of atomic spectroscopy devoted to ascertaining whether the orbital angular momentum (OAM) of photons has the same property of interacting with atoms or molecules as occurs for the spin angular momentum (SAM). In our experiment, rubidium vapors are excited by means of laser radiation with different combinations of OAM and SAM, particularly selected to inhibit or enhance the fluorescence according to the selection rules for the electric dipole transitions between the fundamental state and the first excited doublet. Our results clearly show that an electric-dipole-type transition is insensitive to the OAM value, and provide an original validation of a problem long debated in theoretical works.

Experimental comparison of direct detection Nyquist SSB transmission based on silicon dual-drive and IQ Mach-Zehnder modulators with electrical packaging.

PubMed

Ruan, Xiaoke; Li, Ke; Thomson, David J; Lacava, Cosimo; Meng, Fanfan; Demirtzioglou, Iosif; Petropoulos, Periklis; Zhu, Yixiao; Reed, Graham T; Zhang, Fan

2017-08-07

We have designed and fabricated a silicon photonic in-phase-quadrature (IQ) modulator based on a nested dual-drive Mach-Zehnder structure incorporating electrical packaging. We have assessed its use for generating Nyquist-shaped single sideband (SSB) signals by operating it either as an IQ Mach-Zehnder modulator (IQ-MZM) or using just a single branch of the dual-drive Mach-Zehnder modulator (DD-MZM). The impact of electrical packaging on the modulator bandwidth is also analyzed. We demonstrate 40 Gb/s (10Gbaud) 16-ary quadrature amplitude modulation (16-QAM) Nyquist-shaped SSB transmission over 160 km standard single mode fiber (SSMF). Without using any chromatic dispersion compensation, the bit error rates (BERs) of 5.4 × 10 -4 and 9.0 × 10 -5 were measured for the DD-MZM and IQ-MZM, respectively, far below the 7% hard-decision forward error correction threshold. The performance difference between IQ-MZM and DD-MZM is most likely due to the non-ideal electrical packaging. Our work is the first experimental comparison between silicon IQ-MZM and silicon DD-MZM in generating SSB signals. We also demonstrate 50 Gb/s (12.5Gbaud) 16-QAM Nyquist-shaped SSB transmission over 320 km SSMF with a BER of 2.7 × 10 -3 . Both the silicon IQ-MZM and the DD-MZM show potential for optical transmission at metro scale and for data center interconnection.

Radiative Processes in Graphene and Similar Nanostructures in Strong Electric Fields

NASA Astrophysics Data System (ADS)

Gavrilov, S. P.; Gitman, D. M.

2017-03-01

Low-energy single-electron dynamics in graphene monolayers and similar nanostructures is described by the Dirac model, being a 2+1 dimensional version of massless QED with the speed of light replaced by the Fermi velocity vF ≃ c/300. Methods of strong-field QFT are relevant for the Dirac model, since any low-frequency electric field requires a nonperturbative treatment of massless carriers in the case it remains unchanged for a sufficiently long time interval. In this case, the effects of creation and annihilation of electron-hole pairs produced from vacuum by a slowly varying and small-gradient electric field are relevant, thereby substantially affecting the radiation pattern. For this reason, the standard QED text-book theory of photon emission cannot be of help. We construct the Fock-space representation of the Dirac model, which takes exact accounts of the effects of vacuum instability caused by external electric fields, and in which the interaction between electrons and photons is taken into account perturbatively, following the general theory (the generalized Furry representation). We consider the effective theory of photon emission in the first-order approximation and construct the corresponding total probabilities, taking into account the unitarity relation.

Effects of electric fields on the photonic crystal formation from block copolymers

NASA Astrophysics Data System (ADS)

Lee, Taekun; Ju, Jin-wook; Ryoo, Won

2012-03-01

Effects of electric fields on the self-assembly of block copolymers have been investigated for thin films of polystyrene-bpoly( 2-vinyl pyridine); PS-b-P2VP, 52 kg/mol-b-57 kg/mol and 133 kg/mol-b-132 kg/mol. Block copolymers of polystyrene and poly(2-vinyl pyridine) have been demonstrated to form photonic crystals of 1D lamellar structure with optical band gaps that correspond to UV-to-visible light. The formation of lamellar structure toward minimum freeenergy state needs increasing polymer chain mobility, and the self-assembly process is accelerated usually by annealing, that is exposing the thin film to solvent vapor such as chloroform and dichloromethane. In this study, thin films of block copolymers were spin-coated on substrates and placed between electrode arrays of various patterns including pin-points, crossing and parallel lines. As direct or alternating currents were applied to electrode arrays during annealing process, the final structure of thin films was altered from the typical 1D lamellae in the absence of electric fields. The formation of lamellar structure was spatially controlled depending on the shape of electrode arrays, and the photonic band gap also could be modulated by electric field strength. The spatial formation of lamellar structure was examined with simulated distribution of electrical potentials by finite difference method (FDM). P2VP layers in self-assembled film were quaternized with methyl iodide vapor, and the remaining lamellar structure was investigated by field emission scanning electron microscope (FESEM). The result of this work is expected to provide ways of fabricating functional structures for display devices utilizing photonic crystal array.

Photonic crystal light source

DOEpatents

Fleming, James G [Albuquerque, NM; Lin, Shawn-Yu [Albuquerque, NM; Bur, James A [Corrales, NM

2004-07-27

A light source is provided by a photonic crystal having an enhanced photonic density-of-states over a band of frequencies and wherein at least one of the dielectric materials of the photonic crystal has a complex dielectric constant, thereby producing enhanced light emission at the band of frequencies when the photonic crystal is heated. The dielectric material can be a metal, such as tungsten. The spectral properties of the light source can be easily tuned by modification of the photonic crystal structure and materials. The photonic crystal light source can be heated electrically or other heating means. The light source can further include additional photonic crystals that exhibit enhanced light emission at a different band of frequencies to provide for color mixing. The photonic crystal light source may have applications in optical telecommunications, information displays, energy conversion, sensors, and other optical applications.

Next Generation Driver for Attosecond and Laser-plasma Physics.

PubMed

Rivas, D E; Borot, A; Cardenas, D E; Marcus, G; Gu, X; Herrmann, D; Xu, J; Tan, J; Kormin, D; Ma, G; Dallari, W; Tsakiris, G D; Földes, I B; Chou, S-W; Weidman, M; Bergues, B; Wittmann, T; Schröder, H; Tzallas, P; Charalambidis, D; Razskazovskaya, O; Pervak, V; Krausz, F; Veisz, L

2017-07-12

The observation and manipulation of electron dynamics in matter call for attosecond light pulses, routinely available from high-order harmonic generation driven by few-femtosecond lasers. However, the energy limitation of these lasers supports only weak sources and correspondingly linear attosecond studies. Here we report on an optical parametric synthesizer designed for nonlinear attosecond optics and relativistic laser-plasma physics. This synthesizer uniquely combines ultra-relativistic focused intensities of about 10 20  W/cm 2 with a pulse duration of sub-two carrier-wave cycles. The coherent combination of two sequentially amplified and complementary spectral ranges yields sub-5-fs pulses with multi-TW peak power. The application of this source allows the generation of a broad spectral continuum at 100-eV photon energy in gases as well as high-order harmonics in relativistic plasmas. Unprecedented spatio-temporal confinement of light now permits the investigation of electric-field-driven electron phenomena in the relativistic regime and ultimately the rise of next-generation intense isolated attosecond sources.

On-chip generation of heralded photon-number states

NASA Astrophysics Data System (ADS)

Vergyris, Panagiotis; Meany, Thomas; Lunghi, Tommaso; Sauder, Gregory; Downes, James; Steel, M. J.; Withford, Michael J.; Alibart, Olivier; Tanzilli, Sébastien

2016-10-01

Beyond the use of genuine monolithic integrated optical platforms, we report here a hybrid strategy enabling on-chip generation of configurable heralded two-photon states. More specifically, we combine two different fabrication techniques, i.e., non-linear waveguides on lithium niobate for efficient photon-pair generation and femtosecond-laser-direct-written waveguides on glass for photon manipulation. Through real-time device manipulation capabilities, a variety of path-coded heralded two-photon states can be produced, ranging from product to entangled states. Those states are engineered with high levels of purity, assessed by fidelities of 99.5 ± 8% and 95.0 ± 8%, respectively, obtained via quantum interferometric measurements. Our strategy therefore stands as a milestone for further exploiting entanglement-based protocols, relying on engineered quantum states, and enabled by scalable and compatible photonic circuits.

On-chip generation of heralded photon-number states

PubMed Central

Vergyris, Panagiotis; Meany, Thomas; Lunghi, Tommaso; Sauder, Gregory; Downes, James; Steel, M. J.; Withford, Michael J.; Alibart, Olivier; Tanzilli, Sébastien

2016-01-01

Beyond the use of genuine monolithic integrated optical platforms, we report here a hybrid strategy enabling on-chip generation of configurable heralded two-photon states. More specifically, we combine two different fabrication techniques, i.e., non-linear waveguides on lithium niobate for efficient photon-pair generation and femtosecond-laser-direct-written waveguides on glass for photon manipulation. Through real-time device manipulation capabilities, a variety of path-coded heralded two-photon states can be produced, ranging from product to entangled states. Those states are engineered with high levels of purity, assessed by fidelities of 99.5 ± 8% and 95.0 ± 8%, respectively, obtained via quantum interferometric measurements. Our strategy therefore stands as a milestone for further exploiting entanglement-based protocols, relying on engineered quantum states, and enabled by scalable and compatible photonic circuits. PMID:27775062

Current trends on 2D materials for photonics devices: an NSF perspective (Conference Presentation)

NASA Astrophysics Data System (ADS)

Fallahi, Mahmoud

2017-05-01

Recent advancements in two-dimensional (2D) materials have opened significant research opportunities in optics and photonics. While the initial focus on 2D materials was on Graphene, new generation of 2D materials such as hexagonal boron nitride (h-BN), transition metal dichalcogenides (TMDCs), monolayer black phosphorous (BP) and other monolayer structures have shown unique electrical and optical properties. For example, h-BN is an insulator, while monolayers of some TMDCs such as MoS2 and WSe2 are direct band-gap semiconductors. Depending on the choice of material compositional and layer variations their optical properties can be engineered, making them particularly attractive as novel light sources, photodetectors, modulators and photovoltaic components, in particular for few photon applications. Plasmonic properties of 2D materials make them suitable for nanophotonics and monolithic integration with other conventional materials. The National Science Foundation (NSF) is a US federal agency dedicated to promote progress of science and engineering. NSF is the funding source for approximately 24 percent of all federally supported basic research conducted by America's colleges and universities. NSF has recently supported several initiatives related to novel 2D material and device research. In this talk, I will first give an overview of the NSF programs and funding opportunities. The second part of the talk will be focused on the programs related to 2D materials for photonic devices and program specific initiatives. Several highlights of the recent achievements and awards in the field of 2D materials for photonic devices will be presented.

Time-Bin-Encoded Boson Sampling with a Single-Photon Device.

PubMed

He, Yu; Ding, X; Su, Z-E; Huang, H-L; Qin, J; Wang, C; Unsleber, S; Chen, C; Wang, H; He, Y-M; Wang, X-L; Zhang, W-J; Chen, S-J; Schneider, C; Kamp, M; You, L-X; Wang, Z; Höfling, S; Lu, Chao-Yang; Pan, Jian-Wei

2017-05-12

Boson sampling is a problem strongly believed to be intractable for classical computers, but can be naturally solved on a specialized photonic quantum simulator. Here, we implement the first time-bin-encoded boson sampling using a highly indistinguishable (∼94%) single-photon source based on a single quantum-dot-micropillar device. The protocol requires only one single-photon source, two detectors, and a loop-based interferometer for an arbitrary number of photons. The single-photon pulse train is time-bin encoded and deterministically injected into an electrically programmable multimode network. The observed three- and four-photon boson sampling rates are 18.8 and 0.2 Hz, respectively, which are more than 100 times faster than previous experiments based on parametric down-conversion.

Single photon generation through exciton-exciton annihilation in air-suspended carbon nanotubes

NASA Astrophysics Data System (ADS)

Ishii, Akihiro; Uda, Takushi; Kato, Yuichiro K.

Carbon nanotubes have great potential for single photon sources as they have stable exciton states even at room temperature and their emission wavelengths cover the telecommunication bands. In recent years, single photon emission from carbon nanotubes has been achieved by creating localized states of excitons. In contrast to such an approach, here we utilize mobile excitons and show that single photons can be generated in air-suspended carbon nanotubes, where exciton diffusion length is as long as several hundred nanometers and exciton-exciton annihilation is efficient. We perform photoluminescence microscopy on as-grown air-suspended carbon nanotubes in order to determine their chirality and suspended length. Photon correlation measurements are performed on nanotube emission at room temperature using a Hanbury-Brown-Twiss setup with InGaAs/InP single photon detectors. We observe antibunching with a clear excitation power dependence, where we obtain g (2) (0) value less than 0.5 at low excitation powers, indicating single photon generation. We show such g (2) (0) data with different chiralities and suspended lengths, and the effects of exciton diffusion on single photon generation processes are discussed. Work supported by KAKENHI (26610080, 16H05962), The Canon Foundation, and MEXT (Photon Frontier Network Program, Nanotechnology Platform). A.I. is supported by MERIT and JSPS Research Fellowship, and T.U. is supported by ALPS.

Finite element method analysis of band gap and transmission of two-dimensional metallic photonic crystals at terahertz frequencies.

PubMed

Degirmenci, Elif; Landais, Pascal

2013-10-20

Photonic band gap and transmission characteristics of 2D metallic photonic crystals at THz frequencies have been investigated using finite element method (FEM). Photonic crystals composed of metallic rods in air, in square and triangular lattice arrangements, are considered for transverse electric and transverse magnetic polarizations. The modes and band gap characteristics of metallic photonic crystal structure are investigated by solving the eigenvalue problem over a unit cell of the lattice using periodic boundary conditions. A photonic band gap diagram of dielectric photonic crystal in square lattice array is also considered and compared with well-known plane wave expansion results verifying our FEM approach. The photonic band gap designs for both dielectric and metallic photonic crystals are consistent with previous studies obtained by different methods. Perfect match is obtained between photonic band gap diagrams and transmission spectra of corresponding lattice structure.

Design automation for integrated nonlinear logic circuits (Conference Presentation)

NASA Astrophysics Data System (ADS)

Van Vaerenbergh, Thomas; Pelc, Jason; Santori, Charles; Bose, Ranojoy; Kielpinski, Dave; Beausoleil, Raymond G.

2016-05-01

A key enabler of the IT revolution of the late 20th century was the development of electronic design automation (EDA) tools allowing engineers to manage the complexity of electronic circuits with transistor counts now reaching into the billions. Recently, we have been developing large-scale nonlinear photonic integrated logic circuits for next generation all-optical information processing. At this time a sufficiently powerful EDA-style software tool chain to design this type of complex circuits does not yet exist. Here we describe a hierarchical approach to automating the design and validation of photonic integrated circuits, which can scale to several orders of magnitude higher complexity than the state of the art. Most photonic integrated circuits developed today consist of a small number of components, and only limited hierarchy. For example, a simple photonic transceiver may contain on the order of 10 building-block components, consisting of grating couplers for photonic I/O, modulators, and signal splitters/combiners. Because this is relatively easy to lay out by hand (or simple script) existing photonic design tools have relatively little automation in comparison to electronics tools. But demonstrating all-optical logic will require significantly more complex photonic circuits containing up to 1,000 components, hence becoming infeasible to design manually. Our design framework is based off Python-based software from Luceda Photonics which provides an environment to describe components, simulate their behavior, and export design files (GDS) to foundries for fabrication. At a fundamental level, a photonic component is described as a parametric cell (PCell) similarly to electronics design. PCells are described by geometric characteristics of their layout. A critical part of the design framework is the implementation of PCells as Python objects. PCell objects can then use inheritance to simplify design, and hierarchical designs can be made by creating composite PCells (modules) which consist of primitive building-block PCells (components). To automatically produce layouts, we built on a construct provided by Luceda called a PlaceAndAutoRoute cell: we create a module component by supplying a list of child cells, and a list of the desired connections between the cells (e.g. the out0 port of a microring is connected to a grating coupler). This functionality allowed us to write algorithms to automatically lay out the components: for instance, by laying out the first component and walking through the list of connections to check to see if the next component is already placed or not. The placement and orientation of the new component is determined by minimizing the length of a connecting waveguide. Our photonic circuits also utilize electrical signals to tune the photonic elements (setting propagation phases or microring resonant frequencies via thermo-optical tuning): the algorithm also routes the contacts for the metal heaters to contact pads at the edge of the circuit being designed where it can be contacted by electrical probes. We are currently validating a test run fabricated over the summer, and will use detailed characterization results to prepare our final design cycle in which we aim to demonstrate complex operational logic circuits containing ~50-100 nonlinear resonators.

Effect of Loss on Multiplexed Single-Photon Sources (Open Access Publisher’s Version)

DTIC Science & Technology

2015-04-28

lossy components on near- and long-term experimental goals, we simulate themultiplexed sources when used formany- photon state generation under various...efficient integer factorization and digital quantum simulation [7, 8], which relies critically on the development of a high-performance, on-demand photon ...SPDC) or spontaneous four-wave mixing: parametric processes which use a pump laser in a nonlinearmaterial to spontaneously generate photon pairs

A versatile design for resonant guided-wave parametric down-conversion sources for quantum repeaters

NASA Astrophysics Data System (ADS)

Brecht, Benjamin; Luo, Kai-Hong; Herrmann, Harald; Silberhorn, Christine

2016-05-01

Quantum repeaters—fundamental building blocks for long-distance quantum communication—are based on the interaction between photons and quantum memories. The photons must fulfil stringent requirements on central frequency, spectral bandwidth and purity in order for this interaction to be efficient. We present a design scheme for monolithically integrated resonant photon-pair sources based on parametric down-conversion in nonlinear waveguides, which facilitate the generation of such photons. We investigate the impact of different design parameters on the performance of our source. The generated photon spectral bandwidths can be varied between several tens of MHz up to around 1 GHz, facilitating an efficient coupling to different memories. The central frequency of the generated photons can be coarsely tuned by adjusting the pump frequency, poling period and sample temperature, and we identify stability requirements on the pump laser and sample temperature that can be readily fulfilled with off-the-shelf components. We find that our source is capable of generating high-purity photons over a wide range of photon bandwidths. Finally, the PDC emission can be frequency fine-tuned over several GHz by simultaneously adjusting the sample temperature and pump frequency. We conclude our study with demonstrating the adaptability of our source to different quantum memories.

Harnessing rogue wave for supercontinuum generation in cascaded photonic crystal fiber.

PubMed

Zhao, Saili; Yang, Hua; Zhao, Chujun; Xiao, Yuzhe

2017-04-03

Based on induced modulation instability, we present a numerical study on harnessing rogue wave for supercontinuum generation in cascaded photonic crystal fibers. By selecting optimum modulation frequency, we achieve supercontinuum with a great improvement on spectrum stability when long-pulse is used as the pump. In this case, rogue wave can be obtained in the first segmented photonic crystal fiber with one zero dispersion wavelength in a controllable manner. Numerical simulations show that spectral range and flatness can be regulated in an extensive range by cascading a photonic crystal fiber with two zero dispersion wavelengths. Some novel phenomena are observed in the second segmented photonic crystal fiber. When the second zero dispersion wavelength is close to the first one, rogue wave is directly translated into dispersion waves, which is conducive to the generation of smoother supercontinuum. When the second zero dispersion wavelength is far away from the first one, rogue wave is translated into the form of fundamental soliton steadily propagating in the vicinity of the second zero dispersion wavelength. Meanwhile, the corresponding red-shifted dispersion wave is generated when the phase matching condition is met, which is beneficial to the generation of wider supercontinuum. The results presented in this work provide a better application of optical rogue wave to generate flat and broadband supercontinuum in cascaded photonic crystal fibers.

Integrated spatial multiplexing of heralded single-photon sources

PubMed Central

Collins, M.J.; Xiong, C.; Rey, I.H.; Vo, T.D.; He, J.; Shahnia, S.; Reardon, C.; Krauss, T.F.; Steel, M.J.; Clark, A.S.; Eggleton, B.J.

2013-01-01

The non-deterministic nature of photon sources is a key limitation for single-photon quantum processors. Spatial multiplexing overcomes this by enhancing the heralded single-photon yield without enhancing the output noise. Here the intrinsic statistical limit of an individual source is surpassed by spatially multiplexing two monolithic silicon-based correlated photon pair sources in the telecommunications band, demonstrating a 62.4% increase in the heralded single-photon output without an increase in unwanted multipair generation. We further demonstrate the scalability of this scheme by multiplexing photons generated in two waveguides pumped via an integrated coupler with a 63.1% increase in the heralded photon rate. This demonstration paves the way for a scalable architecture for multiplexing many photon sources in a compact integrated platform and achieving efficient two-photon interference, required at the core of optical quantum computing and quantum communication protocols. PMID:24107840

Generation of Nonclassical Biphoton States through Cascaded Quantum Walks on a Nonlinear Chip

NASA Astrophysics Data System (ADS)

Solntsev, Alexander S.; Setzpfandt, Frank; Clark, Alex S.; Wu, Che Wen; Collins, Matthew J.; Xiong, Chunle; Schreiber, Andreas; Katzschmann, Fabian; Eilenberger, Falk; Schiek, Roland; Sohler, Wolfgang; Mitchell, Arnan; Silberhorn, Christine; Eggleton, Benjamin J.; Pertsch, Thomas; Sukhorukov, Andrey A.; Neshev, Dragomir N.; Kivshar, Yuri S.

2014-07-01

We demonstrate a nonlinear optical chip that generates photons with reconfigurable nonclassical spatial correlations. We employ a quadratic nonlinear waveguide array, where photon pairs are generated through spontaneous parametric down-conversion and simultaneously spread through quantum walks between the waveguides. Because of the quantum interference of these cascaded quantum walks, the emerging photons can become entangled over multiple waveguide positions. We experimentally observe highly nonclassical photon-pair correlations, confirming the high fidelity of on-chip quantum interference. Furthermore, we demonstrate biphoton-state tunability by spatial shaping and frequency tuning of the classical pump beam.

Multiresponsive Graphene-Aerogel-Directed Phase-Change Smart Fibers.

PubMed

Li, Guangyong; Hong, Guo; Dong, Dapeng; Song, Wenhui; Zhang, Xuetong

2018-06-14

Wearable devices and systems demand multifunctional units with intelligent and integrative functions. Smart fibers with response to external stimuli, such as electrical, thermal, and photonic signals, etc., as well as offering energy storage/conversion are essential units for wearable electronics, but still remain great challenges. Herein, flexible, strong, and self-cleaning graphene-aerogel composite fibers, with tunable functions of thermal conversion and storage under multistimuli, are fabricated. The fibers made from porous graphene aerogel/organic phase-change materials coated with hydrophobic fluorocarbon resin render a wide range of phase transition temperature and enthalpy (0-186 J g -1 ). The strong and compliant fibers are twisted into yarn and woven into fabrics, showing a self-clean superhydrophobic surface and excellent multiple responsive properties to external stimuli (electron/photon/thermal) together with reversible energy storage and conversion. Such aerogel-directed smart fibers promise for broad applications in the next-generation of wearable systems. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Parallel and Multivalued Logic by the Two-Dimensional Photon-Echo Response of a Rhodamine–DNA Complex

PubMed Central

2015-01-01

Implementing parallel and multivalued logic operations at the molecular scale has the potential to improve the miniaturization and efficiency of a new generation of nanoscale computing devices. Two-dimensional photon-echo spectroscopy is capable of resolving dynamical pathways on electronic and vibrational molecular states. We experimentally demonstrate the implementation of molecular decision trees, logic operations where all possible values of inputs are processed in parallel and the outputs are read simultaneously, by probing the laser-induced dynamics of populations and coherences in a rhodamine dye mounted on a short DNA duplex. The inputs are provided by the bilinear interactions between the molecule and the laser pulses, and the output values are read from the two-dimensional molecular response at specific frequencies. Our results highlights how ultrafast dynamics between multiple molecular states induced by light–matter interactions can be used as an advantage for performing complex logic operations in parallel, operations that are faster than electrical switching. PMID:25984269

Discovery of Emergent Photon and Monopoles in a Quantum Spin Liquid

NASA Astrophysics Data System (ADS)

Tokiwa, Yoshifumi; Yamashita, Takuya; Terazawa, Daiki; Kimura, Kenta; Kasahara, Yuichi; Onishi, Takafumi; Kato, Yasuyuki; Halim, Mario; Gegenwart, Philipp; Shibauchi, Takasada; Nakatsuji, Satoru; Moon, Eun-Gook; Matsuda, Yuji

2018-06-01

Quantum spin liquid (QSL) is an exotic quantum phase of matter whose ground state is quantum-mechanically entangled without any magnetic ordering. A central issue concerns emergent excitations that characterize QSLs, which are hypothetically associated with quasiparticle fractionalization and topological order. Here we report highly unusual heat conduction generated by the spin degrees of freedom in a QSL state of the pyrochlore magnet Pr2Zr2O7, which hosts spin-ice correlations with strong quantum fluctuations. The thermal conductivity in high temperature regime exhibits a two-gap behavior, which is consistent with the gapped excitations of magnetic (M-) and electric monopoles (E-particles). At very low temperatures below 200 mK, the thermal conductivity unexpectedly shows a dramatic enhancement, which well exceeds purely phononic conductivity, demonstrating the presence of highly mobile spin excitations. This new type of excitations can be attributed to emergent photons (ν-particle), coherent gapless spin excitations in a spin-ice manifold.

