Science.gov

Sample records for 1d nanophotonic waveguides

  1. Mode conversion using stimulated Brillouin scattering in nanophotonic silicon waveguides.

    PubMed

    Aryanfar, Iman; Wolff, Christian; Steel, M J; Eggleton, Benjamin J; Poulton, Christopher G

    2014-11-17

    We theoretically and numerically investigate Stimulated Brillouin Scattering generated mode conversion in high-contrast suspended silicon nanophotonic waveguides. We predict significantly enhanced mode conversion when the linked effects of radiation pressure and motion of the waveguide boundaries are taken into account. The mode conversion is more than 10 times larger than would be predicted if the effect of radiation pressure is not taken into account: we find a waveguide length of 740 μm is required for 20dB of mode conversion, assuming a total pump power of 1W. This is sufficient to bring the effect into the realm of chip-scale photonic waveguides. We explore the interaction between the different types of acoustic modes that can exist within these waveguides, and show how the presence of these modes leads to enhanced conversion between the different possible optical modes. PMID:25402165

  2. Metallic nanowires for subwavelength waveguiding and nanophotonic devices

    NASA Astrophysics Data System (ADS)

    Pan, Deng; Wei, Hong; Xu, Hong-Xing

    2013-09-01

    Plasmonics is a rapidly developing field concerning light manipulation at the nanoscale with many potential applications, of which plasmonic circuits are promising for future information technology. Plasmonic waveguides are fundamental elements for constructing plasmonic integrated circuits. Among the proposed different plasmonic waveguides, metallic nanowires have drawn much attention due to the highly confined electromagnetic waves and relatively low propagation loss. Here we review the recent research progress in the waveguiding characteristics of metallic nanowires and nanowire-based nanophotonic devices. Plasmon modes of both cylindrical and pentagonal metallic nanowires with and without substrate are discussed. Typical methods for exciting and detecting the plasmons in metallic nanowires are briefly summarized. Because of the multimode characteristic, the plasmon propagation and emission in the nanowire have many unique properties, benefiting the design of plasmonic devices. A few nanowire-based devices are highlighted, including quarter-wave plate, Fabry—Pérot resonator, router and logic gates.

  3. High efficiency and broad bandwidth grating coupler between nanophotonic waveguide and fibre

    NASA Astrophysics Data System (ADS)

    Zhu, Yu; Xu, Xue-Jun; Li, Zhi-Yong; Zhou, Liang; Han, Wei-Hua; Fan, Zhong-Chao; Yu, Yu-De; Yu, Jin-Zhong

    2010-01-01

    A high efficiency and broad bandwidth grating coupler between a silicon-on-insulator (SOI) nanophotonic waveguide and fibre is designed and fabricated. Coupling efficiencies of 46% and 25% at a wavelength of 1.55 μm are achieved by simulation and experiment, respectively. An optical 3 dB bandwidth of 45 nm from 1530 nm to 1575 nm is also obtained in experiment. Numerical calculation shows that a tolerance to fabrication error of 10 nm in etch depth is achievable. The measurement results indicate that the alignment error of ±2 μm results in less than 1 dB additional coupling loss.

  4. Efficient photon triplet generation in integrated nanophotonic waveguides.

    PubMed

    Moebius, Michael G; Herrera, Felipe; Griesse-Nascimento, Sarah; Reshef, Orad; Evans, Christopher C; Guerreschi, Gian Giacomo; Aspuru-Guzik, Alán; Mazur, Eric

    2016-05-01

    Generation of entangled photons in nonlinear media constitutes a basic building block of modern photonic quantum technology. Current optical materials are severely limited in their ability to produce three or more entangled photons in a single event due to weak nonlinearities and challenges achieving phase-matching. We use integrated nanophotonics to enhance nonlinear interactions and develop protocols to design multimode waveguides that enable sustained phase-matching for third-order spontaneous parametric down-conversion (TOSPDC). We predict a generation efficiency of 0.13 triplets/s/mW of pump power in TiO2-based integrated waveguides, an order of magnitude higher than previous theoretical and experimental demonstrations. We experimentally verify our device design methods in TiO2 waveguides using third-harmonic generation (THG), the reverse process of TOSPDC that is subject to the same phase-matching constraints. We finally discuss the effect of finite detector bandwidth and photon losses on the energy-time coherence properties of the expected TOSPDC source. PMID:27137604

  5. Optical investigation of nanophotonic lithium niobate-based optical waveguide

    NASA Astrophysics Data System (ADS)

    Fakhri, Makram A.; Al-Douri, Y.; Hashim, U.; Salim, Evan T.; Prakash, Deo; Verma, K. D.

    2015-10-01

    Lithium niobate (LiNbO3) nanophotonics are prepared on quartz substrate by sol-gel method. They have been deposited with different molarity concentrations and annealed at 500 °C. These samples are characterized and analyzed by scanning electron microscope, atomic force microscopy, X-ray diffraction and ultraviolet-visible. The measured results show an importance of increasing molarity that indicates the structure starts to crystallize to become more regular. The estimated lattice constants, energy gaps and refractive index give good accordance with experimental results. Also, the calculated refractive index and optical dielectric constant are in agreement with experimental data.

  6. Design of T-shaped nanophotonic wire waveguide for optical interconnection in H-tree network.

    PubMed

    Kurt, H; Giden, I H; Citrin, D S

    2011-12-19

    Nanophotonic wire waveguides play an important role for the realization of highly dense integrated photonic circuits. The miniaturization of optoelectronic devices and realization of ultra-small integrated circuits strongly demand compact waveguide branches. T-shaped versions of nanophotonic wires are the first stage of both power splitting and optical-interconnection systems based on guided-wave optics; however, the acute transitions at the waveguide junctions typically induce huge bending losses in terms of radiated modes. Both 2D and 3D finite-difference time-domain methods are employed to monitor the efficient light propagation. By introducing appropriate combinations of dielectric posts around the dielectric-waveguide junctions within the 4.096μm×4.096μm region, we are able to reduce the bending losses dramatically and increase the transmission efficiency from low values of 18% in the absence of the dielectric posts to approximately 49% and 43% in 2D and 3D cases, respectively. These findings may lead to the implementation of such T-junctions in near-future high-density integrated photonics to deliver optical-clock signals via H-tree network. PMID:22274265

  7. Sensitivity Enhancement in Si Nanophotonic Waveguides Used for Refractive Index Sensing

    PubMed Central

    Shi, Yaocheng; Ma, Ke; Dai, Daoxin

    2016-01-01

    A comparative study is given for the sensitivity of several typical Si nanophotonic waveguides, including SOI (silicon-on-insulator) nanowires, nanoslot waveguides, suspended Si nanowires, and nanofibers. The cases for gas sensing (ncl ~ 1.0) and liquid sensing (ncl ~ 1.33) are considered. When using SOI nanowires (with a SiO2 buffer layer), the sensitivity for liquid sensing (S ~ 0.55) is higher than that for gas sensing (S ~ 0.35) due to lower asymmetry in the vertical direction. By using SOI nanoslot waveguides, suspended Si nanowires, and Si nanofibers, one could achieve a higher sensitivity compared to sensing with a free-space beam (S = 1.0). The sensitivity for gas sensing is higher than that for liquid sensing due to the higher index-contrast. The waveguide sensitivity of an optimized suspended Si nanowire for gas sensing is as high as 1.5, which is much higher than that of a SOI nanoslot waveguide. Furthermore, the optimal design has very large tolerance to the core width variation due to the fabrication error (∆w ~ ±50 nm). In contrast, a Si nanofiber could also give a very high sensitivity (e.g., ~1.43) while the fabrication tolerance is very small (i.e., ∆w < ±5 nm). The comparative study shows that suspended Si nanowire is a good choice to achieve ultra-high waveguide sensitivity. PMID:26950132

  8. Sensitivity Enhancement in Si Nanophotonic Waveguides Used for Refractive Index Sensing.

    PubMed

    Shi, Yaocheng; Ma, Ke; Dai, Daoxin

    2016-01-01

    A comparative study is given for the sensitivity of several typical Si nanophotonic waveguides, including SOI (silicon-on-insulator) nanowires, nanoslot waveguides, suspended Si nanowires, and nanofibers. The cases for gas sensing (ncl ~ 1.0) and liquid sensing (ncl ~ 1.33) are considered. When using SOI nanowires (with a SiO₂ buffer layer), the sensitivity for liquid sensing (S ~ 0.55) is higher than that for gas sensing (S ~ 0.35) due to lower asymmetry in the vertical direction. By using SOI nanoslot waveguides, suspended Si nanowires, and Si nanofibers, one could achieve a higher sensitivity compared to sensing with a free-space beam (S = 1.0). The sensitivity for gas sensing is higher than that for liquid sensing due to the higher index-contrast. The waveguide sensitivity of an optimized suspended Si nanowire for gas sensing is as high as 1.5, which is much higher than that of a SOI nanoslot waveguide. Furthermore, the optimal design has very large tolerance to the core width variation due to the fabrication error (∆w ~ ±50 nm). In contrast, a Si nanofiber could also give a very high sensitivity (e.g., ~1.43) while the fabrication tolerance is very small (i.e., ∆w < ±5 nm). The comparative study shows that suspended Si nanowire is a good choice to achieve ultra-high waveguide sensitivity. PMID:26950132

  9. Broadband polarization independent nanophotonic coupler for silicon waveguides with ultra-high efficiency.

    PubMed

    Cheben, Pavel; Schmid, Jens H; Wang, Shurui; Xu, Dan-Xia; Vachon, Martin; Janz, Siegfried; Lapointe, Jean; Painchaud, Yves; Picard, Marie-Josée

    2015-08-24

    Coupling of light to and from integrated optical circuits has been recognized as a major practical challenge since the early years of photonics. The coupling is particularly difficult for high index contrast waveguides such as silicon-on-insulator, since the cross-sectional area of silicon wire waveguides is more than two orders of magnitude smaller than that of a standard single-mode fiber. Here, we experimentally demonstrate unprecedented control over the light coupling between the optical fiber and silicon chip by constructing the nanophotonic coupler with ultra-high coupling efficiency simultaneously for both transverse electric and transverse magnetic polarizations. We specifically demonstrate a subwavelength refractive index engineered nanostructure to mitigate loss and wavelength resonances by suppressing diffraction effects, enabling a coupling efficiency over 92% (0.32 dB) and polarization independent operation for a broad spectral range exceeding 100 nm. PMID:26368222

  10. Vertical optical ring resonators fully integrated with nanophotonic waveguides on silicon-on-insulator substrates

    NASA Astrophysics Data System (ADS)

    Madani, Abbas; Kleinert, Moritz; Stolarek, David; Zimmermann, Lars; Ma, Libo; Schmidt, Oliver G.

    2015-08-01

    We demonstrate full integration of vertical optical ring resonators with silicon nanophotonic waveguides on silicon-on-insulator substrates to accomplish a significant step towards 3D photonic integration. The on-chip integration is realized by rolling up 2D differentially strained TiO2 nanomembranes into 3D microtube cavities on a nanophotonic microchip. The integration configuration allows for out of plane optical coupling between the in-plane nanowaveguides and the vertical microtube cavities as a compact and mechanically stable optical unit, which could enable refined vertical light transfer in 3D stacks of multiple photonic layers. In this vertical transmission scheme, resonant filtering of optical signals at telecommunication wavelengths is demonstrated based on subwavelength thick walled microcavities. Moreover, an array of microtube cavities is prepared and each microtube cavity is integrated with multiple waveguides which opens up interesting perspectives towards parallel and multi-routing through a single cavity device as well as high-throughput optofluidic sensing schemes.

  11. Chirality of nanophotonic waveguide with embedded quantum emitter for unidirectional spin transfer

    NASA Astrophysics Data System (ADS)

    Coles, R. J.; Price, D. M.; Dixon, J. E.; Royall, B.; Clarke, E.; Kok, P.; Skolnick, M. S.; Fox, A. M.; Makhonin, M. N.

    2016-03-01

    Scalable quantum technologies may be achieved by faithful conversion between matter qubits and photonic qubits in integrated circuit geometries. Within this context, quantum dots possess well-defined spin states (matter qubits), which couple efficiently to photons. By embedding them in nanophotonic waveguides, they provide a promising platform for quantum technology implementations. In this paper, we demonstrate that the naturally occurring electromagnetic field chirality that arises in nanobeam waveguides leads to unidirectional photon emission from quantum dot spin states, with resultant in-plane transfer of matter-qubit information. The chiral behaviour occurs despite the non-chiral geometry and material of the waveguides. Using dot registration techniques, we achieve a quantum emitter deterministically positioned at a chiral point and realize spin-path conversion by design. We further show that the chiral phenomena are much more tolerant to dot position than in standard photonic crystal waveguides, exhibit spin-path readout up to 95+/-5% and have potential to serve as the basis of spin-logic and network implementations.

  12. Chirality of nanophotonic waveguide with embedded quantum emitter for unidirectional spin transfer.

    PubMed

    Coles, R J; Price, D M; Dixon, J E; Royall, B; Clarke, E; Kok, P; Skolnick, M S; Fox, A M; Makhonin, M N

    2016-01-01

    Scalable quantum technologies may be achieved by faithful conversion between matter qubits and photonic qubits in integrated circuit geometries. Within this context, quantum dots possess well-defined spin states (matter qubits), which couple efficiently to photons. By embedding them in nanophotonic waveguides, they provide a promising platform for quantum technology implementations. In this paper, we demonstrate that the naturally occurring electromagnetic field chirality that arises in nanobeam waveguides leads to unidirectional photon emission from quantum dot spin states, with resultant in-plane transfer of matter-qubit information. The chiral behaviour occurs despite the non-chiral geometry and material of the waveguides. Using dot registration techniques, we achieve a quantum emitter deterministically positioned at a chiral point and realize spin-path conversion by design. We further show that the chiral phenomena are much more tolerant to dot position than in standard photonic crystal waveguides, exhibit spin-path readout up to 95±5% and have potential to serve as the basis of spin-logic and network implementations. PMID:27029961

  13. Chirality of nanophotonic waveguide with embedded quantum emitter for unidirectional spin transfer

    PubMed Central

    Coles, R. J.; Price, D. M.; Dixon, J. E.; Royall, B.; Clarke, E.; Kok, P.; Skolnick, M. S.; Fox, A. M.; Makhonin, M. N.

    2016-01-01

    Scalable quantum technologies may be achieved by faithful conversion between matter qubits and photonic qubits in integrated circuit geometries. Within this context, quantum dots possess well-defined spin states (matter qubits), which couple efficiently to photons. By embedding them in nanophotonic waveguides, they provide a promising platform for quantum technology implementations. In this paper, we demonstrate that the naturally occurring electromagnetic field chirality that arises in nanobeam waveguides leads to unidirectional photon emission from quantum dot spin states, with resultant in-plane transfer of matter-qubit information. The chiral behaviour occurs despite the non-chiral geometry and material of the waveguides. Using dot registration techniques, we achieve a quantum emitter deterministically positioned at a chiral point and realize spin-path conversion by design. We further show that the chiral phenomena are much more tolerant to dot position than in standard photonic crystal waveguides, exhibit spin-path readout up to 95±5% and have potential to serve as the basis of spin-logic and network implementations. PMID:27029961

  14. An octave-spanning mid-infrared frequency comb generated in a silicon nanophotonic wire waveguide

    NASA Astrophysics Data System (ADS)

    Kuyken, Bart; Ideguchi, Takuro; Holzner, Simon; Yan, Ming; Hänsch, Theodor W.; van Campenhout, Joris; Verheyen, Peter; Coen, Stéphane; Leo, Francois; Baets, Roel; Roelkens, Gunther; Picqué, Nathalie

    2015-02-01

    Laser frequency combs, sources with a spectrum consisting of hundred thousands evenly spaced narrow lines, have an exhilarating potential for new approaches to molecular spectroscopy and sensing in the mid-infrared region. The generation of such broadband coherent sources is presently under active exploration. Technical challenges have slowed down such developments. Identifying a versatile highly nonlinear medium for significantly broadening a mid-infrared comb spectrum remains challenging. Here we take a different approach to spectral broadening of mid-infrared frequency combs and investigate CMOS-compatible highly nonlinear dispersion-engineered silicon nanophotonic waveguides on a silicon-on-insulator chip. We record octave-spanning (1,500-3,300 nm) spectra with a coupled input pulse energy as low as 16 pJ. We demonstrate phase-coherent comb spectra broadened on a room-temperature-operating CMOS-compatible chip.

  15. An octave-spanning mid-infrared frequency comb generated in a silicon nanophotonic wire waveguide

    PubMed Central

    Kuyken, Bart; Ideguchi, Takuro; Holzner, Simon; Yan, Ming; Hänsch, Theodor W.; Van Campenhout, Joris; Verheyen, Peter; Coen, Stéphane; Leo, Francois; Baets, Roel; Roelkens, Gunther; Picqué, Nathalie

    2015-01-01

    Laser frequency combs, sources with a spectrum consisting of hundred thousands evenly spaced narrow lines, have an exhilarating potential for new approaches to molecular spectroscopy and sensing in the mid-infrared region. The generation of such broadband coherent sources is presently under active exploration. Technical challenges have slowed down such developments. Identifying a versatile highly nonlinear medium for significantly broadening a mid-infrared comb spectrum remains challenging. Here we take a different approach to spectral broadening of mid-infrared frequency combs and investigate CMOS-compatible highly nonlinear dispersion-engineered silicon nanophotonic waveguides on a silicon-on-insulator chip. We record octave-spanning (1,500–3,300 nm) spectra with a coupled input pulse energy as low as 16 pJ. We demonstrate phase-coherent comb spectra broadened on a room-temperature-operating CMOS-compatible chip. PMID:25697764

  16. Free-carrier-induced soliton fission unveiled by in situ measurements in nanophotonic waveguides

    NASA Astrophysics Data System (ADS)

    Husko, Chad; Wulf, Matthias; Lefrancois, Simon; Combrié, Sylvain; Lehoucq, Gaëlle; de Rossi, Alfredo; Eggleton, Benjamin J.; Kuipers, L.

    2016-04-01

    Solitons are localized waves formed by a balance of focusing and defocusing effects. These nonlinear waves exist in diverse forms of matter yet exhibit similar properties including stability, periodic recurrence and particle-like trajectories. One important property is soliton fission, a process by which an energetic higher-order soliton breaks apart due to dispersive or nonlinear perturbations. Here we demonstrate through both experiment and theory that nonlinear photocarrier generation can induce soliton fission. Using near-field measurements, we directly observe the nonlinear spatial and temporal evolution of optical pulses in situ in a nanophotonic semiconductor waveguide. We develop an analytic formalism describing the free-carrier dispersion (FCD) perturbation and show the experiment exceeds the minimum threshold by an order of magnitude. We confirm these observations with a numerical nonlinear Schrödinger equation model. These results provide a fundamental explanation and physical scaling of optical pulse evolution in free-carrier media and could enable improved supercontinuum sources in gas based and integrated semiconductor waveguides.

  17. Free-carrier-induced soliton fission unveiled by in situ measurements in nanophotonic waveguides.

    PubMed

    Husko, Chad; Wulf, Matthias; Lefrancois, Simon; Combrié, Sylvain; Lehoucq, Gaëlle; De Rossi, Alfredo; Eggleton, Benjamin J; Kuipers, L

    2016-01-01

    Solitons are localized waves formed by a balance of focusing and defocusing effects. These nonlinear waves exist in diverse forms of matter yet exhibit similar properties including stability, periodic recurrence and particle-like trajectories. One important property is soliton fission, a process by which an energetic higher-order soliton breaks apart due to dispersive or nonlinear perturbations. Here we demonstrate through both experiment and theory that nonlinear photocarrier generation can induce soliton fission. Using near-field measurements, we directly observe the nonlinear spatial and temporal evolution of optical pulses in situ in a nanophotonic semiconductor waveguide. We develop an analytic formalism describing the free-carrier dispersion (FCD) perturbation and show the experiment exceeds the minimum threshold by an order of magnitude. We confirm these observations with a numerical nonlinear Schrödinger equation model. These results provide a fundamental explanation and physical scaling of optical pulse evolution in free-carrier media and could enable improved supercontinuum sources in gas based and integrated semiconductor waveguides. PMID:27079683

  18. Free-carrier-induced soliton fission unveiled by in situ measurements in nanophotonic waveguides

    DOE PAGESBeta

    Husko, Chad; Wulf, Matthias; Lefrancois, Simon; Combrié, Sylvain; Lehoucq, Gaëlle; De Rossi, Alfredo; Eggleton, Benjamin J.; Kuipers, L.

    2016-04-15

    Solitons are localized waves formed by a balance of focusing and defocusing effects. These nonlinear waves exist in diverse forms of matter yet exhibit similar properties including stability, periodic recurrence and particle-like trajectories. One important property is soliton fission, a process by which an energetic higher-order soliton breaks apart due to dispersive or nonlinear perturbations. Here we demonstrate through both experiment and theory that nonlinear photocarrier generation can induce soliton fission. Using near-field measurements, we directly observe the nonlinear spatial and temporal evolution of optical pulses in situ in a nanophotonic semiconductor waveguide. We develop an analytic formalism describing themore » free-carrier dispersion (FCD) perturbation and show the experiment exceeds the minimum threshold by an order of magnitude. We confirm these observations with a numerical nonlinear Schrodinger equation model. Finally, these results provide a fundamental explanation and physical scaling of optical pulse evolution in free-carrier media and could enable improved supercontinuum sources in gas based and integrated semiconductor waveguides.« less

  19. Free-carrier-induced soliton fission unveiled by in situ measurements in nanophotonic waveguides

    PubMed Central

    Husko, Chad; Wulf, Matthias; Lefrancois, Simon; Combrié, Sylvain; Lehoucq, Gaëlle; De Rossi, Alfredo; Eggleton, Benjamin J.; Kuipers, L.

    2016-01-01

    Solitons are localized waves formed by a balance of focusing and defocusing effects. These nonlinear waves exist in diverse forms of matter yet exhibit similar properties including stability, periodic recurrence and particle-like trajectories. One important property is soliton fission, a process by which an energetic higher-order soliton breaks apart due to dispersive or nonlinear perturbations. Here we demonstrate through both experiment and theory that nonlinear photocarrier generation can induce soliton fission. Using near-field measurements, we directly observe the nonlinear spatial and temporal evolution of optical pulses in situ in a nanophotonic semiconductor waveguide. We develop an analytic formalism describing the free-carrier dispersion (FCD) perturbation and show the experiment exceeds the minimum threshold by an order of magnitude. We confirm these observations with a numerical nonlinear Schrödinger equation model. These results provide a fundamental explanation and physical scaling of optical pulse evolution in free-carrier media and could enable improved supercontinuum sources in gas based and integrated semiconductor waveguides. PMID:27079683

  20. Photon transport in a one-dimensional nanophotonic waveguide QED system

    NASA Astrophysics Data System (ADS)

    Liao, Zeyang; Zeng, Xiaodong; Nha, Hyunchul; Zubairy, M. Suhail

    2016-06-01

    The waveguide quantum electrodynamics (QED) system may have important applications in quantum device and quantum information technology. In this article we review the methods being proposed to calculate photon transport in a one-dimensional (1D) waveguide coupled to quantum emitters. We first introduce the Bethe ansatz approach and the input–output formalism to calculate the stationary results of a single photon transport. Then we present a dynamical time-dependent theory to calculate the real-time evolution of the waveguide QED system. In the longtime limit, both the stationary theory and the dynamical calculation give the same results. Finally, we also briefly discuss the calculations of the multiphoton transport problems.

  1. Single-photon transport through an atomic chain coupled to a one-dimensional nanophotonic waveguide

    NASA Astrophysics Data System (ADS)

    Liao, Zeyang; Zeng, Xiaodong; Zhu, Shi-Yao; Zubairy, M. Suhail

    2015-08-01

    We study the dynamics of a single-photon pulse traveling through a linear atomic chain coupled to a one-dimensional (1D) single mode photonic waveguide. We derive a time-dependent dynamical theory for this collective many-body system which allows us to study the real time evolution of the photon transport and the atomic excitations. Our analytical result is consistent with previous numerical calculations when there is only one atom. For an atomic chain, the collective interaction between the atoms mediated by the waveguide mode can significantly change the dynamics of the system. The reflectivity of a photon can be tuned by changing the ratio of coupling strength and the photon linewidth or by changing the number of atoms in the chain. The reflectivity of a single-photon pulse with finite bandwidth can even approach 100 % . The spectrum of the reflected and transmitted photon can also be significantly different from the single-atom case. Many interesting physical phenomena can occur in this system such as the photonic band-gap effects, quantum entanglement generation, Fano-like interference, and superradiant effects. For engineering, this system may serve as a single-photon frequency filter, single-photon modulation, and may find important applications in quantum information.

  2. Broadband nanophotonic waveguides and resonators based on epitaxial GaN thin films

    SciTech Connect

    Bruch, Alexander W.; Xiong, Chi; Leung, Benjamin; Poot, Menno; Han, Jung; Tang, Hong X.

    2015-10-05

    We demonstrate broadband, low loss optical waveguiding in single crystalline GaN grown epitaxially on c-plane sapphire wafers through a buffered metal-organic chemical vapor phase deposition process. High Q optical microring resonators are realized in near infrared, infrared, and near visible regimes with intrinsic quality factors exceeding 50 000 at all the wavelengths we studied. TEM analysis of etched waveguide reveals growth and etch-induced defects. Reduction of these defects through improved material and device processing could lead to even lower optical losses and enable a wideband photonic platform based on GaN-on-sapphire material system.