Correlation in photon pairs generated using four-wave mixing in a cold atomic ensemble

NASA Astrophysics Data System (ADS)

Ferdinand, Andrew Richard; Manjavacas, Alejandro; Becerra, Francisco Elohim

2017-04-01

Spontaneous four-wave mixing (FWM) in atomic ensembles can be used to generate narrowband entangled photon pairs at or near atomic resonances. While extensive research has been done to investigate the quantum correlations in the time and polarization of such photon pairs, the study and control of high dimensional quantum correlations contained in their spatial degrees of freedom has not been fully explored. In our work we experimentally investigate the generation of correlated light from FWM in a cold ensemble of cesium atoms as a function of the frequencies of the pump fields in the FWM process. In addition, we theoretically study the spatial correlations of the photon pairs generated in the FWM process, specifically the joint distribution of their orbital angular momentum (OAM). We investigate the width of the distribution of the OAM modes, known as the spiral bandwidth, and the purity of OAM correlations as a function of the properties of the pump fields, collected photons, and the atomic ensemble. These studies will guide experiments involving high dimensional entanglement of photons generated from this FWM process and OAM-based quantum communication with atomic ensembles. This work is supported by AFORS Grant FA9550-14-1-0300.

Electrical instability of InGaZnO thin-film transistors with and without titanium sub-oxide layer under light illumination

NASA Astrophysics Data System (ADS)

Chiu, Y. C.; Zheng, Z. W.; Cheng, C. H.; Chen, P. C.; Yen, S. S.; Fan, C. C.; Hsu, H. H.; Kao, H. L.; Chang, C. Y.

2017-03-01

The electrical instability behaviors of amorphous indium-gallium-zinc oxide thin-film transistors with and without titanium sub-oxide passivation layer were investigated under light illumination in this study. For the unpassivated IGZO TFT device, in contrast with the dark case, a noticeable increase of the sub-threshold swing was observed when under the illumination environment, which can be attributed to the generation of ionized oxygen vacancies within the α-IGZO active layer by high energy photons. For the passivated TFT device, the much smaller SS of 70 mV/dec and high device mobility of >100 cm2/Vs at a drive voltage of 3 V with negligible degradation under light illumination are achieved due to the passivation effect of n-type titanium sub-oxide semiconductor, which may create potential application for high-performance display.

Design and Manufacturing Criteria for Beam Position Monitor (BPM) of Taiwan Photon Source (TPS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsueh, H. P.; Chang, C. C.; Hsu, S. N.

2010-06-23

There are quite some considerations when the button feedthrough is designed and manufactured in a new 3rd generation synchrotron light source like the to-be-constructed TPS. It is the responsibility of the button feedthrough designer to design a feedthrough with the lowest probable HOM problem. It is also required for the designer to analyze the consequences for each possible mechanical error during manufacturing and therefore set standards of tolerance. We have been using MAFIA to optimize the design of feedthrough including flange type on bending chamber section and primary BPM on insertion device section. We also have set some criteria formore » feedthrough manufacturing, inspection, and welding based on hands-on experience on feedthrough electrical properties measuring, sorting, inspection, and laser welding. Here we will present the MAFIA results, electrical measurement results, and laser welding results and analysis. Criteria based on these results will also be presented.« less

Self-assembled fibre optoelectronics with discrete translational symmetry

PubMed Central

Rein, Michael; Levy, Etgar; Gumennik, Alexander; Abouraddy, Ayman F.; Joannopoulos, John; Fink, Yoel

2016-01-01

Fibres with electronic and photonic properties are essential building blocks for functional fabrics with system level attributes. The scalability of thermal fibre drawing approach offers access to large device quantities, while constraining the devices to be translational symmetric. Lifting this symmetry to create discrete devices in fibres will increase their utility. Here, we draw, from a macroscopic preform, fibres that have three parallel internal non-contacting continuous domains; a semiconducting glass between two conductors. We then heat the fibre and generate a capillary fluid instability, resulting in the selective transformation of the cylindrical semiconducting domain into discrete spheres while keeping the conductive domains unchanged. The cylindrical-to-spherical expansion bridges the continuous conducting domains to create ∼104 self-assembled, electrically contacted and entirely packaged discrete spherical devices per metre of fibre. The photodetection and Mie resonance dependent response are measured by illuminating the fibre while connecting its ends to an electrical readout. PMID:27698454

Self-assembled fibre optoelectronics with discrete translational symmetry.

PubMed

Rein, Michael; Levy, Etgar; Gumennik, Alexander; Abouraddy, Ayman F; Joannopoulos, John; Fink, Yoel

2016-10-04

Fibres with electronic and photonic properties are essential building blocks for functional fabrics with system level attributes. The scalability of thermal fibre drawing approach offers access to large device quantities, while constraining the devices to be translational symmetric. Lifting this symmetry to create discrete devices in fibres will increase their utility. Here, we draw, from a macroscopic preform, fibres that have three parallel internal non-contacting continuous domains; a semiconducting glass between two conductors. We then heat the fibre and generate a capillary fluid instability, resulting in the selective transformation of the cylindrical semiconducting domain into discrete spheres while keeping the conductive domains unchanged. The cylindrical-to-spherical expansion bridges the continuous conducting domains to create ∼10 4 self-assembled, electrically contacted and entirely packaged discrete spherical devices per metre of fibre. The photodetection and Mie resonance dependent response are measured by illuminating the fibre while connecting its ends to an electrical readout.

High-sensitivity silicon ultraviolet p+-i-n avalanche photodiode using ultra-shallow boron gradient doping

DOE PAGES

Xia, Zhenyang; Zang, Kai; Liu, Dong; ...

2017-08-21

Photo detection of ultraviolet (UV) light remains a challenge since the penetration depth of UV light is limited to the nanometer scale. Therefore, the doping profile and electric field in the top nanometer range of the photo detection devices become critical. Traditional UV photodetectors usually use a constant doping profile near the semiconductor surface, resulting in a negligible electric field, which limits the photo-generated carrier collection efficiency of the photodetector. Here, we demonstrate, via the use of an optimized gradient boron doping technique, that the carrier collection efficiency and photo responsivity under the UV wavelength region have been enhanced. Moreover,more » the ultrathin p+-i-n junction shows an avalanche gain of 2800 and an ultra-low junction capacitance (sub pico-farad), indicating potential applications in the low timing jitter single photon detection area.« less

High-sensitivity silicon ultraviolet p+-i-n avalanche photodiode using ultra-shallow boron gradient doping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xia, Zhenyang; Zang, Kai; Liu, Dong

Photo detection of ultraviolet (UV) light remains a challenge since the penetration depth of UV light is limited to the nanometer scale. Therefore, the doping profile and electric field in the top nanometer range of the photo detection devices become critical. Traditional UV photodetectors usually use a constant doping profile near the semiconductor surface, resulting in a negligible electric field, which limits the photo-generated carrier collection efficiency of the photodetector. Here, we demonstrate, via the use of an optimized gradient boron doping technique, that the carrier collection efficiency and photo responsivity under the UV wavelength region have been enhanced. Moreover,more » the ultrathin p+-i-n junction shows an avalanche gain of 2800 and an ultra-low junction capacitance (sub pico-farad), indicating potential applications in the low timing jitter single photon detection area.« less

Design and Manufacturing Criteria for Beam Position Monitor (BPM) of Taiwan Photon Source (TPS)

NASA Astrophysics Data System (ADS)

Hsueh, H. P.; Chang, C. C.; Hsu, S. N.; Huang, I. T.; Chen, Y. B.; Kuan, C. K.; Hsiung, G. Y.; Chen, J. R.

2010-06-01

There are quite some considerations when the button feedthrough is designed and manufactured in a new 3rd generation synchrotron light source like the to-be-constructed TPS. It is the responsibility of the button feedthrough designer to design a feedthrough with the lowest probable HOM problem. It is also required for the designer to analyze the consequences for each possible mechanical error during manufacturing and therefore set standards of tolerance. We have been using MAFIA to optimize the design of feedthrough including flange type on bending chamber section and primary BPM on insertion device section. We also have set some criteria for feedthrough manufacturing, inspection, and welding based on hands-on experience on feedthrough electrical properties measuring, sorting, inspection, and laser welding. Here we will present the MAFIA results, electrical measurement results, and laser welding results and analysis. Criteria based on these results will also be presented.

Continuous-Variable Triple-Photon States Quantum Entanglement

NASA Astrophysics Data System (ADS)

González, E. A. Rojas; Borne, A.; Boulanger, B.; Levenson, J. A.; Bencheikh, K.

2018-01-01

We investigate the quantum entanglement of the three modes associated with the three-photon states obtained by triple-photon generation in a phase-matched third-order nonlinear optical interaction. Although the second-order processes have been extensively dealt with, there is no direct analogy between the second and third-order mechanisms. We show, for example, the absence of quantum entanglement between the quadratures of the three modes in the case of spontaneous parametric triple-photon generation. However, we show robust, seeding-dependent, genuine triple-photon entanglement in the fully seeded case.

Continuous-Variable Triple-Photon States Quantum Entanglement.

PubMed

González, E A Rojas; Borne, A; Boulanger, B; Levenson, J A; Bencheikh, K

2018-01-26

We investigate the quantum entanglement of the three modes associated with the three-photon states obtained by triple-photon generation in a phase-matched third-order nonlinear optical interaction. Although the second-order processes have been extensively dealt with, there is no direct analogy between the second and third-order mechanisms. We show, for example, the absence of quantum entanglement between the quadratures of the three modes in the case of spontaneous parametric triple-photon generation. However, we show robust, seeding-dependent, genuine triple-photon entanglement in the fully seeded case.

Two-step photon up-conversion solar cells

PubMed Central

Asahi, Shigeo; Teranishi, Haruyuki; Kusaki, Kazuki; Kaizu, Toshiyuki; Kita, Takashi

2017-01-01

Reducing the transmission loss for below-gap photons is a straightforward way to break the limit of the energy-conversion efficiency of solar cells (SCs). The up-conversion of below-gap photons is very promising for generating additional photocurrent. Here we propose a two-step photon up-conversion SC with a hetero-interface comprising different bandgaps of Al0.3Ga0.7As and GaAs. The below-gap photons for Al0.3Ga0.7As excite GaAs and generate electrons at the hetero-interface. The accumulated electrons at the hetero-interface are pumped upwards into the Al0.3Ga0.7As barrier by below-gap photons for GaAs. Efficient two-step photon up-conversion is achieved by introducing InAs quantum dots at the hetero-interface. We observe not only a dramatic increase in the additional photocurrent, which exceeds the reported values by approximately two orders of magnitude, but also an increase in the photovoltage. These results suggest that the two-step photon up-conversion SC has a high potential for implementation in the next-generation high-efficiency SCs. PMID:28382945

A monolithically integrated polarization entangled photon pair source on a silicon chip

PubMed Central

Matsuda, Nobuyuki; Le Jeannic, Hanna; Fukuda, Hiroshi; Tsuchizawa, Tai; Munro, William John; Shimizu, Kaoru; Yamada, Koji; Tokura, Yasuhiro; Takesue, Hiroki

2012-01-01

Integrated photonic circuits are one of the most promising platforms for large-scale photonic quantum information systems due to their small physical size and stable interferometers with near-perfect lateral-mode overlaps. Since many quantum information protocols are based on qubits defined by the polarization of photons, we must develop integrated building blocks to generate, manipulate, and measure the polarization-encoded quantum state on a chip. The generation unit is particularly important. Here we show the first integrated polarization-entangled photon pair source on a chip. We have implemented the source as a simple and stable silicon-on-insulator photonic circuit that generates an entangled state with 91 ± 2% fidelity. The source is equipped with versatile interfaces for silica-on-silicon or other types of waveguide platforms that accommodate the polarization manipulation and projection devices as well as pump light sources. Therefore, we are ready for the full-scale implementation of photonic quantum information systems on a chip. PMID:23150781

Microgap ultra-violet detector

DOEpatents

Wuest, Craig R.; Bionta, Richard M.

1994-01-01

A microgap ultra-violet detector of photons with wavelengths less than 400 run (4000 Angstroms) which comprises an anode and a cathode separated by a gas-filled gap and having an electric field placed across the gap. Either the anode or the cathode is semi-transparent to UV light. Upon a UV photon striking the cathode an electron is expelled and accelerated across the gap by the electric field causing interactions with other electrons to create an electron avalanche which contacts the anode. The electron avalanche is detected and converted to an output pulse.

IYL project: pinky-powered photons

NASA Astrophysics Data System (ADS)

Dreyer, Elizabeth F. C.; Aku-Leh, Cynthia; Nees, John A.; Sala, Anca L.; Smith, Arlene; Jones, Timothy

2016-09-01

Pinky-powered Photons is an activity created by the Michigan Light Project during the International Year of Light to encourage creativity in learning about light. It is a low-cost project. Participants make and take home a colorful LED light powered entirely by their fingers. Younger visitors "package" the electrical element into their own creation while older visitors solder the electrical parts together and then create their own design. This paper will detail the learning objectives and outcomes of this project as well as how to implement it in an outreach event or classroom.

Microgap ultra-violet detector

DOEpatents

Wuest, C.R.; Bionta, R.M.

1994-09-20

A microgap ultra-violet detector of photons with wavelengths less than 400 run (4,000 Angstroms) which comprises an anode and a cathode separated by a gas-filled gap and having an electric field placed across the gap is disclosed. Either the anode or the cathode is semi-transparent to UV light. Upon a UV photon striking the cathode an electron is expelled and accelerated across the gap by the electric field causing interactions with other electrons to create an electron avalanche which contacts the anode. The electron avalanche is detected and converted to an output pulse. 2 figs.

A Novel Approach to Photonic Generation and Modulation of Ultra-Wideband Pulses

NASA Astrophysics Data System (ADS)

Xiang, Peng; Guo, Hao; Chen, Dalei; Zhu, Huatao

2016-01-01

A novel approach to photonic generation of ultra-wideband (UWB) signals is proposed in this paper. The proposed signal generator is capable of generating UWB doublet pulses with flexible reconfigurability, and many different pulse modulation formats, including the commonly used pulse-position modulation (PPM) and bi-phase modulation (BPM) can be realized. Moreover, the photonic UWB pulse generator is capable of generating UWB signals with a tunable spectral notch-band, which is desirable to realize the interference avoidance between UWB and other narrow band systems, such as Wi-Fi. A mathematical model describing the proposed system is developed and the generation of UWB signals with different modulation formats is demonstrated via computer simulations.

Hong-Ou-Mandel Interference Between Triggered And Heralded Single Photons From Separate Atomic Systems

NASA Astrophysics Data System (ADS)

Cere, Alessandro; Leong, Victor; Kaur Gulati, Gurpreet; Srivathsan, Bharath; Kosen, Sandoko; Kurtsiefer, Christian

2015-05-01

The realization of quantum networks and long distance quantum communication rely on the capability of generating entanglement between separated nodes. We demonstrate the compatibility of two different sources of single photons: a single atom and four-wave mixing in a cold cloud of atoms. The four-wave mixing process in a cloud of cold 87Rb generates photon pairs. The cascade level scheme used ensures the generation of heralded single photons with exponentially decaying temporal envelope. The temporal shape of the heralding photons matches the shape of photons emitted by spontaneous decay but for the shorter coherence time A single 87Rb atom is trapped in an far-off-resonance optical dipole trap and can be excited with high probability using a short (~3 ns) intense pulse of resonant light, emitting a single photon by spontaneous decay. A large numerical aperture lens collects ~4% of the total fluorescence. The heralded and the triggered photons are launched into a Houng-Ou-Mandel interferometer: a symmetrical beam-splitter with outputs connected to single photon detectors. Scanning the relative delay between the two sources we observe the HOM dip with a maximum visibility of 70 +/-4%.

Effect of temperature on terahertz photonic and omnidirectional band gaps in one-dimensional quasi-periodic photonic crystals composed of semiconductor InSb.

PubMed

Singh, Bipin K; Pandey, Praveen C

2016-07-20

Engineering of thermally tunable terahertz photonic and omnidirectional bandgaps has been demonstrated theoretically in one-dimensional quasi-periodic photonic crystals (PCs) containing semiconductor and dielectric materials. The considered quasi-periodic structures are taken in the form of Fibonacci, Thue-Morse, and double periodic sequences. We have shown that the photonic and omnidirectional bandgaps in the quasi-periodic structures with semiconductor constituents are strongly depend on the temperature, thickness of the constituted semiconductor and dielectric material layers, and generations of the quasi-periodic sequences. It has been found that the number of photonic bandgaps increases with layer thickness and generation of the quasi-periodic sequences. Omnidirectional bandgaps in the structures have also been obtained. Results show that the bandwidths of photonic and omnidirectional bandgaps are tunable by changing the temperature and lattice parameters of the structures. The generation of quasi-periodic sequences can also change the properties of photonic and omnidirectional bandgaps remarkably. The frequency range of the photonic and omnidirectional bandgaps can be tuned by the change of temperature and layer thickness of the considered quasi-periodic structures. This work will be useful to design tunable terahertz PC devices.

Fast two-layer two-photon imaging of neuronal cell populations using an electrically tunable lens

PubMed Central

Grewe, Benjamin F.; Voigt, Fabian F.; van ’t Hoff, Marcel; Helmchen, Fritjof

2011-01-01

Functional two-photon Ca2+-imaging is a versatile tool to study the dynamics of neuronal populations in brain slices and living animals. However, population imaging is typically restricted to a single two-dimensional image plane. By introducing an electrically tunable lens into the excitation path of a two-photon microscope we were able to realize fast axial focus shifts within 15 ms. The maximum axial scan range was 0.7 mm employing a 40x NA0.8 water immersion objective, plenty for typically required ranges of 0.2–0.3 mm. By combining the axial scanning method with 2D acousto-optic frame scanning and random-access scanning, we measured neuronal population activity of about 40 neurons across two imaging planes separated by 40 μm and achieved scan rates up to 20–30 Hz. The method presented is easily applicable and allows upgrading of existing two-photon microscopes for fast 3D scanning. PMID:21750778

Comb-based radiofrequency photonic filters with rapid tunability and high selectivity

NASA Astrophysics Data System (ADS)

Supradeepa, V. R.; Long, Christopher M.; Wu, Rui; Ferdous, Fahmida; Hamidi, Ehsan; Leaird, Daniel E.; Weiner, Andrew M.

2012-03-01

Photonic technologies have received considerable attention regarding the enhancement of radiofrequency electrical systems, including high-frequency analogue signal transmission, control of phased arrays, analog-to-digital conversion and signal processing. Although the potential of radiofrequency photonics for the implementation of tunable electrical filters over broad radiofrequency bandwidths has been much discussed, the realization of programmable filters with highly selective filter lineshapes and rapid reconfigurability has faced significant challenges. A new approach for radiofrequency photonic filters based on frequency combs offers a potential route to simultaneous high stopband attenuation, fast tunability and bandwidth reconfiguration. In one configuration, tuning of the radiofrequency passband frequency is demonstrated with unprecedented (~40 ns) speed by controlling the optical delay between combs. In a second, fixed filter configuration, cascaded four-wave mixing simultaneously broadens and smoothes the comb spectra, resulting in Gaussian radiofrequency filter lineshapes exhibiting an extremely high (>60 dB) main lobe to sidelobe suppression ratio and (>70 dB) stopband attenuation.

Non-Thermal Spectra from Pulsar Magnetospheres in the Full Electromagnetic Cascade Scenario

NASA Astrophysics Data System (ADS)

Peng, Qi-Yong; Zhang, Li

2008-08-01

We simulated non-thermal emission from a pulsar magnetosphere within the framework of a full polar-cap cascade scenario by taking the acceleration gap into account, using the Monte Carlo method. For a given electric field parallel to open field lines located at some height above the surface of a neutron star, primary electrons were accelerated by parallel electric fields and lost their energies by curvature radiation; these photons were converted to electron-positron pairs, which emitted photons through subsequent quantum synchrotron radiation and inverse Compton scattering, leading to a cascade. In our calculations, the acceleration gap was assumed to be high above the stellar surface (about several stellar radii); the primary and secondary particles and photons emitted during the journey of those particles in the magnetosphere were traced using the Monte Carlo method. In such a scenario, we calculated the non-thermal photon spectra for different pulsar parameters and compared the model results for two normal pulsars and one millisecond pulsar with the observed data.

Photon-Assisted Resonant Tunneling and 2-D Plasmon Modes in Double Quantum Wells in Intense Terahertz Electric Fields

NASA Astrophysics Data System (ADS)

Peralta, X. G.; Allen, S. J.; Lin, S. Y.; Simmons, J. A.; Blount, M. A.; Baca, W. E.

1998-03-01

We explore photon-assisted resonant tunneling in double quantum well systems in intense terahertz electric fields that have separately- contacted wells. We have two goals in mind: 1) increase the basic understanding of photon assisted tunneling in semiconductors and 2) assess the potential of this structure as a detector. We can control the tunneling current by varying the electron density of each 2D electron gas or by changing the relative separation of the Fermi levels. This allows us to prepare the system in such a way that photons of the appropriate energy may induce resonant tunneling, which is monitored by a change in conductance. We also examine the possible enhancement of the resonant tunneling by resonant excitations of acoustic plasmon modes. This work is supported by ONR, the U. S. Dept. of Energy under Contract DE-AC04-94AL85000 and Consejo Nacional de Ciencia y Tecnología, México.

High event rate ROICs (HEROICs) for astronomical UV photon counting detectors

NASA Astrophysics Data System (ADS)

Harwit, Alex; France, Kevin; Argabright, Vic; Franka, Steve; Freymiller, Ed; Ebbets, Dennis

2014-07-01

The next generation of astronomical photocathode / microchannel plate based UV photon counting detectors will overcome existing count rate limitations by replacing the anode arrays and external cabled electronics with anode arrays integrated into imaging Read Out Integrated Circuits (ROICs). We have fabricated a High Event Rate ROIC (HEROIC) consisting of a 32 by 32 array of 55 μm square pixels on a 60 μm pitch. The pixel sensitivity (threshold) has been designed to be globally programmable between 1 × 103 and 1 × 106 electrons. To achieve the sensitivity of 1 × 103 electrons, parasitic capacitances had to be minimized and this was achieved by fabricating the ROIC in a 65 nm CMOS process. The ROIC has been designed to support pixel counts up to 4096 events per integration period at rates up to 1 MHz per pixel. Integration time periods can be controlled via an external signal with a time resolution of less than 1 microsecond enabling temporally resolved imaging and spectroscopy of astronomical sources. An electrical injection port is provided to verify functionality and performance of each ROIC prior to vacuum integration with a photocathode and microchannel plate amplifier. Test results on the first ROICs using the electrical injection port demonstrate sensitivities between 3 × 103 and 4 × 105 electrons are achieved. A number of fixes are identified for a re-spin of this ROIC.

Optical Dependence of Electrically Detected Magnetic Resonance in Lightly Doped Si:P Devices

NASA Astrophysics Data System (ADS)

Zhu, Lihuang; van Schooten, Kipp J.; Guy, Mallory L.; Ramanathan, Chandrasekhar

2017-06-01

Using frequency-modulated electrically detected magnetic resonance (EDMR), we show that signals measured from lightly doped (1.2 - 5 ×1 015 cm-3 ) silicon devices vary significantly with the wavelength of the optical excitation used to generate the mobile carriers. We measure EDMR spectra at 4.2 K as a function of modulation frequency and applied microwave power using a 980-nm laser, a 405-nm laser, and a broadband white-light source. EDMR signals are observed from the phosphorus donor and two distinct defect species in all of the experiments. With near-infrared irradiation, we find that the EDMR signal primarily arises from donor-defect pairs, while, at higher photon energies, there are significant additional contributions from defect-defect pairs. The contribution of spins from different spatial regions to the EDMR signal is seen to vary as the optical penetration depth changes from about 120 nm at 405-nm illumination to 100 μ m at 980-nm illumination. The modulation frequency dependence of the EDMR signal shows that the energy of the optical excitation strongly modulates the kinetics of the underlying spin-dependent recombination (SDR) process. Careful tuning of the optical photon energy could therefore be used to control both the subset of spin pairs contributing to the EDMR signal and the dynamics of the SDR process.

Vacuum-induced quantum memory in an opto-electromechanical system

NASA Astrophysics Data System (ADS)

Qin, Li-Guo; Wang, Zhong-Yang; Wu, Shi-Chao; Gong, Shang-Qing; Ma, Hong-Yang; Jing, Jun

2018-03-01

We propose a scheme to implement electrically controlled quantum memory based on vacuum-induced transparency (VIT) in a high-Q tunable cavity, which is capacitively coupled to a mechanically variable capacitor by a charged mechanical cavity mirror as an interface. We analyze the changes of the cavity photons arising from vacuum-induced-Raman process and discuss VIT in an atomic ensemble trapped in the cavity. By slowly adjusting the voltage on the capacitor, the VIT can be adiabatically switched on or off, meanwhile, the transfer between the probe photon state and the atomic spin state can be electrically and adiabatically modulated. Therefore, we demonstrate a vacuum-induced quantum memory by electrically manipulating the mechanical mirror of the cavity based on electromagnetically induced transparency mechanism.

Reconfigurable ultra-wideband waveform generation with simple photonic devices

NASA Astrophysics Data System (ADS)

Dastmalchi, Mansour; Abtahi, Mohammad; Lemus, David; Rusch, Leslie A.; LaRochelle, Sophie

2012-08-01

We propose and experimentally demonstrate a low cost, low power consumption technique for ultra-wideband pulse shaping. Our approach is based on thermal apodization of two identical linearly chirped fiber Bragg gratings (LCFBG) placed in both arms of a balanced photodetector. Resistive heating elements with low electrical power consumption are used to tune the LCFBG spectral responses. Using a standard gain switched distributed feedback laser as a pulsed optical source and a simple energy detector receiver, we measured a bit error rate of 1.5×10-4 at a data rate of 1 Gb/s after RF transmission over a 1-m link.

Segmented-spectrum detection mechanism for medical x-ray in CdTe

NASA Astrophysics Data System (ADS)

Shi, Zaifeng; Meng, Qingzhen; Cao, Qingjie; Yao, Suying

2016-01-01

This paper presents a segmented X-ray spectrum detection method based on a layered X-ray detector in Cadmium Telluride (CdTe) substrate. We describe the three-dimensional structure of proposed detector pixel and investigate the matched spectrum-resolving method. Polychromatic X-ray beam enter the CdTe substrate edge on and will be absorbed completely in different thickness varying with photon energy. Discrete potential wells are formed under external controlling voltage to collect the photo-electrons generated in different layers, and segmented X-ray spectrum can be deduced from the quantity of photo-electrons. In this work, we verify the feasibility of the segmented-spectrum detection mechanism by simulating the absorption of monochromatic X-ray in a CdTe substrate. Experiments in simulation show that the number of photo-electrons grow exponentially with the increase of incident thickness, and photons with different energy will be absorbed in various thickness. The charges generated in different layers are collected into adjacent potential wells, and collection efficiency is estimated to be about 87% for different incident intensity under the 40000V/cm electric field. Errors caused by charge sharing between neighboring layers are also analyzed, and it can be considered negligible by setting appropriate size of electrodes.

On chip frequency comb: Characterization and optical arbitrary waveform generation

NASA Astrophysics Data System (ADS)

Ferdous, Fahmida

Recently, on-chip comb generation methods based on nonlinear optical modulation in ultrahigh quality factor monolithic micro-resonators have been demonstrated. In these methods, two pump photons are transformed into sideband photons in a four wave mixing process mediated by the Kerr nonlinearity. The essential advantages of these methods are simplicity, small size, very high repetition rates and sometimes CMOS compatibility. We investigate line-by-line pulse shaping of such combs generated in silicon nitride ring resonators. We demonstrate a simple example of optical arbitrary waveform generation (OAWG) from Kerr comb. We observe two distinct paths to comb formation which exhibit strikingly different time domain behaviors. For combs formed as a cascade of sidebands spaced by a single free spectral range (FSR) that spread from the pump, we are able to compress to nearly bandwidth limited pulses. This indicates high coherence across the spectra and provides new data on the high passive stability of the spectral phase. For combs where the initial sidebands are spaced by multiple FSRs which then fill in to give combs with single FSR spacing, the time domain data reveal partially coherent behavior. We also investigate the behaviors of a few sub-families of the partially coherent combs selected by a pulse shaper. We observe different coherence properties for different groups of comb lines. Furthermore we will discuss an ultrafast characterization techniques called dual comb electric eld cross correlation. This linear technique will provide both low optical power and broader bandwidth capability for full time domain characterization of OAWG from Kerr comb.

Organic phototransistors with nanoscale phase-separated polymer/polymer bulk heterojunction layers

NASA Astrophysics Data System (ADS)

Hwang, Hyemin; Kim, Hwajeong; Nam, Sungho; Bradley, Donal D. C.; Ha, Chang-Sik; Kim, Youngkyoo

2011-05-01

Low-cost detectors for sensing photons at a low light intensity are of crucial importance in modern science. Phototransistors can deliver better signals of low-intensity light by electrical amplification, but conventional inorganic phototransistors have a limitation owing to their high temperature processes in vacuum. In this work, we demonstrate organic phototransistors with polymer/polymer bulk heterojunction blend films (mixtures of p-type and n-type semiconducting polymers), which can be fabricated by inexpensive solution processes at room temperature. The key idea here is to effectively exploit hole charges (from p-type polymer) as major signaling carriers by employing p-type transistor geometry, while the n-type polymer helps efficient charge separation from excitons generated by incoming photons. Results showed that the present organic transistors exhibited proper functions as p-type phototransistors with ~4.3 A W-1 responsivity at a low light intensity (1 µW cm-2), which supports their encouraging potential to replace conventional cooled charge coupled devices (CCD) for low-intensity light detection applications.Low-cost detectors for sensing photons at a low light intensity are of crucial importance in modern science. Phototransistors can deliver better signals of low-intensity light by electrical amplification, but conventional inorganic phototransistors have a limitation owing to their high temperature processes in vacuum. In this work, we demonstrate organic phototransistors with polymer/polymer bulk heterojunction blend films (mixtures of p-type and n-type semiconducting polymers), which can be fabricated by inexpensive solution processes at room temperature. The key idea here is to effectively exploit hole charges (from p-type polymer) as major signaling carriers by employing p-type transistor geometry, while the n-type polymer helps efficient charge separation from excitons generated by incoming photons. Results showed that the present organic transistors exhibited proper functions as p-type phototransistors with ~4.3 A W-1 responsivity at a low light intensity (1 µW cm-2), which supports their encouraging potential to replace conventional cooled charge coupled devices (CCD) for low-intensity light detection applications. Electronic supplementary information (ESI) available: XPS spectra of P3HT:F8BT nanolayers and pristine P3HT and F8BT films, HRTEM images of P3HT:F8BT blend film detached from the substrate, and 1D GIXD profiles of P3HT:F8BT nanolayers and PI layer coated on the ITO-glass substrates. See DOI: 10.1039/c0nr00915f

Electrical and optical modeling of poly(3-hexylthiophene):[6,6]-phenyl-C61 butyric acid methyl ester P3HT-PCBM bulk heterojunction solar cells

NASA Astrophysics Data System (ADS)

Brioua, Fathi; Remram, Mohamed; Nechache, Riad; Bourouina, Hicham

2017-11-01

In this work, we investigate a two-dimensional theoretical model for the photon conversion through an integration of the optical and electrical part of multilayer system in a bulk heterojunction solar cell based on poly(3-hexylthiophene) (P3HT)/6,6-phenyl C61-butyric acid methyl ester (PCBM) blend. The optical properties of the studied structure ITO/PEDOT:PSS/P3HT:PCBM/Ca/Al, such as the exciton generation rate and the electrical field distribution, are predicted at vicinity of the active layer and have been used to solve Poisson and continuity, drift-diffusion equations of the electrical model which characterize the electrical behavior of semiconductor device using finite element method (FEM). The electrical parameters such as power conversion efficiency (PCE), open voltage circuit ( V oc), short-circuit current density ( J sc) and fill factor (FF) are extracted from the current-voltage (J-V) characteristics under illumination and in dark conditions. Highest external quantum efficiency (IPCE), up to 60%, is obtained around 520 nm, while a power conversion efficiency (PCE) value of 3.62% is found to be in good agreement with the literature results. Integration of such theoretical approach into technological applications dealing with optoelectrical material performance will rapidly provide to the user accurate data outputs required for efficient validation of proof-of-concepts.

Coherent manipulation of photons and electrons

NASA Astrophysics Data System (ADS)

Zhao, Lu

In modern physics, coherent manipulation of photons and electrons has been intensively studied, and may have important applications in classical and quantum information processing. In this dissertation, we consider some interesting schemes to realize photonic and electronic coherent manipulation. In order to coherently manipulate photons, electromagnetically induced transparency (EIT) systems have been widely adopted because the optical response of EIT systems can be controlled by the laser-induced atomic coherence. In the second chapter, we theoretically investigate image storage in hot-vapor EIT media. A so-called 4f system is adopted for imaging, and an atomic vapor cell is placed over the transform plane. The Fraunhofer diffraction pattern of an object in the object plane can thus be transformed into atomic Raman coherence according to the idea of "light storage". We investigate how the stored diffraction pattern evolves under diffusion and discuss the essence of the stability of its dark spots. Our result indicates under appropriate conditions that an image can be reconstructed with high fidelity. The main reason for this procedure is the fact that diffusion of opposite-phase components of the diffraction pattern interfere destructively. In the third chapter, we show theoretical evidence that EIT systems can function as optically addressed spatial light modulators with megahertz modulation rates. The transverse spatial properties of continuous-wave probe fields can be modulated rapidly using two-dimensional optical patterns. To exemplify our proposal, we study real-time generation and manipulation of Laguerre-Gaussian beams by means of phase or amplitude modulation using flat-top image-bearing pulse trains as coupling fields in low-cost hot-vapor EIT systems. In order to coherently manipulate electrons, we consider graphene systems, including single-layer graphene and bilayer graphene, which have recently attracted considerable attention. Due to the long coherence length and electrically tunable Fermi levels, electrons in graphene systems have some photon-like behaviors, and could be coherently manipulated. Therefore, in the fourth chapter, we theorize that at a sharp electrostatic step potential in graphene massless Dirac fermions can obtain Goos-Hanchen-like shifts under total internal reflection. Also, we study coherent propagation of the quasiparticles along a sharp graphene p-n-p waveguide, and derive novel dispersion relations for the guided modes. Consequently, coherent graphene-based devices, e.g., movable mirrors, buffers and memories, induced only by the electric field effects may be proposed. Finally, we theoretically investigate the coherent propagation of massive chiral fermions along a sharp bilayer graphene p-n-p waveguide, and indicate that the guided quasiparticles can be coherently slowed, stored and retrieved based on tunable electric field effects. Controlling group velocity in the bilayer graphene p-n-p waveguide is accomplished via interband tunneling through the p-n interfaces, and does not depend on the bandgap opening.

Experimental Demonstration of a Hybrid-Quantum-Emitter Producing Individual Entangled Photon Pairs in the Telecom Band

PubMed Central

Chen, Geng; Zou, Yang; Zhang, Wen-Hao; Zhang, Zi-Huai; Zhou, Zong-Quan; He, De-Yong; Tang, Jian-Shun; Liu, Bi-Heng; Yu, Ying; Zha, Guo-Wei; Ni, Hai-Qiao; Niu, Zhi-Chuan; Han, Yong-Jian; Li, Chuan-Feng; Guo, Guang-Can

2016-01-01

Quantum emitters generating individual entangled photon pairs (IEPP) have significant fundamental advantages over schemes that suffer from multiple photon emission, or schemes that require post-selection techniques or the use of photon-number discriminating detectors. Quantum dots embedded within nanowires (QD-NWs) represent one of the most promising candidate for quantum emitters that provide a high collection efficiency of photons. However, a quantum emitter that generates IEPP in the telecom band is still an issue demanding a prompt solution. Here, we demonstrate in principle that IEPPs in the telecom band can be created by combining a single QD-NW and a nonlinear crystal waveguide. The QD-NW system serves as the single photon source, and the emitted visible single photons are split into IEPPs at approximately 1.55 μm through the process of spontaneous parametric down conversion (SPDC) in a periodically poled lithium niobate (PPLN) waveguide. The compatibility of the QD-PPLN interface is the determinant factor in constructing this novel hybrid-quantum-emitter (HQE). Benefiting from the desirable optical properties of QD-NWs and the extremely high nonlinear conversion efficiency of PPLN waveguides, we successfully generate IEPPs in the telecom band with the polarization degree of freedom. The entanglement of the generated photon pairs is confirmed by the entanglement witness. Our experiment paves the way to producing HQEs inheriting the advantages of multiple systems. PMID:27225881

Experimental Demonstration of a Hybrid-Quantum-Emitter Producing Individual Entangled Photon Pairs in the Telecom Band.

PubMed

Chen, Geng; Zou, Yang; Zhang, Wen-Hao; Zhang, Zi-Huai; Zhou, Zong-Quan; He, De-Yong; Tang, Jian-Shun; Liu, Bi-Heng; Yu, Ying; Zha, Guo-Wei; Ni, Hai-Qiao; Niu, Zhi-Chuan; Han, Yong-Jian; Li, Chuan-Feng; Guo, Guang-Can

2016-05-26

Quantum emitters generating individual entangled photon pairs (IEPP) have significant fundamental advantages over schemes that suffer from multiple photon emission, or schemes that require post-selection techniques or the use of photon-number discriminating detectors. Quantum dots embedded within nanowires (QD-NWs) represent one of the most promising candidate for quantum emitters that provide a high collection efficiency of photons. However, a quantum emitter that generates IEPP in the telecom band is still an issue demanding a prompt solution. Here, we demonstrate in principle that IEPPs in the telecom band can be created by combining a single QD-NW and a nonlinear crystal waveguide. The QD-NW system serves as the single photon source, and the emitted visible single photons are split into IEPPs at approximately 1.55 μm through the process of spontaneous parametric down conversion (SPDC) in a periodically poled lithium niobate (PPLN) waveguide. The compatibility of the QD-PPLN interface is the determinant factor in constructing this novel hybrid-quantum-emitter (HQE). Benefiting from the desirable optical properties of QD-NWs and the extremely high nonlinear conversion efficiency of PPLN waveguides, we successfully generate IEPPs in the telecom band with the polarization degree of freedom. The entanglement of the generated photon pairs is confirmed by the entanglement witness. Our experiment paves the way to producing HQEs inheriting the advantages of multiple systems.

Photon-phonon-enhanced infrared rectification in a two-dimensional nanoantenna-coupled tunnel diode

DOE PAGES

Kadlec, Emil A.; Jarecki, Robert L.; Starbuck, Andrew; ...

2016-12-28

The interplay of strong infrared photon-phonon coupling with electromagnetic confinement in nanoscale devices is demonstrated to have a large impact on ultrafast photon-assisted tunneling in metal-oxide-semiconductor (MOS) structures. Infrared active optical phonon modes in polar oxides lead to strong dispersion and enhanced electric fields at material interfaces. We find that the infrared dispersion of SiO 2 near a longitudinal optical phonon mode can effectively impedance match a photonic surface mode into a nanoscale tunnel gap that results in large transverse-field confinement. An integrated 2D nanoantenna structure on a distributed large-area MOS tunnel-diode rectifier is designed and built to resonantly excitemore » infrared surface modes and is shown to efficiently channel infrared radiation into nanometer-scale gaps in these MOS devices. This enhanced-gap transverse-electric field is converted to a rectified tunneling displacement current resulting in a dc photocurrent. We examine the angular and polarization-dependent spectral photocurrent response of these 2D nanoantenna-coupled tunnel diodes in the photon-enhanced tunneling spectral region. Lastly, our 2D nanoantenna-coupled infrared tunnel-diode rectifier promises to impact large-area thermal energy harvesting and infrared direct detectors.« less

Photon-phonon-enhanced infrared rectification in a two-dimensional nanoantenna-coupled tunnel diode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kadlec, Emil A.; Jarecki, Robert L.; Starbuck, Andrew

The interplay of strong infrared photon-phonon coupling with electromagnetic confinement in nanoscale devices is demonstrated to have a large impact on ultrafast photon-assisted tunneling in metal-oxide-semiconductor (MOS) structures. Infrared active optical phonon modes in polar oxides lead to strong dispersion and enhanced electric fields at material interfaces. We find that the infrared dispersion of SiO 2 near a longitudinal optical phonon mode can effectively impedance match a photonic surface mode into a nanoscale tunnel gap that results in large transverse-field confinement. An integrated 2D nanoantenna structure on a distributed large-area MOS tunnel-diode rectifier is designed and built to resonantly excitemore » infrared surface modes and is shown to efficiently channel infrared radiation into nanometer-scale gaps in these MOS devices. This enhanced-gap transverse-electric field is converted to a rectified tunneling displacement current resulting in a dc photocurrent. We examine the angular and polarization-dependent spectral photocurrent response of these 2D nanoantenna-coupled tunnel diodes in the photon-enhanced tunneling spectral region. Lastly, our 2D nanoantenna-coupled infrared tunnel-diode rectifier promises to impact large-area thermal energy harvesting and infrared direct detectors.« less

Integrated generation of complex optical quantum states and their coherent control

NASA Astrophysics Data System (ADS)

Roztocki, Piotr; Kues, Michael; Reimer, Christian; Romero Cortés, Luis; Sciara, Stefania; Wetzel, Benjamin; Zhang, Yanbing; Cino, Alfonso; Chu, Sai T.; Little, Brent E.; Moss, David J.; Caspani, Lucia; Azaña, José; Morandotti, Roberto

2018-01-01

Complex optical quantum states based on entangled photons are essential for investigations of fundamental physics and are the heart of applications in quantum information science. Recently, integrated photonics has become a leading platform for the compact, cost-efficient, and stable generation and processing of optical quantum states. However, onchip sources are currently limited to basic two-dimensional (qubit) two-photon states, whereas scaling the state complexity requires access to states composed of several (<2) photons and/or exhibiting high photon dimensionality. Here we show that the use of integrated frequency combs (on-chip light sources with a broad spectrum of evenly-spaced frequency modes) based on high-Q nonlinear microring resonators can provide solutions for such scalable complex quantum state sources. In particular, by using spontaneous four-wave mixing within the resonators, we demonstrate the generation of bi- and multi-photon entangled qubit states over a broad comb of channels spanning the S, C, and L telecommunications bands, and control these states coherently to perform quantum interference measurements and state tomography. Furthermore, we demonstrate the on-chip generation of entangled high-dimensional (quDit) states, where the photons are created in a coherent superposition of multiple pure frequency modes. Specifically, we confirm the realization of a quantum system with at least one hundred dimensions. Moreover, using off-the-shelf telecommunications components, we introduce a platform for the coherent manipulation and control of frequencyentangled quDit states. Our results suggest that microcavity-based entangled photon state generation and the coherent control of states using accessible telecommunications infrastructure introduce a powerful and scalable platform for quantum information science.

Dendritic spines linearize the summation of excitatory potentials

PubMed Central

Araya, Roberto; Eisenthal, Kenneth B.; Yuste, Rafael

2006-01-01

In mammalian cortex, most excitatory inputs occur on dendritic spines, avoiding dendritic shafts. Although spines biochemically isolate inputs, nonspiny neurons can also implement biochemical compartmentalization; so, it is possible that spines have an additional function. We have recently shown that the spine neck can filter membrane potentials going into and out of the spine. To investigate the potential function of this electrical filtering, we used two-photon uncaging of glutamate and compared the integration of electrical signals in spines vs. dendritic shafts from basal dendrites of mouse layer 5 pyramidal neurons. Uncaging potentials onto spines summed linearly, whereas potentials on dendritic shafts reduced each other's effect. Linear integration of spines was maintained regardless of the amplitude of the response, distance between spines (as close as <2 μm), distance of the spines to the soma, dendritic diameter, or spine neck length. Our findings indicate that spines serve as electrical isolators to prevent input interaction, and thus generate a linear arithmetic of excitatory inputs. Linear integration could be an essential feature of cortical and other spine-laden circuits. PMID:17132736

Dendritic spines linearize the summation of excitatory potentials.

PubMed

Araya, Roberto; Eisenthal, Kenneth B; Yuste, Rafael

2006-12-05

In mammalian cortex, most excitatory inputs occur on dendritic spines, avoiding dendritic shafts. Although spines biochemically isolate inputs, nonspiny neurons can also implement biochemical compartmentalization; so, it is possible that spines have an additional function. We have recently shown that the spine neck can filter membrane potentials going into and out of the spine. To investigate the potential function of this electrical filtering, we used two-photon uncaging of glutamate and compared the integration of electrical signals in spines vs. dendritic shafts from basal dendrites of mouse layer 5 pyramidal neurons. Uncaging potentials onto spines summed linearly, whereas potentials on dendritic shafts reduced each other's effect. Linear integration of spines was maintained regardless of the amplitude of the response, distance between spines (as close as < 2 microm), distance of the spines to the soma, dendritic diameter, or spine neck length. Our findings indicate that spines serve as electrical isolators to prevent input interaction, and thus generate a linear arithmetic of excitatory inputs. Linear integration could be an essential feature of cortical and other spine-laden circuits.

Growth and characterization of pure and Ca2+ doped MnHg(SCN)4 single crystals

NASA Astrophysics Data System (ADS)

Latha, C.; Mahadevan, C. K.; Guo, Li; Liu, Jinghe

2018-05-01

Manganese-mercury thiocyanate, MnHg(SCN)4, crystal is considered to be an important organometallic nonlinear optical (NLO) material exhibiting higher thermal stability and second harmonic generation (SHG) efficiency. In order to understand the effect of Ca2+ as an impurity on the physicochemical properties, we have grown pure and Ca2+ doped (with a concentration of 1 mol%) MnHg(SCN)4 single crystals by the free evaporation of solvent method and characterized structurally, chemically, optically and electrically by adopting the available standard methods. Results obtained indicate that Ca2+ doping increases significantly the optical transmittance, SHG efficiency, and DC electrical conductivity and decreases the dielectric loss factor (improves the crystal quality), and AC electrical conductivity without distorting the crystal structure. Also, the low dielectric constant (εr) values observed for both the pure and doped crystals considered at near ambient temperatures indicate the possibility of using these crystals not only as potential NLO materials (useful in the photonics industry) but also as promising low εr value dielectric materials (useful in the microelectronics industry).

Physical characterization of single convergent beam device for teletherapy: theoretical and Monte Carlo approach.

PubMed

Figueroa, R G; Valente, M

2015-09-21

The main purpose of this work is to determine the feasibility and physical characteristics of a new teletherapy device of radiation therapy based on the application of a convergent x-ray beam of energies like those used in radiotherapy providing highly concentrated dose delivery to the target. We have denominated it Convergent Beam Radio Therapy (CBRT). Analytical methods are developed first in order to determine the dosimetry characteristic of an ideal convergent photon beam in a hypothetical water phantom. Then, using the PENELOPE Monte Carlo code, a similar convergent beam that is applied to the water phantom is compared with that of the analytical method. The CBRT device (Converay(®)) is designed to adapt to the head of LINACs. The converging beam photon effect is achieved thanks to the perpendicular impact of LINAC electrons on a large thin spherical cap target where Bremsstrahlung is generated (high-energy x-rays). This way, the electrons impact upon various points of the cap (CBRT condition), aimed at the focal point. With the X radiation (Bremsstrahlung) directed forward, a system of movable collimators emits many beams from the output that make a virtually definitive convergent beam. Other Monte Carlo simulations are performed using realistic conditions. The simulations are performed for a thin target in the shape of a large, thin, spherical cap, with an r radius of around 10-30 cm and a curvature radius of approximately 70 to 100 cm, and a cubed water phantom centered in the focal point of the cap. All the interaction mechanisms of the Bremsstrahlung radiation with the phantom are taken into consideration for different energies and cap thicknesses. Also, the magnitudes of the electric and/or magnetic fields, which are necessary to divert clinical-use electron beams (0.1 to 20 MeV), are determined using electromagnetism equations with relativistic corrections. This way the above-mentioned beam is manipulated and guided for its perpendicular impact upon the spherical cap. The first results that were achieved show in-depth dose peaks, having shapes qualitatively similar to those from hadrontherapy techniques. The obtained results demonstrate that in-depth dose peaks are generated at the focus point or isocenter. These results are consistent with those obtained with Monte Carlo codes. The peak-focus is independent of the energy of the photon beam, though its intensity is not. The realistic results achieved with the Monte Carlo code show that the Bremsstrahlung generated on the thin cap is mainly directed towards the focus point. The aperture angle at each impact point depends primarily on the energy beam, the atomic number Z and the thickness of the target. There is also a poly-collimator coaxial to the cap or ring with many holes, permitting a clean convergent-exit x-ray beam with a dose distribution that is similar to the ideal case. The electric and magnetic fields needed to control the deflection of the electron beams in the CBRT geometry are highly feasible using specially designed electric and/or magnetic devices that, respectively, have voltage and current values that are technically achievable. However, it was found that magnetic devices represent a more suitable option for electron beam control, especially at high energies. The main conclusion is that the development of such a device is feasible. Due to its features, this technology might be considered a powerful new tool for external radiotherapy with photons.