  3. Large-Area Binary Blazed Grating Coupler between Nanophotonic Waveguide and LED

    PubMed Central

    Zhou, Wenqian; Zhang, Meiling; Liu, Yu; Zhang, Cheng; Li, Enbang; Miao, Changyun; Tang, Chunxiao

    2014-01-01

    A large-area binary blazed grating coupler for the arrayed waveguide grating (AWG) demodulation integrated microsystem on silicon-on-insulator (SOI) was designed for the first time. Through the coupler, light can be coupled into the SOI waveguide from the InP-based C-band LED for the AWG demodulation integrated microsystem to function. Both the length and width of the grating coupler are 360 μm, as large as the InP-based C-band LED light emitting area in the system. The coupler was designed and optimized based on the finite difference time domain method. When the incident angle of the light source is 0°, the coupling efficiency of the binary blazed grating is 40.92%, and the 3 dB bandwidth is 72 nm at a wavelength of 1550 nm. PMID:25126602

  4. Scattering of a cross-polarized linear wave by a soliton at an optical event horizon in a birefringent nanophotonic waveguide

    NASA Astrophysics Data System (ADS)

    Ciret, Charles; Gorza, Simon-Pierre

    2016-06-01

    The scattering of a linear wave on an optical event horizon, induced by a cross polarized soliton, is experimentally and numerically investigated in integrated structures. The experiments are performed in a dispersion-engineered birefringent silicon nanophotonic waveguide. In stark contrast with co-polarized waves, the large difference between the group velocity of the two cross-polarized waves enables a frequency conversion almost independent on the soliton wavelength. It is shown that the generated idler is only shifted by 10 nm around 1550 nm over a pump tuning range of 350 nm. Simulations using two coupled full vectorial nonlinear Schr\\"odinger equations fully support the experimental results.

  5. Scattering of a cross-polarized linear wave by a soliton at an optical event horizon in a birefringent nanophotonic waveguide.

    PubMed

    Ciret, Charles; Gorza, Simon-Pierre

    2016-06-15

    The scattering of a linear wave on an optical event horizon, induced by a cross-polarized soliton, is experimentally and numerically investigated in integrated structures. The experiments are performed in a dispersion-engineered birefringent silicon nanophotonic waveguide. In stark contrast with copolarized waves, the large difference between the group velocity of the two cross-polarized waves enables a frequency conversion almost independent of the soliton wavelength. It is shown that the generated idler is only shifted by 10 nm around 1550 nm over a pump tuning range of 350 nm. Simulations using two coupled full vectorial nonlinear Schrödinger equations fully support the experimental results. PMID:27304314

  6. Connection between wave transport through disordered 1D waveguides and energy density inside the sample: A maximum-entropy approach

    NASA Astrophysics Data System (ADS)

    Mello, Pier A.; Shi, Zhou; Genack, Azriel Z.

    2015-11-01

    We study the average energy - or particle - density of waves inside disordered 1D multiply-scattering media. We extend the transfer-matrix technique that was used in the past for the calculation of the intensity beyond the sample to study the intensity in the interior of the sample by considering the transfer matrices of the two segments that form the entire waveguide. The statistical properties of the two disordered segments are found using a maximum-entropy ansatz subject to appropriate constraints. The theoretical expressions are shown to be in excellent agreement with 1D transfer-matrix simulations.

  7. Density controlled nanophotonic waveguide gratings for efficient on-chip out-coupling in the near field (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Vercruysse, Dries; Mukund, Vignesh; Jansen, Roelof; Stahl, Richard; Van Dorpe, Pol; Lagae, Liesbet; Rottenberg, Xavier

    2016-05-01

    Waveguide optics takes up a prominent role in the progressing miniaturization of optical devices. Chip integrated photonic waveguides especially allow for complex routing schemes of light across a chip. In/out-coupling diffraction gratings form an essential tool in waveguide systems, as they facilitate the interaction between the waveguide system and the near or far-field.[1,2] Ideally, these gratings would couple out all light in the waveguide into a beam with a predefined polarization and, phase and intensity profile. As such they should be able to produce any functional beam that is typically prepared by free space optics. Yet, in practice there is typically a design trade-off between beam quality and out-coupling efficiency.[2] Light in the waveguide has to travel laterally through the grating to be coupled out. The light therefore decays exponentially over the grating, causing much more light to be coupled out at the start of the grating than at the end. This asymmetry results in a warped out-coupling intensity that heavily influences the light beam's intensity profile. Especially when the grating is addressing points in the near field, as is the case for focusing waveguide grating couplers, this effect can be highly disruptive. In this work we present a grating constructed from a field of sub-wavelength scatterers, rather than full grating lines. By tuning the position and the density of the scatterers, the phase and the intensity of the out-coupled light can be set precisely over large grating areas. An iterative design algorithm is developed that carefully tunes the density so as to control the light intensity in the waveguide and the amount of out-coupled light. Using FDTD simulations we show that these gratings can efficiently couple out light into a nearly diffraction limited spot with an even angular intensity. We verify this experimentally by fabricating these gratings in the SiN/SiO2 system using e-beam lithography. In addition, we also show that

  8. Analysis of nonlinear frequency mixing in 1D waveguides with a breathing crack using the spectral finite element method

    NASA Astrophysics Data System (ADS)

    Joglekar, D. M.; Mitra, M.

    2015-11-01

    A breathing crack, due to its bilinear stiffness characteristics, modifies the frequency spectrum of a propagating dual-frequency elastic wave, and gives rise to sidebands around the probing frequency. This paper presents an analytical-numerical method to investigate such nonlinear frequency mixing resulting from the modulation effects induced by a breathing crack in 1D waveguides, such as axial rods and the Euler-Bernoulli beams. A transverse edge-crack is assumed to be present in both the waveguides, and the local flexibility caused by the crack is modeled using an equivalent spring approach. A simultaneous treatment of both the waveguides, in the framework of the Fourier transform based spectral finite element method, is presented for analyzing their response to a dual frequency excitation applied in the form of a tone-burst signal. The intermittent contact between the crack surfaces is accounted for by introducing bilinear contact forces acting at the nodes of the damage spectral element. Subsequently, an iterative approach is outlined for solving the resulting system of nonlinear simultaneous equations. Applicability of the proposed method is demonstrated by considering several test cases. The existence of sidebands and the higher order harmonics is confirmed in the frequency domain response of both the waveguides under investigation. A qualitative comparison with the previous experimental observations accentuates the utility of the proposed solution method. Additionally, the influence of the two constituent frequencies in the dual frequency excitation is assessed by varying the relative strengths of their amplitudes. A brief parametric study is performed for bringing out the effects of the relative crack depth and crack location on the degree of modulation, which is quantified in terms of the modulation parameter. Results of the present investigation can find their potential use in providing an analytical-numerical support to the studies geared towards the

  9. Nonlinear analysis of flexural wave propagation through 1D waveguides with a breathing crack

    NASA Astrophysics Data System (ADS)

    Joglekar, D. M.; Mitra, M.

    2015-05-01

    An analytical-numerical approach is presented to investigate the flexural wave propagation through a slender semi-infinite beam with a breathing edge-crack. A Fourier transform based spectral finite element method is employed in an iterative manner to analyze the nonlinear response of the cracked beam subjected to a transverse tone burst excitation. Results obtained using the spectral finite element method are corroborated using 1D finite element analysis that involves the formulation and solution of a linear complementarity problem at every time step. In both the methods, an equivalent rotational spring is used to model the local flexibility caused by an open crack and the respective damaged beam element is formulated. The effect of crack-breathing is accounted for by an intermittent contact force acting at the nodes of the damaged beam element. A parallel study involving the open crack model is performed in the same setting to facilitate a comparison between the open and the breathing crack model. An illustrative case study reveals clearly the existence of higher order harmonics originating from the crack-breathing phenomenon which are absent if the crack is assumed to remain open throughout. A thorough investigation of the wrap-around effect associated with spectral finite element method reveals that the relative strengths of the higher order harmonics are not influenced by the wrap-around effect. A brief parametric study involving the variation of crack depth is presented at the end which suggests that the magnitudes of the higher harmonic peaks increase with increasing levels of crack severity. The present study can be potentially useful in the efforts geared toward the development of damage detection/localization strategies based on the nonlinear wave-damage interaction.

  10. Diamond nanophotonics

    PubMed Central

    Beha, Katja; Wolfer, Marco; Becker, Merle C; Siyushev, Petr; Jamali, Mohammad; Batalov, Anton; Hinz, Christopher; Hees, Jakob; Kirste, Lutz; Obloh, Harald; Gheeraert, Etienne; Naydenov, Boris; Jakobi, Ingmar; Dolde, Florian; Pezzagna, Sébastien; Twittchen, Daniel; Markham, Matthew; Dregely, Daniel; Giessen, Harald; Meijer, Jan; Jelezko, Fedor; Nebel, Christoph E; Bratschitsch, Rudolf; Leitenstorfer, Alfred; Wrachtrup, Jörg

    2012-01-01

    Summary We demonstrate the coupling of single color centers in diamond to plasmonic and dielectric photonic structures to realize novel nanophotonic devices. Nanometer spatial control in the creation of single color centers in diamond is achieved by implantation of nitrogen atoms through high-aspect-ratio channels in a mica mask. Enhanced broadband single-photon emission is demonstrated by coupling nitrogen–vacancy centers to plasmonic resonators, such as metallic nanoantennas. Improved photon-collection efficiency and directed emission is demonstrated by solid immersion lenses and micropillar cavities. Thereafter, the coupling of diamond nanocrystals to the guided modes of micropillar resonators is discussed along with experimental results. Finally, we present a gas-phase-doping approach to incorporate color centers based on nickel and tungsten, in situ into diamond using microwave-plasma-enhanced chemical vapor deposition. The fabrication of silicon–vacancy centers in nanodiamonds by microwave-plasma-enhanced chemical vapor deposition is discussed in addition. PMID:23365803

  11. Reprint of : Connection between wave transport through disordered 1D waveguides and energy density inside the sample: A maximum-entropy approach

    NASA Astrophysics Data System (ADS)

    Mello, Pier A.; Shi, Zhou; Genack, Azriel Z.

    2016-08-01

    We study the average energy - or particle - density of waves inside disordered 1D multiply-scattering media. We extend the transfer-matrix technique that was used in the past for the calculation of the intensity beyond the sample to study the intensity in the interior of the sample by considering the transfer matrices of the two segments that form the entire waveguide. The statistical properties of the two disordered segments are found using a maximum-entropy ansatz subject to appropriate constraints. The theoretical expressions are shown to be in excellent agreement with 1D transfer-matrix simulations.

  12. Planar waveguides with less than 0.1 dB/m propagation loss fabricated with wafer bonding.

    PubMed

    Bauters, Jared F; Heck, Martijn J R; John, Demis D; Barton, Jonathon S; Bruinink, Christiaan M; Leinse, Arne; Heideman, René G; Blumenthal, Daniel J; Bowers, John E

    2011-11-21

    We demonstrate a wafer-bonded silica-on-silicon planar waveguide platform with record low total propagation loss of (0.045 ± 0.04) dB/m near the free space wavelength of 1580 nm. Using coherent optical frequency domain reflectometry, we characterize the group index, fiber-to-chip coupling loss, critical bend radius, and propagation loss of these waveguides. PMID:22109434

  13. Engineered atom-light interactions in 1D photonic crystals

    NASA Astrophysics Data System (ADS)

    Martin, Michael J.; Hung, Chen-Lung; Yu, Su-Peng; Goban, Akihisa; Muniz, Juan A.; Hood, Jonathan D.; Norte, Richard; McClung, Andrew C.; Meenehan, Sean M.; Cohen, Justin D.; Lee, Jae Hoon; Peng, Lucas; Painter, Oskar; Kimble, H. Jeff

    2014-05-01

    Nano- and microscale optical systems offer efficient and scalable quantum interfaces through enhanced atom-field coupling in both resonators and continuous waveguides. Beyond these conventional topologies, new opportunities emerge from the integration of ultracold atomic systems with nanoscale photonic crystals. One-dimensional photonic crystal waveguides can be engineered for both stable trapping configurations and strong atom-photon interactions, enabling novel cavity QED and quantum many-body systems, as well as distributed quantum networks. We present the experimental realization of such a nanophotonic quantum interface based on a nanoscale photonic crystal waveguide, demonstrating a fractional waveguide coupling of Γ1 D /Γ' of 0 . 32 +/- 0 . 08 , where Γ1 D (Γ') is the atomic emission rate into the guided (all other) mode(s). We also discuss progress towards intra-waveguide trapping of ultracold Cs. This work was supported by the IQIM, an NSF Physics Frontiers Center with support from the Moore Foundation, the DARPA ORCHID program, the AFOSR QuMPASS MURI, the DoD NSSEFF program, NSF, and the Kavli Nanoscience Institute (KNI) at Caltech.

  14. Time domain topology optimization of 3D nanophotonic devices

    NASA Astrophysics Data System (ADS)

    Elesin, Y.; Lazarov, B. S.; Jensen, J. S.; Sigmund, O.

    2014-02-01

    We present an efficient parallel topology optimization framework for design of large scale 3D nanophotonic devices. The code shows excellent scalability and is demonstrated for optimization of broadband frequency splitter, waveguide intersection, photonic crystal-based waveguide and nanowire-based waveguide. The obtained results are compared to simplified 2D studies and we demonstrate that 3D topology optimization may lead to significant performance improvements.

  15. Nanophotonics for Optoelectronic Devices: Extrinsic Silicon Photonic Receivers and Organic Photovoltaics

    NASA Astrophysics Data System (ADS)

    Grote, Richard R.

    The demand for high data rate communications and renewable energy sources has led to new materials and platforms for optoelectronic devices, which require nanometer scale feature sizes. Devices that operate in the visible and near-infrared commonly have active areas with dimensions on the order of the diffraction limit ( l2n , where lambda is the free space wavelength and n is the index of refraction), for which the ray optics modeling techniques and bulk focusing optics traditionally used in optoelectronic device design are no longer applicable. In this subwavelength regime, nanophotonic light-trapping strategies are required to localize electromagnetic fields in the active area. This dissertation details the application of nanophotonics to two optoelectronic systems: extrinsic photodetectors for silicon photonics and light-trapping in organic photovoltaics. Error-free reception of 10 Gb/s data at lambda = 1.55 mum is demonstrated with a Si+ ion-implanted silicon waveguide photodiode. To mitigate the relatively small absorption coefficient of ion-implanted silicon, resonant cavity enhancement using in-line Fabry-Perot and 1D photonic crystal cavities, as well as slow light enhancement using a coupled resonator optical waveguide are discussed. The extension of these photodiodes to the mid-infrared is demonstrated using Zn+ implantation to detect over a range of lambda = 2.2-2.4 mum, and a new method for modulation and switching in integrated optics by using interference in a resonant cavity, termed coherent perfect loss (CPL), is presented. Finally, the upper limit of nanophotonic light trapping is derived for organic photovoltaics with material anisotropy included.

  16. Special issue on graphene nanophotonics

    NASA Astrophysics Data System (ADS)

    Nikitin, A. Yu; Maier, S. A.; Martin-Moreno, L.

    2013-11-01

    , although it cannot be considered as the proceedings of that workshop, was conceived there. Several topics at the cutting edge of research into graphene nanophotonics are covered in this publication. The papers by Polyushkin et al [3] and Thackray et al [4] consider structures where graphene is placed in close proximity to metallic plasmonic resonators. There graphene is used either as a substrate for metallic nanoparticles [3] or as a top layer covering metallic stripes [4]. Both studies find that the plasmonic response of metallic nanoparticles is notably modified by the presence of a graphene. The papers of Nefedov et al [5] and Bludov et al [6] analyze how a metamaterial based on a stack of graphene layers can provide unusually high absorption and reflection. These findings suggest that dynamical tuning of the reflectance and absorbance is possible at specific frequencies. The theory of the transverse current response for graphene within the random phase approximation is presented, from a general standpoint, in the paper by Gutiérrez-Rubio et al [7], which considers non-local effects, as well as the dependence of both temperature and surrounding dielectric media. Forati et al [8] present a study on conductivity and current distributions in a graphene sheet located over a ridge-perturbed ground plane, showing how the resulting plasmonic waveguide is more sensitive to the bias voltage than to the geometric ridge parameters. Effective analytical methods to address the electromagnetic resonances related to the excitation of graphene plasmons in different structures are presented in the papers by Balaban et al [9] (devoted to individual graphene discs and stripes) and Slipchenko et al [10] (which considers periodic graphene gratings). Popov et al [11] predict lasing of terahertz radiation in graphene due to the stimulated generation of plasmons. Their paper demonstrates that the dynamic and frequency ranges, as well as the energy conversion efficiency, of the terahertz

  17. From molecular design and materials construction to organic nanophotonic devices.

    PubMed

    Zhang, Chuang; Yan, Yongli; Zhao, Yong Sheng; Yao, Jiannian

    2014-12-16

    CONSPECTUS: Nanophotonics has recently received broad research interest, since it may provide an alternative opportunity to overcome the fundamental limitations in electronic circuits. Diverse optical materials down to the wavelength scale are required to develop nanophotonic devices, including functional components for light emission, transmission, and detection. During the past decade, the chemists have made their own contributions to this interdisciplinary field, especially from the controlled fabrication of nanophotonic molecules and materials. In this context, organic micro- or nanocrystals have been developed as a very promising kind of building block in the construction of novel units for integrated nanophotonics, mainly due to the great versatility in organic molecular structures and their flexibility for the subsequent processing. Following the pioneering works on organic nanolasers and optical waveguides, the organic nanophotonic materials and devices have attracted increasing interest and developed rapidly during the past few years. In this Account, we review our research on the photonic performance of molecular micro- or nanostructures and the latest breakthroughs toward organic nanophotonic devices. Overall, the versatile features of organic materials are highlighted, because they brings tunable optical properties based on molecular design, size-dependent light confinement in low-dimensional structures, and various device geometries for nanophotonic integration. The molecular diversity enables abundant optical transitions in conjugated π-electron systems, and thus brings specific photonic functions into molecular aggregates. The morphology of these micro- or nanostructures can be further controlled based on the weak intermolecular interactions during molecular assembly process, making the aggregates show photon confinement or light guiding properties as nanophotonic materials. By adoption of some active processes in the composite of two or more

  18. Broadband directional coupling in aluminum nitride nanophotonic circuits.

    PubMed

    Stegmaier, Matthias; Pernice, Wolfram H P

    2013-03-25

    Aluminum nitride (AlN)-on-insulator has emerged as a promising platform for the realization of linear and non-linear integrated photonic circuits. In order to efficiently route optical signals on-chip, precise control over the interaction and polarization of evanescently coupled waveguide modes is required. Here we employ nanophotonic AlN waveguides to realize directional couplers with a broad coupling bandwidth and low insertion loss. We achieve uniform splitting of incoming modes, confirmed by high extinction-ratio exceeding 33dB in integrated Mach-Zehnder Interferometers. Optimized three-waveguide couplers furthermore allow for extending the coupling bandwidth over traditional side-coupled devices by almost an order of magnitude, with variable splitting ratio. Our work illustrates the potential of AlN circuits for coupled waveguide optics, DWDM applications and integrated polarization diversity schemes. PMID:23546114

  19. Nanophotonics and supramolecular chemistry

    NASA Astrophysics Data System (ADS)

    Ariga, Katsuhiko; Komatsu, Hirokazu; Hill, Jonathan P.

    2013-10-01

    Supramolecular chemistry has become a key area in emerging bottom-up nanoscience and nanotechnology. In particular, supramolecular systems that can produce a photonic output are increasingly important research targets and present various possibilities for practical applications. Accordingly, photonic properties of various supramolecular systems at the nanoscale are important in current nanotechnology. In this short review, nanophotonics in supramolecular chemistry will be briefly summarized by introducing recent examples of control of photonic responses of supramolecular systems. Topics are categorized according to the fundamental actions of their supramolecular systems: (i) self-assembly; (ii) recognition; (iii) manipulation.

  20. Dielectric resonator antenna for applications in nanophotonics.

    PubMed

    Malheiros-Silveira, Gilliard N; Wiederhecker, Gustavo S; Hernández-Figueroa, Hugo E

    2013-01-14

    Optical nanoantennas, especially of the dipole type, have been theoretically and experimentally demonstrated by many research groups. Likewise, the plasmonic waveguides and optical circuits have experienced significant advances. In radio frequencies and microwaves a category of antenna known as dielectric resonator antenna (DRA), whose radiant element is a dielectric resonator (DR), has been designed for several applications, including satellite and radar systems. In this letter, we explore the possibilities and advantages to design nano DRAs (NDRAs), i. e., DRAs for nanophotonics applications. Numerical demonstrations showing the fundamental antenna parameters for a circular cylindrical NDRA type have been carried out for the short (S), conventional (C), and long (L) bands of the optical communication spectrum. PMID:23389016

  1. Nanoscale observation of waveguide modes enhancing the efficiency of solar cells.

    PubMed

    Paetzold, Ulrich W; Lehnen, Stephan; Bittkau, Karsten; Rau, Uwe; Carius, Reinhard

    2014-11-12

    Nanophotonic light management concepts are on the way to advance photovoltaic technologies and accelerate their economical breakthrough. Most of these concepts make use of the coupling of incident sunlight to waveguide modes via nanophotonic structures such as photonic crystals, nanowires, or plasmonic gratings. Experimentally, light coupling to these modes was so far exclusively investigated with indirect and macroscopic methods, and thus, the nanoscale physics of light coupling and propagation of waveguide modes remain vague. In this contribution, we present a nanoscopic observation of light coupling to waveguide modes in a nanophotonic thin-film silicon solar cell. Making use of the subwavelength resolution of the scanning near-field optical microscopy, we resolve the electric field intensities of a propagating waveguide mode at the surface of a state-of-the-art nanophotonic thin-film solar cell. We identify the resonance condition for light coupling to this individual waveguide mode and associate it to a pronounced resonance in the external quantum efficiency that is found to increase significantly the power conversion efficiency of the device. We show that a maximum of the incident light couples to the investigated waveguide mode if the period of the electric field intensity of the waveguide mode matches the periodicity of the nanophotonic two-dimensional grating. Our novel experimental approach establishes experimental access to the local analysis of light coupling to waveguide modes in a number of optoelectronic devices concerned with nanophotonic light-trapping as well as nanophotonic light emission. PMID:25350265

  2. Multiscaffold DNA Origami Nanoparticle Waveguides

    PubMed Central

    2013-01-01

    DNA origami templated self-assembly has shown its potential in creating rationally designed nanophotonic devices in a parallel and repeatable manner. In this investigation, we employ a multiscaffold DNA origami approach to fabricate linear waveguides of 10 nm diameter gold nanoparticles. This approach provides independent control over nanoparticle separation and spatial arrangement. The waveguides were characterized using atomic force microscopy and far-field polarization spectroscopy. This work provides a path toward large-scale plasmonic circuitry. PMID:23841957

  3. Nanophotonic Filters and Integrated Networks in Flexible 2D Polymer Photonic Crystals

    PubMed Central

    Gan, Xuetao; Clevenson, Hannah; Tsai, Cheng-Chia; Li, Luozhou; Englund, Dirk

    2013-01-01

    Polymers have appealing optical, biochemical, and mechanical qualities, including broadband transparency, ease of functionalization, and biocompatibility. However, their low refractive indices have precluded wavelength-scale optical confinement and nanophotonic applications in polymers. Here, we introduce a suspended polymer photonic crystal (SPPC) architecture that enables the implementation of nanophotonic structures typically limited to high-index materials. Using the SPPC platform, we demonstrate nanophotonic band-edge filters, waveguides, and nanocavities featuring quality (Q) factors exceeding 2, 300 and mode volumes (Vmode) below 1.7(λ/n)3. The unprecedentedly high Q/Vmode ratio results in a spectrally selective enhancement of radiative transitions of embedded emitters via the cavity Purcell effect with an enhancement factor exceeding 100. Moreover, the SPPC architecture allows straightforward integration of nanophotonic networks, shown here by a waveguide-coupled cavity drop filter with sub-nanometer spectral resolution. The nanoscale optical confinement in polymer promises new applications ranging from optical communications to organic opto-electronics, and nanophotonic polymer sensors. PMID:23828320

  4. All-nanophotonic NEMS biosensor on a chip

    PubMed Central

    Fedyanin, Dmitry Yu.; Stebunov, Yury V.

    2015-01-01

    Integrated chemical and biological sensors give advantages in cost, size and weight reduction and open new prospects for parallel monitoring and analysis. Biosensors based on nanoelectromechanical systems (NEMS) are the most attractive candidates for the integrated platform. However, actuation and transduction techniques (e.g. electrostatic, magnetomotive, thermal or piezoelectric) limit their operation to laboratory conditions. All-optical approach gives the possibility to overcome this problem, nevertheless, the existing schemes are either fundamentally macroscopic or excessively complicated and expensive in mass production. Here we propose a novel scheme of extremely compact NEMS biosensor monolithically integrated on a chip with all-nanophotonic transduction and actuation. It consists of the nanophotonic waveguide and the nanobeam cantilever placed above the waveguide, both fabricated in the same CMOS-compatible process. Being in the near field of the strongly confined photonic or plasmonic mode, cantilever is efficiently actuated and its response is directly read out using the same waveguide, which results in a very high sensitivity and capability of single-molecule detection even in atmosphere. PMID:26043287

  5. All-nanophotonic NEMS biosensor on a chip

    NASA Astrophysics Data System (ADS)

    Fedyanin, Dmitry Yu.; Stebunov, Yury V.

    2015-06-01

    Integrated chemical and biological sensors give advantages in cost, size and weight reduction and open new prospects for parallel monitoring and analysis. Biosensors based on nanoelectromechanical systems (NEMS) are the most attractive candidates for the integrated platform. However, actuation and transduction techniques (e.g. electrostatic, magnetomotive, thermal or piezoelectric) limit their operation to laboratory conditions. All-optical approach gives the possibility to overcome this problem, nevertheless, the existing schemes are either fundamentally macroscopic or excessively complicated and expensive in mass production. Here we propose a novel scheme of extremely compact NEMS biosensor monolithically integrated on a chip with all-nanophotonic transduction and actuation. It consists of the nanophotonic waveguide and the nanobeam cantilever placed above the waveguide, both fabricated in the same CMOS-compatible process. Being in the near field of the strongly confined photonic or plasmonic mode, cantilever is efficiently actuated and its response is directly read out using the same waveguide, which results in a very high sensitivity and capability of single-molecule detection even in atmosphere.