Creating and optimizing interfaces for electric-field and photon-induced charge transfer.

PubMed

Park, Byoungnam; Whitham, Kevin; Cho, Jiung; Reichmanis, Elsa

2012-11-27

We create and optimize a structurally well-defined electron donor-acceptor planar heterojunction interface in which electric-field and/or photon-induced charge transfer occurs. Electric-field-induced charge transfer in the dark and exciton dissociation at a pentacene/PCBM interface were probed by in situ thickness-dependent threshold voltage shift measurements in field-effect transistor devices during the formation of the interface. Electric-field-induced charge transfer at the interface in the dark is correlated with development of the pentacene accumulation layer close to PCBM, that is, including interface area, and dielectric relaxation time in PCBM. Further, we demonstrate an in situ test structure that allows probing of both exciton diffusion length and charge transport properties, crucial for optimizing optoelectronic devices. Competition between the optical absorption length and the exciton diffusion length in pentacene governs exciton dissociation at the interface. Charge transfer mechanisms in the dark and under illumination are detailed.

Characterization of Lasers for Use in Analog Photonic Links

DTIC Science & Technology

2011-11-22

measurements. Trade-offs for each of the lasers characterized are discussed as well as their impact on analog photonic link performance. 22-11-2011... impact on the performance of a photonic link when it occurs with high intensity at radio and microwave frequencies such as decreased sensitivity and...from being straightforward. The first subtlety is the fact that the noise of the lasers will typically be below the noise floor of the electrical

Silicon photonics integrated circuits: a manufacturing platform for high density, low power optical I/O's.

PubMed

Absil, Philippe P; Verheyen, Peter; De Heyn, Peter; Pantouvaki, Marianna; Lepage, Guy; De Coster, Jeroen; Van Campenhout, Joris

2015-04-06

Silicon photonics integrated circuits are considered to enable future computing systems with optical input-outputs co-packaged with CMOS chips to circumvent the limitations of electrical interfaces. In this paper we present the recent progress made to enable dense multiplexing by exploiting the integration advantage of silicon photonics integrated circuits. We also discuss the manufacturability of such circuits, a key factor for a wide adoption of this technology.

Ion photon emission microscope

DOEpatents

Doyle, Barney L.

2003-04-22

An ion beam analysis system that creates microscopic multidimensional image maps of the effects of high energy ions from an unfocussed source upon a sample by correlating the exact entry point of an ion into a sample by projection imaging of the ion-induced photons emitted at that point with a signal from a detector that measures the interaction of that ion within the sample. The emitted photons are collected in the lens system of a conventional optical microscope, and projected on the image plane of a high resolution single photon position sensitive detector. Position signals from this photon detector are then correlated in time with electrical effects, including the malfunction of digital circuits, detected within the sample that were caused by the individual ion that created these photons initially.

Biofield Physiology: A Framework for an Emerging Discipline

PubMed Central

Levin, Michael; McCraty, Rollin; Bat, Namuun; Ives, John A.; Lutgendorf, Susan K.; Oschman, James L.

2015-01-01

Biofield physiology is proposed as an overarching descriptor for the electromagnetic, biophotonic, and other types of spatially-distributed fields that living systems generate and respond to as integral aspects of cellular, tissue, and whole organism self-regulation and organization. Medical physiology, cell biology, and biophysics provide the framework within which evidence for biofields, their proposed receptors, and functions is presented. As such, biofields can be viewed as affecting physiological regulatory systems in a manner that complements the more familiar molecular-based mechanisms. Examples of clinically relevant biofields are the electrical and magnetic fields generated by arrays of heart cells and neurons that are detected, respectively, as electrocardiograms (ECGs) or magnetocardiograms (MCGs) and electroencephalograms (EEGs) or magnetoencephalograms (MEGs). At a basic physiology level, electromagnetic activity of neural assemblies appears to modulate neuronal synchronization and circadian rhythmicity. Numerous nonneural electrical fields have been detected and analyzed, including those arising from patterns of resting membrane potentials that guide development and regeneration, and from slowly-varying transepithelial direct current fields that initiate cellular responses to tissue damage. Another biofield phenomenon is the coherent, ultraweak photon emissions (UPE), detected from cell cultures and from the body surface. A physiological role for biophotons is consistent with observations that fluctuations in UPE correlate with cerebral blood flow, cerebral energy metabolism, and EEG activity. Biofield receptors are reviewed in 3 categories: molecular-level receptors, charge flux sites, and endogenously generated electric or electromagnetic fields. In summary, sufficient evidence has accrued to consider biofield physiology as a viable scientific discipline. Directions for future research are proposed. PMID:26665040

Biofield Physiology: A Framework for an Emerging Discipline.

PubMed

Hammerschlag, Richard; Levin, Michael; McCraty, Rollin; Bat, Namuun; Ives, John A; Lutgendorf, Susan K; Oschman, James L

2015-11-01

Biofield physiology is proposed as an overarching descriptor for the electromagnetic, biophotonic, and other types of spatially-distributed fields that living systems generate and respond to as integral aspects of cellular, tissue, and whole organism self-regulation and organization. Medical physiology, cell biology, and biophysics provide the framework within which evidence for biofields, their proposed receptors, and functions is presented. As such, biofields can be viewed as affecting physiological regulatory systems in a manner that complements the more familiar molecular-based mechanisms. Examples of clinically relevant biofields are the electrical and magnetic fields generated by arrays of heart cells and neurons that are detected, respectively, as electrocardiograms (ECGs) or magnetocardiograms (MCGs) and electroencephalograms (EEGs) or magnetoencephalograms (MEGs). At a basic physiology level, electromagnetic activity of neural assemblies appears to modulate neuronal synchronization and circadian rhythmicity. Numerous nonneural electrical fields have been detected and analyzed, including those arising from patterns of resting membrane potentials that guide development and regeneration, and from slowly-varying transepithelial direct current fields that initiate cellular responses to tissue damage. Another biofield phenomenon is the coherent, ultraweak photon emissions (UPE), detected from cell cultures and from the body surface. A physiological role for biophotons is consistent with observations that fluctuations in UPE correlate with cerebral blood flow, cerebral energy metabolism, and EEG activity. Biofield receptors are reviewed in 3 categories: molecular-level receptors, charge flux sites, and endogenously generated electric or electromagnetic fields. In summary, sufficient evidence has accrued to consider biofield physiology as a viable scientific discipline. Directions for future research are proposed.

Electrical controllable spin pump based on a zigzag silicene nanoribbon junction.

PubMed

Zhang, Lin; Tong, Peiqing

2017-12-13

We propose a possible electrical controllable spin pump based on a zigzag silicene nanoribbon ferromagnetic junction by applying two time-dependent perpendicular electric fields. By using the Keldysh Green's function method, we derive the analytic expression of the spin-resolved current at the adiabatic approximation and demonstrate that two asymmetric spin up and spin down currents can be pumped out in the device without an external bias. The pumped currents mainly come from the interplay between the photon-assisted spin pump effect and the electrically-modulated energy band structure of the tunneling junction. The spin valve phenomena are not only related to the energy gap opened by two perpendicular staggered potentials, but also dependent on the system parameters such as the pumping frequency, the pumping phase difference, the spin-orbit coupling and the Fermi level, which can be tuned by the electrical methods. The proposed device can also be used to produce a pure spin current and a 100% polarized spin current through the photon-assisted pumping process. Our investigations may provide an electrical manipulation of spin-polarized electrons in graphene-like pumping devices.

Memory Device and Nanofabrication Techniques Using Electrically Configurable Materials

NASA Astrophysics Data System (ADS)

Ascenso Simões, Bruno

Development of novel nanofabrication techniques and single-walled carbon nanotubes field configurable transistor (SWCNT-FCT) memory devices using electrically configurable materials is presented. A novel lithographic technique, electric lithography (EL), that uses electric field for pattern generation has been demonstrated. It can be used for patterning of biomolecules on a polymer surface and patterning of resist as well. Using electrical resist composed of a polymer having Boc protected amine group and iodonium salt, Boc group on the surface of polymer was modified to free amine by applying an electric field. On the modified surface of the polymer, Streptavidin pattern was fabricated with a sub-micron scale. Also patterning of polymer resin composed of epoxy monomers and diaryl iodonium salt by EL has been demonstrated. Reaction mechanism for electric resist configuration is believed to be induced by an acid generation via electrochemical reduction in the resist. We show a novel field configurable transistor (FCT) based on single-walled carbon nanotube network field-effect transistors in which poly (ethylene glycol) crosslinked by electron-beam is incorporated into the gate. The device conductance can be configured to arbitrary states reversibly and repeatedly by applying external gate voltages. Raman spectroscopy revealed that evolution of the ratio of D- to G-band intensity in the SWCNTs of the FCT progressively increases as the device is configured to lower conductance states. Electron transport studies at low temperatures showed a strong temperature dependence of the resistance. Band gap widening of CNTs up to ˜ 4 eV has been observed by examining the differential conductance-gate voltage-bias voltage relationship. The switching mechanism of the FCT is attributed a structural transformation of CNTs via reversible hydrogenation and dehydrogenations induced by gate voltages, which tunes the CNT bandgap continuously and reversibly to non-volatile analog values. The CNT transistors with field tunable band gaps would facilitate field programmable circuits based on the self-organized CNTs, and might also lead to novel analog memory, neuromorphic, and photonic devices.

Space-Borne Observations of Intense Gamma-Ray Flashes (TGFs) Above Thunderstorms

NASA Technical Reports Server (NTRS)

Fishman, Gerald J.

2010-01-01

Intense millisecond flashes of MeV photons are being observed with space-borne detectors. These terrestrial gamma-ray flashes (TGFs) were discovered with the Burst and Transient Source Experiment (BATSE) aboard the Compton Gamma-Ray Observatory (CGRO) in the early 1990s. They are now being observed with several other instruments, including the Gamma-ray Burst Monitor (GBM) detectors on the Fermi Gamma-ray Space Telescope. Although Fermi-GBM was designed and optimized for the observation of cosmic gamma-ray bursts (GRBs), it has unprecedented capabilities for TGF observations. The TGFs usually have extremely hard continuous spectra, typical of highly-Comptonized bremsstrahlung radiation. These spectral are harder than those of GRBs, with photons extending to over 40 MeV. The most likely origin of these high-energy photons is bremsstrahlung radiation produced by a relativistic runaway avalanche electron beam. Such a beam is expected to be produced in an extended, intense electric field in or above thunderstorm regions. The altitude of origin and beaming characteristics of the radiation are quite uncertain. These TGFs may produce an appreciable radiation dose to passengers and crew in nearby aircraft. They have generated considerable observational and theoretical interest in recent years. Instruments are being designed specifically for TGF observations from new spacecraft as well as from airborne platforms.

Single-molecule photon emission statistics for systems with explicit time dependence: Generating function approach

NASA Astrophysics Data System (ADS)

Peng, Yonggang; Xie, Shijie; Zheng, Yujun; Brown, Frank L. H.

2009-12-01

Generating function calculations are extended to allow for laser pulse envelopes of arbitrary shape in numerical applications. We investigate photon emission statistics for two-level and V- and Λ-type three-level systems under time-dependent excitation. Applications relevant to electromagnetically induced transparency and photon emission from single quantum dots are presented.

Electro-optic routing of photons from a single quantum dot in photonic integrated circuits

NASA Astrophysics Data System (ADS)

Midolo, Leonardo; Hansen, Sofie L.; Zhang, Weili; Papon, Camille; Schott, Rüdiger; Ludwig, Arne; Wieck, Andreas D.; Lodahl, Peter; Stobbe, Søren

2017-12-01

Recent breakthroughs in solid-state photonic quantum technologies enable generating and detecting single photons with near-unity efficiency as required for a range of photonic quantum technologies. The lack of methods to simultaneously generate and control photons within the same chip, however, has formed a main obstacle to achieving efficient multi-qubit gates and to harness the advantages of chip-scale quantum photonics. Here we propose and demonstrate an integrated voltage-controlled phase shifter based on the electro-optic effect in suspended photonic waveguides with embedded quantum emitters. The phase control allows building a compact Mach-Zehnder interferometer with two orthogonal arms, taking advantage of the anisotropic electro-optic response in gallium arsenide. Photons emitted by single self-assembled quantum dots can be actively routed into the two outputs of the interferometer. These results, together with the observed sub-microsecond response time, constitute a significant step towards chip-scale single-photon-source de-multiplexing, fiber-loop boson sampling, and linear optical quantum computing.

A bright triggered twin-photon source in the solid state

PubMed Central

Heindel, T.; Thoma, A.; von Helversen, M.; Schmidt, M.; Schlehahn, A.; Gschrey, M.; Schnauber, P.; Schulze, J. -H.; Strittmatter, A.; Beyer, J.; Rodt, S.; Carmele, A.; Knorr, A.; Reitzenstein, S.

2017-01-01

A non-classical light source emitting pairs of identical photons represents a versatile resource of interdisciplinary importance with applications in quantum optics and quantum biology. To date, photon twins have mostly been generated using parametric downconversion sources, relying on Poissonian number distributions, or atoms, exhibiting low emission rates. Here we propose and experimentally demonstrate the efficient, triggered generation of photon twins using the energy-degenerate biexciton–exciton radiative cascade of a single semiconductor quantum dot. Deterministically integrated within a microlens, this nanostructure emits highly correlated photon pairs, degenerate in energy and polarization, at a rate of up to (234±4) kHz. Furthermore, we verify a significant degree of photon indistinguishability and directly observe twin-photon emission by employing photon-number-resolving detectors, which enables the reconstruction of the emitted photon number distribution. Our work represents an important step towards the realization of efficient sources of twin-photon states on a fully scalable technology platform. PMID:28367950

Influence of pump-field scattering on nonclassical-light generation in a photonic-band-gap nonlinear planar waveguide

NASA Astrophysics Data System (ADS)

Peřina, Jan, Jr.; Sibilia, Concita; Tricca, Daniela; Bertolotti, Mario

2005-04-01

Optical parametric process occurring in a nonlinear planar waveguide can serve as a source of light with nonclassical properties. The properties of the generated fields are substantially modified by scattering of the nonlinearly interacting fields in a photonic-band-gap structure inside the waveguide. A general quantum model of linear operator amplitude corrections to the amplitude mean values and its numerical analysis provide conditions for efficient squeezed-light generation as well as generation of light with sub-Poissonian photon-number statistics. The destructive influence of phase mismatch of the nonlinear interaction can fully be compensated using a suitable photonic-band-gap structure inside the waveguide. Also an increase of the signal-to-noise ratio of the incident optical field can be reached in the waveguide.

High-yield entangled single photon source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soh, Daniel B. S.; Bisson, Scott E.

The various technologies presented herein relate to utilizing photons at respective idler and signal frequencies to facilitate generation of photons at a pump frequency. A strong pump field can be applied at the .omega..sub.i and the .omega..sub.s frequencies, with the generated idler and signal pulses being utilized to generate a photon pair at the .omega..sub.p frequency. Further, the idler pump power can be increased relative to the signal pump power such that the pump power P.sub.i>pump power P.sub.s. Such reversed operation (e.g., .omega..sub.i+.omega..sub.s.fwdarw..omega..sub.p1+.omega..sub.p2) can minimize and/or negate Raman scattering effects. By complying with an energy conservation requirement, the .omega..sub.i andmore » .omega..sub.s photons interacting with the material through the four-wave mixing process facilitates the entanglement of the .omega..sub.p1 and .omega..sub.p2 photons. The .omega..sub.i and .omega..sub.s photons can be respectively formed in different length waveguides with a delay utilized to facilitate common timing between the .omega..sub.i and .omega..sub.s photons.« less

Experimental entangled photon pair generation using crystals with parallel optical axes.

PubMed

Villar, Aitor; Lohrmann, Alexander; Ling, Alexander

2018-05-14

We present an optical design where polarization-entangled photon pairs are generated within two β-Barium Borate crystals whose optical axes are parallel. This design increases the spatial mode overlap of the emitted photon pairs enhancing single mode collection without the need for additional spatial walk-off compensators. The observed photon pair rate is at least 65 000 pairs/s/mW with a quantum state fidelity of 99.53 ± 0.22% when pumped with an elliptical spatial profile.

Experimental entangled photon pair generation using crystals with parallel optical axes

NASA Astrophysics Data System (ADS)

Villar, Aitor; Lohrmann, Alexander; Ling, Alexander

2018-05-01

We present an optical design where polarization-entangled photon pairs are generated within two $\\beta$-Barium Borate crystals whose optical axes are parallel. This design increases the spatial mode overlap of the emitted photon pairs enhancing single mode collection without the need for additional spatial walk-off compensators. The observed photon pair rate is at least 65000 pairs/s/mW with a quantum state fidelity of 99.53$\\pm$0.22% when pumped with an elliptical spatial profile.

Rates of Charged Clocks in an Electric Field.

NASA Astrophysics Data System (ADS)

Ozer, Murat

2008-04-01

The gravitational arguments leading to time dilation, redshift, and spacetime curvature are adapted to electric fields. The energy levels of two identical positively charged atoms at different potentials in a static electric field are shown to undergo blueshift. Secondly, the period of a charged simple pendulum (clock) in the electric field of a metallic sphere is shown to vary with the electric potential. The spacetime diagram for the world lines of two photons emitted and absorbed by two pendulums at different potentials at different times and the world lines of the pendulums, as in Schild's argument, is shown to be not a parallelogram in Minkowski spacetime, concluding that spacetime must be curved. A Pound-Rebka-Snider experiment in an electric field is proposed to confirm that photons undergo a frequency shift in an electric field and hence the spacetime manifold is curved. Next, Torretti's gravitational argument that spacetime around a mass distribution concentrated at a point is curved is extended to electric charge distributions to conclude that the nonuniform electric fields of such charge distributions too curve spacetime. Finally, the local equivalence of a uniform electric field times the charge to mass ratio to a uniform acceleration is shown through spacetime transformations and the electrical redshift is obtained in a uniformly accelerated frame by using this principle. These arguments lead to the conclusion that special relativistic electromagnetism is an approximation to a general relativistic multi-metric theory.

Ramp compression of a metallic liner driven by a shaped 5 MA current on the SPHINX machine

NASA Astrophysics Data System (ADS)

D'Almeida, Thierry; Lassalle, Francis; Morell, Alain; Grunenwald, Julien; Zucchini, Frédéric; Loyen, Arnaud; Maysonnave, Thomas; Chuvatin, Alexandre

2013-06-01

SPHINX is a 6MA, 1- μs Linear Transformer Driver operated by the CEA Gramat (France) and primarily used for imploding Z-pinch loads for radiation effects studies. Among the options that are currently being considered for improving the generator performances, there is a compact Dynamic Load Current Amplifier (DLCM). A method for performing magnetic ramp compression experiments, without modifying the generator operation scheme, was developed using the DLCM to shape the initial current pulse. We present the overall experimental configuration chosen for these experiments, based on electrical and hydrodynamic simulations. Initial results obtained over a set of experiments on an aluminum cylindrical liner, ramp-compressed to a peak pressure of 23 GPa, are presented. Details of the electrical and Photonic Doppler Velocimetry (PDV) setups used to monitor and diagnose the ramp compression experiments are provided. Current profiles measured at various locations across the system, particularly the load current, agree with simulated current profile and demonstrate adequate pulse shaping by the DLCM. The liner inner free surface velocity measurements agree with the hydrocode results obtained using the measured load current as the input. Higher ramp pressure levels are foreseen in future experiments with an improved DLCM system.

Quantum Random Number Generation Using a Quanta Image Sensor

PubMed Central

Amri, Emna; Felk, Yacine; Stucki, Damien; Ma, Jiaju; Fossum, Eric R.

2016-01-01

A new quantum random number generation method is proposed. The method is based on the randomness of the photon emission process and the single photon counting capability of the Quanta Image Sensor (QIS). It has the potential to generate high-quality random numbers with remarkable data output rate. In this paper, the principle of photon statistics and theory of entropy are discussed. Sample data were collected with QIS jot device, and its randomness quality was analyzed. The randomness assessment method and results are discussed. PMID:27367698

Rapid Generation of Large Dimension Photon Sieve Designs

NASA Technical Reports Server (NTRS)

Hariharan, Shravan; Fitzpatrick, Sean; Kim, Hyun Jung; Julian, Matthew; Sun, Wenbo; Tedjojuwono, Ken; MacDonnell, David

2017-01-01

A photon sieve is a revolutionary optical instrument that provides high resolution imaging at a fraction of the weight of typical telescopes (areal density of 0.3 kg/m2 compared to 25 kg/m2 for the James Webb Space Telescope). The photon sieve is a variation of a Fresnel Zone Plate consisting of many small holes spread out in a ring-like pattern, which focuses light of a specific wavelength by diffraction. The team at NASA Langley Research Center has produced a variety of small photon sieves for testing. However, it is necessary to increase both the scale and rate of production, as a single sieve previously took multiple weeks to design and fabricate. This report details the different methods used in producing photon sieve designs in two file formats: CIF and DXF. The difference between these methods, and the two file formats were compared, to determine the most efficient design process. Finally, a step-by-step sieve design and fabrication process was described. The design files can be generated in both formats using an editing tool such as Microsoft Excel. However, an approach using a MATLAB program reduced the computing time of the designs and increased the ability of the user to generate large photon sieve designs. Although the CIF generation process was deemed the most efficient, the design techniques for both file types have been proven to generate complete photon sieves that can be used for scientific applications

Final Technical Report Project: Low-Energy Photonuclear Studies at HIGS and Lund

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feldman, Gerald

This report summarizes a program of low-energy photonuclear studies at MAX-Lab in Lund (Sweden) and at the High Intensity Gamma Source (HIGS) at Duke University. A major emphasis has been on Compton scattering from deuterium in order to determine the electric and magnetic polarizabilities of the neutron. The studies at Lund utilized unpolarized photons at Egamma = 62-115 MeV to measure differential cross sections. The studies at HIGS utilized polarized and unpolarized photon beams (both linear and circular) at Egamma < 90 MeV. Polarization observables will be exploited to improve our understanding of the electric and magnetic polarizabilities, and inmore » particular, double-polarization observables (using polarized targets) will be measured in the future to provide new information about the spin polarizabilities of the nucleon. The MAX-Lab experiments (using unpolarized photons) focused on an approved PAC proposal for Compton scattering on the deuteron aimed at making a precise determination of the electromagnetic polarizabilities of the neutron. At MAX-Lab we had three of the largest NaI detectors in the world, each capable of ~2% energy resolution. We have completed our measurements in two separate tagged photon energy ranges which overlap each other (62-97 MeV and 90-115 MeV) and the results of these experiments have been published. The photon beam at the High Intensity Gamma Source (HIGS) has several distinct advantages that make it unique: (1) ultra-high photon flux, ultimately reaching 100 MHz, (2) 100% linearly polarized photon beam, as well as circular polarization, (3) monoenergetic beam, with ~2% energy resolution, and (4) extremely low-background beam environment. Exploiting the high flux and polarization capabilities of the HIGS photon beam is central in the series of experiments being performed at this facility. Very little data exist on Compton scattering using polarized photons. We will exploit clear sensitivities in the polarization observables to the electric and magnetic polarizabilities of the nucleon, and we will ultimately extend these studies to the investigation of the spin polarizabilities. To accomplish these objectives, a liquid hydrogen/deuterium/helium cryotarget has been constructed at HIGS, and an array of NaI detectors has been commissioned for Compton studies.« less

All about Eve: Secret Sharing using Quantum Effects

NASA Technical Reports Server (NTRS)

Jackson, Deborah J.

2005-01-01

This document discusses the nature of light (including classical light and photons), encryption, quantum key distribution (QKD), light polarization and beamsplitters and their application to information communication. A quantum of light represents the smallest possible subdivision of radiant energy (light) and is called a photon. The QKD key generation sequence is outlined including the receiver broadcasting the initial signal indicating reception availability, timing pulses from the sender to provide reference for gated detection of photons, the sender generating photons through random polarization while the receiver detects photons with random polarization and communicating via data link to mutually establish random keys. The QKD network vision includes inter-SATCOM, point-to-point Gnd Fiber and SATCOM-fiber nodes. QKD offers an unconditionally secure method of exchanging encryption keys. Ongoing research will focus on how to increase the key generation rate.

On-demand semiconductor source of 780-nm single photons with controlled temporal wave packets

NASA Astrophysics Data System (ADS)

Béguin, Lucas; Jahn, Jan-Philipp; Wolters, Janik; Reindl, Marcus; Huo, Yongheng; Trotta, Rinaldo; Rastelli, Armando; Ding, Fei; Schmidt, Oliver G.; Treutlein, Philipp; Warburton, Richard J.

2018-05-01

We report on a fast, bandwidth-tunable single-photon source based on an epitaxial GaAs quantum dot. Exploiting spontaneous spin-flip Raman transitions, single photons at 780 nm are generated on demand with tailored temporal profiles of durations exceeding the intrinsic quantum dot lifetime by up to three orders of magnitude. Second-order correlation measurements show a low multiphoton emission probability [g2(0 ) ˜0.10 -0.15 ] at a generation rate up to 10 MHz. We observe Raman photons with linewidths as low as 200 MHz, which is narrow compared to the 1.1-GHz linewidth measured in resonance fluorescence. The generation of such narrow-band single photons with controlled temporal shapes at the rubidium wavelength is a crucial step towards the development of an optimized hybrid semiconductor-atom interface.

Quantum teleportation from a propagating photon to a solid-state spin qubit

NASA Astrophysics Data System (ADS)

Gao, W. B.; Fallahi, P.; Togan, E.; Delteil, A.; Chin, Y. S.; Miguel-Sanchez, J.; Imamoğlu, A.

2013-11-01

A quantum interface between a propagating photon used to transmit quantum information and a long-lived qubit used for storage is of central interest in quantum information science. A method for implementing such an interface between dissimilar qubits is quantum teleportation. Here we experimentally demonstrate transfer of quantum information carried by a photon to a semiconductor spin using quantum teleportation. In our experiment, a single photon in a superposition state is generated using resonant excitation of a neutral dot. To teleport this photonic qubit, we generate an entangled spin-photon state in a second dot located 5 m away and interfere the photons from the two dots in a Hong-Ou-Mandel set-up. Thanks to an unprecedented degree of photon-indistinguishability, a coincidence detection at the output of the interferometer heralds successful teleportation, which we verify by measuring the resulting spin state after prolonging its coherence time by optical spin-echo.

Quantum teleportation from a propagating photon to a solid-state spin qubit.

PubMed

Gao, W B; Fallahi, P; Togan, E; Delteil, A; Chin, Y S; Miguel-Sanchez, J; Imamoğlu, A

2013-01-01

A quantum interface between a propagating photon used to transmit quantum information and a long-lived qubit used for storage is of central interest in quantum information science. A method for implementing such an interface between dissimilar qubits is quantum teleportation. Here we experimentally demonstrate transfer of quantum information carried by a photon to a semiconductor spin using quantum teleportation. In our experiment, a single photon in a superposition state is generated using resonant excitation of a neutral dot. To teleport this photonic qubit, we generate an entangled spin-photon state in a second dot located 5 m away and interfere the photons from the two dots in a Hong-Ou-Mandel set-up. Thanks to an unprecedented degree of photon-indistinguishability, a coincidence detection at the output of the interferometer heralds successful teleportation, which we verify by measuring the resulting spin state after prolonging its coherence time by optical spin-echo.

Enhancing a slow and weak optomechanical nonlinearity with delayed quantum feedback

NASA Astrophysics Data System (ADS)

Wang, Zhaoyou; Safavi-Naeini, Amir H.

2017-07-01

A central goal of quantum optics is to generate large interactions between single photons so that one photon can strongly modify the state of another one. In cavity optomechanics, photons interact with the motional degrees of freedom of an optical resonator, for example, by imparting radiation pressure forces on a movable mirror or sensing minute fluctuations in the position of the mirror. Here, we show that the optical nonlinearity arising from these effects, typically too small to operate on single photons, can be sufficiently enhanced with feedback to generate large interactions between single photons. We propose a protocol that allows photons propagating in a waveguide to interact with each other through multiple bounces off an optomechanical system. The protocol is analysed by evolving the full many-body quantum state of the waveguide-coupled system, illustrating that large photon-photon interactions mediated by mechanical motion may be within experimental reach.

Temporal interference with frequency-controllable long photons from independent cold atomic sources

NASA Astrophysics Data System (ADS)

Qian, Peng; Gu, Zhenjie; Wen, Rong; Zhang, Weiping; Chen, J. F.

2018-01-01

The interference of single photons from independent sources is an essential tool in quantum information processing. However, the interfering of photons with long temporal states in a time-resolved manner has rarely been studied. This is because without transmitting spectral filters or coupling to a cavity mode single photons generated in traditional nonlinear crystals suffer from a short temporal profile below 1 ns. With spectral correlation maintained in the biphotons generated from spontaneous four-wave mixing process in cold atom clouds, here we demonstrate the temporal interference of two frequency-tunable long photons from two independent cold atomic sources. We observe and analyze the interference of frequency-mismatched photons, where the phenomenon of the quantum beat at megahertz separation is displayed. Our paper provides more details for the quantum beat of two independent narrow-band single photons, which may find potential application in frequency-encoded photonic qubits in quantum information processing.

Provably secure time distribution for the electric grid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith IV, Amos M; Evans, Philip G; Williams, Brian P

We demonstrate a quantum time distribution (QTD) method that combines the precision of optical timing techniques with the integrity of quantum key distribution (QKD). Critical infrastructure is dependent on microprocessor- and programmable logic-based monitoring and control systems. The distribution of timing information across the electric grid is accomplished by GPS signals which are known to be vulnerable to spoofing. We demonstrate a method for synchronizing remote clocks based on the arrival time of photons in a modifed QKD system. This has the advantage that the signal can be veried by examining the quantum states of the photons similar to QKD.

Bi-directional evolutionary optimization for photonic band gap structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Fei; School of Civil Engineering, Central South University, Changsha 410075; Huang, Xiaodong, E-mail: huang.xiaodong@rmit.edu.au

2015-12-01

Toward an efficient and easy-implement optimization for photonic band gap structures, this paper extends the bi-directional evolutionary structural optimization (BESO) method for maximizing photonic band gaps. Photonic crystals are assumed to be periodically composed of two dielectric materials with the different permittivity. Based on the finite element analysis and sensitivity analysis, BESO starts from a simple initial design without any band gap and gradually re-distributes dielectric materials within the unit cell so that the resulting photonic crystal possesses a maximum band gap between two specified adjacent bands. Numerical examples demonstrated the proposed optimization algorithm can successfully obtain the band gapsmore » from the first to the tenth band for both transverse magnetic and electric polarizations. Some optimized photonic crystals exhibit novel patterns markedly different from traditional designs of photonic crystals.« less

EDITORIAL: Progress in quantum technology: one photon at a time Progress in quantum technology: one photon at a time

NASA Astrophysics Data System (ADS)

Demming, Anna

2012-07-01

Technological developments sparked by quantum mechanics and wave-particle duality are still gaining ground over a hundred years after the theories were devised. While the impact of the theories in fundamental research, philosophy and even art and literature is widely appreciated, the implications in device innovations continue to breed potential. Applications inspired by these concepts include quantum computation and quantum cryptography protocols based on single photons, among many others. In this issue, researchers in Germany and the US report a step towards precisely triggered single-photon sources driven by surface acoustic waves (SAWs) [1]. The work brings technology based on quantum mechanics yet another step closer to practical device reality. Generation of single 'antibunched' photons has been one of the key challenges to progress in quantum information processing and communication. Researchers from Toshiba and Cambridge University in the UK recently reported what they described as 'the first electrically driven single-photon source capable of emitting indistinguishable photons' [2]. Single-photon sources have been reported previously [3]. However the approach demonstrated by Shields and colleagues allows electrical control, which is particularly useful for implementing in compact devices. The researchers used a layer of InAs quantum dots embedded in the intrinsic region of a p-i-n diode to demonstrate interference between single photons. They also present a complete theory based on the interference of photons with a Lorentzian spectrum, which they compare with both continuous-wave and pulsed experiments. The application of SAWs in achieving precisely triggered single-photon sources develops the work of researchers in Germany in the late 1990s [4]. Surface acoustic waves travel like sound waves, but are characterized by an amplitude that typically decays exponentially with depth into the substrate. As Rocke and colleagues demonstrated, they can be used to dissociate an optically excited exciton and spatially separate the electron and hole, thereby increasing the radiative lifetime by orders of magnitude. The interesting behaviour of SAWs has led to studies towards a number of other applications including sensing [5-7], synthesis and nanoassembly [8]. For applications in single-photon sources, the electron-hole pairs are transported by the SAW to a quantum dot where they recombine emitting a single photon. However, so far various limiting factors in the system, such as the low quality of the quantum dots used leading to multiple-exciton recombinations, have hindered potential applications of the system as a single-photon source. Control over high-quality quantum-dot self-assembly is constantly improving. Researchers at the University of California at Berkeley and Harvard University in the US report the ability to successfully position a small number of colloidal quantum dots to within less than 100 nm accuracy on metallic surfaces [9]. They use single-stranded DNA both to act as an anchor to the gold or silver substrates and to selectively bind to the quantum dots, allowing programmed assembly of quantum dots on plasmonic structures. More recently still, researchers in Germany have reported how they can controllably reduce the density of self-assembled InP quantum dots by cyclic deposition with growth interruptions [10]. The impressive control has great potential for quantum emitter use. In this issue, Völk, Krenner and colleagues use an alternative approach to demonstrate how they can improve the performance of single-photon sources using SAWs. They use an optimized system of isolated self-assembled quantum posts in a quantum-well structure and inject the carriers at a distance from the posts where recombination and emission take place [3]. The SAW dissociates the electron-hole pairs and transports them to the quantum posts, so the two carrier types arrive at the quantum post with a set time delay. Other approaches, such as Coulomb blockade ones, have struggled to achieve the sequential injection of the carriers

Twin photon pairs in a high-Q silicon microresonator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rogers, Steven; Lu, Xiyuan; Jiang, Wei C.

2015-07-27

We report the generation of high-purity twin photon pairs through cavity-enhanced non-degenerate four-wave mixing (FWM) in a high-Q silicon microdisk resonator. Twin photon pairs are created within the same cavity mode and are consequently expected to be identical in all degrees of freedom. The device is able to produce twin photons at telecommunication wavelengths with a pair generation rate as large as (3.96 ± 0.03) × 10{sup 5} pairs/s, within a narrow bandwidth of 0.72 GHz. A coincidence-to-accidental ratio of 660 ± 62 was measured, the highest value reported to date for twin photon pairs, at a pair generation rate of (2.47 ±more » 0.04) × 10{sup 4} pairs/s. Through careful engineering of the dispersion matching window, we have reduced the ratio of photons resulting from degenerate FWM to non-degenerate FWM to less than 0.15.« less

On-chip photonic particle sensor

NASA Astrophysics Data System (ADS)

Singh, Robin; Ma, Danhao; Agarwal, Anu; Anthony, Brian

2018-02-01

We propose an on-chip photonic particle sensor design that can perform particle sizing and counting for various environmental applications. The sensor is based on micro photonic ring resonators that are able to detect the presence of the free space particles through the interaction with their evanescent electric field tail. The sensor can characterize a wide range of the particle size ranging from a few nano meters to micron ( 1 micron). The photonic platform offers high sensitivity, compactness, fast response of the device. Further, FDTD simulations are performed to analyze different particle-light interactions. Such a compact and portable platform, packaged with integrated photonic circuit provides a useful sensing modality in space shuttle and environmental applications.

On-chip phase-change photonic memory and computing

NASA Astrophysics Data System (ADS)

Cheng, Zengguang; Ríos, Carlos; Youngblood, Nathan; Wright, C. David; Pernice, Wolfram H. P.; Bhaskaran, Harish

2017-08-01

The use of photonics in computing is a hot topic of interest, driven by the need for ever-increasing speed along with reduced power consumption. In existing computing architectures, photonic data storage would dramatically improve the performance by reducing latencies associated with electrical memories. At the same time, the rise of `big data' and `deep learning' is driving the quest for non-von Neumann and brain-inspired computing paradigms. To succeed in both aspects, we have demonstrated non-volatile multi-level photonic memory avoiding the von Neumann bottleneck in the existing computing paradigm and a photonic synapse resembling the biological synapses for brain-inspired computing using phase-change materials (Ge2Sb2Te5).

Frequency-multiplexed bias and readout of a 16-pixel superconducting nanowire single-photon detector array

NASA Astrophysics Data System (ADS)

Doerner, S.; Kuzmin, A.; Wuensch, S.; Charaev, I.; Boes, F.; Zwick, T.; Siegel, M.

2017-07-01

We demonstrate a 16-pixel array of microwave-current driven superconducting nanowire single-photon detectors with an integrated and scalable frequency-division multiplexing architecture, which reduces the required number of bias and readout lines to a single microwave feed line. The electrical behavior of the photon-sensitive nanowires, embedded in a resonant circuit, as well as the optical performance and timing jitter of the single detectors is discussed. Besides the single pixel measurements, we also demonstrate the operation of a 16-pixel array with a temporal, spatial, and photon-number resolution.

Monolithic integration of a silica AWG and Ge photodiodes on Si photonic platform for one-chip WDM receiver.

PubMed

Nishi, Hidetaka; Tsuchizawa, Tai; Kou, Rai; Shinojima, Hiroyuki; Yamada, Takashi; Kimura, Hideaki; Ishikawa, Yasuhiko; Wada, Kazumi; Yamada, Koji

2012-04-09

On the silicon (Si) photonic platform, we monolithically integrated a silica-based arrayed-waveguide grating (AWG) and germanium (Ge) photodiodes (PDs) using low-temperature fabrication technology. We confirmed demultiplexing by the AWG, optical-electrical signal conversion by Ge PDs, and high-speed signal detection at all channels. In addition, we mounted a multichannel transimpedance amplifier/limiting amplifier (TIA/LA) circuit on the fabricated AWG-PD device using flip-chip bonding technology. The results show the promising potential of our Si photonic platform as a photonics-electronics convergence.

Spin Pumping in Electrodynamically Coupled Magnon-Photon Systems.

PubMed

Bai, Lihui; Harder, M; Chen, Y P; Fan, X; Xiao, J Q; Hu, C-M

2015-06-05

We use electrical detection, in combination with microwave transmission, to investigate both resonant and nonresonant magnon-photon coupling at room temperature. Spin pumping in a dynamically coupled magnon-photon system is found to be distinctly different from previous experiments. Characteristic coupling features such as modes anticrossing, linewidth evolution, peculiar line shape, and resonance broadening are systematically measured and consistently analyzed by a theoretical model set on the foundation of classical electrodynamic coupling. Our experimental and theoretical approach paves the way for pursuing microwave coherent manipulation of pure spin current via the combination of spin pumping and magnon-photon coupling.

Efficient generation of twin photons at telecom wavelengths with 2.5 GHz repetition-rate-tunable comb laser.

PubMed

Jin, Rui-Bo; Shimizu, Ryosuke; Morohashi, Isao; Wakui, Kentaro; Takeoka, Masahiro; Izumi, Shuro; Sakamoto, Takahide; Fujiwara, Mikio; Yamashita, Taro; Miki, Shigehito; Terai, Hirotaka; Wang, Zhen; Sasaki, Masahide

2014-12-19

Efficient generation and detection of indistinguishable twin photons are at the core of quantum information and communications technology (Q-ICT). These photons are conventionally generated by spontaneous parametric down conversion (SPDC), which is a probabilistic process, and hence occurs at a limited rate, which restricts wider applications of Q-ICT. To increase the rate, one had to excite SPDC by higher pump power, while it inevitably produced more unwanted multi-photon components, harmfully degrading quantum interference visibility. Here we solve this problem by using recently developed 10 GHz repetition-rate-tunable comb laser, combined with a group-velocity-matched nonlinear crystal, and superconducting nanowire single photon detectors. They operate at telecom wavelengths more efficiently with less noises than conventional schemes, those typically operate at visible and near infrared wavelengths generated by a 76 MHz Ti Sapphire laser and detected by Si detectors. We could show high interference visibilities, which are free from the pump-power induced degradation. Our laser, nonlinear crystal, and detectors constitute a powerful tool box, which will pave a way to implementing quantum photonics circuits with variety of good and low-cost telecom components, and will eventually realize scalable Q-ICT in optical infra-structures.

Perovskite photonic sources

NASA Astrophysics Data System (ADS)

Sutherland, Brandon R.; Sargent, Edward H.

2016-05-01

The field of solution-processed semiconductors has made great strides; however, it has yet to enable electrically driven lasers. To achieve this goal, improved materials are required that combine efficient (>50% quantum yield) radiative recombination under high injection, large and balanced charge-carrier mobilities in excess of 10 cm2 V-1 s-1, free-carrier densities greater than 1017 cm-3 and gain coefficients exceeding 104 cm-1. Solid-state perovskites are -- in addition to galvanizing the field of solar electricity -- showing great promise in photonic sources, and may be the answer to realizing solution-cast laser diodes. Here, we discuss the properties of perovskites that benefit light emission, review recent progress in perovskite electroluminescent diodes and optically pumped lasers, and examine the remaining challenges in achieving continuous-wave and electrically driven lasing.

DC Stark addressing for quantum memory in Tm:YAG

NASA Astrophysics Data System (ADS)

Gerasimov, Konstantin; Minnegaliev, Mansur; Urmancheev, Ravil; Moiseev, Sergey

2017-10-01

We observed a linear DC Stark effect for 3H6 - 3H4 optical transition of Tm3+ ions in Y3Al5O12. We observed that application of electric field pulse suppresses the two-pulse photon echo signal. If we then apply a second electric pulse of opposite polarity the echo signal is restored again, which indicates the linear nature of the observed effect. The effect is present despite the D2 symmetry of the Tm3+ sites that prohibits a linear Stark effect. Experimental data analysis shows that the observed electric field influence can be attributed to defects that break the local crystal field symmetry near Tm3+ ions. Using this effect we demonstrate selective retrieval of light pulses in two-pulse photon echo.

Optimizing photon-pair generation electronically using a p-i-n diode incorporated in a silicon microring resonator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savanier, Marc, E-mail: msavanier@eng.ucsd.edu; Kumar, Ranjeet; Mookherjea, Shayan, E-mail: smookherjea@eng.ucsd.edu

Silicon photonic microchips may be useful for compact, inexpensive, room-temperature optically pumped photon-pair sources, which unlike conventional photon-pair generators based on crystals or optical fibers, can be manufactured using CMOS-compatible processes on silicon wafers. It has been shown that photon pairs can be created in simple structures such as microring resonators at a rate of a few hundred kilohertz using less than a milliwatt of optical pump power, based on the process of spontaneous four-wave mixing. To create a practical photon-pair source, however, also requires some way of monitoring the device and aligning the pump wavelength when the temperature varies,more » since silicon resonators are highly sensitive to temperature. In fact, monitoring photodiodes are standard components in classical laser diodes, but the incorporation of germanium or InGaAs photodiodes would raise the cost and fabrication complexity. Here, we present a simple and effective all-electronic technique for finding the optimum operating point for the microring used to generate photon pairs, based on measuring the reverse-biased current in a silicon p-i-n junction diode fabricated across the waveguide that constitutes the silicon microring. We show that by monitoring the current, and using it to tune the pump laser wavelength, the photon-pair generation properties of the microring can be preserved over a temperature range of more than 30 °C.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Jason D.; Schroeppel, Richard Crabtree; Robertson, Perry J.

With the build-out of large transport networks utilizing optical technologies, more and more capacity is being made available. Innovations in Dense Wave Division Multiplexing (DWDM) and the elimination of optical-electrical-optical conversions have brought on advances in communication speeds as we move into 10 Gigabit Ethernet and above. Of course, there is a need to encrypt data on these optical links as the data traverses public and private network backbones. Unfortunately, as the communications infrastructure becomes increasingly optical, advances in encryption (done electronically) have failed to keep up. This project examines the use of optical logic for implementing encryption in themore » photonic domain to achieve the requisite encryption rates. This paper documents the innovations and advances of work first detailed in 'Photonic Encryption using All Optical Logic,' [1]. A discussion of underlying concepts can be found in SAND2003-4474. In order to realize photonic encryption designs, technology developed for electrical logic circuits must be translated to the photonic regime. This paper examines S-SEED devices and how discrete logic elements can be interconnected and cascaded to form an optical circuit. Because there is no known software that can model these devices at a circuit level, the functionality of S-SEED devices in an optical circuit was modeled in PSpice. PSpice allows modeling of the macro characteristics of the devices in context of a logic element as opposed to device level computational modeling. By representing light intensity as voltage, 'black box' models are generated that accurately represent the intensity response and logic levels in both technologies. By modeling the behavior at the systems level, one can incorporate systems design tools and a simulation environment to aid in the overall functional design. Each black box model takes certain parameters (reflectance, intensity, input response), and models the optical ripple and time delay characteristics. These 'black box' models are interconnected and cascaded in an encrypting/scrambling algorithm based on a study of candidate encryption algorithms. Demonstration circuits show how these logic elements can be used to form NAND, NOR, and XOR functions. This paper also presents functional analysis of a serial, low gate count demonstration algorithm suitable for scrambling/encryption using S-SEED devices.« less

Atom-Resonant Heralded Single Photons by Interaction-Free Measurement

NASA Astrophysics Data System (ADS)

Wolfgramm, Florian; de Icaza Astiz, Yannick A.; Beduini, Federica A.; Cerè, Alessandro; Mitchell, Morgan W.

2011-02-01

We demonstrate the generation of rubidium-resonant heralded single photons for quantum memories. Photon pairs are created by cavity-enhanced down-conversion and narrowed in bandwidth to 7 MHz with a novel atom-based filter operating by “interaction-free measurement” principles. At least 94% of the heralded photons are atom-resonant as demonstrated by a direct absorption measurement with rubidium vapor. A heralded autocorrelation measurement shows gc(2)(0)=0.040±0.012, i.e., suppression of multiphoton contributions by a factor of 25 relative to a coherent state. The generated heralded photons can readily be used in quantum memories and quantum networks.

Entanglement generation and manipulation in the Hong-Ou-Mandel experiment: a hidden scenario beyond two-photon interference

NASA Astrophysics Data System (ADS)

Yang, Li-Kai; Cai, Han; Peng, Tao; Wang, Da-Wei

2018-06-01

The Hong‑Ou‑Mandel (HOM) effect was long believed to be a two-photon interference phenomenon. It describes the fact that two indistinguishable photons mixed at a beam splitter will bunch together to one of the two output modes. Considering the two single-photon emitters such as trapped ions, we explore a hidden scenario of the HOM effect, where entanglement can be generated between the two ions when a single photon is detected by one of the detectors. A second photon emitted by the entangled photon sources will be subsequently detected by the same detector. However, we can also control the fate of the second photon by manipulating the entangled state. Instead of two-photon interference, the phase of the entangled state is responsible for the photon’s path in our proposal. Toward a feasible experimental realization, we conduct a quantum jump simulation on the system to show its robustness against experimental errors.

Towards Scalable Entangled Photon Sources with Self-Assembled InAs /GaAs Quantum Dots

NASA Astrophysics Data System (ADS)

Wang, Jianping; Gong, Ming; Guo, G.-C.; He, Lixin

2015-08-01

The biexciton cascade process in self-assembled quantum dots (QDs) provides an ideal system for realizing deterministic entangled photon-pair sources, which are essential to quantum information science. The entangled photon pairs have recently been generated in experiments after eliminating the fine-structure splitting (FSS) of excitons using a number of different methods. Thus far, however, QD-based sources of entangled photons have not been scalable because the wavelengths of QDs differ from dot to dot. Here, we propose a wavelength-tunable entangled photon emitter mounted on a three-dimensional stressor, in which the FSS and exciton energy can be tuned independently, thereby enabling photon entanglement between dissimilar QDs. We confirm these results via atomistic pseudopotential calculations. This provides a first step towards future realization of scalable entangled photon generators for quantum information applications.

True random bit generators based on current time series of contact glow discharge electrolysis

NASA Astrophysics Data System (ADS)

Rojas, Andrea Espinel; Allagui, Anis; Elwakil, Ahmed S.; Alawadhi, Hussain

2018-05-01

Random bit generators (RBGs) in today's digital information and communication systems employ a high rate physical entropy sources such as electronic, photonic, or thermal time series signals. However, the proper functioning of such physical systems is bound by specific constrains that make them in some cases weak and susceptible to external attacks. In this study, we show that the electrical current time series of contact glow discharge electrolysis, which is a dc voltage-powered micro-plasma in liquids, can be used for generating random bit sequences in a wide range of high dc voltages. The current signal is quantized into a binary stream by first using a simple moving average function which makes the distribution centered around zero, and then applying logical operations which enables the binarized data to pass all tests in industry-standard randomness test suite by the National Institute of Standard Technology. Furthermore, the robustness of this RBG against power supply attacks has been examined and verified.