  6. Nanophotonic Ion Sources

    NASA Astrophysics Data System (ADS)

    Stolee, Jessica A.; Walker, Bennett N.; Chen, Yong; Vertes, Akos

    2010-10-01

    Interactions between laser radiation and photonic structures at elevated laser intensities give rise to the production of positive and negative ions from adsorbates. These new types of ion sources exhibit properties that are significantly different from conventional laser desorption ionization sources. In this contribution comparisons are made between matrix-assisted laser desorption ionization (MALDI) of biomolecules with ion production from laser-induced silicon microcolumn arrays (LISMA) and nanopost arrays (NAPA). The sharp increase of ion yields from the nanophotonic ion sources follow a power law behavior with an exponent of up to n≈7, whereas in the case of MALDI n≈5. The strong field enhancement in the vicinity of the columns and posts scales with their aspect ratio. Slender high aspect ratio posts show reduced laser fluence threshold for ionization. Posts with diameters at or below the thermal diffusion length demonstrate high surface temperatures due to the radial confinement of the deposited energy. As a consequence enhanced fragmentation, i.e., lower survival yield of the molecular ions is observed. The origin of protons in the ionization of adsorbates was identified as the entrapped residues of the solvent.

  7. Successful commercialization of nanophotonic technology

    NASA Astrophysics Data System (ADS)

    Jaiswal, Supriya L.; Clarke, Roger B. M.; Hyde, Sam C. W.

    2006-08-01

    The exploitation of nanotechnology from proof of principle to realizable commercial applications encounters considerable challenges in regards to high volume, large scale, low cost manufacturability and social ethics. This has led to concerns over converting powerful intellectual property into realizable, industry attractive technologies. At The Technology Partnership we specifically address the issue of successful integration of nanophotonics into industry in markets such as biomedical, ophthalmic, energy, telecommunications, and packaging. In this paper we draw on a few examples where we have either developed industrial scale nanophotonic technology or engineering platforms which may be used to fortify nano/microphotonic technologies and enhance their commercial viability.

  8. Nanophotonics for Tailoring Light-Matter Interaction

    NASA Astrophysics Data System (ADS)

    Qiu, Wenjun

    In this thesis, we will theoretically explore three nanophotonics phenomena which enable strong light-matter interaction. The first phenomenon is plasmonic resonance, where the surface plasmon mode at metal and dielectric boundaries significantly enhances the optical response of nanoparticles. We propose an optimization-based theoretical approach to tailor the optical response of silver/silica multilayer nanospheres over the visible spectrum. We show that the structure that provides the largest cross-section per volume/mass, averaged over a wide frequency range, is the silver coated silica sphere. We also show how properly chosen mixture of several species of different nanospheres can have an even larger minimal cross-section per volume/mass over the entire visible spectrum. The second phenomenon is photonic chiral edge state, where the breaking of time-reversal symmetry forces light to travel in only one direction. Based on the directional coupling between one-way waveguide and conventional two-waveguide, we propose a new type of optical circulators, which has the potential for simultaneous broadband operation and small device footprint. The third phenomenon is Stimulated Brillouin Scattering (SBS), where photon and phonon are coupled through optical forces such as electrostriction force and radiation pressure. We develop a general method of calculating SBS gain via the overlap integral between optical and elastic modes. Applying this method to a rectangular waveguide, we demonstrate that the distribution of optical force and elastic modal profile jointly determine the magnitude and scaling of SBS gains. Applying this method to a periodic waveguide, we demonstrate that SBS gain can be further enhanced in the slow light regime. Based on this framework, we theoretically characterize a novel class of hybrid photon-phonon waveguides. Our analysis reveals that photon-phonon coupling via SBS can be directed and tailored over an exceptionally wide frequency range

  9. Disorder improves nanophotonic light trapping in thin-film solar cells

    SciTech Connect

    Paetzold, U. W. Smeets, M.; Meier, M.; Bittkau, K.; Merdzhanova, T.; Smirnov, V.; Carius, R.; Rau, U.; Michaelis, D.; Waechter, C.

    2014-03-31

    We present a systematic experimental study on the impact of disorder in advanced nanophotonic light-trapping concepts of thin-film solar cells. Thin-film solar cells made of hydrogenated amorphous silicon were prepared on imprint-textured glass superstrates. For periodically textured superstrates of periods below 500 nm, the nanophotonic light-trapping effect is already superior to state-of-the-art randomly textured front contacts. The nanophotonic light-trapping effect can be associated to light coupling to leaky waveguide modes causing resonances in the external quantum efficiency of only a few nanometer widths for wavelengths longer than 500 nm. With increasing disorder of the nanotextured front contact, these resonances broaden and their relative altitude decreases. Moreover, overall the external quantum efficiency, i.e., the light-trapping effect, increases incrementally with increasing disorder. Thereby, our study is a systematic experimental proof that disorder is conceptually an advantage for nanophotonic light-trapping concepts employing grating couplers in thin-film solar cells. The result is relevant for the large field of research on nanophotonic light trapping in thin-film solar cells which currently investigates and prototypes a number of new concepts including disordered periodic and quasi periodic textures.

  10. Nanoimprint lithography: an enabling technology for nanophotonics

    NASA Astrophysics Data System (ADS)

    Yao, Yuhan; Liu, He; Wang, Yifei; Li, Yuanrui; Song, Boxiang; Bratkovsk, Alexandre; Wang, Shih-Yuan; Wu, Wei

    2015-11-01

    Nanoimprint lithography (NIL) is an indispensable tool to realize a fast and accurate nanoscale patterning in nanophotonics due to high resolution and high yield. The number of publication on NIL has increased from less than a hundred per year to over three thousand per year. In this paper, the most recent developments on NIL patterning transfer processes and its applications on nanophotonics are discussed and reviewed. NIL has been opening up new opportunities for nanophotonics, especially in fabricating optical meta-materials. With more researches on this low-cost high-throughput fabrication technology, we should anticipate a brighter future for nanophotonics and NIL.

  11. Near-infrared III-nitride-on-silicon nanophotonic platform with microdisk resonators.

    PubMed

    Roland, I; Zeng, Y; Checoury, X; El Kurdi, M; Sauvage, S; Brimont, C; Guillet, T; Gayral, B; Gromovyi, M; Duboz, J Y; Semond, F; de Micheli, M P; Boucaud, P

    2016-05-01

    We have developed a nanophotonic platform with microdisks using epitaxial III-nitride materials on silicon. The two-dimensional platform consists of suspended waveguides and mushroom-type microdisks as resonators side-coupled with a bus waveguide. Loaded quality factors up to 80000 have been obtained in the near-infrared spectral range for microdisk diameters between 8 and 15 μm. We analyze the dependence of the quality factors as a function of coupling efficiency. We have performed continuous-wave second harmonic generation experiments in resonance with the whispering gallery modes supported by the microdisks. PMID:27137573

  12. Near-unity coupling efficiency of a quantum emitter to a photonic crystal waveguide.

    PubMed

    Arcari, M; Söllner, I; Javadi, A; Lindskov Hansen, S; Mahmoodian, S; Liu, J; Thyrrestrup, H; Lee, E H; Song, J D; Stobbe, S; Lodahl, P

    2014-08-29

    A quantum emitter efficiently coupled to a nanophotonic waveguide constitutes a promising system for the realization of single-photon transistors, quantum-logic gates based on giant single-photon nonlinearities, and high bit-rate deterministic single-photon sources. The key figure of merit for such devices is the β factor, which is the probability for an emitted single photon to be channeled into a desired waveguide mode. We report on the experimental achievement of β=98.43%±0.04% for a quantum dot coupled to a photonic crystal waveguide, corresponding to a single-emitter cooperativity of η=62.7±1.5. This constitutes a nearly ideal photon-matter interface where the quantum dot acts effectively as a 1D "artificial" atom, since it interacts almost exclusively with just a single propagating optical mode. The β factor is found to be remarkably robust to variations in position and emission wavelength of the quantum dots. Our work demonstrates the extraordinary potential of photonic crystal waveguides for highly efficient single-photon generation and on-chip photon-photon interaction. PMID:25215983

  13. New Perspectives in Silicon Micro and Nanophotonics

    NASA Astrophysics Data System (ADS)

    Casalino, M.; Coppola, G.; De Stefano, L.; Calio, A.; Rea, I.; Mocella, V.; Dardano, P.; Romano, S.; Rao, S.; Rendina, I.

    2015-05-01

    In the last two decades, there has been growing interest in silicon-based photonic devices for many optical applications: telecommunications, interconnects and biosensors. In this work, an advance overview of our results in this field is presented. Proposed devices allow overcoming silicon intrinsic drawbacks limiting its application as a photonic substrate. Taking advantages of both non-linear and linear effects, size reduction at nanometric scale and new two-dimensional emerging materials, we have obtained a progressive increase in device performance along the last years. In this work we show that a suitable design of a thin photonic crystal slab realized in silicon nitride can exhibit a very strong field enhancement. This result is very promising for all photonic silicon devices based on nonlinear phenomena. Moreover we report on the fabrication and characterization of silicon photodetectors working at near-infrared wavelengths based on the internal photoemission absorption in a Schottky junction. We show as an increase in device performance can be obtained by coupling light into both micro-resonant cavity and waveguiding structures. In addition, replacing metal with graphene in a Schottky junction, a further improve in PD performance can be achieved. Finally, silicon-based microarray for biomedical applications, are reported. Microarray of porous silicon Bragg reflectors on a crystalline silicon substrate have been realized using a technological process based on standard photolithography and electrochemical anodization of the silicon. Our insights show that silicon is a promising platform for the integration of various optical functionalities on the same chip opening new frontiers in the field of low-cost silicon micro and nanophotonics.

  14. Butterfly scales as bionic templates for complex ordered nanophotonic materials: A pathway to biomimetic plasmonics

    NASA Astrophysics Data System (ADS)

    Jakšić, Zoran; Pantelić, Dejan; Sarajlić, Milija; Savić-Šević, Svetlana; Matović, Jovan; Jelenković, Branislav; Vasiljević-Radović, Dana; Ćurčić, Srećko; Vuković, Slobodan; Pavlović, Vladimir; Buha, Jelena; Lačković, Vesna; Labudović-Borović, Milica; Ćurčić, Božidar

    2013-08-01

    In this paper we propose a possible use of butterfly scales as templates for ordered 2D or 3D nanophotonic materials, with complexity not easily reproducible by conventional micro/nanofabrication methods. Functionalization through laminar nanocompositing is utilized to impart novel properties to the biological scaffold. An extremely wide variability of butterfly scale forms, shapes, sizes and fine structures is observed in nature, many of them already possessing peculiar optical properties. Their nanophotonic functionalization ensures a large choice of forms and functions, including enhanced light localization, light and plasmon waveguiding and general metamaterial behavior, to mention a few. We show that one is able to achieve a combination of plasmonics and bionics, resulting in functionalities seldom if ever met in nature. As an illustration we have analyzed the photonic properties of the nanostructured scales on the wings of Purple Emperor butterflies Apatura ilia, Apatura iris and Sasakia charonda. Their intricate nanometer-sized structures produce remarkable ultraviolet-blue iridescence, spectrally and directionally narrow. We present our analysis of their plasmonic/nanophotonic functionalization including preliminary calculations and initial experimental results. As a simple example, we used radiofrequent sputtering to produce nanoaperture-based plasmonic structures at a fraction of the cost and necessary engineering efforts compared to the conventional top-down methods. We conclude that the described pathway to biomimetic plasmonics offers potentials for significant expansion of the nanophotonic and nanoplasmonic material toolbox.

  15. Nanophotonic Design for Broadband Light Management

    SciTech Connect

    Kosten, Emily; Callahan, Dennis; Horowitz, Kelsey; Pala, Ragip; Atwater, Harry

    2014-10-13

    We describe nanophotonic design approaches for broadband light management including i) crossed-trapezoidal Si structures ii) Si photonic crystal superlattices, and iii) tapered and inhomogeneous diameter III-V/Si nanowire arrays.

  16. Nanophotonic graphene-based racetrack-resonator add/drop filter

    NASA Astrophysics Data System (ADS)

    Wirth L., A.; da Silva, M. G.; Neves, D. M. C.; Sombra, A. S. B.

    2016-05-01

    We are presenting and analyzing a graphene-based nanophotonic device to operate as a resonator-add/drop filter, whose control is obtained by varying the graphene chemical potential. That device consists of graphene-based waveguides, two directional couplers and a racetrack resonator with 90° bends. Since the graphene chemical potential provides the achievement of the necessary parameters, the resonance and filtering of the signals are obtained by applying the correct value of the graphene chemical potential in the graphene nanoribbons. The results of this study should help in the development of new graphene-based nanophotonic devices operating in the terahertz and infrared range (including in the C-band of the International Telecommunication Union - ITU), for use in future communications networks.

  17. Heterogeneous Integration of Materials on Si for Nanophotonics Devices

    NASA Astrophysics Data System (ADS)

    Assefa, Solomon

    2009-03-01

    Optical interconnects are attractive candidates for achieving communication bandwidth well beyond terabit-per-second for high-performance multi-core microprocessors. Silicon has become a desirable material due to its transparency in the infrared wavelength range and the ease for integrating optical devices at the vicinity of CMOS circuitry utilizing standard processes. While state-of-the-art patterning techniques provide precise dimension control as well as pattern placement, standard doping and metallization steps enable utilization of phenomena such as carrier injection and depletion to render the devices tunable. As a result, large progress has been made on Si-based nanophotonic devices such as modulators, switches, and wavelength division multiplexing (WDM) systems [1, 2]. To make photodetectors, however, a heterogeneous integration of other materials that absorb light in the infrared is necessary. Available in standard front-end CMOS processes for gate strain engineering, Germanium is suitable due to its high absorption coefficient at 1.3μm and 1.5μm wavelengths. Thus, Ge can be directly integrated into the process to fabricate compact photodetectors simultaneously with amplifier circuits in order to make a receiver for an optical network. Nevertheless, the integration of Ge photodetector into the CMOS process flow is very challenging due to process complexity and severe temperature constraints; as a result, photodetectors fabricated only after completing the front-end processes have been previously demonstrated. This talk will discuss Ge waveguide photodetectors that have been integrated into the front-end before the activation of CMOS well implants. By utilizing a lateral seeded crystallization method wherein the Ge waveguides are melted during high-temperature dopant activation, 20μm-long single-crystal Ge-on-insulator waveguides were formed. This approach eliminates the need for selective epitaxial growth of Ge, and avoids high-density misfit

  18. Superluminal and stopped light due to mode coupling in confined hyperbolic metamaterial waveguides

    NASA Astrophysics Data System (ADS)

    Neira, Andres D.; Wurtz, Gregory A.; Zayats, Anatoly V.

    2015-12-01

    Anisotropic metamaterials with hyperbolic dispersion can be used to design waveguides with unusual properties. We show that, in contrast to planar waveguides, geometric confinement leads to coupling of ordinary (forward) and extraordinary (backward) modes and formation of hybrid waveguided modes, which near the crossing point may exhibit slow, stopped or superluminal behavior accompanied by very strong group velocity dispersion. These modes can be used for designing stopped-light nanolasers for nanophotonic applications and dispersion-facilitated signal reshaping in telecom applications.

  19. Nanophotonic filters for digital imaging

    NASA Astrophysics Data System (ADS)

    Walls, Kirsty

    There has been an increasing demand for low cost, portable CMOS image sensors because of increased integration, and new applications in the automotive, mobile communication and medical industries, amongst others. Colour reproduction remains imperfect in conventional digital image sensors, due to the limitations of the dye-based filters. Further improvement is required if the full potential of digital imaging is to be realised. In alternative systems, where accurate colour reproduction is a priority, existing equipment is too bulky for anything but specialist use. In this work both these issues are addressed by exploiting nanophotonic techniques to create enhanced trichromatic filters, and multispectral filters, all of which can be fabricated on-chip, i.e. integrated into a conventional digital image sensor, to create compact, low cost, mass produceable imaging systems with accurate colour reproduction. The trichromatic filters are based on plasmonic structures. They exploit the excitation of surface plasmon resonances in arrays of subwavelength holes in metal films to filter light. The currently-known analytical expressions are inadequate for optimising all relevant parameters of a plasmonic structure. In order to obtain arbitrary filter characteristics, an automated design procedure was developed that integrated a genetic algorithm and 3D finite-difference time-domain tool. The optimisation procedure's efficacy is demonstrated by designing a set of plasmonic filters that replicate the CIE (1931) colour matching functions, which themselves mimic the human eye's daytime colour response.

  20. Alternative materials lead to practical nanophotonic components (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Kinsey, Nathaniel; Ferrera, Marcello; DeVault, Clayton; Kim, Jongbum; Kildishev, Alexander V.; Shalaev, Vladimir M.; Boltasseva, Alexandra

    2015-09-01

    Recently, there has been a flurry of research in the field of alternative plasmonic materials, but for telecommunication applications, CMOS compatible materials titanium nitride and doped zinc oxides are among the most promising materials currently available. TiN is a gold-like ceramic with a permittivity cross-over near 500nm. In addition, TiN can attain ultra-thin, ultra-smooth epitaxial films on substrates such as c-sapphire, MgO, and silicon. Partnering TiN with CMOS compatible silicon nitride enables a fully solid state waveguide which is able to achieve a propagation length greater than 1cm for a ~8μm mode size at 1.55μm. Utilizing doped zinc oxide films as a dynamic material, high performance modulators can also be realized due to the low-loss achieved by the TiN/Si3N4 waveguide. Simply by placing a thin layer of aluminum doped zinc oxide (AZO) on top of the waveguide structure, a modulator with very low insertion loss is achieved. Our recent work has investigated optical tuning of AZO films by the pump-probe method, demonstrating a change in the refractive index of -0.17+0.25i at 1.3μm with an ultrafast response of 1ps. Assuming this change in the refractive index for the AZO film, a modulation of ~0.7dB/μm is possible in the structure with ~0.5dB insertion loss and an operational speed of 1THz. Further optimization of the design is expected to lead to an increased modulation depth without sacrificing insertion loss or speed. Consequently, nanophotonic technologies are reaching a critical point where many applications including telecom, medicine, and quantum science can see practical systems which provide new functionalities.

  1. Deposited amorphous silicon-on-insulator technology for nano-photonic integrated circuits

    NASA Astrophysics Data System (ADS)

    Kumar Selvaraja, Shankar; Schaekers, Marc; Bogaerts, Wim; Van Thourhout, Dries

    2014-02-01

    Low-loss deposited amorphous silicon (α-Si:H) layers for nano-photonic integrated circuit have been prepared using complementary-metal-oxide-semiconductor (CMOS) compatible technology. Waveguide loss as low as 3.45 dB/cm is reported for films deposited at a low temperature (300 °C) using plasma enhanced chemical vapour deposition process. The influence of the deposition parameters such as gas dilution, plasma power and pressure on the quality of the deposited material is thoroughly characterized using Fourier transform infrared spectroscopy (FTIR), spectroscopic ellipsometry, X-ray diffraction and atomic force microscopy. We show that the optical quality of the deposited film can be directly assessed from distinct frequency bands (2090, 2000 and 840 cm-1) using FTIR, without the need for further waveguide loss measurements.

  2. Optically Resonant Nanophotonic Devices for Label-Free Biomolecular Detection

    NASA Astrophysics Data System (ADS)

    Goddard, Julie; Mandal, Sudeep; Erickson, David

    Optical devices, such as surface plasmon resonance chips and waveguide-based Mach-Zehnder interferometers, have long been successfully used as label-free biomolecular sensors. Recently, however, there has been increased interest in developing new approaches to biomolecular detection that can improve on the limit of detection, specificity, and multiplexibility of these early devices and address emerging challenges in pathogen detection, disease diagnosis, and drug discovery. As we describe in this chapter, planar optically resonant nanophotonic devices (such as ring resonators, whispering gallery modes, and photonic crystal cavities) are one method that shows promise in significantly advancing the technology. Here we first provide a short review of these devices focusing on a handful of approaches illustrative of the state of the art. We then frame the major challenge to improving the technology as being the ability to provide simultaneously spatial localization of the electromagnetic energy and biomolecular binding events. We then introduce our “Nanoscale Optofluidic Sensor Arrays” which represents our approach to addressing this challenge. It is demonstrated how these devices serve to enable multiplexed detection while localizing the electromagnetic energy to a volume as small as a cubic wavelength. Challenges involved in the targeted immobilization of biomolecules over such a small area are discussed and our solutions presented. In general, we have tried to write this chapter with the novice in mind, providing details on the fabrication and immobilization methods that we have used and how one might adapt our approach to their designs.

  3. Nanophotonic front electrodes for perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Paetzold, Ulrich Wilhelm; Qiu, Weiming; Finger, Friedhelm; Poortmans, Jef; Cheyns, David

    2015-04-01

    In less than 3 years' time, a vast progress in power conversion efficiencies of organometal halide perovskite solar cells has been achieved by optimization of the device architecture, charge transport layers, and interfaces. A further increase in these efficiencies is expected from an improvement in the optical properties via anti-reflection coatings and nanophotonic light management concepts. In this contribution, we report on the development and implementation of a nanophotonic front electrode for perovskite solar cells. The nanostructures were replicated via the versatile and large-area compatible UV-nanoimprint lithography. The shallow design of the used transparent and conductive nanostructures enabled easy integration into our solution-based baseline process. Prototype methylammonium lead iodide perovskite solar cells show an improvement of 5% in short-circuit current density and an improvement from 9.6% to 9.9% in power conversion efficiency compared to the flat reference device.

  4. Engineering metallic nanostructures for plasmonics and nanophotonics

    PubMed Central

    Lindquist, Nathan C; Nagpal, Prashant; McPeak, Kevin M; Norris, David J; Oh, Sang-Hyun

    2012-01-01

    Metallic nanostructures now play an important role in many applications. In particular, for the emerging fields of plasmonics and nanophotonics, the ability to engineer metals on nanometric scales allows the development of new devices and the study of exciting physics. This review focuses on top-down nanofabrication techniques for engineering metallic nanostructures, along with computational and experimental characterization techniques. A variety of current and emerging applications are also covered. PMID:22790420

  5. Precision tuning of silicon nanophotonic devices through post-fabrication processes

    NASA Astrophysics Data System (ADS)

    Chen, Charlton J.

    In recent years, silicon photonics has begun to transition from research to commercialization. Decades of relentless advances in the field of computing have led to fundamental bottlenecks in the design of computers, especially in interconnect bandwidth density. For IBM, silicon photonics has become a potential technological solution for enabling the future of server systems and cutting-edge supercomputers. For Intel, silicon photonics has become a cost-effective solution for supplying the necessary bandwidth needed by future generations of consumer computing products. While the field of silicon photonics is now advancing at a rapid pace there is still a great deal of research to be done. This thesis investigates ways of improving the performance of fundamental silicon nanophotonic devices through post-fabrication processes. These devices include numerous optical resonator designs as well as slow-light waveguides. Optical resonators are used to confine photons both spatially and temporally. In recent years, there has been much research, both theoretical and experimental, into improving the design of optical resonators. Improving these devices through fabrication processes has generally been less studied. Optical waveguides are used to guide the flow of photons over chip-level distances. Slow-light waveguides have also been studied by many research groups in recent years and can be applied to an increasingly wide-range of applications. The work can be divided into several parts: Chapter 1 is an introduction to the field of silicon photonics as well as an overview of the fabrication, experimental and computational techniques used throughout this work. Chapters 2, 3 and 4 describe our investigations into the precision tuning of nanophotonic devices using laser-assisted thermal oxidation and atomic layer deposition. Chapters 5 and 6 describe our investigations into improving the sidewall roughness of silicon photonic devices using hydrogen annealing and excimer laser

  6. Transfer Printing of Semiconductor Nanowires with Lasing Emission for Controllable Nanophotonic Device Fabrication.

    PubMed

    Guilhabert, Benoit; Hurtado, Antonio; Jevtics, Dimitars; Gao, Qian; Tan, Hark Hoe; Jagadish, Chennupati; Dawson, Martin D

    2016-04-26

    Accurate positioning and organization of indium phosphide (InP) nanowires (NWs) with lasing emission at room temperature is achieved using a nanoscale transfer printing (TP) technique. The NWs retained their lasing emission after their transfer to targeted locations on different receiving substrates (e.g., polymers, silica, and metal surfaces). The NWs were also organized into complex spatial patterns, including 1D and 2D arrays, with a controlled number of elements and dimensions. The developed TP technique enables the fabrication of bespoke nanophotonic systems using NW lasers and other NW devices as building blocks. PMID:26974392

  7. Photonic bandgap structures in planar waveguides.

    PubMed

    Ctyroký, J

    2001-02-01

    If a one-dimensional (1D) or two-dimensional (2D) photonic bandgap (PBG) structure is incorporated into a planar optical waveguide, the refractive-index nonuniformity in the direction perpendicular to the waveguide plane responsible for waveguiding may affect its behavior detrimentally. Such influence is demonstrated in the paper by numerical modeling of a deeply etched first-order waveguide Bragg grating. On the basis of physical considerations, a simple condition for the design of 1D and 2D waveguide PBG structures free of this degradation is formulated; it is, in fact the separability condition for the wave equation. Its positive effect is verified by numerical modeling of a modified waveguide Bragg grating that fulfills the separability condition. PMID:11205991

  8. Hybrid Silicon Nanophotonic Devices: Enhancing Light Emission, Modulation, and Confinement

    NASA Astrophysics Data System (ADS)

    Briggs, Ryan Morrow

    Silicon has become an increasingly important photonic material for communications, information processing, and sensing applications. Silicon is inexpensive compared to compound semiconductors, and it is well suited for confining and guiding light at standard telecommunication wavelengths due to its large refractive index and minimal intrinsic absorption. Furthermore, silicon-based optical devices can be fabricated alongside microelectronics while taking advantage of advanced silicon processing technologies. In order to realize complete chip-based photonic systems, certain critical components must continue to be developed and refined on the silicon platform, including compact light sources, modulators, routers, and sensing elements. However, bulk silicon is not necessarily an ideal material for many active devices because of its meager light emission characteristics, limited refractive index tunability, and fundamental limitations in confining light beyond the diffraction limit. In this thesis, we present three examples of hybrid devices that use different materials to bring additional optical functionality to silicon photonics. First, we analyze high-index-contrast silicon slot waveguides and their integration with light-emitting erbium-doped glass materials. Theoretical and experimental results show significant enhancement of spontaneous emission rates in slot structures. We then demonstrate the integration of vanadium dioxide, a thermochromic phase-change material, with silicon waveguides to form micron-scale absorption modulators. It is shown experimentally that a 2-mum long waveguide-integrated device exhibits broadband modulation of more than 6.5 dB at wavelengths near 1550 nm. Finally, we demonstrate polymer-on-gold dielectric-loaded surface-plasmon waveguides and ring resonators coupled to silicon waveguides with 1.0+/-0.1 dB insertion loss. The plasmonic waveguides are shown to support a single surface mode at telecommunication wavelengths, with strong

  9. Local and nonlocal optically induced transparency effects in graphene-silicon hybrid nanophotonic integrated circuits.