Generating single microwave photons in a circuit.

PubMed

Houck, A A; Schuster, D I; Gambetta, J M; Schreier, J A; Johnson, B R; Chow, J M; Frunzio, L; Majer, J; Devoret, M H; Girvin, S M; Schoelkopf, R J

2007-09-20

Microwaves have widespread use in classical communication technologies, from long-distance broadcasts to short-distance signals within a computer chip. Like all forms of light, microwaves, even those guided by the wires of an integrated circuit, consist of discrete photons. To enable quantum communication between distant parts of a quantum computer, the signals must also be quantum, consisting of single photons, for example. However, conventional sources can generate only classical light, not single photons. One way to realize a single-photon source is to collect the fluorescence of a single atom. Early experiments measured the quantum nature of continuous radiation, and further advances allowed triggered sources of photons on demand. To allow efficient photon collection, emitters are typically placed inside optical or microwave cavities, but these sources are difficult to employ for quantum communication on wires within an integrated circuit. Here we demonstrate an on-chip, on-demand single-photon source, where the microwave photons are injected into a wire with high efficiency and spectral purity. This is accomplished in a circuit quantum electrodynamics architecture, with a microwave transmission line cavity that enhances the spontaneous emission of a single superconducting qubit. When the qubit spontaneously emits, the generated photon acts as a flying qubit, transmitting the quantum information across a chip. We perform tomography of both the qubit and the emitted photons, clearly showing that both the quantum phase and amplitude are transferred during the emission. Both the average power and voltage of the photon source are characterized to verify performance of the system. This single-photon source is an important addition to a rapidly growing toolbox for quantum optics on a chip.

Full Polarization Conical Dispersion and Zero-Refractive-Index in Two-Dimensional Photonic Hypercrystals

PubMed Central

Wang, Jia-Rong; Chen, Xiao-Dong; Zhao, Fu-Li; Dong, Jian-Wen

2016-01-01

Photonic conical dispersion has been found in either transverse magnetic or transverse electric polarization, and the predominant zero-refractive-index behavior in a two-dimensional photonic crystal is polarization-dependent. Here, we show that two-dimensional photonic hypercrystals can be designed that exhibit polarization independent conical dispersion at the Brillouin zone center, as two sets of triply-degenerate point for each polarization are accidentally at the same Dirac frequency. Such photonic hypercrystals consist of periodic dielectric cylinders embedded in elliptic metamaterials, and can be viewed as full-polarized near zero-refractive-index materials around Dirac frequency by using average eigen-field evaluation. Numerical simulations including directional emissions and invisibility cloak are employed to further demonstrate the double-zero-index characteristics for both polarizations in the photonic hypercrystals. PMID:26956377

Enhancement of Rydberg-mediated single-photon nonlinearities by electrically tuned Förster resonances

PubMed Central

Gorniaczyk, H.; Tresp, C.; Bienias, P.; Paris-Mandoki, A.; Li, W.; Mirgorodskiy, I.; Büchler, H. P.; Lesanovsky, I.; Hofferberth, S.

2016-01-01

Mapping the strong interaction between Rydberg atoms onto single photons via electromagnetically induced transparency enables manipulation of light at the single-photon level and few-photon devices such as all-optical switches and transistors operated by individual photons. Here we demonstrate experimentally that Stark-tuned Förster resonances can substantially increase this effective interaction between individual photons. This technique boosts the gain of a single-photon transistor to over 100, enhances the non-destructive detection of single Rydberg atoms to a fidelity beyond 0.8, and enables high-precision spectroscopy on Rydberg pair states. On top, we achieve a gain larger than 2 with gate photon read-out after the transistor operation. Theory models for Rydberg polariton propagation on Förster resonance and for the projection of the stored spin-wave yield excellent agreement to our data and successfully identify the main decoherence mechanism of the Rydberg transistor, paving the way towards photonic quantum gates. PMID:27515278

Efficient 525 nm laser generation in single or double resonant cavity

NASA Astrophysics Data System (ADS)

Liu, Shilong; Han, Zhenhai; Liu, Shikai; Li, Yinhai; Zhou, Zhiyuan; Shi, Baosen

2018-03-01

This paper reports the results of a study into highly efficient sum frequency generation from 792 and 1556 nm wavelength light to 525 nm wavelength light using either a single or double resonant ring cavity based on a periodically poled potassium titanyl phosphate crystal (PPKTP). By optimizing the cavity's parameters, the maximum power achieved for the resultant 525 nm laser was 263 and 373 mW for the single and double resonant cavity, respectively. The corresponding quantum conversion efficiencies were 8 and 77% for converting 1556 nm photons to 525 nm photons with the single and double resonant cavity, respectively. The measured intra-cavity single pass conversion efficiency for both configurations was about 5%. The performances of the sum frequency generation in these two configurations was studied and compared in detail. This work will provide guidelines for optimizing the generation of sum frequency generated laser light for a variety of configurations. The high conversion efficiency achieved in this work will help pave the way for frequency up-conversion of non-classical quantum states, such as the squeezed vacuum and single photon states. The proposed green laser source will be used in our future experiments, which includes a plan to generate two-color entangled photon pairs and achieve the frequency down-conversion of single photons carrying orbital angular momentum.

Ultralow-Threshold Electrically Pumped Quantum-Dot Photonic-Crystal Nanocavity Laser

DTIC Science & Technology

2011-05-01

we demonstrate a quantum-dot photonic-crystal nanocavity laser in gallium arsenide pumped by a lateral p–i–n junction formed by ion implantation...330 nm layer of silicon nitride was then deposited on the sample using plasma-enhanced chemical vapour deposition (PECVD) to serve as a mask for ion

CMOS-Compatible Fabrication for Photonic Crystal-Based Nanofluidic Structure.

PubMed

Peng, Wang; Chen, Youping; Ai, Wu; Zhang, Dailin; Song, Han; Xiong, Hui; Huang, Pengcheng

2017-12-01

Photonic crystal (PC)-based devices have been widely used since 1990s, while PC has just stepped into the research area of nanofluidic. In this paper, photonic crystal had been used as a complementary metal oxide semiconductors (CMOS) compatible part to create a nanofluidic structure. A nanofluidic structure prototype had been fabricated with CMOS-compatible techniques. The nanofluidic channels were sealed by direct bonding polydimethylsiloxane (PDMS) and the periodic gratings on photonic crystal structure. The PC was fabricated on a 4-in. Si wafer with Si 3 N 4 as the guided mode layer and SiO 2 film as substrate layer. The higher order mode resonance wavelength of PC-based nanofluidic structure had been selected, which can confine the enhanced electrical field located inside the nanochannel area. A design flow chart was used to guide the fabrication process. By optimizing the fabrication device parameters, the periodic grating of PC-based nanofluidic structure had a high-fidelity profile with fill factor at 0.5. The enhanced electric field was optimized and located within the channel area, and it can be used for PC-based nanofluidic applications with high performance.

Sensitivity Limits of Rydberg Atom-Based Radio Frequency Electric Field Sensing

NASA Astrophysics Data System (ADS)

Jahangiri, Akbar J.; Kumar, Santosh; Kuebler, Harald; Fan, Haoquan; Shaffer, James P.

2017-04-01

We present progress on Rydberg atom-based RF electric field sensing using Rydberg state electromagnetically induced transparency (EIT) in room temperature atomic vapor cells. In recent experiments on homodyne detection with a Mach-Zehnder interferometer and frequency modulation spectroscopy with active control of residual amplitude modulation we determined that photon shot noise on the probe laser detector limits the sensitivity. Another factor that limits the accuracy is residual Doppler broadening due to the wave-vector mismatch between the coupling and the probe lasers. The sensor as limited by project noise can be orders of magnitude better. A multi-photon scheme is presented that can eliminate the residual Doppler effect by matching the wave-vectors of three lasers and reduce the photon shot noise limit by correctly choosing the Rabi frequencies of the first two steps of the EIT scheme. Using density matrix calculations, we predict that the three-photon approach can improve the detection sensitivity to below 200 nV cm-1 Hz- 1 / 2 and expand the Autler-Townes regime which improves the accuracy. This work is supported by DARPA and the NRO.

A solid-state amorphous selenium avalanche technology for low photon flux imaging applications

PubMed Central

Wronski, M. M.; Zhao, W.; Reznik, A.; Tanioka, K.; DeCrescenzo, G.; Rowlands, J. A.

2010-01-01

Purpose: The feasibility of a practical solid-state technology for low photon flux imaging applications was investigated. The technology is based on an amorphous selenium photoreceptor with a voltage-controlled avalanche multiplication gain. If this photoreceptor can provide sufficient internal gain, it will be useful for an extensive range of diagnostic imaging systems. Methods: The avalanche photoreceptor under investigation is referred to as HARP-DRL. This is a novel concept in which a high-gain avalanche rushing photoconductor (HARP) is integrated with a distributed resistance layer (DRL) and sandwiched between two electrodes. The avalanche gain and leakage current characteristics of this photoreceptor were measured. Results: HARP-DRL has been found to sustain very high electric field strengths without electrical breakdown. It has shown avalanche multiplication gains as high as 104 and a very low leakage current (≤20 pA∕mm2). Conclusions: This is the first experimental demonstration of a solid-state amorphous photoreceptor which provides sufficient internal avalanche gain for photon counting and photon starved imaging applications. PMID:20964217

Highly sensitive determination of transient generation of biophotons during hypersensitive response to cucumber mosaic virus in cowpea.

PubMed

Kobayashi, Masaki; Sasaki, Kensuke; Enomoto, Masaru; Ehara, Yoshio

2007-01-01

The hypersensitive response (HR) is one mechanism of the resistance of plants to pathogen infection. It involves the generation of reactive oxygen species (ROS) which have crucial roles in signal transduction or as toxic agents leading to cell death. Often, ROS generation is accompanied by an ultraweak photon emission resulting from radical reactions that are initiated by ROS through the oxidation of living materials such as lipids, proteins, and DNA. This photon emission, referred to as 'biophotons', is extremely weak, but, based on the technique of photon counting imaging, a system has been developed to analyse the spatiotemporal properties of photon emission. Using this system, the dynamics of photon emission which might be associated with the oxidative burst, which promotes the HR, have been determined. Here, the transient generation of biophotons is demonstrated during the HR process in cowpea elicited by cucumber mosaic virus. The distinctive dynamics in spatiotemporal properties of biophoton emission during the HR expression on macroscopic and microscopic levels are also described. This study reveals the involvement of ROS generation in biophoton emission in the process of HR through the determination of the inhibitory effect of an antioxidant (Tiron) on biophoton emission.

Quantum efficiency as a device-physics interpretation tool for thin-film solar cells

NASA Astrophysics Data System (ADS)

Nagle, Timothy J.

2007-12-01

Thin-film solar cells made from CdTe and CIGS p-type absorbers are promising candidates for generating pollution-free electricity. The challenge faced by the thin-film photovoltaics (PV) community is to improve the electrical properties of devices, without straying from low-cost, industry-friendly techniques. This dissertation will focus on the use of quantum-efficiency (QE) measurements to deduce the device physics of thin-film devices, in the hope of improving electrical properties and efficiencies of PV materials. Photons which are absorbed, but not converted into electrical energy can modify the energy bands in the solar cell. Under illumination, photoconductivity in the CdS window layer can result in bands different from those in the dark. QE data presented here was taken under a variety of light-bias conditions. These results suggest that 0.10 sun of white-light bias incident on the CdS layer is usually sufficient to achieve accurate QE results. QE results are described by models based on carrier collection by drift and diffusion, and photon absorption. These models are sensitive to parameters such as carrier mobility and lifetime. Comparing calculated QE curves with experiments, it was determined that electron lifetimes in CdTe are less than 0.1 ns. Lifetime determinations also suggest that copper serves as a recombination center in CdTe. The spatial uniformity of QE results has been investigated with the LBIC apparatus, and several experiments are described which investigate cell uniformity. Electrical variations that occur in solar cells often occur in a nonuniform fashion, and can be detected with the LBIC apparatus. Studies discussed here include investigation of patterned deposition of Cu in back-contacts, the use of high-resistivity TCO layers to mitigate nonuniformity, optical effects, and local shunts. CdTe devices with transparent back contacts were also studied with LBIC, including those that received a strong bromine/dichrol/hydrazine (BDH) etch and those that received a weak bromine etch at the back contact. Back-side results showed improved uniformity in BDH-etched devices, attributed to better back contacts in these devices. In thin-absorber devices, the uniformity trend would likely extend to front-side measurements.

Triggered generation of single guided photons from a single atom in a nanofiber cavity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Le Kien, Fam; Hakuta, K.

2011-04-15

We study the deterministic generation of single guided-mode photons from an atom in the vicinity of a nanofiber with two fiber-Bragg-grating (FBG) mirrors. The technique is based on a cavity-enhanced Raman scattering process involving an adiabatic passage. We take into account the scattering of the pump field from the fiber, the multilevel structure of the atom, and the surface-induced van der Waals potential in describing the photon generation process. We find that, due to the confinement of the cavity field in the transverse plane of the fiber and in the space between the FBG mirrors, the probability of the generationmore » of a single guided-mode photon can be close to unity even when the finesse of the nanofiber cavity is moderate. We show the possibilities of saturation and power broadening in the behavior of the number of photons emitted into the nanofiber.« less

Distribution of hybrid entanglement and hyperentanglement with time-bin for secure quantum channel under noise via weak cross-Kerr nonlinearity.

PubMed

Heo, Jino; Kang, Min-Sung; Hong, Chang-Ho; Yang, Hyung-Jin; Choi, Seong-Gon; Hong, Jong-Phil

2017-08-31

We design schemes to generate and distribute hybrid entanglement and hyperentanglement correlated with degrees of freedom (polarization and time-bin) via weak cross-Kerr nonlinearities (XKNLs) and linear optical devices (including time-bin encoders). In our scheme, the multi-photon gates (which consist of XKNLs, quantum bus [qubus] beams, and photon-number-resolving [PNR] measurement) with time-bin encoders can generate hyperentanglement or hybrid entanglement. And we can also purify the entangled state (polarization) of two photons using only linear optical devices and time-bin encoders under a noisy (bit-flip) channel. Subsequently, through local operations (using a multi-photon gate via XKNLs) and classical communications, it is possible to generate a four-qubit hybrid entangled state (polarization and time-bin). Finally, we discuss how the multi-photon gate using XKNLs, qubus beams, and PNR measurement can be reliably performed under the decoherence effect.

Maser mechanism of optical pulsations from anomalous X-ray pulsar 4U 0142+61

NASA Astrophysics Data System (ADS)

Lu, Y.; Zhang, S. N.

2004-11-01

Based on the work of Luo & Melrose from the early 1990s, a maser curvature emission mechanism in the presence of curvature drift is used to explain the optical pulsations from anomalous X-ray pulsars (AXPs). The model comprises a rotating neutron star with a strong surface magnetic field, i.e. a magnetar. Assuming the space-charge-limited flow acceleration mechanism, in which the strongly magnetized neutron star induces strong electric fields that pull the charges from its surface and flow along the open field lines, the neutron star generates a dense flow of electrons and positrons (relativistic pair plasma) by either two-photon pair production or one-photon pair creation resulting from inverse Compton scattering of the thermal photons above the pulsar polar cap (PC). The motion of the pair plasma is essentially one-dimensional along the field lines. We propose that optical pulsations from AXPs are generated by a curvature-drift-induced maser developing in the PC of magnetars. Pair plasma is considered as an active medium that can amplify its normal modes. The curvature drift, which is energy-dependent, is another essential ingredient in allowing negative absorption (maser action) to occur. For the source AXP 4U 0142+61, we find that the optical pulsation triggered by curvature-drift maser radiation occurs at the radial distance R(νM) ~ 4.75 × 109 cm to the neutron star. The corresponding curvature maser frequency is about νM~ 1.39 × 1014 Hz, and the pulse component from the maser amplification is about 27 per cent. The result is consistent with the observation of the optical pulsations from AXP 4U 0142+61.

Experimental generation of complex noisy photonic entanglement

NASA Astrophysics Data System (ADS)

Dobek, K.; Karpiński, M.; Demkowicz-Dobrzański, R.; Banaszek, K.; Horodecki, P.

2013-02-01

We present an experimental scheme based on spontaneous parametric down-conversion to produce multiple-photon pairs in maximally entangled polarization states using an arrangement of two type-I nonlinear crystals. By introducing correlated polarization noise in the paths of the generated photons we prepare mixed-entangled states whose properties illustrate fundamental results obtained recently in quantum information theory, in particular those concerning bound entanglement and privacy.

Entangled photon pair generation by spontaneous parametric down-conversion in finite-length one-dimensional photonic crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Centini, M.; Sciscione, L.; Sibilia, C.

A description of spontaneous parametric down-conversion in finite-length one-dimensional nonlinear photonic crystals is developed using semiclassical and quantum approaches. It is shown that if a suitable averaging is added to the semiclassical model, its results are in very good agreement with the quantum approach. We propose two structures made with GaN/AlN that generate both degenerate and nondegenerate entangled photon pairs. Both structures are designed so as to achieve a high efficiency of the nonlinear process.

Correlated Photon-Pair Generation in Reverse Proton-Exchange PPLN Waveguides With Integrated Mode Demultiplexer at 10 GHz Clock

DTIC Science & Technology

2007-07-31

number of photon-pairs per pulse is μ ( 1<<μ ) and the laser repetition frequency isν . The average noise photon numbers per pulse are sμ and iμ for the...and 1563-nm center wavelength pass through a tunable bandpass filter to remove the background noise from the EDFA. The pump is then frequency doubled...generation in dispersion-shifted fiber: suppression of noise photons by cooling fiber", Opt. Express, 13, 7832 (2005) #83485 - $15.00 USD Received 29 May

Photon wave function formalism for analysis of Mach–Zehnder interferometer and sum-frequency generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ritboon, Atirach, E-mail: atirach.3.14@gmail.com; Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai 90112; Daengngam, Chalongrat, E-mail: chalongrat.d@psu.ac.th

2016-08-15

Biakynicki-Birula introduced a photon wave function similar to the matter wave function that satisfies the Schrödinger equation. Its second quantization form can be applied to investigate nonlinear optics at nearly full quantum level. In this paper, we applied the photon wave function formalism to analyze both linear optical processes in the well-known Mach–Zehnder interferometer and nonlinear optical processes for sum-frequency generation in dispersive and lossless medium. Results by photon wave function formalism agree with the well-established Maxwell treatments and existing experimental verifications.

Economic analysis of greenhouse lighting: light emitting diodes vs. high intensity discharge fixtures.

PubMed

Nelson, Jacob A; Bugbee, Bruce

2014-01-01

Lighting technologies for plant growth are improving rapidly, providing numerous options for supplemental lighting in greenhouses. Here we report the photosynthetic (400-700 nm) photon efficiency and photon distribution pattern of two double-ended HPS fixtures, five mogul-base HPS fixtures, ten LED fixtures, three ceramic metal halide fixtures, and two fluorescent fixtures. The two most efficient LED and the two most efficient double-ended HPS fixtures had nearly identical efficiencies at 1.66 to 1.70 micromoles per joule. These four fixtures represent a dramatic improvement over the 1.02 micromoles per joule efficiency of the mogul-base HPS fixtures that are in common use. The best ceramic metal halide and fluorescent fixtures had efficiencies of 1.46 and 0.95 micromoles per joule, respectively. We also calculated the initial capital cost of fixtures per photon delivered and determined that LED fixtures cost five to ten times more than HPS fixtures. The five-year electric plus fixture cost per mole of photons is thus 2.3 times higher for LED fixtures, due to high capital costs. Compared to electric costs, our analysis indicates that the long-term maintenance costs are small for both technologies. If widely spaced benches are a necessary part of a production system, the unique ability of LED fixtures to efficiently focus photons on specific areas can be used to improve the photon capture by plant canopies. Our analysis demonstrates, however, that the cost per photon delivered is higher in these systems, regardless of fixture category. The lowest lighting system costs are realized when an efficient fixture is coupled with effective canopy photon capture.

Deterministic photon-emitter coupling in chiral photonic circuits.

PubMed

Söllner, Immo; Mahmoodian, Sahand; Hansen, Sofie Lindskov; Midolo, Leonardo; Javadi, Alisa; Kiršanskė, Gabija; Pregnolato, Tommaso; El-Ella, Haitham; Lee, Eun Hye; Song, Jin Dong; Stobbe, Søren; Lodahl, Peter

2015-09-01

Engineering photon emission and scattering is central to modern photonics applications ranging from light harvesting to quantum-information processing. To this end, nanophotonic waveguides are well suited as they confine photons to a one-dimensional geometry and thereby increase the light-matter interaction. In a regular waveguide, a quantum emitter interacts equally with photons in either of the two propagation directions. This symmetry is violated in nanophotonic structures in which non-transversal local electric-field components imply that photon emission and scattering may become directional. Here we show that the helicity of the optical transition of a quantum emitter determines the direction of single-photon emission in a specially engineered photonic-crystal waveguide. We observe single-photon emission into the waveguide with a directionality that exceeds 90% under conditions in which practically all the emitted photons are coupled to the waveguide. The chiral light-matter interaction enables deterministic and highly directional photon emission for experimentally achievable on-chip non-reciprocal photonic elements. These may serve as key building blocks for single-photon optical diodes, transistors and deterministic quantum gates. Furthermore, chiral photonic circuits allow the dissipative preparation of entangled states of multiple emitters for experimentally achievable parameters, may lead to novel topological photon states and could be applied for directional steering of light.

Deterministic photon-emitter coupling in chiral photonic circuits

NASA Astrophysics Data System (ADS)

Söllner, Immo; Mahmoodian, Sahand; Hansen, Sofie Lindskov; Midolo, Leonardo; Javadi, Alisa; Kiršanskė, Gabija; Pregnolato, Tommaso; El-Ella, Haitham; Lee, Eun Hye; Song, Jin Dong; Stobbe, Søren; Lodahl, Peter

2015-09-01

Engineering photon emission and scattering is central to modern photonics applications ranging from light harvesting to quantum-information processing. To this end, nanophotonic waveguides are well suited as they confine photons to a one-dimensional geometry and thereby increase the light-matter interaction. In a regular waveguide, a quantum emitter interacts equally with photons in either of the two propagation directions. This symmetry is violated in nanophotonic structures in which non-transversal local electric-field components imply that photon emission and scattering may become directional. Here we show that the helicity of the optical transition of a quantum emitter determines the direction of single-photon emission in a specially engineered photonic-crystal waveguide. We observe single-photon emission into the waveguide with a directionality that exceeds 90% under conditions in which practically all the emitted photons are coupled to the waveguide. The chiral light-matter interaction enables deterministic and highly directional photon emission for experimentally achievable on-chip non-reciprocal photonic elements. These may serve as key building blocks for single-photon optical diodes, transistors and deterministic quantum gates. Furthermore, chiral photonic circuits allow the dissipative preparation of entangled states of multiple emitters for experimentally achievable parameters, may lead to novel topological photon states and could be applied for directional steering of light.

Quantum optical measurement with tripartite entangled photons generated by triple parametric down-conversion

NASA Astrophysics Data System (ADS)

Cho, Minhaeng

2018-05-01

Parametric down-conversion is a second-order nonlinear optical process annihilating a pump photon and creating a pair of photons in the signal and idler modes. Then, by using two parametric down-converters and introducing a path indistinguishability for the two generated idler modes, a quantum coherence between two conjugate signal beams can be induced. Such a double spontaneous or stimulated parametric down-conversion scheme has been used to demonstrate quantum spectroscopy and imaging with undetected idler photons via measuring one-photon interference between their correlated signal beams. Recently, we considered another quantum optical measurement scheme utilizing W-type tripartite entangled signal photons that can be generated by employing three spontaneous parametric down-conversion crystals and by inducing coherences or path-indistinguishabilities between their correlated idler beams and between quantum vacuum fields. Here, we consider an extended triple stimulated parametric down-conversion scheme for quantum optical measurement of sample properties with undetected idler and photons. Noting the real effect of vacuum field indistinguishability on the fringe visibility as well as the role of zero-point field energy in the interferometry, we show that this scheme is an ideal and efficient way to create a coherent state of W-type entangled signal photons. We anticipate that this scheme would be of critical use in further developing quantum optical measurements in spectroscopy and microscopy with undetected photons.

Quantum optical measurement with tripartite entangled photons generated by triple parametric down-conversion.

PubMed

Cho, Minhaeng

2018-05-14

Parametric down-conversion is a second-order nonlinear optical process annihilating a pump photon and creating a pair of photons in the signal and idler modes. Then, by using two parametric down-converters and introducing a path indistinguishability for the two generated idler modes, a quantum coherence between two conjugate signal beams can be induced. Such a double spontaneous or stimulated parametric down-conversion scheme has been used to demonstrate quantum spectroscopy and imaging with undetected idler photons via measuring one-photon interference between their correlated signal beams. Recently, we considered another quantum optical measurement scheme utilizing W-type tripartite entangled signal photons that can be generated by employing three spontaneous parametric down-conversion crystals and by inducing coherences or path-indistinguishabilities between their correlated idler beams and between quantum vacuum fields. Here, we consider an extended triple stimulated parametric down-conversion scheme for quantum optical measurement of sample properties with undetected idler and photons. Noting the real effect of vacuum field indistinguishability on the fringe visibility as well as the role of zero-point field energy in the interferometry, we show that this scheme is an ideal and efficient way to create a coherent state of W-type entangled signal photons. We anticipate that this scheme would be of critical use in further developing quantum optical measurements in spectroscopy and microscopy with undetected photons.

Four-terminal circuit element with photonic core

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sampayan, Stephen

A four-terminal circuit element is described that includes a photonic core inside of the circuit element that uses a wide bandgap semiconductor material that exhibits photoconductivity and allows current flow through the material in response to the light that is incident on the wide bandgap material. The four-terminal circuit element can be configured based on various hardware structures using a single piece or multiple pieces or layers of a wide bandgap semiconductor material to achieve various designed electrical properties such as high switching voltages by using the photoconductive feature beyond the breakdown voltages of semiconductor devices or circuits operated basedmore » on electrical bias or control designs. The photonic core aspect of the four-terminal circuit element provides unique features that enable versatile circuit applications to either replace the semiconductor transistor-based circuit elements or semiconductor diode-based circuit elements.« less

Electrically tunable artificial gauge potential for polaritons

PubMed Central

Lim, Hyang-Tag; Togan, Emre; Kroner, Martin; Miguel-Sanchez, Javier; Imamoğlu, Atac

2017-01-01

Neutral particles subject to artificial gauge potentials can behave as charged particles in magnetic fields. This fascinating premise has led to demonstrations of one-way waveguides, topologically protected edge states and Landau levels for photons. In ultracold neutral atoms, effective gauge fields have allowed the emulation of matter under strong magnetic fields leading to realization of Harper-Hofstadter and Haldane models. Here we show that application of perpendicular electric and magnetic fields effects a tunable artificial gauge potential for two-dimensional microcavity exciton polaritons. For verification, we perform interferometric measurements of the associated phase accumulated during coherent polariton transport. Since the gauge potential originates from the magnetoelectric Stark effect, it can be realized for photons strongly coupled to excitations in any polarizable medium. Together with strong polariton–polariton interactions and engineered polariton lattices, artificial gauge fields could play a key role in investigation of non-equilibrium dynamics of strongly correlated photons. PMID:28230047

Electrically-pumped, broad-area, single-mode photonic crystal lasers.

PubMed

Zhu, Lin; Chak, Philip; Poon, Joyce K S; DeRose, Guy A; Yariv, Amnon; Scherer, Axel

2007-05-14

Planar broad-area single-mode lasers, with modal widths of the order of tens of microns, are technologically important for high-power applications and improved coupling efficiency into optical fibers. They may also find new areas of applications in on-chip integration with devices that are of similar size scales, such as for spectroscopy in microfluidic chambers or optical signal processing with micro-electromechanical systems. An outstanding challenge is that broad-area lasers often require external means of control, such as injection-locking or a frequency/spatial filter to obtain single-mode operation. In this paper, we propose and demonstrate effective index-guided, large-area, edge-emitting photonic crystal lasers driven by pulsed electrical current injection at the optical telecommunication wavelength of 1550 nm. By suitable design of the photonic crystal lattice, our lasers operate in a single mode with a 1/e(2) modal width of 25 microm and a length of 600 microm.

Physics of the Brain. Prevention of the Epileptic Seizures by the Multi-photon Pulsed-operated Fiber Lasers in the Ultraviolet Range of Frequencies.

NASA Astrophysics Data System (ADS)

Stefan, V. Alexander; IAPS Team

The novel study of the epileptogenesis mechanisms is proposed. It is based on the pulsed-operated (amplitude modulation) multi-photon (frequency modulation) fiber-laser interaction with the brain epilepsy-topion (the epilepsy onset area), so as to prevent the excessive electrical discharge (epileptic seizure) in the brain. The repetition frequency, Ω, matches the low frequency (epileptic) phonon waves in the brain. The laser repetition frequency (5-100 pulses per second) enables the resonance-scanning of the wide range of the phonon (possible epileptic-to-be) activity in the brain. The tunable fiber laser frequencies, Δω (multi photon operation), are in the ultraviolet frequency range, thus enabling monitoring of the electrical charge imbalance (within the 10s of milliseconds), and the DNA-corruption in the epilepsy-topion, as the possible cause of the disease. Supported by Nikola Tesla Labs., Stefan University.

Ab Initio Calculation of Photoionization and Inelastic Photon Scattering Spectra of He below the N=2 Threshold in a dc Electric Field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mihelic, Andrej; Zitnik, Matjaz

2007-06-15

We study the Stark effect on doubly excited states of the helium atom below N=2. We present the ab initio photoionization and total inelastic photon scattering cross sections calculated with the method of complex scaling for field strengths F{<=}100 kV/cm. The calculations are compared to the measurements of the ion [Phys. Rev. Lett. 90, 133002 (2003)] and vacuum ultraviolet fluorescence yields [Phys. Rev. Lett. 96, 093001 (2006)]. For the case of photoionization and for incident photons with polarization vector P parallel to the electric field F, we confirm the propensity rule proposed by Tong and Lin [Phys. Rev. Lett. 92,more » 223003 (2004)]. Furthermore, the rule is also shown to apply for F perpendicular P and for the case of the inelastic scattering in both experimental geometries.« less

Optical pulse generation in a transistor laser via intra-cavity photon-assisted tunneling and excess base carrier redistribution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, M.; Iverson, E. W.; Wang, C. Y.

2015-11-02

For a direct-gap semiconductor (e.g., a p-n junction), photon-assisted tunneling is known to exhibit a high nonlinear absorption. In a transistor laser, as discussed here, the coherent photons generated at the quantum well interact with the collector junction field and “assist” electron tunneling from base to collector, thus resulting in the nonlinear modulation of the laser and the realization of optical pulse generation. 1 and 2 GHz optical pulses are demonstrated in the transistor laser using collector voltage control.

Phonon Counting and Intensity Interferometry of a Nanomechanical Resonator

DTIC Science & Technology

2014-10-04

photon detectors, Γdark, and the residual pump laser light which is transmitted through the filters. In this work we use a cascaded pair of tunable...T. Gerrits, I. Vayshenker, B. Baek, M. D. Shaw, R. P. Mirin, and S. W. Nam, Nature Photon . 7, 210 6 a b 0 1 10−1 FIG. 5. FEM simulations . a, Electric... photon detection we have performed effective phonon counting measurements of the acoustic emission and absorption processes in a nanomechanical res

NASA Electronic Parts and Packaging (NEPP): Space Qualification Guidelines of Optoelectronic and Photonic Devices for Optical Communication Systems

NASA Technical Reports Server (NTRS)

Kim, Quiesup

2001-01-01

Key elements of space qualification of opto-electric and photonic optical devices were overviewed. Efforts were concentrated on the reliability concerns of the devices needed for potential applications in space environments. The ultimate goal for this effort is to gradually establish enough data to develop a space qualification plan of newly developed specific photonic parts using empirical and numerical models to assess the life-time and degradation of the devices for potential long term space missions.

Photonic Crystal Enhanced Fluorescence for Early Breast Cancer Biomarker Detection

PubMed Central

Cunningham, Brian T.; Zangar, Richard C.

2013-01-01

Photonic crystal surfaces offer a compelling platform for improving the sensitivity of surface-based fluorescent assays used in disease diagnostics. Through the complementary processes of photonic crystal enhanced excitation and enhanced extraction, a periodic dielectric-based nanostructured surface can simultaneously increase the electric field intensity experienced by surface-bound fluorophores and increase the collection efficiency of emitted fluorescent photons. Through the ability to inexpensively fabricate photonic crystal surfaces over substantial surface areas, they are amenable to single-use applications in biological sensing, such as disease biomarker detection in serum. In this review, we will describe the motivation for implementing high-sensitivity, multiplexed biomarker detection in the context of breast cancer diagnosis. We will summarize recent efforts to improve the detection limits of such assays though the use of photonic crystal surfaces. Reduction of detection limits is driven by low autofluorescent substrates for photonic crystal fabrication, and detection instruments that take advantage of their unique features. PMID:22736539

Bimodal exciton-plasmon light sources controlled by local charge carrier injection.

PubMed

Merino, Pablo; Rosławska, Anna; Große, Christoph; Leon, Christopher C; Kuhnke, Klaus; Kern, Klaus

2018-05-01

Electrical charges can generate photon emission in nanoscale quantum systems by two independent mechanisms. First, radiative recombination of pairs of oppositely charged carriers generates sharp excitonic lines. Second, coupling between currents and collective charge oscillations results in broad plasmonic bands. Both luminescence modes can be simultaneously generated upon charge carrier injection into thin C 60 crystallites placed in the plasmonic nanocavity of a scanning tunneling microscope (STM). Using the sharp tip of the STM as a subnanometer-precise local electrode, we show that the two types of electroluminescence are induced by two separate charge transport channels. Holes injected into the valence band promote exciton generation, whereas electrons extracted from the conduction band cause plasmonic luminescence. The different dynamics of the two mechanisms permit controlling their relative contribution in the combined bimodal emission. Exciton recombination prevails for low charge injection rates, whereas plasmon decay outshines for high tunneling currents. The continuous transition between both regimes is described by a rate model characterizing emission dynamics on the nanoscale. Our work provides the basis for developing blended exciton-plasmon light sources with advanced functionalities.

Photoionization pathways and thresholds in generation of Lyman-α radiation by resonant four-wave mixing in Kr-Ar mixture

NASA Astrophysics Data System (ADS)

Louchev, Oleg A.; Saito, Norihito; Oishi, Yu; Miyazaki, Koji; Okamura, Kotaro; Nakamura, Jumpei; Iwasaki, Masahiko; Wada, Satoshi

2016-09-01

We develop a set of analytical approximations for the estimation of the combined effect of various photoionization processes involved in the resonant four-wave mixing generation of ns pulsed Lyman-α (L-α ) radiation by using 212.556 nm and 820-845 nm laser radiation pulses in Kr-Ar mixture: (i) multi-photon ionization, (ii) step-wise (2+1)-photon ionization via the resonant 2-photon excitation of Kr followed by 1-photon ionization and (iii) laser-induced avalanche ionization produced by generated free electrons. Developed expressions validated by order of magnitude estimations and available experimental data allow us to identify the area for the operation under high input laser intensities avoiding the onset of full-scale discharge, loss of efficiency and inhibition of generated L-α radiation. Calculations made reveal an opportunity for scaling up the output energy of the experimentally generated pulsed L-α radiation without significant enhancement of photoionization.

Direct photonic coupling of a semiconductor quantum dot and a trapped ion.

PubMed

Meyer, H M; Stockill, R; Steiner, M; Le Gall, C; Matthiesen, C; Clarke, E; Ludwig, A; Reichel, J; Atatüre, M; Köhl, M

2015-03-27

Coupling individual quantum systems lies at the heart of building scalable quantum networks. Here, we report the first direct photonic coupling between a semiconductor quantum dot and a trapped ion and we demonstrate that single photons generated by a quantum dot controllably change the internal state of a Yb^{+} ion. We ameliorate the effect of the 60-fold mismatch of the radiative linewidths with coherent photon generation and a high-finesse fiber-based optical cavity enhancing the coupling between the single photon and the ion. The transfer of information presented here via the classical correlations between the σ_{z} projection of the quantum-dot spin and the internal state of the ion provides a promising step towards quantum-state transfer in a hybrid photonic network.

Review of Microwave Photonics Technique to Generate the Microwave Signal by Using Photonics Technology

NASA Astrophysics Data System (ADS)

Raghuwanshi, Sanjeev Kumar; Srivastav, Akash

2017-12-01

Microwave photonics system provides high bandwidth capabilities of fiber optic systems and also contains the ability to provide interconnect transmission properties, which are virtually independent of length. The low-loss wide bandwidth capability of optoelectronic systems makes them attractive for the transmission and processing of microwave signals, while the development of high-capacity optical communication systems has required the use of microwave techniques in optical transmitters and receivers. These two strands have led to the development of the research area of microwave photonics. So, we can considered microwave photonics as the field that studies the interaction between microwave and optical waves for applications such as communications, radars, sensors and instrumentations. In this paper we have thoroughly reviewed the microwave generation techniques by using photonics technology.

Micro-optical foundry: 3D lithography by freezing liquid instabilities at nanoscale

NASA Astrophysics Data System (ADS)

Grilli, S.; Coppola, S.; Vespini, V.; Merola, F.; Finizio, A.; Ferraro, P.

2012-06-01

The pyroelectric functionality of a Lithium Niobate (LN) substrate is used for non-contact manipulation of polymeric material. In this work we introduced a novel approach for fabricating a wide variety of soft solid-like microstructures, thus leading to a new concept in 3D lithography. A relatively easy to accomplish technique has been demonstrated for curing different transient stages of polymer fluids by rapid cross-linking of PDMS. The method is twofold innovative thanks to the electrode-less configuration and to the rapid formation of a wide variety of 3D solid-like structures by exploiting polymer instabilities. This new and unique technique is named "pyro-electrohydrodynamic (PEHD) lithography", meaning the generation of structures by using forces produced by electric fields generated by the pyroelectric effect. The fabrication of polymer wires, needles, pillars, cones, or microspheres is reported, and practical proofs of their use in photonics are presented.

Broadband noise limit in the photodetection of ultralow jitter optical pulses.

PubMed

Sun, Wenlu; Quinlan, Franklyn; Fortier, Tara M; Deschenes, Jean-Daniel; Fu, Yang; Diddams, Scott A; Campbell, Joe C

2014-11-14

Applications with optical atomic clocks and precision timing often require the transfer of optical frequency references to the electrical domain with extremely high fidelity. Here we examine the impact of photocarrier scattering and distributed absorption on the photocurrent noise of high-speed photodiodes when detecting ultralow jitter optical pulses. Despite its small contribution to the total photocurrent, this excess noise can determine the phase noise and timing jitter of microwave signals generated by detecting ultrashort optical pulses. A Monte Carlo simulation of the photodetection process is used to quantitatively estimate the excess noise. Simulated phase noise on the 10 GHz harmonic of a photodetected pulse train shows good agreement with previous experimental data, leading to the conclusion that the lowest phase noise photonically generated microwave signals are limited by photocarrier scattering well above the quantum limit of the optical pulse train.

Alternative generation of well-aligned uniform lying helix texture in a cholesteric liquid crystal cell

NASA Astrophysics Data System (ADS)

Yu, Chia-Hua; Wu, Po-Chang; Lee, Wei

2017-10-01

This work demonstrates a simple approach for obtaining a well-aligned uniform lying helix (ULH) texture and a tri-bistable feature at ambient temperature in a typical 90°-twisted cell filled with a short-pitch cholesteric liquid crystal. This ULH texture is obtained at room temperature from initially field-induced helix-free homeotropic state by gradually decreasing the applied voltage. Depending on the way and rate of reducing the voltage, three stable states (i.e., Grandjean planar, focal conic, and ULH) are generated and switching between any two of them is realized. Moreover, the electrical operation of the cell in the ULH state enables the tunability in phase retardation via the deformation of the ULH. The observations made in this work may be useful for applications such as tunable phase modulators and energy-efficient photonic devices.

Defect generation in electronic devices under plasma exposure: Plasma-induced damage

NASA Astrophysics Data System (ADS)

Eriguchi, Koji

2017-06-01

The increasing demand for higher performance of ULSI circuits requires aggressive shrinkage of device feature sizes in accordance with Moore’s law. Plasma processing plays an important role in achieving fine patterns with anisotropic features in metal-oxide-semiconductor field-effect transistors (MOSFETs). This article comprehensively addresses the negative aspect of plasma processing — plasma-induced damage (PID). PID naturally not only modifies the surface morphology of materials but also degrades the performance and reliability of MOSFETs as a result of defect generation in the materials. Three key mechanisms of PID, i.e., physical, electrical, and photon-irradiation interactions, are overviewed in terms of modeling, characterization techniques, and experimental evidence reported so far. In addition, some of the emerging topics — control of parameter variability in ULSI circuits caused by PID and recovery of PID — are discussed as future perspectives.

Protocol for generating multiphoton entangled states from quantum dots in the presence of nuclear spin fluctuations

NASA Astrophysics Data System (ADS)

Denning, Emil V.; Iles-Smith, Jake; McCutcheon, Dara P. S.; Mork, Jesper

2017-12-01

Multiphoton entangled states are a crucial resource for many applications in quantum information science. Semiconductor quantum dots offer a promising route to generate such states by mediating photon-photon correlations via a confined electron spin, but dephasing caused by the host nuclear spin environment typically limits coherence (and hence entanglement) between photons to the spin T2* time of a few nanoseconds. We propose a protocol for the deterministic generation of multiphoton entangled states that is inherently robust against the dominating slow nuclear spin environment fluctuations, meaning that coherence and entanglement is instead limited only by the much longer spin T2 time of microseconds. Unlike previous protocols, the present scheme allows for the generation of very low error probability polarization encoded three-photon GHZ states and larger entangled states, without the need for spin echo or nuclear spin calming techniques.

Annual-ring-type quasi-phase-matching crystal for generation of narrowband high-dimensional entanglement

NASA Astrophysics Data System (ADS)

Hua, Yi-Lin; Zhou, Zong-Quan; Liu, Xiao; Yang, Tian-Shu; Li, Zong-Feng; Li, Pei-Yun; Chen, Geng; Xu, Xiao-Ye; Tang, Jian-Shun; Xu, Jin-Shi; Li, Chuan-Feng; Guo, Guang-Can

2018-01-01

A photon pair can be entangled in many degrees of freedom such as polarization, time bins, and orbital angular momentum (OAM). Among them, the OAM of photons can be entangled in an infinite-dimensional Hilbert space which enhances the channel capacity of sharing information in a network. Twisted photons generated by spontaneous parametric down-conversion offer an opportunity to create this high-dimensional entanglement, but a photon pair generated by this process is typically wideband, which makes it difficult to interface with the quantum memories in a network. Here we propose an annual-ring-type quasi-phase-matching (QPM) crystal for generation of the narrowband high-dimensional entanglement. The structure of the QPM crystal is designed by tracking the geometric divergences of the OAM modes that comprise the entangled state. The dimensionality and the quality of the entanglement can be greatly enhanced with the annual-ring-type QPM crystal.

Generation and applications of an ultrahigh-fidelity four-photon Greenberger-Horne-Zeilinger state.

PubMed

Zhang, Chao; Huang, Yun-Feng; Zhang, Cheng-Jie; Wang, Jian; Liu, Bi-Heng; Li, Chuan-Feng; Guo, Guang-Can

2016-11-28

High-quality entangled photon pairs generated via spontaneous parametric down-conversion have made great contributions to the modern quantum information science and the fundamental tests of quantum mechanics. However, the quality of the entangled states decreases sharply when moving from biphoton to multiphoton experiments, mainly due to the lack of interactions between photons. Here, for the first time, we generate a four-photon Greenberger-Horne-Zeilinger state with a fidelity of 98%, which is even comparable to the best fidelity of biphoton entangled states. Thus, it enables us to demonstrate an ultrahigh-fidelity entanglement swapping-the key ingredient in various quantum information tasks. Our results push the fidelity of multiphoton entanglement generation to a new level and would be useful in some demanding tasks, e.g., we successfully demonstrate the genuine multipartite nonlocality of the observed state in the nonsignaling scenario by violating a novel Hardy-like inequality, which requires very high state-fidelity.

Photonic crystal enhanced silicon cell based thermophotovoltaic systems

DOE PAGES

Yeng, Yi Xiang; Chan, Walker R.; Rinnerbauer, Veronika; ...

2015-01-30

We report the design, optimization, and experimental results of large area commercial silicon solar cell based thermophotovoltaic (TPV) energy conversion systems. Using global non-linear optimization tools, we demonstrate theoretically a maximum radiative heat-to-electricity efficiency of 6.4% and a corresponding output electrical power density of 0.39 W cm⁻² at temperature T = 1660 K when implementing both the optimized two-dimensional (2D) tantalum photonic crystal (PhC) selective emitter, and the optimized 1D tantalum pentoxide – silicon dioxide PhC cold-side selective filter. In addition, we have developed an experimental large area TPV test setup that enables accurate measurement of radiative heat-to-electricity efficiency formore » any emitter-filter-TPV cell combination of interest. In fact, the experimental results match extremely well with predictions of our numerical models. Our experimental setup achieved a maximum output electrical power density of 0.10W cm⁻² and radiative heat-to-electricity efficiency of 1.18% at T = 1380 K using commercial wafer size back-contacted silicon solar cells.« less

Deep-subwavelength imaging of both electric and magnetic localized optical fields by plasmonic campanile nanoantenna

DOE PAGES

Caselli, Niccolò; La China, Federico; Bao, Wei; ...

2015-06-05

Tailoring the electromagnetic field at the nanoscale has led to artificial materials exhibiting fascinating optical properties unavailable in naturally occurring substances. Besides having fundamental implications for classical and quantum optics, nanoscale metamaterials provide a platform for developing disruptive novel technologies, in which a combination of both the electric and magnetic radiation field components at optical frequencies is relevant to engineer the light-matter interaction. Thus, an experimental investigation of the spatial distribution of the photonic states at the nanoscale for both field components is of crucial importance. Here we experimentally demonstrate a concomitant deep-subwavelength near-field imaging of the electric and magneticmore » intensities of the optical modes localized in a photonic crystal nanocavity. We take advantage of the “campanile tip”, a plasmonic near-field probe that efficiently combines broadband field enhancement with strong far-field to near-field coupling. In conclusion, by exploiting the electric and magnetic polarizability components of the campanile tip along with the perturbation imaging method, we are able to map in a single measurement both the electric and magnetic localized near-field distributions.« less

Quantum correlated pulse-pair generation during pulse-trapping propagation in optical fibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirosawa, Kenichi; Kannari, Fumihiko; Takeoka, Masahiro

2007-10-15

We study a different scheme for generating photon number correlation and squeezing for two copropagating pulses, a soliton and a trapped pulse, in an optical fiber. When the center wavelength of a trapped pulse is close to that of a soliton pulse, the two pulses interact with each other through the third-order optical nonlinear process and exchange photons between the two pulses. The soliton pulse exhibits photon number squeezing. When the center wavelengths of the two pulses are sufficiently separated and no photon-number exchange takes place, the strong negative correlation in the photon number between the parts of the trappedmore » pulse and the soliton pulse is formed via cross-phase modulation. By measuring the photon number of the negatively correlated part of the trapped pulse, we can obtain the photon number of the soliton pulse with a variance less than the shot-noise limit.« less

Enhancing a slow and weak optomechanical nonlinearity with delayed quantum feedback

PubMed Central

Wang, Zhaoyou; Safavi-Naeini, Amir H.

2017-01-01

A central goal of quantum optics is to generate large interactions between single photons so that one photon can strongly modify the state of another one. In cavity optomechanics, photons interact with the motional degrees of freedom of an optical resonator, for example, by imparting radiation pressure forces on a movable mirror or sensing minute fluctuations in the position of the mirror. Here, we show that the optical nonlinearity arising from these effects, typically too small to operate on single photons, can be sufficiently enhanced with feedback to generate large interactions between single photons. We propose a protocol that allows photons propagating in a waveguide to interact with each other through multiple bounces off an optomechanical system. The protocol is analysed by evolving the full many-body quantum state of the waveguide-coupled system, illustrating that large photon–photon interactions mediated by mechanical motion may be within experimental reach. PMID:28677674

Coherent dynamics of a telecom-wavelength entangled photon source.