    PubMed

    Yu, Longhai; Zheng, Jiajiu; Xu, Yang; Dai, Daoxin; He, Sailing

    2014-11-25

    Graphene is well-known as a two-dimensional sheet of carbon atoms arrayed in a honeycomb structure. It has some unique and fascinating properties, which are useful for realizing many optoelectronic devices and applications, including transistors, photodetectors, solar cells, and modulators. To enhance light-graphene interactions and take advantage of its properties, a promising approach is to combine a graphene sheet with optical waveguides, such as silicon nanophotonic wires considered in this paper. Here we report local and nonlocal optically induced transparency (OIT) effects in graphene-silicon hybrid nanophotonic integrated circuits. A low-power, continuous-wave laser is used as the pump light, and the power required for producing the OIT effect is as low as ∼0.1 mW. The corresponding power density is several orders lower than that needed for the previously reported saturated absorption effect in graphene, which implies a mechanism involving light absorption by the silicon and photocarrier transport through the silicon-graphene junction. The present OIT effect enables low power, all-optical, broadband control and sensing, modulation and switching locally and nonlocally. PMID:25372937

  10. Scalable Fabrication of Integrated Nanophotonic Circuits on Arrays of Thin Single Crystal Diamond Membrane Windows.

    PubMed

    Piracha, Afaq H; Rath, Patrik; Ganesan, Kumaravelu; Kühn, Stefan; Pernice, Wolfram H P; Prawer, Steven

    2016-05-11

    Diamond has emerged as a promising platform for nanophotonic, optical, and quantum technologies. High-quality, single crystalline substrates of acceptable size are a prerequisite to meet the demanding requirements on low-level impurities and low absorption loss when targeting large photonic circuits. Here, we describe a scalable fabrication method for single crystal diamond membrane windows that achieves three major goals with one fabrication method: providing high quality diamond, as confirmed by Raman spectroscopy; achieving homogeneously thin membranes, enabled by ion implantation; and providing compatibility with established planar fabrication via lithography and vertical etching. On such suspended diamond membranes we demonstrate a suite of photonic components as building blocks for nanophotonic circuits. Monolithic grating couplers are used to efficiently couple light between photonic circuits and optical fibers. In waveguide coupled optical ring resonators, we find loaded quality factors up to 66 000 at a wavelength of 1560 nm, corresponding to propagation loss below 7.2 dB/cm. Our approach holds promise for the scalable implementation of future diamond quantum photonic technologies and all-diamond photonic metrology tools. PMID:27111636

  11. Ideal, constant-loss nanophotonic mode converter using a Lagrangian approach.

    PubMed

    Horth, Alexandre; Cheben, Pavel; Schmid, Jens H; Kashyap, Raman; Quitoriano, Nathaniel J

    2016-03-21

    Coupling light between an optical fiber and a silicon nanophotonic waveguide is a challenge facing the field of silicon photonics to which various mode converters have been proposed. Inverted tapers stand out as a practical solution enabling efficient and broadband mode conversion. Current design approaches often use linearly-shaped tapers and two dimensional approximations; however, these approaches have not been rigorously verified and there is not an overarching design framework to guide the design process. Here, using a Lagrangian formulation, we propose an original, constant-loss framework for designing shape-controlled photonic devices and apply this formalism to derive an ideal constant-loss taper (CLT). We specifically report on the experimental demonstration of a fabrication-tolerant, 15-µm-long CLT coupler, that produces 0.56 dB fiber-chip coupling efficiency, the highest efficiency-per-length ratio ever reported. PMID:27136856

  12. Low-loss, infrared and terahertz nanophotonics using surface phonon polaritons

    NASA Astrophysics Data System (ADS)

    Caldwell, Joshua D.; Lindsay, Lucas; Giannini, Vincenzo; Vurgaftman, Igor; Reinecke, Thomas L.; Maier, Stefan A.; Glembocki, Orest J.

    2015-04-01

    The excitation of surface-phonon-polariton (SPhP) modes in polar dielectric crystals and the associated new developments in the field of SPhPs are reviewed. The emphasis of this work is on providing an understanding of the general phenomenon, including the origin of the Reststrahlen band, the role that optical phonons in polar dielectric lattices play in supporting sub-diffraction-limited modes and how the relatively long optical phonon lifetimes can lead to the low optical losses observed within these materials. Based on this overview, the achievements attained to date and the potential technological advantages of these materials are discussed for localized modes in nanostructures, propagating modes on surfaces and in waveguides and novel metamaterial designs, with the goal of realizing low-loss nanophotonics and metamaterials in the mid-infrared to terahertz spectral ranges.

  13. Grating-assisted coupling to nanophotonic circuits in microcrystalline diamond thin films.

    PubMed

    Rath, Patrik; Khasminskaya, Svetlana; Nebel, Christoph; Wild, Christoph; Pernice, Wolfram Hp

    2013-01-01

    Synthetic diamond films can be prepared on a waferscale by using chemical vapour deposition (CVD) on suitable substrates such as silicon or silicon dioxide. While such films find a wealth of applications in thermal management, in X-ray and terahertz window design, and in gyrotron tubes and microwave transmission lines, their use for nanoscale optical components remains largely unexplored. Here we demonstrate that CVD diamond provides a high-quality template for realizing nanophotonic integrated optical circuits. Using efficient grating coupling devices prepared from partially etched diamond thin films, we investigate millimetre-sized optical circuits and achieve single-mode waveguiding at telecoms wavelengths. Our results pave the way towards broadband optical applications for sensing in harsh environments and visible photonic devices. PMID:23766953

  14. Grating-assisted coupling to nanophotonic circuits in microcrystalline diamond thin films

    PubMed Central

    Rath, Patrik; Khasminskaya, Svetlana; Nebel, Christoph; Wild, Christoph

    2013-01-01

    Summary Synthetic diamond films can be prepared on a waferscale by using chemical vapour deposition (CVD) on suitable substrates such as silicon or silicon dioxide. While such films find a wealth of applications in thermal management, in X-ray and terahertz window design, and in gyrotron tubes and microwave transmission lines, their use for nanoscale optical components remains largely unexplored. Here we demonstrate that CVD diamond provides a high-quality template for realizing nanophotonic integrated optical circuits. Using efficient grating coupling devices prepared from partially etched diamond thin films, we investigate millimetre-sized optical circuits and achieve single-mode waveguiding at telecoms wavelengths. Our results pave the way towards broadband optical applications for sensing in harsh environments and visible photonic devices. PMID:23766953

  15. Bulk plasmon-polaritons in hyperbolic nanorod metamaterial waveguides

    PubMed Central

    Vasilantonakis, Nikolaos; Nasir, Mazhar E; Dickson, Wayne; Wurtz, Gregory A; Zayats, Anatoly V

    2015-01-01

    Hyperbolic metamaterials comprised of an array of plasmonic nanorods provide a unique platform for designing optical sensors and integrating nonlinear and active nanophotonic functionalities. In this work, the waveguiding properties and mode structure of planar anisotropic metamaterial waveguides are characterized experimentally and theoretically. While ordinary modes are the typical guided modes of the highly anisotropic waveguides, extraordinary modes, below the effective plasma frequency, exist in a hyperbolic metamaterial slab in the form of bulk plasmon-polaritons, in analogy to planar-cavity exciton-polaritons in semiconductors. They may have very low or negative group velocity with high effective refractive indices (up to 10) and have an unusual cut-off from the high-frequency side, providing deep-subwavelength (λ0/6–λ0/8 waveguide thickness) single-mode guiding. These properties, dictated by the hyperbolic anisotropy of the metamaterial, may be tuned by altering the geometrical parameters of the nanorod composite. PMID:26693254

  16. Free-standing nanomechanical and nanophotonic structures in single-crystal diamond

    NASA Astrophysics Data System (ADS)

    Burek, Michael John

    Realizing complex three-dimensional structures in a range of material systems is critical to a variety of emerging nanotechnologies. This is particularly true of nanomechanical and nanophotonic systems, both relying on free-standing small-scale components. In the case of nanomechanics, necessary mechanical degrees of freedom require physically isolated structures, such as suspended beams, cantilevers, and membranes. For nanophotonics, elements like waveguides and photonic crystal cavities rely on light confinement provided by total internal reflection or distributed Bragg reflection, both of which require refractive index contrast between the device and surrounding medium (often air). Such suspended nanostructures are typically fabricated in a heterolayer structure, comprising of device (top) and sacrificial (middle) layers supported by a substrate (bottom), using standard surface nanomachining techniques. A selective, isotropic etch is then used to remove the sacrificial layer, resulting in free-standing devices. While high-quality, crystalline, thin film heterolayer structures are readily available for silicon (as silicon-on-insulator (SOI)) or III-V semiconductors (i.e. GaAs/AlGaAs), there remains an extensive list of materials with attractive electro-optic, piezoelectric, quantum optical, and other properties for which high quality single-crystal thin film heterolayer structures are not available. These include complex metal oxides like lithium niobate (LiNbO3), silicon-based compounds such as silicon carbide (SiC), III-V nitrides including gallium nitride (GaN), and inert single-crystals such as diamond. Diamond is especially attractive for a variety of nanoscale technologies due to its exceptional physical and chemical properties, including high mechanical hardness, stiffness, and thermal conductivity. Optically, it is transparent over a wide wavelength range (from 220 nm to the far infrared), has a high refractive index (n ~ 2.4), and is host to a vast

  17. Superluminal and stopped light due to mode coupling in confined hyperbolic metamaterial waveguides.

    PubMed

    Neira, Andres D; Wurtz, Gregory A; Zayats, Anatoly V

    2015-01-01

    Anisotropic metamaterials with hyperbolic dispersion can be used to design waveguides with unusual properties. We show that, in contrast to planar waveguides, geometric confinement leads to coupling of ordinary (forward) and extraordinary (backward) modes and formation of hybrid waveguided modes, which near the crossing point may exhibit slow, stopped or superluminal behavior accompanied by very strong group velocity dispersion. These modes can be used for designing stopped-light nanolasers for nanophotonic applications and dispersion-facilitated signal reshaping in telecom applications. PMID:26643503

  18. Nano-photonics: past and present

    NASA Astrophysics Data System (ADS)

    Szu, Harold

    2010-04-01

    Nanotech is at the scale of 10-9 meters, located at the mesocopic transition phase, which can take both classical mechanics (CM) and quantum mechanics (QM) descriptions bridging ten orders of magnitude phenomena, between the microscopic world of a single atom at 10-10 meters with the macroscopic world at meters. However, QM principles aid the understanding of any unusual property at the nanotech level. The other major difference between nano-photonics and other forms of optics is that the nano-scale is not very 'hands on'. For the most part, we will not be able to see the components with our naked eyes, but will be required to use some nanotech imaging tools, as follows:

  19. LOADED WAVEGUIDES

    DOEpatents

    Mullett, L.B.; Loach, B.G.; Adams, G.L.

    1958-06-24

    >Loaded waveguides are described for the propagation of electromagnetic waves with reduced phase velocities. A rectangular waveguide is dimensioned so as to cut-off the simple H/sub 01/ mode at the operating frequency. The waveguide is capacitance loaded, so as to reduce the phase velocity of the transmitted wave, by connecting an electrical conductor between directly opposite points in the major median plane on the narrower pair of waveguide walls. This conductor may take a corrugated shape or be an aperature member, the important factor being that the electrical length of the conductor is greater than one-half wavelength at the operating frequency. Prepared for the Second U.N. International ConferThe importance of nuclear standards is duscussed. A brief review of the international callaboration in this field is given. The proposal is made to let the International Organization for Standardization (ISO) coordinate the efforts from other groups. (W.D.M.)

  20. Micro- and nanophotonic structures in the visible and near infrared spectral region for optical devices

    NASA Astrophysics Data System (ADS)

    Pham, Van Hoi; Bui, Huy; Van Nguyen, Thuy; Nguyen, The Anh; Son Pham, Thanh; Cam Hoang, Thi Hong; Ngo, Quang Minh

    2013-06-01

    In this paper we present some research results on the micro and nano-photonic structures in the visible and near infrared spectral region for optical devices that have been done within the framework of Nanoscience and Nanotechnology Program of Institute of Materials Science. In the first part, we report the design and fabrication of 1D photonic structure based on porous silicon layers fabricated by electrochemical etching method and some of their potential applications such as optical filters, microcavity and optical sensors for distinguishing the content of bio-gasoline. In addition, we demonstrate some results on preparation of the 2D and 3D nanophotonic structures based on silica opal layers prepared by sol-gel and self-assembled methods. In the second part, we demonstrate the results of lasing emissions of erbium ions in the visible and near infrared zone from microcavity. The observation of emission of single-mode green light at the wavelength of 537 nm from erbium ions in the microcavity is interesting for the study of atom-photon interaction phenomenon. In the last part, we will show some new results of design and fabrication of nanocomposite based on nanoscale TiO2 and/or ZnO and nanoparticles of semiconductors and metals, which are oriented to the fabrication of energy conversion and photo-reactor devices. Invited talk at the 6th International Workshop on Advanced Materials Science and Nanotechnology IWAMSN2012, 30 October-2 November, 2012, Ha Long, Vietnam.

  1. A nanophotonic atom trap toward collective atom-light interactions and the design of a novel protection layer for superconducting circuits toward a hybrid quantum system

    NASA Astrophysics Data System (ADS)

    Lee, J.; Meng, Y.; Park, D. H.; Dagenais, M.; Rolston, S. L.

    2014-05-01

    A centimeter long silicon nitride nanophotonic waveguide with inverse-tapered ends has been developed to address and trap many cold neutral atoms (87Rb) for studying collective atom-light interactions and a hybrid quantum system. Two-color evanescent trapping fields (750 nm and 1064 nm) of guided modes (TE0) can confine cold neutral atoms above the waveguide, and its inverse-tapered waveguide-end has been used for higher input coupling. For a hybrid quantum system which couples trapped cold neutral atoms to superconducting (SC) circuits through magnetic dipole coupling, we consider a novel SC protection layer because SC circuits are vulnerable to the scattered light from trapping fields. Therefore, we design several types of dielectric and lossy multi-wavelength Bragg layers to protect SC circuits from NIR scattered optical photons and from a broadband MIR blackbody radiation of the nanophotonic device, considering the maximal back-transmission of the SC circuits' electro-magnetic fields through the layer and the heat transfer to SC circuits through the protection layer from absorbed scattered photons. This work is supported by ARO MURI award W911NF0910406.

  2. Rigorous calculation of nonlinear parameters in graphene-comprising waveguides

    NASA Astrophysics Data System (ADS)

    Chatzidimitriou, Dimitrios; Pitilakis, Alexandros; Kriezis, Emmanouil E.

    2015-07-01

    We describe a rigorous formalism for the calculation of the nonlinear parameter of arbitrary three-dimensional nanophotonic graphene-comprising waveguides. Graphene is naturally implemented as a zero-thickness conductive sheet, modeled solely by complex linear and nonlinear surface conductivity tensors, whose values are extracted from theoretical models. This representation is compared to the more commonly employed equivalent bulk-medium representation and is found superior. We numerically calculate the nonlinear parameters of several optical waveguide archetypes overlaid with infinite graphene monolayers, including silicon-wire and plasmonic metal-slot and metal-stripe configurations. The metal-slot configuration offers the most promising performance for Kerr-type nonlinear applications. Finally, we apply the same formalism to probe the potential of graphene nanoribbon waveguide nonlinearity in the terahertz band.

  3. Photonic crystal slab waveguides in moderate index contrast media: Generalized transverse Bragg waveguides

    NASA Astrophysics Data System (ADS)

    Burckel, David Bruce

    wavelength to period ratio. These optical results indicated a need for a deeper understanding of the confinement/guiding mechanisms in such waveguide structures. A simplification of the full 2-D problem to a more tractable "tilted 1-D" geometry led to the proposal of a new waveguide geometry, Generalized Transverse Bragg Waveguides (GTBW), as well as a new propagation mode characterized by spatial variation in both the transverse direction as well as the direction of propagation. GTBW demonstrate many of the same dispersion tunability traits exhibited in complete bandgap photonic crystal waveguides, under more modest fabrication demands, and moreover provide much insight into photonic crystal waveguide modes of all types. Generalized Transverse Bragg Waveguides are presented in terms of the standard physical properties associated with waveguides, including the dispersion relation, expressions for the spatial field profile, and the concepts of phase and group velocity. In addition, the proposal of at least one obvious application, semiconductor optical amplifiers, is offered.

  4. Free-standing nanomechanical and nanophotonic structures in single-crystal diamond

    NASA Astrophysics Data System (ADS)

    Burek, Michael John

    Realizing complex three-dimensional structures in a range of material systems is critical to a variety of emerging nanotechnologies. This is particularly true of nanomechanical and nanophotonic systems, both relying on free-standing small-scale components. In the case of nanomechanics, necessary mechanical degrees of freedom require physically isolated structures, such as suspended beams, cantilevers, and membranes. For nanophotonics, elements like waveguides and photonic crystal cavities rely on light confinement provided by total internal reflection or distributed Bragg reflection, both of which require refractive index contrast between the device and surrounding medium (often air). Such suspended nanostructures are typically fabricated in a heterolayer structure, comprising of device (top) and sacrificial (middle) layers supported by a substrate (bottom), using standard surface nanomachining techniques. A selective, isotropic etch is then used to remove the sacrificial layer, resulting in free-standing devices. While high-quality, crystalline, thin film heterolayer structures are readily available for silicon (as silicon-on-insulator (SOI)) or III-V semiconductors (i.e. GaAs/AlGaAs), there remains an extensive list of materials with attractive electro-optic, piezoelectric, quantum optical, and other properties for which high quality single-crystal thin film heterolayer structures are not available. These include complex metal oxides like lithium niobate (LiNbO3), silicon-based compounds such as silicon carbide (SiC), III-V nitrides including gallium nitride (GaN), and inert single-crystals such as diamond. Diamond is especially attractive for a variety of nanoscale technologies due to its exceptional physical and chemical properties, including high mechanical hardness, stiffness, and thermal conductivity. Optically, it is transparent over a wide wavelength range (from 220 nm to the far infrared), has a high refractive index (n ~ 2.4), and is host to a vast

  5. High-density information transmission and waveguide integration with low crosstalk and propagation loss

    NASA Astrophysics Data System (ADS)

    Guo, Jianjun; Su, Weiheng; Liang, Yao; Zhang, Fengchun; Huang, Xuguang

    2016-03-01

    Photonic waveguides are fundamental components for photonic integrated circuits (PICs). Although a wide spectrum of nanophotonic structures, i.e., silicon waveguides and plasmonic waveguides, have been exploited for optical interconnects, these structures either can only support one polarization or they are not able to be integrated within a 1-μm scale due to strong crosstalk. The hurdle for high-density information transmission and waveguide integration is mainly the lack of a compact waveguide structure that can support different polarization states with low crosstalk. We propose and numerically demonstrate an ultralong-range waveguide that supports both transverse electric- and transverse magnetic-like polarizations. The propagation length of this waveguide is several decimeters with working bandwidths as great as 160 nm for both polarizations. In addition, this design is very compact with a small center-to-center distance of 1 μm between two adjacent waveguides while the isolation is as high as more than 69.3 dB. This waveguide is also able to guide light efficiently through a 90 deg bend with a 1-μm bending radius for both polarizations. Our work opens new perspectives for high-density waveguide integration in PICs, which would benefit various applications with limited physical space, such as on-chip information processing and sensing.

  6. Nanophotonic materials and devices: driving the big data engine

    NASA Astrophysics Data System (ADS)

    Norwood, R. A.

    2014-09-01

    Photonics has been critical to the growth of the Internet that now carries a vast array of information over optical fiber. The future growth of information technology, including the transmission and processing of vast amounts of data, will require a new class of photonic devices that readily integrate directly with semiconductor circuits and processors. Nanophotonics will play a key role in this development, providing both designer optical materials and radically smaller and lower power consumption devices. We present our developments in engineered nanophotonic polymer materials and electro-optic polymer/silicon nanowire devices in the context of this burgeoning field.

  7. Diamond electro-optomechanical resonators integrated in nanophotonic circuits

    SciTech Connect

    Rath, P.; Ummethala, S.; Pernice, W. H. P.; Diewald, S.; Lewes-Malandrakis, G.; Brink, D.; Heidrich, N.; Nebel, C.

    2014-12-22

    Diamond integrated photonic devices are promising candidates for emerging applications in nanophotonics and quantum optics. Here, we demonstrate active modulation of diamond nanophotonic circuits by exploiting mechanical degrees of freedom in free-standing diamond electro-optomechanical resonators. We obtain high quality factors up to 9600, allowing us to read out the driven nanomechanical response with integrated optical interferometers with high sensitivity. We are able to excite higher order mechanical modes up to 115 MHz and observe the nanomechanical response also under ambient conditions.

  8. Nanophotonic quantum computer based on atomic quantum transistor

    NASA Astrophysics Data System (ADS)

    Andrianov, S. N.; Moiseev, S. A.

    2015-10-01

    We propose a scheme of a quantum computer based on nanophotonic elements: two buses in the form of nanowaveguide resonators, two nanosized units of multiatom multiqubit quantum memory and a set of nanoprocessors in the form of photonic quantum transistors, each containing a pair of nanowaveguide ring resonators coupled via a quantum dot. The operation modes of nanoprocessor photonic quantum transistors are theoretically studied and the execution of main logical operations by means of them is demonstrated. We also discuss the prospects of the proposed nanophotonic quantum computer for operating in high-speed optical fibre networks.

  9. Nonlinear waveguides

    NASA Astrophysics Data System (ADS)

    SjöBerg, Daniel

    2003-04-01

    We investigate the propagation of electromagnetic waves in a cylindrical waveguide with an arbitrary cross section filled with a nonlinear material. The electromagnetic field is expanded in the usual eigenmodes of the waveguide, and the coupling between the modes is quantified. We derive the wave equations governing each mode with special emphasis on the situation with a dominant TE mode. The result is a strictly hyperbolic system of nonlinear partial differential equations for the dominating mode, whereas the minor modes satisfy hyperbolic systems of linear, nonstationary, and partial differential equations. A growth estimate is given for the minor modes.

  10. Tailorable stimulated Brillouin scattering in nanoscale silicon waveguides

    PubMed Central

    Shin, Heedeuk; Qiu, Wenjun; Jarecki, Robert; Cox, Jonathan A.; Olsson, Roy H.; Starbuck, Andrew; Wang, Zheng; Rakich, Peter T.

    2013-01-01

    Nanoscale modal confinement is known to radically enhance the effect of intrinsic Kerr and Raman nonlinearities within nanophotonic silicon waveguides. By contrast, stimulated Brillouin-scattering nonlinearities, which involve coherent coupling between guided photon and phonon modes, are stifled in conventional nanophotonics, preventing the realization of a host of Brillouin-based signal-processing technologies in silicon. Here we demonstrate stimulated Brillouin scattering in silicon waveguides, for the first time, through a new class of hybrid photonic–phononic waveguides. Tailorable travelling-wave forward-stimulated Brillouin scattering is realized—with over 1,000 times larger nonlinearity than reported in previous systems—yielding strong Brillouin coupling to phonons from 1 to 18 GHz. Experiments show that radiation pressures, produced by subwavelength modal confinement, yield enhancement of Brillouin nonlinearity beyond those of material nonlinearity alone. In addition, such enhanced and wideband coherent phonon emission paves the way towards the hybridization of silicon photonics, microelectromechanical systems and CMOS signal-processing technologies on chip. PMID:23739586

  11. Waveguide model

    NASA Technical Reports Server (NTRS)

    1981-01-01

    A model is presented which quantifies the electromagnetic modes (field configurations) in the immediate vicinity of the rectenna element. Specifically, the waveguide model characterizes the electromagnetic modes generated by planar waves normal to the array. The model applies only to incidence normal to the array.

  12. Laser fabrication of crystalline silicon nanoresonators from an amorphous film for low-loss all-dielectric nanophotonics.

    PubMed

    Dmitriev, P A; Makarov, S V; Milichko, V A; Mukhin, I S; Gudovskikh, A S; Sitnikova, A A; Samusev, A K; Krasnok, A E; Belov, P A

    2016-03-01

    The concept of high refractive index subwavelength dielectric nanoresonators, supporting electric and magnetic optical resonance, is a promising platform for waveguiding, sensing, and nonlinear nanophotonic devices. However, high concentration of defects in the nanoresonators diminishes their resonant properties, which are crucially dependent on their internal losses. Therefore, it seems to be inevitable to use initially crystalline materials for fabrication of the nanoresonators. Here, we show that the fabrication of crystalline (low-loss) resonant silicon nanoparticles by femtosecond laser ablation of amorphous (high-loss) silicon thin films is possible. We apply two conceptually different approaches: recently proposed laser-induced transfer and a novel laser writing technique for large-scale fabrication of the crystalline nanoparticles. The crystallinity of the fabricated nanoparticles is proven by Raman spectroscopy and electron transmission microscopy, whereas optical resonant properties of the nanoparticles are studied using dark-field optical spectroscopy and full-wave electromagnetic simulations. PMID:26864805

  13. Laser fabrication of crystalline silicon nanoresonators from an amorphous film for low-loss all-dielectric nanophotonics

    NASA Astrophysics Data System (ADS)

    Dmitriev, P. A.; Makarov, S. V.; Milichko, V. A.; Mukhin, I. S.; Gudovskikh, A. S.; Sitnikova, A. A.; Samusev, A. K.; Krasnok, A. E.; Belov, P. A.