PubMed

Ward, M B; Dean, M C; Stevenson, R M; Bennett, A J; Ellis, D J P; Cooper, K; Farrer, I; Nicoll, C A; Ritchie, D A; Shields, A J

2014-01-01

Quantum networks can interconnect remote quantum information processors, allowing interaction between different architectures and increasing net computational power. Fibre-optic telecommunications technology offers a practical platform for routing weakly interacting photonic qubits, allowing quantum correlations and entanglement to be established between distant nodes. Although entangled photons have been produced at telecommunications wavelengths using spontaneous parametric downconversion in nonlinear media, as system complexity increases their inherent excess photon generation will become limiting. Here we demonstrate entangled photon pair generation from a semiconductor quantum dot at a telecommunications wavelength. Emitted photons are intrinsically anti-bunched and violate Bell's inequality by 17 standard deviations High-visibility oscillations of the biphoton polarization reveal the time evolution of the emitted state with exceptional clarity, exposing long coherence times. Furthermore, we introduce a method to evaluate the fidelity to a time-evolving Bell state, revealing entanglement between photons emitted up to 5 ns apart, exceeding the exciton lifetime.

Qubit entanglement between ring-resonator photon-pair sources on a silicon chip

PubMed Central

Silverstone, J. W.; Santagati, R.; Bonneau, D.; Strain, M. J.; Sorel, M.; O'Brien, J. L.; Thompson, M. G.

2015-01-01

Entanglement—one of the most delicate phenomena in nature—is an essential resource for quantum information applications. Scalable photonic quantum devices must generate and control qubit entanglement on-chip, where quantum information is naturally encoded in photon path. Here we report a silicon photonic chip that uses resonant-enhanced photon-pair sources, spectral demultiplexers and reconfigurable optics to generate a path-entangled two-qubit state and analyse its entanglement. We show that ring-resonator-based spontaneous four-wave mixing photon-pair sources can be made highly indistinguishable and that their spectral correlations are small. We use on-chip frequency demultiplexers and reconfigurable optics to perform both quantum state tomography and the strict Bell-CHSH test, both of which confirm a high level of on-chip entanglement. This work demonstrates the integration of high-performance components that will be essential for building quantum devices and systems to harness photonic entanglement on the large scale. PMID:26245267

Electrical Tuning of Exciton-Plasmon Polariton Coupling in Monolayer MoS2 Integrated with Plasmonic Nanoantenna Lattice.

PubMed

Lee, Bumsu; Liu, Wenjing; Naylor, Carl H; Park, Joohee; Malek, Stephanie C; Berger, Jacob S; Johnson, A T Charlie; Agarwal, Ritesh

2017-07-12

Active control of light-matter interactions in semiconductors is critical for realizing next generation optoelectronic devices with real-time control of the system's optical properties and hence functionalities via external fields. The ability to dynamically manipulate optical interactions by applied fields in active materials coupled to cavities with fixed geometrical parameters opens up possibilities of controlling the lifetimes, oscillator strengths, effective mass, and relaxation properties of a coupled exciton-photon (or plasmon) system. Here, we demonstrate electrical control of exciton-plasmon coupling strengths between strong and weak coupling limits in a two-dimensional semiconductor integrated with plasmonic nanoresonators assembled in a field-effect transistor device by electrostatic doping. As a result, the energy-momentum dispersions of such an exciton-plasmon coupled system can be altered dynamically with applied electric field by modulating the excitonic properties of monolayer MoS 2 arising from many-body effects. In addition, evidence of enhanced coupling between charged excitons (trions) and plasmons was also observed upon increased carrier injection, which can be utilized for fabricating Fermionic polaritonic and magnetoplasmonic devices. The ability to dynamically control the optical properties of a coupled exciton-plasmonic system with electric fields demonstrates the versatility of the coupled system and offers a new platform for the design of optoelectronic devices with precisely tailored responses.

Interaction of atmospheric pressure plasmas with dry and wet wounded skin

NASA Astrophysics Data System (ADS)

Babaeva, Natalia; Kushner, Mark

2010-11-01

Non-equilibrium plasmas in direct contact with living tissue can produce therapeutic effects. Dielectric barrier discharge (DBD) devices used for this purpose contain the powered electrode while the tissue being treated is usually the floating electrode. The plasma produces beneficial effects through: (i) electric fields, (ii) production of radicals and charged species, (iii) photons and (iv) energetic ions impinging onto wounds and tissue surfaces. Using a 2-d plasma hydrodynamics model, we discuss the interaction of DBD filaments with human skin. We model the propagation of the streamer across the gap, its intersection with skin, the charging of cell surfaces and the generation of conduction and displacement currents, and electric fields in the cells. The cellular structure in the first few mm of human skin is incorporated into the computational mesh with permittivity and conductivity to represent the electrical properties of the intra- and inter-cell structures. In this talk, we concentrate on the effects of plasmas on open wounds which are either dry or filled with blood serum. We will discuss the penetration of electric fields through the blood serum and into the underlying cells, including the possible interactions with blood platelets, and the distribution of ion energies onto the liquid and cellular surfaces.

Generation of surface-wave microwave microplasmas in hollow-core photonic crystal fiber based on a split-ring resonator.

PubMed

Vial, Florian; Gadonna, Katell; Debord, Benoît; Delahaye, Frédéric; Amrani, Foued; Leroy, Olivier; Gérôme, Frédéric; Benabid, Fetah

2016-05-15

We report on a new and highly compact scheme for the generation and sustainment of microwave-driven plasmas inside the core of an inhibited coupling Kagome hollow-core photonic crystal fiber. The microwave plasma generator consists of a split-ring resonator that efficiently couples the microwave field into the gas-filled fiber. This coupling induces the concomitant generation of a microwave surface wave at the fiber core surround and a stable plasma column confined in the fiber core. The scheme allowed the generation of several centimeters long argon microplasma columns with a very low excitation power threshold. This result represents an important step toward highly compact plasma lasers or plasma-based photonic components.

FIBER AND INTEGRATED OPTICS. OTHER TOPICS IN QUANTUM ELECTRONICS: Monokinetization of atomic beams by the method of laser photodetachment of electrons

NASA Astrophysics Data System (ADS)

Rivlin, Lev A.

1990-05-01

A method is suggested for the generation of atomic beams with a high degree of monokinetization from beams of negative ions accelerated in an electric field up to a threshold moment at which, subject to the Doppler effect, the longitudinal component of the ion velocity becomes sufficient for the photodetachment of an electron from an ion by photons in a laser beam collinear with the ion beam. The resultant neutral atoms continue to move without acceleration and at the same longitudinal velocities equal to the threshold value. An analysis of a number of factors limiting this effect is given below.

Peripheral nerve recruitment curve using near-infrared stimulation

NASA Astrophysics Data System (ADS)

Dautrebande, Marie; Doguet, Pascal; Gorza, Simon-Pierre; Delbeke, Jean; Nonclercq, Antoine

2018-02-01

In the context of near-infrared neurostimulation, we report on an experimental hybrid electrode allowing for simultaneous photonic or electrical neurostimulation and for electrical recording of evoked action potentials. The electrode includes three contacts and one optrode. The optrode is an opening in the cuff through which the tip of an optical fibre is held close to the epineurium. Two contacts provide action potential recording. The remaining contact, together with a remote subcutaneous electrode, is used for electric stimulation which allows periodical assessment of the viability of the nerve during the experiment. A 1470 nm light source was used to stimulate a mouse sciatic nerve. Neural action potentials were not successfully recorded because of the electrical noise so muscular activity was used to reflect the motor fibres stimulation. A recruitment curve was obtained by stimulating with photonic pulses of same power and increasing duration and recording the evoked muscular action potentials. Motor fibres can be recruited with radiant exposures between 0.05 and 0.23 J/cm2 for pulses in the 100 to 500 μs range. Successful stimulation at short duration and at a commercial wavelength is encouraging in the prospect of miniaturisation and practical applications. Motor fibres recruitment curve is a first step in an ongoing research work. Neural action potential acquisition will be improved, with aim to shed light on the mechanism of action potential initiation under photonic stimulation.

On-chip III-V monolithic integration of heralded single photon sources and beamsplitters

NASA Astrophysics Data System (ADS)

Belhassen, J.; Baboux, F.; Yao, Q.; Amanti, M.; Favero, I.; Lemaître, A.; Kolthammer, W. S.; Walmsley, I. A.; Ducci, S.

2018-02-01

We demonstrate a monolithic III-V photonic circuit combining a heralded single photon source with a beamsplitter, at room temperature and telecom wavelength. Pulsed parametric down-conversion in an AlGaAs waveguide generates counterpropagating photons, one of which is used to herald the injection of its twin into the beamsplitter. We use this configuration to implement an integrated Hanbury-Brown and Twiss experiment, yielding a heralded second-order correlation gher(2 )(0 )=0.10 ±0.02 that confirms single-photon operation. The demonstrated generation and manipulation of quantum states on a single III-V semiconductor chip opens promising avenues towards real-world applications in quantum information.

Quantum yield measurements of light-induced H₂ generation in a photosystem I-[FeFe]-H₂ase nanoconstruct.

PubMed

Applegate, Amanda M; Lubner, Carolyn E; Knörzer, Philipp; Happe, Thomas; Golbeck, John H

2016-01-01

The quantum yield for light-induced H2 generation was measured for a previously optimized bio-hybrid cytochrome c 6-crosslinked PSI(C13G)-1,8-octanedithiol-[FeFe]-H2ase(C97G) (PSI-H2ase) nanoconstruct. The theoretical quantum yield for the PSI-H2ase nanoconstruct is 0.50 molecules of H2 per photon absorbed, which equates to a requirement of two photons per H2 generated. Illumination of the PSI-H2ase nanoconstruct with visible light between 400 and 700 nm resulted in an average quantum yield of 0.10-0.15 molecules of H2 per photon absorbed, which equates to a requirement of 6.7-10 photons per H2 generated. A possible reason for the difference between the theoretical and experimental quantum yield is the occurrence of non-productive PSI(C13G)-1,8-octanedithiol-PSIC13G (PSI-PSI) conjugates, which would absorb light without generating H2. Assuming the thiol-Fe coupling is equally efficient at producing PSI-PSI conjugates as well as in producing PSI-H2ase nanoconstructs, the theoretical quantum yield would decrease to 0.167 molecules of H2 per photon absorbed, which equates to 6 photons per H2 generated. This value is close to the range of measured values in the current study. A strategy that purifies the PSI-H2ase nanoconstructs from the unproductive PSI-PSI conjugates or that incorporates different chemistries on the PSI and [FeFe]-H2ase enzyme sites could potentially allow the PSI-H2ase nanoconstruct to approach the expected theoretical quantum yield for light-induced H2 generation.

Photon emissions from rice cells elicited by N-acetylchitooligosaccharide are generated through phospholipid signaling in close association with the production of reactive oxygen species.

PubMed

Kageyama, C; Kato, K; Iyozumi, H; Inagaki, H; Yamaguchi, A; Furuse, K; Baba, K

2006-01-01

Biophotons are ultraweak light emissions from biochemical reactions in a living body. They increase in suspension-cultured rice (Oryza sativa L.) cells when elicited by N-acetylchitooligosaccharide. Biochemical analyses were undertaken to investigate the relationship between disease response and biophotons in order to clarify the emission mechanism of biophotons caused by this elicitor. Photon emissions induced by N-acetylchitohexaose were suppressed when cells were pretreated with the reactive oxygen species (ROS)-generating inhibitors: pyrocatechol-3,5-disulfonic acid disodium salt (Tiron); diphenylene iodonium (DPI); and salicylhydroxamic acid (SHAM). Conversely, exogenously applied ROS (superoxide and hydrogen peroxide) were able to induce photon emissions. The effects of protein phosphorylation (K-252a) and the Ca(2+) signaling inhibitors, ethylene glycol-bis(beta-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA) and LaCl(3), caused photon emissions to decrease. It is clear that photon emissions from rice cells elicited by N-acetylchitohexaose are closely associated with the ROS-generating system, and are regulated by Ca(2+) signaling and protein phosphorylation. Exogenously applied phosphatidic acid (PA), the second messenger in the signal transduction of disease response, raised photon emissions in rice cells. Comparisons of photon emissions from PA and N-acetylchitohexaose regarding time courses, spectral compositions, and the inhibition ratios of several inhibitors, as well as a loss- and gain-of-function assay using the protein synthesis inhibitor cycloheximide (CHX) and PA, showed the possibility that photon emissions from rice cells elicited by N-acetylchitooligosaccharide were generated through PA, an intermediate of phospholipid signaling.

Precise Two-Photon Photodynamic Therapy using an Efficient Photosensitizer with Aggregation-Induced Emission Characteristics.

PubMed

Gu, Bobo; Wu, Wenbo; Xu, Gaixia; Feng, Guangxue; Yin, Feng; Chong, Peter Han Joo; Qu, Junle; Yong, Ken-Tye; Liu, Bin

2017-07-01

Two-photon photodynamic therapy (PDT) is able to offer precise 3D manipulation of treatment volumes, providing a target level that is unattainable with current therapeutic techniques. The advancement of this technique is greatly hampered by the availability of photosensitizers with large two-photon absorption (TPA) cross section, high reactive-oxygen-species (ROS) generation efficiency, and bright two-photon fluorescence. Here, an effective photosensitizer with aggregation-induced emission (AIE) characteristics is synthesized, characterized, and encapsulated into an amphiphilic block copolymer to form organic dots for two-photon PDT applications. The AIE dots possess large TPA cross section, high ROS generation efficiency, and excellent photostability and biocompatibility, which overcomes the limitations of many conventional two-photon photosensitizers. Outstanding therapeutic performance of the AIE dots in two-photon PDT is demonstrated using in vitro cancer cell ablation and in vivo brain-blood-vessel closure as examples. This shows therapy precision up to 5 µm under two-photon excitation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Spatial Multiplexing of Atom-Photon Entanglement Sources using Feedforward Control and Switching Networks.

PubMed

Tian, Long; Xu, Zhongxiao; Chen, Lirong; Ge, Wei; Yuan, Haoxiang; Wen, Yafei; Wang, Shengzhi; Li, Shujing; Wang, Hai

2017-09-29

The light-matter quantum interface that can create quantum correlations or entanglement between a photon and one atomic collective excitation is a fundamental building block for a quantum repeater. The intrinsic limit is that the probability of preparing such nonclassical atom-photon correlations has to be kept low in order to suppress multiexcitation. To enhance this probability without introducing multiexcitation errors, a promising scheme is to apply multimode memories to the interface. Significant progress has been made in temporal, spectral, and spatial multiplexing memories, but the enhanced probability for generating the entangled atom-photon pair has not been experimentally realized. Here, by using six spin-wave-photon entanglement sources, a switching network, and feedforward control, we build a multiplexed light-matter interface and then demonstrate a ∼sixfold (∼fourfold) probability increase in generating entangled atom-photon (photon-photon) pairs. The measured compositive Bell parameter for the multiplexed interface is 2.49±0.03 combined with a memory lifetime of up to ∼51  μs.

On-demand semiconductor single-photon source with near-unity indistinguishability.

PubMed

He, Yu-Ming; He, Yu; Wei, Yu-Jia; Wu, Dian; Atatüre, Mete; Schneider, Christian; Höfling, Sven; Kamp, Martin; Lu, Chao-Yang; Pan, Jian-Wei

2013-03-01

Single-photon sources based on semiconductor quantum dots offer distinct advantages for quantum information, including a scalable solid-state platform, ultrabrightness and interconnectivity with matter qubits. A key prerequisite for their use in optical quantum computing and solid-state networks is a high level of efficiency and indistinguishability. Pulsed resonance fluorescence has been anticipated as the optimum condition for the deterministic generation of high-quality photons with vanishing effects of dephasing. Here, we generate pulsed single photons on demand from a single, microcavity-embedded quantum dot under s-shell excitation with 3 ps laser pulses. The π pulse-excited resonance-fluorescence photons have less than 0.3% background contribution and a vanishing two-photon emission probability. Non-postselective Hong-Ou-Mandel interference between two successively emitted photons is observed with a visibility of 0.97(2), comparable to trapped atoms and ions. Two single photons are further used to implement a high-fidelity quantum controlled-NOT gate.

Quantum Communication with a High-Rate Entangled Photon Source

NASA Technical Reports Server (NTRS)

Wilson, Nathaniel C.; Chaffee, Dalton W.; Lekki, John D.; Wilson, Jeffrey D.

2016-01-01

A high generation rate photon-pair source using a dual element periodically-poled potassium titanyl phosphate (PP KTP) waveguide is described. The photon-pair source features a high pair generation rate, a compact power-efficient package, and continuous wave (CW) or pulsed operation. Characterization and test results are presented. Details and preliminary results of a laboratory free-space QKD experiment with the B92 protocol are also presented.

Heterogeneously Integrated Microwave Signal Generators with Narrow Linewidth Lasers

DTIC Science & Technology

2017-03-20

the linewidth in two ways: (1) increasing the photon lifetime due to effective cavity length enhancement, and (2) providing negative optical...structures. Some devices are also labeled. Figure 1. Microscope image of the photonic microwave generator comprising of two tunable lasers, a coupler...Integrated Photodiodes on Silicon,” IEEE JQE, vol.51, no.11, pp.1-6, Nov. 2015 Figure 9. (left) Optical spectra of two lasers comprising a photonic

Efficient generation of twin photons at telecom wavelengths with 2.5 GHz repetition-rate-tunable comb laser

PubMed Central

Jin, Rui-Bo; Shimizu, Ryosuke; Morohashi, Isao; Wakui, Kentaro; Takeoka, Masahiro; Izumi, Shuro; Sakamoto, Takahide; Fujiwara, Mikio; Yamashita, Taro; Miki, Shigehito; Terai, Hirotaka; Wang, Zhen; Sasaki, Masahide

2014-01-01

Efficient generation and detection of indistinguishable twin photons are at the core of quantum information and communications technology (Q-ICT). These photons are conventionally generated by spontaneous parametric down conversion (SPDC), which is a probabilistic process, and hence occurs at a limited rate, which restricts wider applications of Q-ICT. To increase the rate, one had to excite SPDC by higher pump power, while it inevitably produced more unwanted multi-photon components, harmfully degrading quantum interference visibility. Here we solve this problem by using recently developed 10 GHz repetition-rate-tunable comb laser, combined with a group-velocity-matched nonlinear crystal, and superconducting nanowire single photon detectors. They operate at telecom wavelengths more efficiently with less noises than conventional schemes, those typically operate at visible and near infrared wavelengths generated by a 76 MHz Ti Sapphire laser and detected by Si detectors. We could show high interference visibilities, which are free from the pump-power induced degradation. Our laser, nonlinear crystal, and detectors constitute a powerful tool box, which will pave a way to implementing quantum photonics circuits with variety of good and low-cost telecom components, and will eventually realize scalable Q-ICT in optical infra-structures. PMID:25524646

Independent tuning of excitonic emission energy and decay time in single semiconductor quantum dots

NASA Astrophysics Data System (ADS)

Höfer, B.; Zhang, J.; Wildmann, J.; Zallo, E.; Trotta, R.; Ding, F.; Rastelli, A.; Schmidt, O. G.

2017-04-01

Independent tuning of emission energy and decay time of neutral excitons confined in single self-assembled In(Ga)As/GaAs quantum dots is achieved by simultaneously employing vertical electric fields and lateral biaxial strain fields. By locking the emission energy via a closed-loop feedback on the piezoelectric actuator used to control the strain in the quantum dot, we continuously decrease the decay time of an exciton from 1.4 to 0.7 ns. Both perturbations are fully electrically controlled and their combination offers a promising route to engineer the indistinguishability of photons emitted from spatially separated single photon sources.

Photon Mass, Graviton Mass: Zero or Not?

NASA Astrophysics Data System (ADS)

Scharff Goldhaber, Alfred; Nieto, Michael Martin

2007-04-01

Testing for deviations from simple laws is a time-honored part of physics research. In electricity and magnetism the first approach to such testing, from the eighteenth century well into the twentieth, was to look for departures from -2 of the power of distance between two electric charges or two magnetic poles determining the force between them. Absent a particular length scale, this was a natural choice for parameterizing possible deviations from the simple and esthetic inverse square law. With the advent of relativity and quantum mechanics, and the realization that certain phenomena of light can be described in terms of photon particles, it became appealing to ask if these particles might have a non-zero mass, and Proca found the appropriate modification of the Maxwell equations. Despite the particle-motion origin of this idea, the most powerful way to constrain the size of a possible photon mass is by setting a lower bound on the Compton wavelength, by looking at static electric and especially magnetic fields over increasing length scales. For gravity similar statements apply, but graviton mass is theoretically questionable, and observed phenomena imply either additional sources or departures from Einstein's general relativity.

Silicon photonic integrated circuits with electrically programmable non-volatile memory functions.

PubMed

Song, J-F; Lim, A E-J; Luo, X-S; Fang, Q; Li, C; Jia, L X; Tu, X-G; Huang, Y; Zhou, H-F; Liow, T-Y; Lo, G-Q

2016-09-19

Conventional silicon photonic integrated circuits do not normally possess memory functions, which require on-chip power in order to maintain circuit states in tuned or field-configured switching routes. In this context, we present an electrically programmable add/drop microring resonator with a wavelength shift of 426 pm between the ON/OFF states. Electrical pulses are used to control the choice of the state. Our experimental results show a wavelength shift of 2.8 pm/ms and a light intensity variation of ~0.12 dB/ms for a fixed wavelength in the OFF state. Theoretically, our device can accommodate up to 65 states of multi-level memory functions. Such memory functions can be integrated into wavelength division mutiplexing (WDM) filters and applied to optical routers and computing architectures fulfilling large data downloading demands.

Radiation dose response of N channel MOSFET submitted to filtered X-ray photon beam

NASA Astrophysics Data System (ADS)

Gonçalves Filho, Luiz C.; Monte, David S.; Barros, Fabio R.; Santos, Luiz A. P.

2018-01-01

MOSFET can operate as a radiation detector mainly in high-energy photon beams, which are normally used in cancer treatments. In general, such an electronic device can work as a dosimeter from threshold voltage shift measurements. The purpose of this article is to show a new way for measuring the dose-response of MOSFETs when they are under X-ray beams generated from 100kV potential range, which is normally used in diagnostic radiology. Basically, the method consists of measuring the MOSFET drain current as a function of the radiation dose. For this the type of device, it has to be biased with a high value resistor aiming to see a substantial change in the drain current after it has been irradiated with an amount of radiation dose. Two types of N channel device were used in the experiment: a signal transistor and a power transistor. The delivered dose to the device was varied and the electrical curves were plotted. Also, a sensitivity analysis of the power MOSFET response was made, by varying the tube potential of about 20%. The results show that both types of devices have responses very similar, the shift in the electrical curve is proportional to the radiation dose. Unlike the power MOSFET, the signal transistor does not provide a linear function between the dose rate and its drain current. We also have observed that the variation in the tube potential of the X-ray equipment produces a very similar dose-response.

Gamma-burst emission from neutron-star accretion

NASA Technical Reports Server (NTRS)

Colgate, S. A.; Petschek, A. G.; Sarracino, R.

1983-01-01

A model for emission of the hard photons of gamma bursts is presented. The model assumes accretion at nearly the Eddington limited rate onto a neutron star without a magnetic field. Initially soft photons are heated as they are compressed between the accreting matter and the star. A large electric field due to relatively small charge separation is required to drag electrons into the star with the nuclei against the flux of photons leaking out through the accreting matter. The photon number is not increased substantially by Bremsstrahlung or any other process. It is suggested that instability in an accretion disc might provide the infalling matter required.

Semiconductor Quantum Dots for Applications to Advanced Concepts for Solar Photon Conversion to Electricity and Solar Fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nozik, Arthur J; Beard, Matthew C

The challenge of photoconversion research is to produce photovoltaic electricity at costs much less than those based on fossil fuels. Novel photoactive semiconductors and molecules of various types and structures are discussed for this purpose.

An accurate behavioral model for single-photon avalanche diode statistical performance simulation

NASA Astrophysics Data System (ADS)

Xu, Yue; Zhao, Tingchen; Li, Ding

2018-01-01

An accurate behavioral model is presented to simulate important statistical performance of single-photon avalanche diodes (SPADs), such as dark count and after-pulsing noise. The derived simulation model takes into account all important generation mechanisms of the two kinds of noise. For the first time, thermal agitation, trap-assisted tunneling and band-to-band tunneling mechanisms are simultaneously incorporated in the simulation model to evaluate dark count behavior of SPADs fabricated in deep sub-micron CMOS technology. Meanwhile, a complete carrier trapping and de-trapping process is considered in afterpulsing model and a simple analytical expression is derived to estimate after-pulsing probability. In particular, the key model parameters of avalanche triggering probability and electric field dependence of excess bias voltage are extracted from Geiger-mode TCAD simulation and this behavioral simulation model doesn't include any empirical parameters. The developed SPAD model is implemented in Verilog-A behavioral hardware description language and successfully operated on commercial Cadence Spectre simulator, showing good universality and compatibility. The model simulation results are in a good accordance with the test data, validating high simulation accuracy.