    2016-02-01

    The concept of high refractive index subwavelength dielectric nanoresonators, supporting electric and magnetic optical resonance, is a promising platform for waveguiding, sensing, and nonlinear nanophotonic devices. However, high concentration of defects in the nanoresonators diminishes their resonant properties, which are crucially dependent on their internal losses. Therefore, it seems to be inevitable to use initially crystalline materials for fabrication of the nanoresonators. Here, we show that the fabrication of crystalline (low-loss) resonant silicon nanoparticles by femtosecond laser ablation of amorphous (high-loss) silicon thin films is possible. We apply two conceptually different approaches: recently proposed laser-induced transfer and a novel laser writing technique for large-scale fabrication of the crystalline nanoparticles. The crystallinity of the fabricated nanoparticles is proven by Raman spectroscopy and electron transmission microscopy, whereas optical resonant properties of the nanoparticles are studied using dark-field optical spectroscopy and full-wave electromagnetic simulations.

  14. High-speed and high-efficiency travelling wave single-photon detectors embedded in nanophotonic circuits

    PubMed Central

    Pernice, W.H.P.; Schuck, C.; Minaeva, O.; Li, M.; Goltsman, G.N.; Sergienko, A.V.; Tang, H.X.

    2012-01-01

    Ultrafast, high-efficiency single-photon detectors are among the most sought-after elements in modern quantum optics and quantum communication. However, imperfect modal matching and finite photon absorption rates have usually limited their maximum attainable detection efficiency. Here we demonstrate superconducting nanowire detectors atop nanophotonic waveguides, which enable a drastic increase of the absorption length for incoming photons. This allows us to achieve high on-chip single-photon detection efficiency up to 91% at telecom wavelengths, repeatable across several fabricated chips. We also observe remarkably low dark count rates without significant compromise of the on-chip detection efficiency. The detectors are fully embedded in scalable silicon photonic circuits and provide ultrashort timing jitter of 18 ps. Exploiting this high temporal resolution, we demonstrate ballistic photon transport in silicon ring resonators. Our direct implementation of a high-performance single-photon detector on chip overcomes a major barrier in integrated quantum photonics. PMID:23271658

  15. Integrating nanophotonic concepts and topics into optics curricula

    NASA Astrophysics Data System (ADS)

    Sonek, Gregory J.

    2007-06-01

    Nanophotonics has emerged as a new and important field of study, not only in research, but also in undergraduate optics and photonics education and training. Beyond the study of classical and quantum optics, it is important for students to learn about how the flow of light can be manipulated on a nanoscale level, and used in applications such as telecommunications, imaging, and medicine. This paper reports on our work to integrate basic nanophotonic concepts and topics into existing optics and optical electronics courses, as well as independent study projects, at the undergraduate level. Through classroom lectures, topical readings, computer modeling exercises, and laboratory experiments, students are introduced to nanophotonic concepts subsequent to a study of physical and geometrical optics. A compare and contrast methodology is employed to help students identify similarities and differences that exist in the optical behavior of bulk and nanostructured media. Training is further developed through engineering design and simulation exercises that use advanced, vector-diffraction-based, modeling software for simulating the performance of various materials and structures. To date, the addition of a nanophotonics component to the optics curriculum has proven successful, been enthusiastically received by students, and should serve as a basis for further course development efforts that emphasize the combined capabilities of nanotechnology and photonics.

  16. Observation of an optical event horizon in a silicon-on-insulator photonic wire waveguide.

    PubMed

    Ciret, Charles; Leo, François; Kuyken, Bart; Roelkens, Gunther; Gorza, Simon-Pierre

    2016-01-11

    We report on the first experimental observation of an optical analogue of an event horizon in integrated nanophotonic waveguides, through the reflection of a continuous wave on an intense pulse. The experiment is performed in a dispersion-engineered silicon-on-insulator waveguide. In this medium, solitons do not suffer from Raman induced self-frequency shift as in silica fibers, a feature that is interesting for potential applications of optical event horizons. As shown by simulations, this also allows the observation of multiple reflections at the same time on fundamental solitons ejected by soliton fission. PMID:26832243

  17. Characteristics of surface plasmon polaritons in a dielectrically chiral-metal-chiral waveguiding structure.

    PubMed

    Zhang, Qiang; Li, Junqing

    2016-07-15

    We demonstrate theoretically the characteristics of surface plasmon polaritons (SPPs) with an asymmetric chiral-metal-chiral (CMC) waveguide structure, under realistic frequency dependencies of the permittivity and chirality parameters. Generalized dispersion relations are derived which can be applied to the nonchiral SPPs. We find that the existence of cutoffs in different modes for the CMC structures may facilitate the design of mode-selective surface plasmon waveguides. CMC-SPPs also exhibit an interesting dependence of the polarization on the chiral strength. These novel characteristics of CMC-SPPs provide new possibilities for the design of more compact nanophotonic devices. PMID:27420505

  18. Waveguide Transition for Submillimeter-Wave MMICs

    NASA Technical Reports Server (NTRS)

    Leong, Kevin M.; Deal, William R.; Radisic, Vesna; Mei, Xiaobing; Uyeda, Jansen; Lai, Richard; Fung, King Man; Gaier, Todd C.

    2009-01-01

    An integrated waveguide-to-MMIC (monolithic microwave integrated circuit) chip operating in the 300-GHz range is designed to operate well on high-permittivity semiconductor substrates typical for an MMIC amplifier, and allows a wider MMIC substrate to be used, enabling integration with larger MMICs (power amplifiers). The waveguide-to- CBCPW (conductor-backed coplanar waveguide) transition topology is based on an integrated dipole placed in the E-plane of the waveguide module. It demonstrates low loss and good impedance matching. Measurement and simulation demonstrate that the loss of the transition and waveguide loss is less than 1-dB over a 340-to-380-GHz bandwidth. A transition is inserted along the propagation direction of the waveguide. This transition uses a planar dipole aligned with the maximum E-field of the TE10 waveguide mode as an inter face between the waveguide and the MMIC. Mode conversion between the coplanar striplines (CPS) that feed the dipole and the CBCPW transmission line is accomplished using a simple air-bridge structure. The bottom side ground plane is truncated at the same reference as the top-side ground plane, leaving the end of the MMIC suspended in air.

  19. Nanophotonic technologies for innovative all- optical signal processor using photonic crystals and quantum dots

    SciTech Connect

    Sugimoto, Y.; Ikeda, N.; Ozaki, N.; Watanabe, Y.; Asakawa, K.; Ohkouchi, S.; Nakamura, S.

    2009-06-29

    GaAs-based two-dimensional photonic crystal (2DPC) slab waveguides (WGs) and InAs quantum dots (QDs) were developed for key photonic device structures in the future. An ultrasmall and ultrafast symmetrical Mach-Zehnder (SMZ)-type all-optical switch (PC-SMZ) and an optical flip-flop device (PC-FF) have been developed based on these nanophotonic structures for an ultrafast digital photonic network. To realize these devices, two important techniques were developed. One is a new simulation method, i.e., topology optimization method of 2DPC WGs with wide/flat bandwidth, high transmittance and low reflectivity. Another is a new selective-area-growth method, i.e., metal-mask molecular beam epitaxy method of InAs QDs. This technique contributes to achieving high-density and highly uniform InAs QDs in a desired area such as an optical nonlinearity-induced phase shift arm in the PC-FF. Furthermore, as a unique site-controlled QD technique, a nano-jet probe method is also developed for positioning QDs at the centre of the optical nonlinearity-induced phase shift arm.

  20. Resonant Nanophotonic Spectrum Splitting for Ultrathin Multijunction Solar Cells

    PubMed Central

    2015-01-01

    We present an approach to spectrum splitting for photovoltaics that utilizes the resonant optical properties of nanostructures for simultaneous voltage enhancement and spatial separation of different colors of light. Using metal–insulator–metal resonators commonly used in broadband metamaterial absorbers we show theoretically that output voltages can be enhanced significantly compared to single-junction devices. However, the approach is general and works for any type of resonator with a large absorption cross section. Due to its resonant nature, the spectrum splitting occurs within only a fraction of the wavelength, as opposed to traditional spectrum splitting methods, where many wavelengths are required. Combining nanophotonic spectrum splitting with other nanophotonic approaches to voltage enhancements, such as angle restriction and concentration, may lead to highly efficient but deeply subwavelength photovoltaic devices. PMID:26322319

  1. Controlling Quantum Transport with a Programmable Nanophotonic Processor

    NASA Astrophysics Data System (ADS)

    Harris, Nicholas; Steinbrecher, Gregory; Mower, Jacob; Lihini, Yoav; Prabhu, Mihika; Baehr-Jones, Tom; Hochberg, Michael; Lloyd, Seth; Englund, Dirk

    Recent experimental and theoretical work has revealed emergent, counter-intuitive quantum transport effects in a range of physical medial including solid-state and biological systems. Photonic integrated circuits are promising platforms for studying such effects. A central goal in for photonic quantum transport simulators has been the ability to rapidly control all parameters of the transport problem. Here, we present a large-scale programmable nanophotonic processor composed of 56 Mach-Zehnder interferometers that enables control over modal couplings and differential phases between modes--enabling observations of Anderson localization, environment-assisted quantum transport, ballistic transport, and a number of intermediate quantum transport regimes. Rapid programmability enables tens of thousands of realizations of disordered and noisy systems. In addition, low loss makes this nanophotonic processor a promising platform for many-boson quantum simulation experiments.

  2. Fundamental limit of nanophotonic light trapping in solar cells

    PubMed Central

    Yu, Zongfu; Raman, Aaswath; Fan, Shanhui

    2010-01-01

    Establishing the fundamental limit of nanophotonic light-trapping schemes is of paramount importance and is becoming increasingly urgent for current solar cell research. The standard theory of light trapping demonstrated that absorption enhancement in a medium cannot exceed a factor of 4n2/ sin2θ, where n is the refractive index of the active layer, and θ is the angle of the emission cone in the medium surrounding the cell. This theory, however, is not applicable in the nanophotonic regime. Here we develop a statistical temporal coupled-mode theory of light trapping based on a rigorous electromagnetic approach. Our theory reveals that the conventional limit can be substantially surpassed when optical modes exhibit deep-subwavelength-scale field confinement, opening new avenues for highly efficient next-generation solar cells. PMID:20876131

  3. Silicone polymer waveguide bridge for Si to glass optical fibers

    NASA Astrophysics Data System (ADS)

    Kruse, Kevin L.; Riegel, Nicholas J.; Middlebrook, Christopher T.

    2015-03-01

    Multimode step index polymer waveguides achieve high-speed, (<10 Gb/s) low bit-error-rates for onboard and embedded circuit applications. Using several multimode waveguides in parallel enables overall capacity to reach beyond 100 Gb/s, but the intrinsic bandwidth limitations due to intermodal dispersion limit the data transmission rates within multimode waveguides. Single mode waveguides, where intermodal dispersion is not present, have the potential to further improve data transmission rates. Single mode waveguide size is significantly less than their multimode counterparts allowing for greater density of channels leading to higher bandwidth capacity per layer. Challenges in implementation of embedded single mode waveguides within printed circuit boards involves mass production fabrication techniques to create precision dimensional waveguides, precision alignment tolerances necessary to launch a mode, and effective coupling between adjoining waveguides and devices. An emerging need in which single mode waveguides can be utilized is providing low loss fan out techniques and coupling between on-chip transceiver devices containing Si waveguide structures to traditional single mode optical fiber. A polymer waveguide bridge for Si to glass optical fibers can be implemented using silicone polymers at 1310 nm. Fabricated and measured prototype devices with modeling and simulation analysis are reported for a 12 member 1-D tapered PWG. Recommendations and designs are generated with performance factors such as numerical aperture and alignment tolerances.

  4. EDITORIAL: Selected papers from Optical MEMS and Nanophotonics 2007

    NASA Astrophysics Data System (ADS)

    Jagadish, Chennupati; Sasaki, Minoru; Yeh, J. Andrew

    2008-04-01

    This special issue on optical MEMS and nanophotonics features papers presented at the International Optical MEMS and Nanophotonics Conference held in Hualien, Taiwan, 12-16 August 2007, chaired by J Andrew Yeh. Minoru Sasaki and Chennupati Jagadish served as Program Co-Chairs of optical MEMS and nanophotonics, respectively. The conference featured a broad range of technologies in both topical areas with participation from academia, government laboratories and industry. The conference covered the latest technical developments in the fields of optical micro-electro-mechanical systems (MEMS) and integrated micro-optics. Integration and miniaturization of photonic and optical MEMS components and systems towards micro- and nanoscale for various applications were discussed. The conference also featured nanophotonics which is expected to provide high-speed, high-bandwidth and compact photonic devices. The interaction of light with nanoscale structures including generation, manipulation and detection was discussed at the conference and covered photonic crystals, quantum dots, nanowires and plasmonics. Integrated systems combining nanostructures and optical MEMS were discussed. We would like to thank Hans Zappe for suggesting the special issue and providing timely advice on various related matters and also to Julia Dickinson and Claire Bedrock for their professionalism and help. Carol Chan of the National Tsing Hua University is gratefully acknowledged for her help with the conference. Administration by staff from the Instrument Technology Research Center is highly appreciated. The assistance of the students of the National Dong Hua University and the National Tsing Hua University made the conference most enjoyable. The next conference will be held in Freiburg, Germany, 11-14 August 2008 and will be chaired by Hans Zappe.

  5. Nanophotonics technology watch at the European Patent Office

    NASA Astrophysics Data System (ADS)

    Verbandt, Y.; Kallinger, C.; Scheu, M.; Förster, W.

    2008-04-01

    Since its inception, the nanotechnology working group at the European Patent Office has been constantly updating the content of its different nanotechnology classification tags which it applies to patent publications worldwide. The main technologies in the nanophotonics area are photonic crystals, surface plasmon devices, semiconductor superlattices and scanning near-field microscopy. Some patent statistics are shown and a brief summary of legal issues is given.

  6. Silicon Nanophotonics for Many-Core On-Chip Networks

    NASA Astrophysics Data System (ADS)

    Mohamed, Moustafa

    Number of cores in many-core architectures are scaling to unprecedented levels requiring ever increasing communication capacity. Traditionally, architects follow the path of higher throughput at the expense of latency. This trend has evolved into being problematic for performance in many-core architectures. Moreover, the trends of power consumption is increasing with system scaling mandating nontraditional solutions. Nanophotonics can address these problems, offering benefits in the three frontiers of many-core processor design: Latency, bandwidth, and power. Nanophotonics leverage circuit-switching flow control allowing low latency; in addition, the power consumption of optical links is significantly lower compared to their electrical counterparts at intermediate and long links. Finally, through wave division multiplexing, we can keep the high bandwidth trends without sacrificing the throughput. This thesis focuses on realizing nanophotonics for communication in many-core architectures at different design levels considering reliability challenges that our fabrication and measurements reveal. First, we study how to design on-chip networks for low latency, low power, and high bandwidth by exploiting the full potential of nanophotonics. The design process considers device level limitations and capabilities on one hand, and system level demands in terms of power and performance on the other hand. The design involves the choice of devices, designing the optical link, the topology, the arbitration technique, and the routing mechanism. Next, we address the problem of reliability in on-chip networks. Reliability not only degrades performance but can block communication. Hence, we propose a reliability-aware design flow and present a reliability management technique based on this flow to address reliability in the system. In the proposed flow reliability is modeled and analyzed for at the device, architecture, and system level. Our reliability management technique is

  7. Silicon integrated nanophotonics for on-chip interconnects

    NASA Astrophysics Data System (ADS)

    Vlasov, Yurii

    2008-03-01

    Current trend in microelectronics industry is to increase the parallelism in computation by multi-threading, by building large scale multi-chip systems and, more recently, by increasing the number of cores on a single chip. With such increase of parallelization the interconnect bandwidth between the racks, chips or different cores is becoming a limiting factor for the design of high performance computer systems. The on-chip ultrahigh-bandwidth silicon-based photonic network might provide an attractive solution to this bandwidth bottleneck. We will review recent results on silicon nanophotonic circuits based on photonic wires and photonic crystals. Strong light confinement at the diffraction limit enables dramatic scaling of the device area and allows unprecedented control over optical signals. Silicon nanophotonic devices have immense capacity for low-loss, high-bandwidth data processing that might enable the design of ultra-compact on-chip optical networks. In particular we will show recent results on design and characterization of various ultra-compact (<0.03mm2) silicon nanophotonic circuits as optical delay lines, electro-optic modulators, broadband optical switches, wavelength filters, etc.

  8. Novel Trapping and Scattering of Light in Resonant Nanophotonic Structures

    NASA Astrophysics Data System (ADS)

    Hsu, Chia Wei

    Nanophotonic structures provide unique ways to control light and alter its behaviors in ways not possible in macroscopic structures. In this thesis, we explore novel behaviors of light created by nanophotonic structures, with a common theme on resonance effects. The first half of the thesis focuses on a peculiar type of electromagnetic resonance, where the resonance lifetime diverges to infinity. These states, called bound states in the continuum, remain localized in space even though their frequency lie within a continuum of extended modes. We find such states in photonic crystal slabs and the surface of bulk photonic crystals. We show the conditions necessary for them to exist, and provide the first experimental observation of these unusual states. We also show that these states have a topological nature, with conserved and quantized topological charges that govern their generation, evolution, and annihilation. The second half of the thesis concerns light scattering from resonant nanophotonic structures, where resonances can enhance or suppress scattering at particular wavelengths and angles. We show that multiple resonances in one nanostructure and in the same multipole channel generally lead to a scattering dark state where the structure becomes transparent. Based on the coherent interference from multiple scatterers, we show there are geometries that can achieve a sharp structural color where the hue, saturation, and brightness are all viewing-angle independent. We also invent a new type of transparent display based on wavelength-selective light scattering from nanostructures.

  9. VTT's micron-scale silicon rib+strip waveguide platform

    NASA Astrophysics Data System (ADS)

    Aalto, Timo; Harjanne, Mikko; Cherchi, Matteo

    2016-05-01

    Silicon rib waveguides enable single-mode (SM) operation even with the combination of multi-micron core dimensions and high refractive index contrast. In such large waveguides the optical mode field is almost completely confined inside the Si core, which leads to small propagation losses and small polarization dependency. The unique SM condition of the rib waveguide also enables the use of an ultra-wide wavelength range, for example from 1.2 to <1.7 μm, without sacrificing either SM operation or low propagation loss. This makes micron-scale Si waveguides particularly well-suited for spectroscopy and extensive wavelength division multiplexing. However, rib waveguides require large bending radii, which lead to large circuit sizes. There are two solutions for this. So-called Euler bends in Si strip waveguides enable low-loss bends down to 1 μm bending radius with less than 0.1 dB/90° loss for both polarizations. Another alternative is a total-internal reflection mirror that can have loss as low as 0.1 dB for both polarizations in either strip or rib waveguides. The excitation of higher order modes in large strip waveguides is avoided by using adiabatic rib-strip converters and low-loss components. With rib and strip waveguides it is possible to reach a unique combination of low loss, extremely small footprint, small polarization dependency, ultra-wide bandwidth and tolerance to high optical powers.

  10. Nano-photonic Light Trapping In Thin Film Solar Cells

    NASA Astrophysics Data System (ADS)

    Callahan, Dennis M., Jr.

    Over the last several decades there have been significant advances in the study and understanding of light behavior in nanoscale geometries. Entire fields such as those based on photonic crystals, plasmonics and metamaterials have been developed, accelerating the growth of knowledge related to nanoscale light manipulation. Coupled with recent interest in cheap, reliable renewable energy, a new field has blossomed, that of nanophotonic solar cells. In this thesis, we examine important properties of thin-film solar cells from a nanophotonics perspective. We identify key differences between nanophotonic devices and traditional, thick solar cells. We propose a new way of understanding and describing limits to light trapping and show that certain nanophotonic solar cell designs can have light trapping limits above the so called ray-optic or ergodic limit. We propose that a necessary requisite to exceed the traditional light trapping limit is that the active region of the solar cell must possess a local density of optical states (LDOS) higher than that of the corresponding, bulk material. Additionally, we show that in addition to having an increased density of states, the absorber must have an appropriate incoupling mechanism to transfer light from free space into the optical modes of the device. We outline a portfolio of new solar cell designs that have potential to exceed the traditional light trapping limit and numerically validate our predictions for select cases. We emphasize the importance of thinking about light trapping in terms of maximizing the optical modes of the device and efficiently coupling light into them from free space. To further explore these two concepts, we optimize patterns of superlattices of air holes in thin slabs of Si and show that by adding a roughened incoupling layer the total absorbed current can be increased synergistically. We suggest that the addition of a random scattering surface to a periodic patterning can increase incoupling by

  11. Characterization of bending loss in hollow flexible terahertz waveguides.

    PubMed

    Doradla, Pallavi; Joseph, Cecil S; Kumar, Jayant; Giles, Robert H

    2012-08-13

    Attenuation characteristics of hollow, flexible, metal and metal/dielectric coated polycarbonate waveguides were investigated using an optically pumped far infrared (FIR) laser at 215 µm. The bending loss of silver coated polycarbonate waveguides were measured as a function of various bending angles, bending radii, and bore diameters. Minimal propagation losses of 1.77, 0.96 dB/m were achieved by coupling the lowest loss TE11 mode into the silver or gold coated waveguide, and HE11 mode into the silver/polystyrene coated waveguides respectively. The maximal bending loss was found to be less than 1 dB/m for waveguides of 2 to 4.1 mm bore diameters, with a 6.4 cm bend radius, and up to 150° bending angle. The investigation shows the preservation of single laser mode in smaller bore waveguides even at greater bending angles. PMID:23038558

  12. 2D materials for nanophotonic devices

    NASA Astrophysics Data System (ADS)

    Xu, Renjing; Yang, Jiong; Zhang, Shuang; Pei, Jiajie; Lu, Yuerui

    2015-12-01

    Two-dimensional (2D) materials have become very important building blocks for electronic, photonic, and phononic devices. The 2D material family has four key members, including the metallic graphene, transition metal dichalcogenide (TMD) layered semiconductors, semiconducting black phosphorous, and the insulating h-BN. Owing to the strong quantum confinements and defect-free surfaces, these atomically thin layers have offered us perfect platforms to investigate the interactions among photons, electrons and phonons. The unique interactions in these 2D materials are very important for both scientific research and application engineering. In this talk, I would like to briefly summarize and highlight the key findings, opportunities and challenges in this field. Next, I will introduce/highlight our recent achievements. We demonstrated atomically thin micro-lens and gratings using 2D MoS2, which is the thinnest optical component around the world. These devices are based on our discovery that the elastic light-matter interactions in highindex 2D materials is very strong. Also, I would like to introduce a new two-dimensional material phosphorene. Phosphorene has strongly anisotropic optical response, which creates 1D excitons in a 2D system. The strong confinement in phosphorene also enables the ultra-high trion (charged exciton) binding energies, which have been successfully measured in our experiments. Finally, I will briefly talk about the potential applications of 2D materials in energy harvesting.

  13. Compact waveguide circular polarizer

    DOEpatents

    Tantawi, Sami G.

    2016-08-16

    A multi-port waveguide is provided having a rectangular waveguide that includes a Y-shape structure with first top arm having a first rectangular waveguide port, a second top arm with second rectangular waveguide port, and a base arm with a third rectangular waveguide port for supporting a TE.sub.10 mode and a TE.sub.20 mode, where the end of the third rectangular waveguide port includes rounded edges that are parallel to a z-axis of the waveguide, a circular waveguide having a circular waveguide port for supporting a left hand and a right hand circular polarization TE.sub.11 mode and is coupled to a base arm broad wall, and a matching feature disposed on the base arm broad wall opposite of the circular waveguide for terminating the third rectangular waveguide port, where the first rectangular waveguide port, the second rectangular waveguide port and the circular waveguide port are capable of supporting 4-modes of operation.

  14. Adiabatic elimination-based coupling control in densely packed subwavelength waveguides

    PubMed Central

    Mrejen, Michael; Suchowski, Haim; Hatakeyama, Taiki; Wu, Chihhui; Feng, Liang; O'Brien, Kevin; Wang, Yuan; Zhang, Xiang

    2015-01-01

    The ability to control light propagation in photonic integrated circuits is at the foundation of modern light-based communication. However, the inherent crosstalk in densely packed waveguides and the lack of robust control of the coupling are a major roadblock toward ultra-high density photonic integrated circuits. As a result, the diffraction limit is often considered as the lower bound for ultra-dense silicon photonics circuits. Here we experimentally demonstrate an active control of the coupling between two closely packed waveguides via the interaction with a decoupled waveguide. This control scheme is analogous to the adiabatic elimination, a well-known procedure in atomic physics. This approach offers an attractive solution for ultra-dense integrated nanophotonics for light-based communications and integrated quantum computing. PMID:26113179

  15. Towards nanoscale multiplexing with parity-time-symmetric plasmonic coaxial waveguides

    NASA Astrophysics Data System (ADS)

    Alaeian, Hadiseh; Baum, Brian; Jankovic, Vladan; Lawrence, Mark; Dionne, Jennifer A.

    2016-05-01

    We theoretically investigate a nanoscale mode-division multiplexing scheme based on parity-time- (PT ) symmetric coaxial plasmonic waveguides. Coaxial waveguides support paired degenerate modes corresponding to distinct orbital angular momentum states. PT -symmetric inclusions of gain and loss break the degeneracy of the paired modes and create new hybrid modes without definite orbital angular momentum. This process can be made thresholdless by matching the mode order with the number of gain and loss sections within the coaxial ring. Using both a Hamiltonian formulation and degenerate perturbation theory, we show how the wave vectors and fields evolve with increased loss/gain and derive sufficient conditions for thresholdless transitions. As a multiplexing filter, this PT -symmetric coaxial waveguide could help double density rates in on-chip nanophotonic networks.

  16. Enabling high-temperature nanophotonics for energy applications

    PubMed Central

    Yeng, Yi Xiang; Ghebrebrhan, Michael; Bermel, Peter; Chan, Walker R.; Joannopoulos, John D.; Soljačić, Marin; Celanovic, Ivan

    2012-01-01

    The nascent field of high-temperature nanophotonics could potentially enable many important solid-state energy conversion applications, such as thermophotovoltaic energy generation, selective solar absorption, and selective emission of light. However, special challenges arise when trying to design nanophotonic materials with precisely tailored optical properties that can operate at high-temperatures (> 1,100 K). These include proper material selection and purity to prevent melting, evaporation, or chemical reactions; severe minimization of any material interfaces to prevent thermomechanical problems such as delamination; robust performance in the presence of surface diffusion; and long-range geometric precision over large areas with severe minimization of very small feature sizes to maintain structural stability. Here we report an approach for high-temperature nanophotonics that surmounts all of these difficulties. It consists of an analytical and computationally guided design involving high-purity tungsten in a precisely fabricated photonic crystal slab geometry (specifically chosen to eliminate interfaces arising from layer-by-layer fabrication) optimized for high performance and robustness in the presence of roughness, fabrication errors, and surface diffusion. It offers near-ultimate short-wavelength emittance and low, ultra-broadband long-wavelength emittance, along with a sharp cutoff offering 4∶1 emittance contrast over 10% wavelength separation. This is achieved via Q-matching, whereby the absorptive and radiative rates of the photonic crystal’s cavity resonances are matched. Strong angular emission selectivity is also observed, with short-wavelength emission suppressed by 50% at 75° compared to normal incidence. Finally, a precise high-temperature measurement technique is developed to confirm that emission at 1,225 K can be primarily confined to wavelengths shorter than the cutoff wavelength. PMID:22308448

  17. Green nanophotonics for future datacom and Ethernet networks

    NASA Astrophysics Data System (ADS)

    Bimberg, Dieter; Arsenijević, Dejan; Larisch, Gunter; Li, Hui; Lott, James A.; Moser, Philip; Schmeckebier, Holger; Wolf, Philip

    2014-05-01

    The use of Internet has increased and continues to increase exponentially, mostly driven by consumers. Thus bit rates in networks from access to WDM and finally the computer clusters and supercomputers increase as well rapidly. Their cost of energy reaches today 5-6 % of raw electricity production. For 2023 a cross over is predicted, if no new "green" technologies or "green" devices" will reduce energy consumption by about 15% per year. We present two distinct approaches for access and computer networks based on nanophotonic devices to reduce power consumption in the next decade.

  18. Metabolic Differences in Microbial Cell Populations Revealed by Nanophotonic Ionization

    SciTech Connect

    Walker, Bennett; Antonakos, Cory; Retterer, Scott T; Vertes, Akos

    2013-01-01

    ellular differences are linked to cell differentiation, the proliferation of cancer and to the development of drug resistance in microbial infections. Due to sensitivity limitations, however, large- scale metabolic analysis at the single cell level is only available for cells significantly larger in volume than Saccharomyces cerevisiae (~30 fL). Here we demonstrate that by a nanophotonic ionization platform and mass spectrometry, over one hundred up to 108 metabolites, or up to 18% of the known S. cerevisiae metabolome, can be identified in very small cell populations (n < 100). Under ideal conditions, r Relative quantitation of up to 4% of the metabolites is achieved at the single cell level.

  19. Hybrid quantum nanophotonic devices for coupling to rare-earth ions

    NASA Astrophysics Data System (ADS)

    Miyazono, Evan; Hartz, Alex; Zhong, Tian; Faraon, Andrei

    2015-03-01

    With an assortment of narrow line-width transitions spanning the visible and IR spectrum and long spin coherence times, rare-earth doped crystals are the leading material system for solid-state quantum memories. Integrating these materials in an on-chip optical platform would create opportunities for highly integrated light-matter interfaces for quantum communication and quantum computing. Nano-photonic resonators with high quality factors and small mode volumes are required for efficient on-chip coupling to the small dipole moment of rare-earth ion transitions. However, direct fabrication of optical cavities in these crystals with current nanofabrication techniques is difficult and unparallelized, as either exotic etch chemistries or physical milling processes are required. We fabricated hybrid devices by mechanically transferring a nanoscale membrane of gallium arsenide (GaAs) onto a neodymium-doped yttrium silicon oxide (Y2SiO5) crystal and then using electron beam lithography and standard III-V dry etching to pattern nanobeam photonic crystal cavities and ring resonator cavities, a technique that is easily adapted to other frequency ranges for arbitrary dopants in any rare earth host system. Single crystalline GaAs was chosen for its low loss and high refractive index at the transition wavelength. We demonstrated the potential to evanescently couple between the cavity field and the 883 nm 4I9/2- 4F3/2 transition of nearby neodymium impurities in the host crystal by examining transmission spectra through a waveguide coupled to the resonator with a custom-built confocal microscope. The prospects and requirements for using this system for scalable quantum networks are discussed.

  20. Waveguide cooling system

    NASA Technical Reports Server (NTRS)

    Chen, B. C. J.; Hartop, R. W. (Inventor)

    1981-01-01

    An improved system is described for cooling high power waveguides by the use of cooling ducts extending along the waveguide, which minimizes hot spots at the flanges where waveguide sections are connected together. The cooling duct extends along substantially the full length of the waveguide section, and each flange at the end of the section has a through hole with an inner end connected to the duct and an opposite end that can be aligned with a flange hole in another waveguide section. Earth flange is formed with a drainage groove in its face, between the through hole and the waveguide conduit to prevent leakage of cooling fluid into the waveguide. The ducts have narrowed sections immediately adjacent to the flanges to provide room for the installation of fasteners closely around the waveguide channel.

  1. Micromachined Silicon Waveguides

    NASA Technical Reports Server (NTRS)

    Mcgrath, William R.; Tai, Yu-Chong; Yap, Markus; Walker, Christopher K.

    1994-01-01

    Components that handle millimeter and submillimeter wavelengths fabricated conveniently. Micromachining rectangular waveguide involves standard steps of masking, etching, and deposition of metal on silicon. Parts made assembled into half-waveguide and finally into full waveguide. Silicon-micromachining approach enables simultaneous fabrication of several versions of waveguide, with variations in critical parameter, on single wafer of silicon. Performances of versions compared and optimized more quickly and at lower cost than is possible if different versions are fabricated sequentially, by conventional machining techniques.

  2. Quantum Optics in the Solid State with Diamond Nanophotonics

    NASA Astrophysics Data System (ADS)

    de Leon, Nathalie; Evans, Ruffin; de Greve, Kristiaan; Goldman, Michael; High, Alex; Markham, Matthew; Stacey, Alastair; Twitchen, Daniel; Loncar, Marko; Park, Hongkun; Lukin, Mikhail

    2015-05-01

    Large-scale quantum networks will require efficient interfaces between photons and stationary quantum bits. Nitrogen-vacancy (NV) centers in diamond are a promising candidate for quantum information processing because they are optically addressable, have spin degrees of freedom with long coherence times, and as solid-state entities, can be integrated into nanophotonic devices. An enabling feature of the NV center is its zero-phonon line (ZPL), which acts as an atom-like cycling transition that can be used for coherent optical manipulation and read-out of the spin. However, the ZPL only accounts for 3-5% of the total emission, and previously demonstrated methods of producing high densities of NV centers yield unstable ZPLs. We have developed techniques to fabricate high quality factor, small mode volume photonic crystal cavities directly out of diamond, and to deterministically position these photonic crystal cavities so that a stable NV center sits at the maximum electric field. We observe an enhancement of the spontaneous emission at the cavity resonance by a factor of up to 100. Crucially, we are able to control the NV center precisely using both microwave and resonant optical manipulation. These nanophotonic elements in diamond will provide key building blocks for quantum information processing such as single photon transistors, enabling distribution of entanglement over quantum networks.

  3. Twisted waveguide accelerating structure.

    SciTech Connect

    Kang, Y. W.

    2000-08-15

    A hollow waveguide with a uniform cross section may be used for accelerating charged particles if the phase velocity of an accelerating mode is equal to or less than the free space speed of light. Regular straight hollow waveguides have phase velocities of propagating electromagnetic waves greater than the free-space speed of light. if the waveguide is twisted, the phase velocities of the waveguide modes become slower. The twisted waveguide structure has been modeled and computer simulated in 3-D electromagnetic solvers to show the slow-wave properties for the accelerating mode.

  4. Micromachined Silicon Waveguide Circuits

    NASA Technical Reports Server (NTRS)

    McGrath, W. R.

    1995-01-01

    Rectangular waveguides are commonly used as circuit elements in remote-sensing heterodyne receivers at millimeter wavelengths. The advantages of waveguides are low loss and mechanical tunability. However, conventional machining techniques for waveguide components operating above a few hundred GHz are complicated and costly. Waveguides micromachined from silicon however would have several important advantages including low-cost; small size for very high frequency (submillimeter wave) operation; high dimensional accuracy (important for high-Q circuits); atomically smooth walls, thereby reducing rf losses; and the ability to integrate active and passive devices directly in the waveguide on thin membranes, thereby solving the traditional problem of mounting thin substrates.

  5. Photonic Crystals from Order to Disorder: Perturbative Methods in Nanophotonics

    ScienceCinema

    Johnson, Steven G. [MIT, Cambridge, Massachusetts, United States

    2010-01-08

    Photonic crystals are periodic dielectric structures in which light can behave much differently than in a homogeneous medium. This talk gives an overview of some of the interesting properties and applications of these media, from switching in subwavelength microcavities to slow-light devices, to guiding light in air. However, some of the most interesting and challenging problems occur when the periodicity is disturbed, either by design or by inevitable fabrication imperfections. The talk focuses especially on small perturbations that have important effects, from slow-light tapers to surface roughness disorder, and will show that many classic perturbative approaches must be rethought for high-contrast nanophotonics. The combination of strong periodicity with large field discontinuities at interfaces causes standard methods to fail, but succumbs to new generalizations, while some problems remain open.

  6. Nanophotonic resonators for InP solar cells.

    PubMed

    Goldman, Daniel A; Murray, Joseph; Munday, Jeremy N

    2016-05-16

    We describe high efficiency thin-film InP solar cells that utilize a periodic array of TiO2 nanocylinders. These nanophotonic resonators are found to reduce the solar-weighted average reflectivity of an InP solar cell to ~1.3%, outperforming the best double-layer antireflection coatings. The coupling between Mie scattering resonances and thin-film interference effects accurately describes the optical enhancement provided by the nanocylinders. The spectrally resolved reflectivity and J-V characteristics of the device under AM1.5G illumination are determined via coupled optical and electrical simulations, resulting in a predicted power conversion efficiency > 23%. We conclude that the nanostructured coating reduces reflection without negatively affecting the electronic properties of the InP solar cell by separating the nanostructured optical components from the active layer of the device. PMID:27409965

  7. Nanophotonic integrated circuits from nanoresonators grown on silicon

    NASA Astrophysics Data System (ADS)

    Chen, Roger; Ng, Kar Wei; Ko, Wai Son; Parekh, Devang; Lu, Fanglu; Tran, Thai-Truong D.; Li, Kun; Chang-Hasnain, Connie

    2014-07-01

    Harnessing light with photonic circuits promises to catalyse powerful new technologies much like electronic circuits have in the past. Analogous to Moore’s law, complexity and functionality of photonic integrated circuits depend on device size and performance scale. Semiconductor nanostructures offer an attractive approach to miniaturize photonics. However, shrinking photonics has come at great cost to performance, and assembling such devices into functional photonic circuits has remained an unfulfilled feat. Here we demonstrate an on-chip optical link constructed from InGaAs nanoresonators grown directly on a silicon substrate. Using nanoresonators, we show a complete toolkit of circuit elements including light emitters, photodetectors and a photovoltaic power supply. Devices operate with gigahertz bandwidths while consuming subpicojoule energy per bit, vastly eclipsing performance of prior nanostructure-based optoelectronics. Additionally, electrically driven stimulated emission from an as-grown nanostructure is presented for the first time. These results reveal a roadmap towards future ultradense nanophotonic integrated circuits.

  8. Ultimate Limit of Light Extinction by Nanophotonic Structures.

    PubMed

    Yang, Zhong-Jian; Antosiewicz, Tomasz J; Verre, Ruggero; García de Abajo, F Javier; Apell, S Peter; Käll, Mikael

    2015-11-11

    Nanophotonic structures make it possible to precisely engineer the optical response at deep subwavelength scales. However, a fundamental understanding of the general performance limits remains a challenge. Here we use extensive electrodynamics simulations to demonstrate that the so-called f-sum rule sets a strict upper bound to the light extinction by nanostructures regardless their internal interactions and retardation effects. In particular, we show that the f-sum rule applies to arbitrarily complex plasmonic metal structures that exhibit an extraordinary spectral sensitivity to size, shape, near-field coupling effects, and incident polarization. The results may be used for benchmarking light scattering and absorption efficiencies, thus imposing fundamental limits on solar light harvesting, biomedical photonics, and optical communications. PMID:26478949

  9. Full loss compensation in hybrid plasmonic waveguides under electrical pumping.

    PubMed

    Svintsov, Dmitry A; Arsenin, Aleksey V; Fedyanin, Dmitry Yu

    2015-07-27

    Surface plasmon polaritons (SPPs) give an opportunity to break the diffraction limit and design nanoscale optical components, however their practical implementation is hindered by high ohmic losses in a metal. Here, we propose a novel approach for efficient SPP amplification under electrical pumping in a deep-subwavelength metal-insulator-semiconductor waveguiding geometry and numerically demonstrate full compensation for the SPP propagation losses in the infrared at an exceptionally low pump current density of 0.8 kA/cm2. This value is an order of magnitude lower than in the previous studies owing to the thin insulator layer between a metal and a semiconductor, which allows injection of minority carriers and blocks majority carriers reducing the leakage current to nearly zero. The presented results provide insight into lossless SPP guiding and development of future high dense nanophotonic and optoelectronic circuits. PMID:26367596

  10. Waveguide disturbance detection method

    DOEpatents

    Korneev, Valeri A.; Nihei, Kurt T.; Myer, Larry R.

    2000-01-01

    A method for detection of a disturbance in a waveguide comprising transmitting a wavefield having symmetric and antisymmetric components from a horizontally and/or vertically polarized source and/or pressure source disposed symmetrically with respect to the longitudinal central axis of the waveguide at one end of the waveguide, recording the horizontal and/or vertical component or a pressure of the wavefield with a vertical array of receivers disposed at the opposite end of the waveguide, separating the wavenumber transform of the wavefield into the symmetric and antisymmetric components, integrating the symmetric and antisymmetric components over a broad frequency range, and comparing the magnitude of the symmetric components and the antisymmetric components to an expected magnitude for the symmetric components and the antisymmetric components for a waveguide of uniform thickness and properties thereby determining whether or not a disturbance is present inside the waveguide.

  11. Planar waveguide optical immunosensors

    NASA Astrophysics Data System (ADS)

    Choquette, Steven J.; Locascio-Brown, Laurie E.; Durst, Richard A.

    1991-03-01

    Monoclonal antibodies were covalently bonded to the surfaces of planar waveguides to confer immunoreacth''ity. Silver-ion diffused waveguides were used to measure theophylline concentrations in a fluorescence immunoassay and silicon nitride waveguides were used to detect theophylline in an absorbance-based immunoassay. Liposomes were employed in both assays as the optically detectable label in a competitive reaction to monitor antigen-antibody complexation. Regeneration of the active antibody site will be discussed.

  12. Lasing in silicon-organic hybrid waveguides.

    PubMed

    Korn, Dietmar; Lauermann, Matthias; Koeber, Sebastian; Appel, Patrick; Alloatti, Luca; Palmer, Robert; Dumon, Pieter; Freude, Wolfgang; Leuthold, Juerg; Koos, Christian

    2016-01-01

    Silicon photonics enables large-scale photonic-electronic integration by leveraging highly developed fabrication processes from the microelectronics industry. However, while a rich portfolio of devices has already been demonstrated on the silicon platform, on-chip light sources still remain a key challenge since the indirect bandgap of the material inhibits efficient photon emission and thus impedes lasing. Here we demonstrate a class of infrared lasers that can be fabricated on the silicon-on-insulator (SOI) integration platform. The lasers are based on the silicon-organic hybrid (SOH) integration concept and combine nanophotonic SOI waveguides with dye-doped organic cladding materials that provide optical gain. We demonstrate pulsed room-temperature lasing with on-chip peak output powers of up to 1.1 W at a wavelength of 1,310 nm. The SOH approach enables efficient mass-production of silicon photonic light sources emitting in the near infrared and offers the possibility of tuning the emission wavelength over a wide range by proper choice of dye materials and resonator geometry. PMID:26949229

  13. Lasing in silicon-organic hybrid waveguides

    NASA Astrophysics Data System (ADS)

    Korn, Dietmar; Lauermann, Matthias; Koeber, Sebastian; Appel, Patrick; Alloatti, Luca; Palmer, Robert; Dumon, Pieter; Freude, Wolfgang; Leuthold, Juerg; Koos, Christian

    2016-03-01

    Silicon photonics enables large-scale photonic-electronic integration by leveraging highly developed fabrication processes from the microelectronics industry. However, while a rich portfolio of devices has already been demonstrated on the silicon platform, on-chip light sources still remain a key challenge since the indirect bandgap of the material inhibits efficient photon emission and thus impedes lasing. Here we demonstrate a class of infrared lasers that can be fabricated on the silicon-on-insulator (SOI) integration platform. The lasers are based on the silicon-organic hybrid (SOH) integration concept and combine nanophotonic SOI waveguides with dye-doped organic cladding materials that provide optical gain. We demonstrate pulsed room-temperature lasing with on-chip peak output powers of up to 1.1 W at a wavelength of 1,310 nm. The SOH approach enables efficient mass-production of silicon photonic light sources emitting in the near infrared and offers the possibility of tuning the emission wavelength over a wide range by proper choice of dye materials and resonator geometry.

  14. Lasing in silicon–organic hybrid waveguides

    PubMed Central

    Korn, Dietmar; Lauermann, Matthias; Koeber, Sebastian; Appel, Patrick; Alloatti, Luca; Palmer, Robert; Dumon, Pieter; Freude, Wolfgang; Leuthold, Juerg; Koos, Christian

    2016-01-01

    Silicon photonics enables large-scale photonic–electronic integration by leveraging highly developed fabrication processes from the microelectronics industry. However, while a rich portfolio of devices has already been demonstrated on the silicon platform, on-chip light sources still remain a key challenge since the indirect bandgap of the material inhibits efficient photon emission and thus impedes lasing. Here we demonstrate a class of infrared lasers that can be fabricated on the silicon-on-insulator (SOI) integration platform. The lasers are based on the silicon–organic hybrid (SOH) integration concept and combine nanophotonic SOI waveguides with dye-doped organic cladding materials that provide optical gain. We demonstrate pulsed room-temperature lasing with on-chip peak output powers of up to 1.1 W at a wavelength of 1,310 nm. The SOH approach enables efficient mass-production of silicon photonic light sources emitting in the near infrared and offers the possibility of tuning the emission wavelength over a wide range by proper choice of dye materials and resonator geometry. PMID:26949229

  15. Broad band waveguide spectrometer

    DOEpatents

    Goldman, Don S.

    1995-01-01

    A spectrometer for analyzing a sample of material utilizing a broad band source of electromagnetic radiation and a detector. The spectrometer employs a waveguide possessing an entry and an exit for the electromagnetic radiation emanating from the source. The waveguide further includes a surface between the entry and exit portions which permits interaction between the electromagnetic radiation passing through the wave guide and a sample material. A tapered portion forms a part of the entry of the wave guide and couples the electromagnetic radiation emanating from the source to the waveguide. The electromagnetic radiation passing from the exit of the waveguide is captured and directed to a detector for analysis.

  16. Birefringent corrugated waveguide

    SciTech Connect

    Moeller, C.P.

    1989-02-15

    A corrugated waveguide having a circular bore and noncircularly symmetric corrugations, and preferably elliptical corrugations, provides birefringence for rotation of polarization in the HE{sub 11} mode. The corrugated waveguide may be fabricated by cutting circular grooves on a lathe in a cylindrical tube or rod of aluminium of a diameter suitable for the bore of the waveguide, and then cutting an approximation to ellipses for the corrugations using a cutting radius R{sub 0} from the bore axis that is greater than the bore radius, and then making two circular cuts using a radius R{sub 1} less than R{sub 0} at centers +b and {minus}b from the axis of the waveguide bore. Alternatively, stock for the mandrel may be formed with an elliptical transverse cross section, and then only the circular grooves need be cut on a lathe, leaving elliptical corrugations between the grooves. In either case, the mandrel is first electroplated and then dissolved leaving a corrugated waveguide with noncircularly symmetric waveguides. A transition waveguide is used that gradually varies from circular to elliptical corrugations to couple a circularly corrugated waveguide to an elliptically corrugated waveguide.

  17. High efficiency light conversion between micro- and nano-photonic circuits

    NASA Astrophysics Data System (ADS)

    Gu, Zhiyuan; Xiao, Shumin; Song, Qinghai

    2016-07-01

    We theoretically demonstrate a tapered waveguide that is compatible with a silicon waveguide and hybrid plasmonic waveguide simultaneously. As much as 90% of the energy can be transferred from the photonic mode to plasmonic mode and vice versa.

  18. Interaction between Atoms and Slow Light: A Study in Waveguide Design

    NASA Astrophysics Data System (ADS)

    Zang, Xiaorun; Yang, Jianji; Faggiani, Rémi; Gill, Christopher; Petrov, Plamen G.; Hugonin, Jean-Paul; Vynck, Kevin; Bernon, Simon; Bouyer, Philippe; Boyer, Vincent; Lalanne, Philippe

    2016-02-01

    The emerging field of on-chip integration of nanophotonic devices and cold atoms offers extremely strong and pure light-matter interaction schemes, which may have a profound impact on quantum information science. In this context, a long-standing obstacle is to achieve a strong interaction between single atoms and single photons and at the same time trap atoms in a vacuum at large separation distances from dielectric surfaces. In this work, we study waveguide geometries that challenge these conflicting objectives. The designed photonic-crystal waveguide is expected to offer a good compromise, which additionally allows for easy manipulation of atomic clouds around the structure, while being tolerant to fabrication imperfections.

  19. Waveguide switch protector

    NASA Technical Reports Server (NTRS)

    Kolbly, R. B.

    1972-01-01

    Device for detecting excessive operation of electric motors used to drive waveguide switches is described. Purpose of device is to prevent burnout of electric motor in event of waveguide stoppage at some point other than extreme limits of travel. Operation of equipment, components used to sense motor performance, and schematic diagram are included.

  20. Birefringent corrugated waveguide

    DOEpatents

    Moeller, Charles P.

    1990-01-01

    A corrugated waveguide having a circular bore and noncircularly symmetric corrugations, and preferably elliptical corrugations, provides birefringence for rotation of polarization in the HE.sub.11 mode. The corrugated waveguide may be fabricated by cutting circular grooves on a lathe in a cylindrical tube or rod of aluminum of a diameter suitable for the bore of the waveguide, and then cutting an approximation to ellipses for the corrugations using a cutting radius R.sub.0 from the bore axis that is greater than the bore radius, and then making two circular cuts using a radius R.sub.1 less than R.sub.0 at centers +b and -b from the axis of the waveguide bore. Alternatively, stock for the mandrel may be formed with an elliptical transverse cross section, and then only the circular grooves need be cut on a lathe, leaving elliptical corrugations between the grooves. In either case, the mandrel is first electroplated and then dissolved leaving a corrugated waveguide with noncircularly symmetric corrugations. A transition waveguide is used that gradually varies from circular to elliptical corrugations to couple a circularly corrugated waveguide to an elliptically corrugated waveguide.

  1. Birefringent corrugated waveguide

    SciTech Connect

    Moeller, C.P.

    1990-03-06

    This patent describes a corrugated waveguide having a circular bore and noncircularly symmetric corrugations, and preferably elliptical corrugations which provides birefringence for rotation of polarization in the HE{sub 11} mode. The corrugated waveguide may be fabricated by cutting circular grooves on a lathe in a cylindrical tube or rod of aluminum of a diameter suitable for the bore of the waveguide, and then cutting an approximation to ellipses for the corrugations using a cutting radius R{sub 0} from the bore axis that is greater than the bore radius, and then making two circular cuts using a radius R{sub 1} less than R{sub 0} at centers + b and {minus} B from the axis of the waveguide bore. Alternatively, stock for the mandrel may be formed with an elliptical transverse cross section, and then only the circular grooves need be cut on a lathe, leaving elliptical corrugations between the grooves. In either case, the mandrel is first electroplated and then dissolved leaving a corrugated waveguide with noncircularly symmetric corrugations. A transition waveguide is used that gradually varies from circular to elliptical corrugations to couple a circularly corrugated waveguide to an elliptically corrugated waveguide.

  2. Composite dielectric waveguides

    NASA Astrophysics Data System (ADS)

    Yamashita, E.; Atsuki, K.; Kuzuya, R.

    1980-09-01

    The modal analysis of a composite circular dielectric waveguide (CCDW) is presented. Computed values of the propagation constant of a CCDW are compared with those of the homogeneous circular dielectric waveguides (HCDW). Microwave experiments concerning the propagation constant of a CCDW of Teflon and Rexolite are described.

  3. CALL FOR PAPERS: Topical issue on the fundamental aspects of nanophotonics

    NASA Astrophysics Data System (ADS)

    Stockman, Mark; Zayats, Anatoly; Zheludev, Nikolay

    2005-05-01

    The broad goals of the new discipline of nanophotonics are to develop concepts of optical functionality on the smallest possible spatial scale, at the lowest possible energy level, and on the shortest possible timescale by employing light interactions with nanostructures. A topical issue of Journal of Optics A: Pure and Applied Optics will be devoted to papers reporting new and challenging results in this burgeoning field. Focused topical reviews within the special issue remit will also be considered, but potential contributors of such reviews should first contact the Guest Editors. Papers in other areas will also be considered for the issue as long as they offer ideas relevant for the field of nanophotonics. The special issue topics will include, but are not limited to: • Plasmonic nanophotonics • Nano-transmission lines and nano-antennas • Light in confined geometries and nano-cavities • Single molecule and single nanoparticle photonics • Quantum and coherent effects in nanophotonics • Nonlinear and ultrafast nanophotonics • Interaction of electron beams with nanophotonic structures • Nano-bio-photonics • Nanoscale imaging and photolithography • Optical atom trapping and manipulation in nanostructures All papers will be peer reviewed, and the normal refereeing standards of Journal of Optics A: Pure and Applied Optics will be maintained. There are no page charges. Advice on preparing your work for publication in the journal, including advice on figures, tables and references, is available from our website at www.iop.org/journals/authors/jopa. Manuscripts should be submitted to the Publisher by 1 September 2005, although authors are strongly encouraged to submit their work as soon as possible. Please include a covering letter stating that the submission is intended for the nanophotonics topical issue, to avoid treatment as a regular submission. Submission address: Dr Claire Bedrock (Publisher) Journal of Optics A: Pure and Applied Optics

  4. Nanocrystal waveguide (NOW) laser

    DOEpatents

    Simpson, John T.; Simpson, Marcus L.; Withrow, Stephen P.; White, Clark W.; Jaiswal, Supriya L.

    2005-02-08

    A solid state laser includes an optical waveguide and a laser cavity including at least one subwavelength mirror disposed in or on the optical waveguide. A plurality of photoluminescent nanocrystals are disposed in the laser cavity. The reflective subwavelength mirror can be a pair of subwavelength resonant gratings (SWG), a pair of photonic crystal structures (PC), or a distributed feedback structure. In the case of a pair of mirrors, a PC which is substantially transmissive at an operating wavelength of the laser can be disposed in the laser cavity between the subwavelength mirrors to improve the mode structure, coherence and overall efficiency of the laser. A method for forming a solid state laser includes the steps of providing an optical waveguide, creating a laser cavity in the optical waveguide by disposing at least one subwavelength mirror on or in the waveguide, and positioning a plurality of photoluminescent nanocrystals in the laser cavity.

  5. Zero-mode waveguides

    DOEpatents

    Levene, Michael J.; Korlach, Jonas; Turner, Stephen W.; Craighead, Harold G.; Webb, Watt W.

    2007-02-20

    The present invention is directed to a method and an apparatus for analysis of an analyte. The method involves providing a zero-mode waveguide which includes a cladding surrounding a core where the cladding is configured to preclude propagation of electromagnetic energy of a frequency less than a cutoff frequency longitudinally through the core of the zero-mode waveguide. The analyte is positioned in the core of the zero-mode waveguide and is then subjected, in the core of the zero-mode waveguide, to activating electromagnetic radiation of a frequency less than the cut-off frequency under conditions effective to permit analysis of the analyte in an effective observation volume which is more compact than if the analysis were carried out in the absence of the zero-mode waveguide.

  6. Nanophotonic quantum phase switch with a single atom.

    PubMed

    Tiecke, T G; Thompson, J D; de Leon, N P; Liu, L R; Vuletić, V; Lukin, M D

    2014-04-10

    By analogy to transistors in classical electronic circuits, quantum optical switches are important elements of quantum circuits and quantum networks. Operated at the fundamental limit where a single quantum of light or matter controls another field or material system, such a switch may enable applications such as long-distance quantum communication, distributed quantum information processing and metrology, and the exploration of novel quantum states of matter. Here, by strongly coupling a photon to a single atom trapped in the near field of a nanoscale photonic crystal cavity, we realize a system in which a single atom switches the phase of a photon and a single photon modifies the atom's phase. We experimentally demonstrate an atom-induced optical phase shift that is nonlinear at the two-photon level, a photon number router that separates individual photons and photon pairs into different output modes, and a single-photon switch in which a single 'gate' photon controls the propagation of a subsequent probe field. These techniques pave the way to integrated quantum nanophotonic networks involving multiple atomic nodes connected by guided light. PMID:24717513

  7. Plasmonic antennas as design elements for coherent ultrafast nanophotonics

    PubMed Central

    Brinks, Daan; Castro-Lopez, Marta; Hildner, Richard; van Hulst, Niek F.

    2013-01-01

    Broadband excitation of plasmons allows control of light-matter interaction with nanometric precision at femtosecond timescales. Research in the field has spiked in the past decade in an effort to turn ultrafast plasmonics into a diagnostic, microscopy, computational, and engineering tool for this novel nanometric–femtosecond regime. Despite great developments, this goal has yet to materialize. Previous work failed to provide the ability to engineer and control the ultrafast response of a plasmonic system at will, needed to fully realize the potential of ultrafast nanophotonics in physical, biological, and chemical applications. Here, we perform systematic measurements of the coherent response of plasmonic nanoantennas at femtosecond timescales and use them as building blocks in ultrafast plasmonic structures. We determine the coherent response of individual nanoantennas to femtosecond excitation. By mixing localized resonances of characterized antennas, we design coupled plasmonic structures to achieve well-defined ultrafast and phase-stable field dynamics in a predetermined nanoscale hotspot. We present two examples of the application of such structures: control of the spectral amplitude and phase of a pulse in the near field, and ultrafast switching of mutually coherent hotspots. This simple, reproducible and scalable approach transforms ultrafast plasmonics into a straightforward tool for use in fields as diverse as room temperature quantum optics, nanoscale solid-state physics, and quantum biology. PMID:24163355

  8. Imaging Nanophotonic Modes of Microresonators using a Focused Ion Beam

    PubMed Central

    Twedt, Kevin A.; Zou, Jie; Davanco, Marcelo; Srinivasan, Kartik; McClelland, Jabez J.; Aksyuk, Vladimir A.

    2016-01-01

    Optical microresonators have proven powerful in a wide range of applications, including cavity quantum electrodynamics1–3, biosensing4, microfludics5, and cavity optomechanics6–8. Their performance depends critically on the exact distribution of optical energy, confined and shaped by the nanoscale device geometry. Near-field optical probes9 can image this distribution, but the physical probe necessarily perturbs the near field, which is particularly problematic for sensitive high quality factor resonances10,11. We present a new approach to mapping nanophotonic modes that uses a controllably small and local optomechanical perturbation introduced by a focused lithium ion beam12. An ion beam (radius ≈50 nm) induces a picometer-scale dynamic deformation of the resonator surface, which we detect through a shift in the optical resonance wavelength. We map five modes of a silicon microdisk resonator (Q≥20,000) with both high spatial and spectral resolution. Our technique also enables in-situ observation of ion implantation damage and relaxation dynamics in a silicon lattice13,14. PMID:27087832

  9. Nanophotonic light trapping with patterned transparent conductive oxides.

    PubMed

    Vasudev, Alok P; Schuller, Jon A; Brongersma, Mark L

    2012-05-01

    Transparent conductive oxides (TCOs) play a crucial role in solar cells by efficiently transmitting sunlight and extracting photo-generated charge. Here, we show how nanophotonics concepts can be used to transform TCO films into effective photon management layers for solar cells. This is accomplished by patterning the TCO layer present on virtually every thin-film solar cell into an array of subwavelength beams that support optical (Mie) resonances. These resonances can be exploited to concentrate randomly polarized sunlight or to effectively couple it to guided and diffracted modes. We first demonstrate these concepts with a model system consisting of a patterned TCO layer on a thin silicon (Si) film and outline a design methodology for high-performance, TCO-based light trapping coatings. We then show that the short circuit current density from a 300 nm thick amorphous silicon (a-Si) cell with an optimized TCO anti-reflection coating can be enhanced from 19.9 mA/cm2 to 21.1 mA/cm2, out of a possible 26.0 mA/cm2, by using an optimized nanobeam array. The key differences and advantages over plasmonic light trapping layers will be discussed. PMID:22712089

  10. True stopping of light: a new regime for nanophotonics

    NASA Astrophysics Data System (ADS)

    Tsakmakidis, Kosmas L.; Zhang, Xiang; Hess, Ortwin

    2014-09-01

    The extremely large speed of light is a tremendous asset but also makes it challenging to control, store or shrink beyond its wavelength. Particularly, reducing the speed of light down to zero is of fundamental scientific interest that could usher in a host of important photonic applications, some of which are hitherto fundamentally inaccessible. These include cavity-free, low-threshold nanolasers, novel solar-cell designs for efficient harvesting of light, nanoscale quantum information processing (owing to the enhanced density of states), as well as enhanced biomolecular sensing. We shall here present nanoplasmonic-based schemes where timedependent sources excite "complex-frequency" modes in uniform (plasmonic) heterostructures, enabling complete and dispersion-free stopping of light pulses, resilient to realistic levels of dissipative, radiative and surface-roughness losses. Our theoretical and computational results demonstrate extraordinary large lightdeceleration factors (of the order of 15,000,000) in integrated nanophotonic media, comparable only to those attainable with ultracold atomic vapours or with quantum coherence effects, such as coherent population oscillations, in ruby crystals.

  11. Nanophotonics-enabled smart windows, buildings and wearables

    NASA Astrophysics Data System (ADS)

    Smith, Geoff; Gentle, Angus; Arnold, Matthew; Cortie, Michael

    2016-06-01

    Design and production of spectrally smart windows, walls, roofs and fabrics has a long history, which includes early examples of applied nanophotonics. Evolving nanoscience has a special role to play as it provides the means to improve the functionality of these everyday materials. Improvement in the quality of human experience in any location at any time of year is the goal. Energy savings, thermal and visual comfort indoors and outdoors, visual experience, air quality and better health are all made possible by materials, whose "smartness" is aimed at designed responses to environmental energy flows. The spectral and angle of incidence responses of these nanomaterials must thus take account of the spectral and directional aspects of solar energy and of atmospheric thermal radiation plus the visible and color sensitivity of the human eye. The structures required may use resonant absorption, multilayer stacks, optical anisotropy and scattering to achieve their functionality. These structures are, in turn, constructed out of particles, columns, ultrathin layers, voids, wires, pure and doped oxides, metals, polymers or transparent conductors (TCs). The need to cater for wavelengths stretching from 0.3 to 35 μm including ultraviolet-visible, near-infrared (IR) and thermal or Planck radiation, with a spectrally and directionally complex atmosphere, and both being dynamic, means that hierarchical and graded nanostructures often feature. Nature has evolved to deal with the same energy flows, so biomimicry is sometimes a useful guide.

  12. Compound semiconductor optical waveguide switch

    DOEpatents

    Spahn, Olga B.; Sullivan, Charles T.; Garcia, Ernest J.

    2003-06-10

    An optical waveguide switch is disclosed which is formed from III-V compound semiconductors and which has a moveable optical waveguide with a cantilevered portion that can be bent laterally by an integral electrostatic actuator to route an optical signal (i.e. light) between the moveable optical waveguide and one of a plurality of fixed optical waveguides. A plurality of optical waveguide switches can be formed on a common substrate and interconnected to form an optical switching network.

  13. Noncontacting waveguide backshort

    NASA Technical Reports Server (NTRS)

    McGrath, William R. (Inventor)

    1992-01-01

    A noncontacting waveguide backshort is provided for use with frequencies of interest between 1 and 1000 GHz including a relatively rugged metallic bar movably mounted within the waveguide in a MYLAR insulator. A series of regularly shaped and spaced circular or rectangular openings are made in the metallic bar to form sections of high impedance alternating with sections of the bar having low impedance. This creates a periodic impedance variation which serves to provided an adjustable short circuit in a waveguide for the frequencies of interest.

  14. Organic nanophotonic materials: the relationship between excited-state processes and photonic performances.

    PubMed

    Zhang, Wei; Zhao, Yong Sheng

    2016-07-12

    Nanophotonics have recently captured broad attention because of their great potential in information processing and communication, which may allow rates and bandwidth beyond what is feasible in the realm of electronics. Organic materials could be well suitable for such applications due to their ability to generate, transmit, modulate and detect light in their lightweight and flexible nanoarchitectures. Their distinct nanophotonic properties strongly depend on their extrinsic morphologies and intrinsic molecular excited-state processes. In this feature article, we mainly focus on a comprehensive understanding of the relationship between molecular excited-state processes and the advanced photonic functionalities of organic micro/nano-crystals in recent organic nanophotonic research, and then expect to provide enlightenment for the design and development of tiny photonic devices with broadband tunable properties by tailoring the excited-state processes of organic microcrystals. PMID:26883812

  15. Mode-selected heat flow through a one-dimensional waveguide network

    SciTech Connect

    Riha, Christian Miechowski, Philipp; Buchholz, Sven S.; Chiatti, Olivio; Fischer, Saskia F.; Wieck, Andreas D.; Reuter, Dirk

    2015-02-23

    Cross-correlated measurements of thermal noise are performed to determine the electron temperature in nanopatterned channels of a GaAs/AlGaAs heterostructure at 4.2 K. Two-dimensional (2D) electron reservoirs are connected via an extended one-dimensional (1D) electron waveguide network. Hot electrons are produced using a current I{sub h} in a source 2D reservoir, are transmitted through the ballistic 1D waveguide, and relax in a drain 2D reservoir. We find that the electron temperature increase, ΔT{sub e}, in the drain is proportional to the square of the heating current I{sub h}, as expected from Joule's law. No temperature increase is observed in the drain when the 1D waveguide does not transmit electrons. Therefore, we conclude that electron-phonon interaction is negligible for heat transport between 2D reservoirs at temperatures below 4.2 K. Furthermore, mode control of the 1D electron waveguide by application of a top-gate voltage reveals that ΔT{sub e} is not proportional to the number of populated subbands N, as previously observed in single 1D conductors. This can be explained with the splitting of the heat flow in the 1D waveguide network.

  16. Axially Modulated Plasma Waveguides

    SciTech Connect

    Layer, B. D.; York, A. G.; Varma, S.; Chen, Y.-H.; Milchberg, H. M.

    2009-01-22

    We demonstrate two techniques for making periodically modulated plasma waveguides-one with sharp, stable voids as short as 50 {mu}m with a period as small as 200 {mu}m, and another which modulates the waveguide diameter with a corrugation period as short as 35 {mu}m[1]. These features persist as the plasma expands for the full lifetime of the waveguide (>6 ns). The waveguides were made using the hydrodynamic shock method in a cluster jet using hydrogen, nitrogen, and argon. We demonstrate guided propagation at intensities up to 2x10{sup 17} W/cm{sup 2}, limited by our laser energy currently available. This technique is useful for quasi-phase matching to allow efficient coupling of laser energy to acceleration of relativistic electrons or generation of coherent electromagnetic radiation at selected frequencies.

  17. Microfabricated bragg waveguide

    DOEpatents

    Fleming, James G.; Lin, Shawn-Yu; Hadley, G. Ronald

    2004-10-19

    A microfabricated Bragg waveguide of semiconductor-compatible material having a hollow core and a multilayer dielectric cladding can be fabricated by integrated circuit technologies. The microfabricated Bragg waveguide can comprise a hollow channel waveguide or a hollow fiber. The Bragg fiber can be fabricated by coating a sacrificial mandrel or mold with alternating layers of high- and low-refractive-index dielectric materials and then removing the mandrel or mold to leave a hollow tube with a multilayer dielectric cladding. The Bragg channel waveguide can be fabricated by forming a trench embedded in a substrate and coating the inner wall of the trench with a multilayer dielectric cladding. The thicknesses of the alternating layers can be selected to satisfy the condition for minimum radiation loss of the guided wave.

  18. Omnidirectional optical waveguide

    DOEpatents

    Bora, Mihail; Bond, Tiziana C.

    2016-08-02

    In one embodiment, a system includes a scintillator material; a detector coupled to the scintillator material; and an omnidirectional waveguide coupled to the scintillator material, the omnidirectional waveguide comprising: a plurality of first layers comprising one or more materials having a refractive index in a first range; and a plurality of second layers comprising one or more materials having a refractive index in a second range, the second range being lower than the first range, a plurality of interfaces being defined between alternating ones of the first and second layers. In another embodiment, a method includes depositing alternating layers of a material having a relatively high refractive index and a material having a relatively low refractive index on a substrate to form an omnidirectional waveguide; and coupling the omnidirectional waveguide to at least one surface of a scintillator material.

  19. Modeling of general 1-D periodic leaky-wave antennas in layered media using EIGER.

    SciTech Connect

    Wilton, Donald R.; Basilio, Lorena I.; Celepcikay, Ferhat T.; Johnson, William Arthur; Baccarelli, Paolo; Valerio, Guido; Paulotto, Simone; Langston, William L.; Jackson, David R.

    2010-09-01

    This paper presents a mixed-potential integral-equation formulation for analyzing 1-D periodic leaky-wave antennas in layered media. The structures are periodic in one dimension and finite in the other two dimensions. The unit cell consists of an arbitrary-shaped metallic/dielectric structure. The formulation has been implemented in the EIGER{trademark} code in order to obtain the real and complex propagation wavenumbers of the bound and leaky modes of such structures. Validation results presented here include a 1-D periodic planar leaky-wave antenna and a fully 3-D waveguide test case.

  20. Modeling of general 1-D periodic leaky-wave antennas in layered media with EIGER.

    SciTech Connect

    Wilton, Donald R.; Basilio, Lorena I.; Celepcikay, F. T.; Johnson, William Arthur; Baccarelli, Paolo; Valerio, G.; Paulotto, Simone; Langston, William L.; Jackson, David R.

    2010-06-01

    This paper presents a mixed-potential integral-equation formulation for analyzing 1-D periodic leaky-wave antennas in layered media. The structures are periodic in one dimension and finite in the other two dimensions. The unit cell consists of an arbitrary-shaped metallic/dielectric structure. The formulation has been implemented in the EIGER{trademark} code in order to obtain the real and complex propagation wavenumbers of the bound and leaky modes of such structures. Validation results presented here include a 1-D periodic planar leaky-wave antenna and a fully 3-D waveguide test case.

  1. Surface modification to waveguides

    DOEpatents

    Timberlake, John R.; Ruzic, David N.; Moore, Richard L.; Cohen, Samuel A.; Manos, Dennis M.

    1983-01-01

    A method of treating the interior surfaces of a waveguide to improve power transmission comprising the steps of mechanically polishing to remove surface protrusions; electropolishing to remove embedded particles; ultrasonically cleaning to remove any residue; coating the interior waveguide surfaces with an alkyd resin solution or electrophoretically depositing carbon lamp black suspended in an alkyd resin solution to form a 1.mu. to 5.mu. thick film; vacuum pyrolyzing the film to form a uniform adherent carbon coating.

  2. Surface modification to waveguides

    DOEpatents

    Timberlake, J.R.; Ruzic, D.N.; Moore, R.L.; Cohen, S.A.; Manos, D.M.

    1982-06-16

    A method is described for treating the interior surfaces of a waveguide to improve power transmission comprising the steps of mechanically polishing to remove surface protrusions; electropolishing to remove embedded particles; ultrasonically cleaning to remove any residue; coating the interior waveguide surfaces with an alkyd resin solution or electrophoretically depositing carbon lamp black suspended in an alkyd resin solution to form a 1..mu.. to 5..mu.. thick film; vacuum pyrolyzing the film to form a uniform adherent carbon coating.

  3. Feasibility study of nanoscaled optical waveguide based on near-resonant surface plasmon polariton.

    PubMed

    Yan, Min; Thylén, Lars; Qiu, Min; Parekh, Devang

    2008-05-12

    Currently subwavelength surface plasmon polariton (SPP) waveguides under intensive theoretical and experimental studies are mostly based on the geometrical singularity property of such waveguides. Typical examples include the metal-insulator-metal based waveguide and the metallic fiber. Both types of waveguides support a mode with divergent propagation constant as the waveguides' geometry (metal gap distance or fiber radius) shrinks to zero. Here we study an alternative way of achieving subwavelength confinement through deploying two materials with close but opposite epsilon values. The interface between such two materials supports a near-resonant SPP. By examining the relationship between mode propagation loss and the mode field size for both planar and fiber waveguides, we show that waveguides based on near-resonant SPP can be as attractive as those solely based on geometrical tailoring. We then explicitly study a silver and silicon based waveguide with a 25nm core size at 600nm wavelength, in its properties like single-mode condition, mode loss and group velocity. It is shown that loss values of both materials have to be decreased by approximately 1000 times in order to have 1dB/microm propagation loss. Hence we point out the necessity of novel engineering of low-loss metamaterials, or introducing gain, for practical applications of such waveguides. Due to the relatively simple geometry, the proposed near-resonant SPP waveguides can be a potential candidate for building optical circuits with a density close to the electronic counterpart. PMID:18545455

  4. Metallic-nanowire-loaded silicon-on-insulator structures: a route to low-loss plasmon waveguiding on the nanoscale

    NASA Astrophysics Data System (ADS)

    Bian, Yusheng; Gong, Qihuang

    2015-02-01

    The simultaneous realization of nanoscale field localization and low transmission loss remains one of the major challenges in nanophotonics. Metal nanowire waveguides can fulfill this goal to a certain extent by confining light within subwavelength space, yet their optical performances are still restricted by the tradeoff between confinement and loss, which results in quite limited propagation distances when their mode sizes are reduced down to the nanometer scale. Here we introduce a class of low-loss guiding schemes by integrating silicon-on-insulator (SOI) waveguides with plasmon nanowire structures. The closely spaced silicon and metal configurations allow efficient light squeezing within the nanometer, low-index silica gaps between them, enabling deep-subwavelength light transmission with low modal attenuation. Optimizations of key structural parameters unravel the wide-range existence of the high-performance hybrid nanowire plasmon mode, which demonstrates improved guiding properties compared to the conventional hybrid and nanowire plasmon polaritons. The excitation strategy of the guided mode and the feasibility of the waveguide for compact photonic integration as well as active components are also discussed to lay the foundation for its practical implementation. The remarkable properties of these metallic-nanowire-loaded SOI waveguides potentially lend themselves to the implementation of high performance nanophotonic components, and open up promising opportunities for a variety of intriguing applications on the nanoscale.The simultaneous realization of nanoscale field localization and low transmission loss remains one of the major challenges in nanophotonics. Metal nanowire waveguides can fulfill this goal to a certain extent by confining light within subwavelength space, yet their optical performances are still restricted by the tradeoff between confinement and loss, which results in quite limited propagation distances when their mode sizes are reduced

  5. Correlations in light propagation in one-dimensional waveguides

    NASA Astrophysics Data System (ADS)

    Javanainen, Juha; Ruostekoski, Janne

    2016-05-01

    We study light propagation between atoms in a one-dimensional waveguide both analytically and using numerical simulations. We employ classical electrodynamics, but in the limit of low light intensity the results are essentially exact also for quantum mechanics. We characterize the cooperative interactions between the atoms mediated by the electromagnetic field. The focus is on resonance shifts for various statistics of the positions of the atoms, such as statistically independent positions or atoms in a regular lattice. These shifts, potentially important if 1D waveguides are to be used in metrology, are different from the usual resonance shifts found in three spatial dimensions.

  6. Bound and scattering properties in waveguides around free-space Feshbach resonance

    NASA Astrophysics Data System (ADS)

    Wang, Gaoren; Giannakeas, Panogiotis; Schmelcher, Peter

    2016-05-01

    The two-body bound and scattering properties in an one-dimensional (1D) harmonic waveguide in the vicinity of free-space magnetic Feshbach resonances are investigated based on the local frame transformation approach. The multichannel characteristics of the interatomic interaction is taken into account. We examine the crossing between the bound state in the waveguide and the ground level of the transverse confinement, i.e. when the bound state crosses the scattering threshold in the waveguide and turns into a continuum state. For s-wave collision, the crossing occurs at the magnetic field where the effective 1D interaction strength g1 D vanishes, and the effective 1D scattering length a1 D diverges. This observation indicates that the molecular formation or atom loss signal in a harmonic waveguide is expected at the magnetic field where a1 D is infinite. Molecule formation is absent at position of the confinement induced resonance which is characterized by the divergence of g1 D . Financial support from Alexander von Humboldt Foundation is acknowledged.

  7. Low-loss segmented joint structure between a slab waveguide and arrayed waveguides designed by simple optimization method

    NASA Astrophysics Data System (ADS)

    Shibuya, K.; Idris, N. A.; Asakura, H.; Tsuda, H.

    2015-02-01

    Arrayed-waveguide gratings (AWG) are key devices in optical communication systems using wavelength division multiplexing (WDM), and it is essential that these AWGs are low-loss. In this paper, we propose low-loss segmented joint structures between the slab waveguide and the waveguide array in an AWG. The effectiveness of these structures is confirmed by the measurement results. In addition, improvements in the loss uniformity can be obtained by utilizing mode converting segmented structures between the waveguide array and the slab waveguide on the output side. Moreover, the passband can be flattened by employing such a structure between the input and slab waveguides. These structures were designed using the same simple calculation and optimization method. Using these optimized structures, the transmittance was improved by 17%, the largest difference in insertion loss was reduced by 1.93 dB, and the 1-dB bandwidth was extended by 20%. These structures can be fabricated with ordinary planar lightwave circuit (PLC) technologies without the need for special fabrication processes.

  8. Silicon integrated nanophotonics: from fundamental science to manufacturable technology (Presentation Video)

    NASA Astrophysics Data System (ADS)

    Vlasov, Yurii A.

    2015-02-01

    The IBM Silicon Nanophotonics technology enables cost-efficient optical links that connect racks, modules, and chips together with ultralow power single-die optical transceivers. I will give an overview of its historical development, technology differentiators, current status and a roadmap.

  9. Large-Scale Nanophotonic Solar Selective Absorbers for High-Efficiency Solar Thermal Energy Conversion.

    PubMed

    Li, Pengfei; Liu, Baoan; Ni, Yizhou; Liew, Kaiyang Kevin; Sze, Jeff; Chen, Shuo; Shen, Sheng

    2015-08-19

    An omnidirectional nanophotonic solar selective absorber is fabricated on a large scale using a template-stripping method. The nanopyramid nickel structure achieves an average absorptance of 95% at a wavelength range below 1.3 μm and a low emittance less than 10% at wavelength >2.5 μm. PMID:26134928

  10. A Simple Optical Waveguide Experiment.

    ERIC Educational Resources Information Center

    Phelps, J.; Sambles, J. R.

    1989-01-01

    Describes a thin film rectangular dielectric waveguide and its laboratory use. Discusses the theory of uniaxial thin film waveguides with mathematical expressions and the laboratory procedures for a classroom experiment with diagrams. (Author/YP)

  11. DESIGN OF INTEGRATING WAVEGUIDE BIOSENSOR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Integrating Waveguide Biosensor allows for rapid and sensitive detection of pathogenic agents, cells and proteins via immunoassay or PCR products. The analytes are captured on the surface of the waveguide and then tagged with fluorescent labels. The waveguides are illuminated by excitation light...

  12. "Waveguidability" of idealized jets

    NASA Astrophysics Data System (ADS)

    Manola, Iris; Selten, Frank; Vries, Hylke; Hazeleger, Wilco

    2013-09-01

    It is known that strong zonal jets can act as waveguides for Rossby waves. In this study we use the European Center for Medium-Range Weather Forecasts (ECMWF) reanalysis data to analyze the connection between jets and zonal waves at timescales beyond 10 days. Moreover, a barotropic model is used to systematically study the ability of idealized jets to trap Rossby wave energy ("waveguidability") as a function of jet strength, jet width, and jet location. In general, strongest waveguidability is found for narrow, fast jets. In addition, when the stationary wave number is integer, a resonant response is found through constructive interference. In Austral summer, the Southern Hemispheric jet is closest to the idealized jets considered and it is for this season that similar jet-zonal wave relationships are identified in the ECMWF reanalysis data.

  13. Compact waveguide splitter networks.

    PubMed

    Qian, Yusheng; Song, Jiguo; Kim, Seunghyun; Hu, Weisheng; Nordin, Gregory P

    2008-03-31

    We demonstrate compact waveguide splitter networks in siliconon- insulator (SOI) rib waveguides using trench-based splitters (TBSs) and bends (TBBs). Rather than a 90 degrees geometry, we use 105 degrees TBSs to facilitate reliable fabrication of high aspect ratio trenches suitable for 50/50 splitting when filled with SU8. Three dimensional (3D) finite difference time domain (FDTD) simulation is used for splitter and bend design. Measured TBB and TBS optical efficiencies are 84% and 68%, respectively. Compact 105 degrees 1 x 4, 1 x 8, and 1 x 32 trench-based splitter networks (TBSNs) are demonstrated. The measured total optical loss of the 1 x 32 TBSN is 9.15 dB. Its size is only 700 microm x 1600 microm for an output waveguide spacing of 50 microm. PMID:18542598

  14. Bound and scattering states in harmonic waveguides in the vicinity of free space Feshbach resonances

    NASA Astrophysics Data System (ADS)

    Wang, Gaoren; Giannakeas, Panagiotis; Schmelcher, Peter

    2016-08-01

    The two-body bound and scattering properties in an one-dimensional harmonic waveguide close to free space magnetic Feshbach resonances are investigated based on the local frame transformation approach within a single partial wave approximation. An energy and magnetic field dependent free space phase shift is adopted in the current theoretical framework. For both s- and p-wave interaction, the least bound state in the waveguide dissociates into the continuum at the resonant magnetic field where the effective one-dimensional scattering length {a}{{1D}} diverges. Consequently, the association of atoms into molecules in the waveguide occurs when the magnetic field is swept adiabatically across the pole of {a}{{1D}}. In the vicinity of broad s-wave resonances, the resonant magnetic field is nearly independent on the transverse confining frequency {ω }\\perp of the waveguide. Close to p-wave and narrow s-wave resonances, the resonant magnetic field changes as {ω }\\perp varies.

  15. Square dielectric THz waveguides.

    PubMed

    Aflakian, N; Yang, N; LaFave, T; Henderson, R M; O, K K; MacFarlane, D L

    2016-06-27

    A holey cladding dielectric waveguide with square cross section is designed, simulated, fabricated and characterized. The TOPAS waveguide is designed to be single mode across the broad frequency range of 180 GHz to 360 GHz as shown by finite-difference time domain simulation and to robustly support simultaneous TE and TM mode propagation. The square fiber geometry is realized by pulling through a heat distribution made square by appropriate furnace design. The transmitted mode profile is imaged using a vector network analyzer with a pinhole at the receiver module. Good agreement between the measured mode distribution and the calculated mode distribution is demonstrated. PMID:27410645

  16. Waveguide apparatuses and methods

    DOEpatents

    Spencer, James E.

    2016-05-10

    Optical fiber waveguides and related approaches are implemented to facilitate communication. As may be implemented in accordance with one or more embodiments, a waveguide has a substrate including a lattice structure having a plurality of lattice regions with a dielectric constant that is different than that of the substrate, a defect in the lattice, and one or more deviations from the lattice. The defect acts with trapped transverse modes (e.g., magnetic and/or electric modes) and facilitates wave propagation along a longitudinal direction while confining the wave transversely. The deviation(s) from the lattice produces additional modes and/or coupling effects.

  17. Optical analogue of relativistic Dirac solitons in binary waveguide arrays

    SciTech Connect

    Tran, Truong X.; Longhi, Stefano; Biancalana, Fabio

    2014-01-15

    We study analytically and numerically an optical analogue of Dirac solitons in binary waveguide arrays in the presence of Kerr nonlinearity. Pseudo-relativistic soliton solutions of the coupled-mode equations describing dynamics in the array are analytically derived. We demonstrate that with the found soliton solutions, the coupled mode equations can be converted into the nonlinear relativistic 1D Dirac equation. This paves the way for using binary waveguide arrays as a classical simulator of quantum nonlinear effects arising from the Dirac equation, something that is thought to be impossible to achieve in conventional (i.e. linear) quantum field theory. -- Highlights: •An optical analogue of Dirac solitons in nonlinear binary waveguide arrays is suggested. •Analytical solutions to pseudo-relativistic solitons are presented. •A correspondence of optical coupled-mode equations with the nonlinear relativistic Dirac equation is established.

  18. Metal-clad optical waveguides: analytical and experimental study.

    PubMed

    Kaminow, I P; Mammel, W L; Weber, H P

    1974-02-01

    Planar optical waveguides consisting of thin dielectric films with metal cladding have been investigated theoretically and experimentally. A computer program was devised to provide the phase and attenuation constants and wavefunctions for TE and TM modes in symmetric and asymmetric guides. Approximate expressions suitable for slide-rule calculation were also derived. Numerical results and illustrations are given for films of photoresist with Al, Ag, and Au cladding. Direct measurements of the attenuation and phase constants at 0.633 microm of numerous experimental waveguides are in reasonable agreement with theory. Attenuations <1 dB/cm, which is sufficiently small for application in devices, were measured. Calculated wavefunctions illustrate the mismatch of modes at transitions between unclad and metal-clad waveguides. Experimentally, we find substantial losses at such abrupt junctions. They can be overcome by simple tapered transitions. PMID:20125992

  19. Vought F4U-1D Corsair

    NASA Technical Reports Server (NTRS)

    1945-01-01

    Vought F4U-1D Corsair: In February and March of 1945 this Corsair was examined in the NACA's 30 x 60 Full Scale Tunnel at Langley Field. The F4U-1D has rockets mounted on its wings for this test. After installation and during testing, the wings would be lowered to their flight position.

  20. Single MoO3 nanoribbon waveguides: good building blocks as elements and interconnects for nanophotonic applications

    NASA Astrophysics Data System (ADS)

    Zhang, Li; Wu, Guoqing; Gu, Fuxing; Zeng, Heping

    2015-11-01

    Exploring new nanowaveguide materials and structures is of great scientific interest and technological significance for optical and photonic applications. In this work, high-quality single-crystal MoO3 nanoribbons (NRs) are synthesized and used for optical guiding. External light sources are efficiently launched into the single MoO3 NRs using silica fiber tapers. It is found that single MoO3 NRs are as good nanowaveguides with loss optical losses (typically less than 0.1 dB/μm) and broadband optical guiding in the visible/near-infrared region. Single MoO3 NRs have good Raman gains that are comparable to those of semiconductor nanowaveguides, but the second harmonic generation efficiencies are about 4 orders less than those of semiconductor nanowaveguides. And also no any third-order nonlinear optical effects are observed at high pump power. A hybrid Fabry-Pérot cavity containing an active CdSe nanowire and a passive MoO3 NR is also demonstrated, and the ability of coupling light from other active nanostructures and fluorescent liquid solutions has been further demonstrated. These optical properties make single MoO3 NRs attractive building blocks as elements and interconnects in miniaturized photonic circuitries and devices.

  1. Single MoO3 nanoribbon waveguides: good building blocks as elements and interconnects for nanophotonic applications

    PubMed Central

    Zhang, Li; Wu, Guoqing; Gu, Fuxing; Zeng, Heping

    2015-01-01

    Exploring new nanowaveguide materials and structures is of great scientific interest and technological significance for optical and photonic applications. In this work, high-quality single-crystal MoO3 nanoribbons (NRs) are synthesized and used for optical guiding. External light sources are efficiently launched into the single MoO3 NRs using silica fiber tapers. It is found that single MoO3 NRs are as good nanowaveguides with loss optical losses (typically less than 0.1 dB/μm) and broadband optical guiding in the visible/near-infrared region. Single MoO3 NRs have good Raman gains that are comparable to those of semiconductor nanowaveguides, but the second harmonic generation efficiencies are about 4 orders less than those of semiconductor nanowaveguides. And also no any third-order nonlinear optical effects are observed at high pump power. A hybrid Fabry-Pérot cavity containing an active CdSe nanowire and a passive MoO3 NR is also demonstrated, and the ability of coupling light from other active nanostructures and fluorescent liquid solutions has been further demonstrated. These optical properties make single MoO3 NRs attractive building blocks as elements and interconnects in miniaturized photonic circuitries and devices. PMID:26611855

  2. Plasmonic and nanophotonics sensors from visible to terahertz

    NASA Astrophysics Data System (ADS)

    Hassani, Alireza

    The global research objective of this thesis is to demonstrate design of novel compact and ultra-sensitive plasmonic sensors operating anywhere from the visible to the THz spectral ranges. The enabling technologies for such sensors are photonic bandgap and microstructured waveguides and fibers containing metallic inclusions. We achieve the stated global objective by systematically addressing several smaller problems. Firstly, this thesis demonstrates plasmonic excitation in metalized microstructured fibers in the context of bio-chemical sensing with enhanced microfluidics for visible and IR ranges. Furthemore, this basic design concept is generalized for the use with photonic bandgap fibers and waveguides; major advantages of using photonic bandgap waveguides in place of Total Internal Reflection (TIR) fibers for plasmonic sensing are discovered. In the first chapter, we discuss the theory of surface plasmons, surface plasmon excitation and sensing methodologies. In the second chapter we show that using microstructured fibers one can solve much easier the problem of phase matching between the surface plasmon wave and fiber core mode, which is common when standard TIR fibers are used. Moreover, the use of microstructured fibers enables integration of the microfluidics and optics during drawing step thus simplifying considerably the sensor fabrication and operation. Furthermore, the different shapes of the metalized surface to enhance the plasmonic excitation were explored with an aim to enhance sensitivity. In the third chapter, the design of photonic crystal waveguide-based surface plasmon resonance sensor is proposed. By judicious design of a photonic crystal waveguide, the effective refractive index of a core mode can be made considerably smaller than that of the core material, thus enabling efficient phase matching with a plasmon, high sensitivity, and high coupling efficiency from an external Gaussian source, at any wavelength of choice from the visible to near

  3. Single-polarization hollow-core square photonic bandgap waveguide

    NASA Astrophysics Data System (ADS)

    Eguchi, Masashi; Tsuji, Yasuhide

    2016-07-01

    Materials with a periodic structure have photonic bandgaps (PBGs), in which light can not be guided within certain wavelength ranges; thus light can be confined within a low-index region by the bandgap effect. In this paper, rectangular-shaped hollow waveguides having waveguide-walls (claddings) using the PBG have been discussed. The design principle for HE modes of hollow-core rectangular PBG waveguides with a Bragg cladding consisting of alternating high- and low-index layers, based on a 1D periodic multilayer approximation for the Bragg cladding, is established and then a novel single-polarization hollow-core square PBG waveguide using the bandgap difference between two polarized waves is proposed. Our results demonstrated that a single-polarization guiding can be achieved by using the square Bragg cladding structure with different layer thickness ratios in the mutually orthogonal directions and the transmission loss of the guided mode in a designed hollow-core square PBG waveguide is numerically estimated to be 0.04 dB/cm.

  4. Transmission of photonic quantum polarization entanglement in a nanoscale hybrid plasmonic waveguide.

    PubMed

    Li, Ming; Zou, Chang-Ling; Ren, Xi-Feng; Xiong, Xiao; Cai, Yong-Jing; Guo, Guo-Ping; Tong, Li-Min; Guo, Guang-Can

    2015-04-01

    Photonic quantum technologies have been extensively studied in quantum information science, owing to the high-speed transmission and outstanding low-noise properties of photons. However, applications based on photonic entanglement are restricted due to the diffraction limit. In this work, we demonstrate for the first time the maintaining of quantum polarization entanglement in a nanoscale hybrid plasmonic waveguide composed of a fiber taper and a silver nanowire. The transmitted state throughout the waveguide has a fidelity of 0.932 with the maximally polarization entangled state Φ(+). Furthermore, the Clauser, Horne, Shimony, and Holt (CHSH) inequality test performed, resulting in value of 2.495 ± 0.147 > 2, demonstrates the violation of the hidden variable model. Because the plasmonic waveguide confines the effective mode area to subwavelength scale, it can bridge nanophotonics and quantum optics and may be used as near-field quantum probe in a quantum near-field micro/nanoscope, which can realize high spatial resolution, ultrasensitive, fiber-integrated, and plasmon-enhanced detection. PMID:25775140

  5. Statistics of scattered photons from a driven three-level emitter in 1D open space

    SciTech Connect

    Roy, Dibyendu; Bondyopadhaya, Nilanjan

    2014-01-07

    We derive the statistics of scattered photons from a Λ- or ladder-type three-level emitter (3LE) embedded in a 1D open waveguide. The weak probe photons in the waveguide are coupled to one of the two allowed transitions of the 3LE, and the other transition is driven by a control beam. This system shows electromagnetically induced transparency (EIT) which is accompanied with the Autler-Townes splitting (ATS) at a strong driving by the control beam, and some of these effects have been observed recently. We show that the nature of second-order coherence of the transmitted probe photons near two-photon resonance changes from bunching to antibunching to constant as strength of the control beam is ramped up from zero to a higher value where the ATS appears.

  6. Experimental investigation of plasmofluidic waveguides

    SciTech Connect

    Ku, Bonwoo; Kwon, Min-Suk; Shin, Jin-Soo

    2015-11-16

    Plasmofluidic waveguides are based on guiding light which is strongly confined in fluid with the assistance of a surface plasmon polariton. To realize plasmofluidic waveguides, metal-insulator-silicon-insulator-metal (MISIM) waveguides, which are hybrid plasmonic waveguides fabricated using standard complementary metal-oxide-semiconductor technology, are employed. The insulator of the MISIM waveguide is removed to form 30-nm-wide channels, and they are filled with fluid. The plasmofluidic waveguide has a subwavelength-scale mode area since its mode is strongly confined in the fluid. The waveguides are experimentally characterized for different fluids. When the refractive index of the fluid is 1.440, the plasmofluidic waveguide with 190-nm-wide silicon has propagation loss of 0.46 dB/μm; the coupling loss between it and an ordinary silicon photonic waveguide is 1.79 dB. The propagation and coupling losses may be reduced if a few fabrication-induced imperfections are removed. The plasmofluidic waveguide may pave the way to a dynamically phase-tunable ultracompact device.

  7. Gap plasmon excitation in plasmonic waveguide using Si waveguide

    NASA Astrophysics Data System (ADS)

    Okuda, Koji; Kamada, Shun; Okamoto, Toshihiro; Haraguchi, Masanobu

    2016-08-01

    Plasmonic waveguides have attracted considerable attention for application in highly integrated optical circuits since they can confine light to areas smaller than the diffraction limit. In this context, in order to realize a highly integrated optical circuit, we fabricate and evaluate the optical characteristics of a poly(methyl methacrylate) junction positioned between Si and plasmonic waveguides. For the plasmonic waveguide, we employ a gap plasmonic waveguide in which the energy of the plasmonic wave can be confined in order to reduce the scattering loss at the junction. By experimental measurement, we determine the coupling efficiency between the Si and gap plasmonic waveguides and the propagation length at the gap plasmonic waveguide to be 52.4% and 11.1 µm, respectively. These values agree with those obtained by the three-dimensional finite-difference time-domain simulation. We believe that our findings can significantly contribute to the development of highly integrated optical circuits.

  8. Waveguide integrated superconducting single-photon detectors with high internal quantum efficiency at telecom wavelengths

    PubMed Central

    Kahl, Oliver; Ferrari, Simone; Kovalyuk, Vadim; Goltsman, Gregory N.; Korneev, Alexander; Pernice, Wolfram H. P.

    2015-01-01

    Superconducting nanowire single-photon detectors (SNSPDs) provide high efficiency for detecting individual photons while keeping dark counts and timing jitter minimal. Besides superior detection performance over a broad optical bandwidth, compatibility with an integrated optical platform is a crucial requirement for applications in emerging quantum photonic technologies. Here we present SNSPDs embedded in nanophotonic integrated circuits which achieve internal quantum efficiencies close to unity at 1550 nm wavelength. This allows for the SNSPDs to be operated at bias currents far below the critical current where unwanted dark count events reach milli-Hz levels while on-chip detection efficiencies above 70% are maintained. The measured dark count rates correspond to noise-equivalent powers in the 10−19 W/Hz−1/2 range and the timing jitter is as low as 35 ps. Our detectors are fully scalable and interface directly with waveguide-based optical platforms. PMID:26061283

  9. Molecular Imaging of Biological Samples on Nanophotonic Laser Desorption Ionization Platforms.

    PubMed

    Stopka, Sylwia A; Rong, Charles; Korte, Andrew R; Yadavilli, Sridevi; Nazarian, Javad; Razunguzwa, Trust T; Morris, Nicholas J; Vertes, Akos

    2016-03-24

    Mass spectrometry imaging (MSI) is a comprehensive tool for the analysis of a wide range of biomolecules. The mainstream method for molecular MSI is matrix-assisted laser desorption ionization, however, the presence of a matrix results in spectral interferences and the suppression of some analyte ions. Herein we demonstrate a new matrix-free MSI technique using nanophotonic ionization based on laser desorption ionization (LDI) from a highly uniform silicon nanopost array (NAPA). In mouse brain and kidney tissue sections, the distributions of over 80 putatively annotated molecular species are determined with 40 μm spatial resolution. Furthermore, NAPA-LDI-MS is used to selectively analyze metabolites and lipids from sparsely distributed algal cells and the lamellipodia of human hepatocytes. Our results open the door for matrix-free MSI of tissue sections and small cell populations by nanophotonic ionization. PMID:26929010

  10. Fabrication and characterization of III-nitride nanophotonic devices

    NASA Astrophysics Data System (ADS)

    Dahal, Rajendra Prasad

    III-nitride photonic devices such as photodetectors (PDs), light emitting diode (LEDs), solar cells and optical waveguide amplifiers were designed, fabricated and characterized. High quality AlN epilayers were grown on sapphire and n-SiC substrates by metal organic chemical vapor deposition and utilized as active deep UV (DUV) photonic materials for the demonstration of metal-semiconductor-metal (MSM) detectors, Schottky barrier detectors, and avalanche photodetectors (APDs). AlN DUV PDs exhibited peak responsivity at 200 nm with a very sharp cutoff wavelength at 207 nm and extremely low dark current (<10 fA), very high breakdown voltages, high responsivity, and more than four orders of DUV to UV/visible rejection ratio. AlN Schottky PDs grown on n-SiC substrates exhibited high zero bias responsivity and a thermal energy limited detectivity of about 1.0 x 1015 cm Hz 1/2 W-1. The linear mode operation of AlN APDs with the shortest cutoff wavelength (210 nm) and a photocurrent multiplication of 1200 was demonstrated. A linear relationship between device size and breakdown field was observed for AlN APDs. Photovoltaic operation of InGaN solar cells in wavelengths longer than that of previous attainments was demonstrated by utilizing In xGa1-xN/GaN MQWs as the active layer. InxGa1-xN/GaN MQWs solar cells with x =0.3 exhibited open circuit voltage of about 2 V, a fill factor of about 60% and external quantum efficiency of 40% at 420 nm and 10% at 450 nm. The performance of InxGa1-xN/GaN MQWs solar cell was found to be highly correlated with the crystalline quality of the InxGa 1-xN active layer. The possible causes of poorer PV characteristics for higher In content in InGaN active layer were explained. Photoluminescence excitation studies of GaN:Er and In0.06Ga 0.94N:Er epilayers showed that Er emission intensity at 1.54 mum increases significantly as the excitation energy is tuned from below to above the energy bandgap of these epilayers. Current-injected 1.54 mum LEDs

  11. Symmetric Waveguide Orthomode Junctions

    NASA Technical Reports Server (NTRS)

    Wollack, E. J.; Grammer, W.

    2003-01-01

    Imaging applications at millimeter and submillimeter wavelengths demand precise characterization of the amplitude, spectrum, and polarization of the electromagnetic radiation. The use of a waveguide orthomode transducer (OMT) can help achieve these goals by increasing spectral coverage and sensitivity while reducing exit aperture size, optical spill, instrumental polarization offsets, and lending itself to integration in focal plane arrays. For these reasons, four-old symmetric OMTs are favored over a traditional quasi-optical wire grid for focal plane imaging arrays from a systems perspective. The design, fabrication, and test of OMTs realized with conventional split-block techniques for millimeter wave-bands are described. The design provides a return loss is -20 dB over a full waveguide band (40% bandwidth), and the cross-polarization and isolation are greater than -40 dB for tolerances readily achievable in practice. Prototype examples realized in WR10.0 and WR3.7 wavebands will be considered in detail.

  12. Symmetric Waveguide Orthomode Junctions

    NASA Technical Reports Server (NTRS)

    Wollack, E. J.; Grammer, W.

    2003-01-01

    Imaging applications at millimeter and submillimeter wavelengths demand precise characterization of the amplitude, spectrum, and polarization of the electromagnetic radiation. The use of a waveguide orthomode transducer (OMT) can help achieve these goals by increasing spectral coverage and sensitivity while reducing exit aperture size, optical spill, instrumental polarization offsets, and lending itself to integration in focal plane arrays. For these reasons, four-fold symmetric OMTs are favored over a traditional quasi-optical wire grid for focal plane imaging arrays from a systems perspective. The design, fabrication, and test of OMTs realized with conventional split-block techniques for millimeter wave-bands are described. The design provides a return loss is -20 dB over a full waveguide band (40% bandwidth), and the cross-polarization and isolation are greater than -40 dB for tolerances readily achievable in practice. Prototype examples realized in WR10.0 and WR3.7 wavebands will be considered in detail.

  13. Computing Scattering Characteristics Of Waveguide Junctions

    NASA Technical Reports Server (NTRS)

    Hoppe, Daniel J.; Manshadi, Farzin

    1994-01-01

    Rectangular WaveGuide Junction SCATtering RWGSCAT computer program solves scattering properties of waveguide device. Modeled as assembly of rectangular waveguides of different cross sections. RWGSCAT written in FORTRAN 77.

  14. Optical waveguide dosimeter

    SciTech Connect

    Kronenberg, S.; Levine, H.; Mclaughlin, W.L.; Siebentritt, C.R.

    1983-03-22

    An optical waveguide dosimeter for personnel dosimetry is provided including a liquid solution of leuko dye hermetically sealed in plastic tubing. Optical transport is improved by dipping the ends of the plastic tubing into clear epoxy, thus forming beads that serve as optical lenses. A layer of clear ultraviolet absorbing varnish coated on these beads and an opaque outer layer over the plastic tubing provides protection against ambient uv.

  15. Investigation of Truncated Waveguides

    NASA Technical Reports Server (NTRS)

    Lourie, Nathan P.; Chuss, David T.; Henry, Ross M.; Wollack, Edward J.

    2013-01-01

    The design, fabrication, and performance of truncated circular and square waveguide cross-sections are presented. An emphasis is placed upon numerical and experimental validation of simple analytical formulae that describe the propagation properties of these structures. A test component, a 90-degree phase shifter, was fabricated and tested at 30 GHz. The concepts explored can be directly applied in the design, synthesis and optimization of components in the microwave to sub-millimeter wavebands.

  16. Microwave waveguide manifold and method

    DOEpatents

    Staehlin, John H.

    1987-01-01

    A controllably electrically coupled, physically intersecting plural waveguide manifold assembly wherein the intersecting waveguide elements are fabricated in integral unitary relationship from a single piece of metal in order to avoid the inaccuracies and difficult-to-control fabrication steps associated with uniting separate waveguide elements into a unitary structure. An X-band aluminum airborne radar manifold example is disclosed, along with a fabrication sequence for the manifold and the electrical energy communicating apertures joining the manifold elements.

  17. Microwave waveguide manifold and method

    DOEpatents

    Staehlin, John H.

    1987-12-01

    A controllably electrically coupled, physically intersecting plural waveguide manifold assembly wherein the intersecting waveguide elements are fabricated in integral unitary relationship from a single piece of metal in order to avoid the inaccuracies and difficult-to-control fabrication steps associated with uniting separate waveguide elements into a unitary structure. An X-band aluminum airborne radar manifold example is disclosed, along with a fabrication sequence for the manifold and the electrical energy communicating apertures joining the manifold elements.

  18. Cup Cylindrical Waveguide Antenna

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.; Darby, William G.; Kory, Carol L.; Lambert, Kevin M.; Breen, Daniel P.

    2008-01-01

    The cup cylindrical waveguide antenna (CCWA) is a short backfire microwave antenna capable of simultaneously supporting the transmission or reception of two distinct signals having opposite circular polarizations. Short backfire antennas are widely used in mobile/satellite communications, tracking, telemetry, and wireless local area networks because of their compactness and excellent radiation characteristics. A typical prior short backfire antenna contains a half-wavelength dipole excitation element for linear polarization or crossed half-wavelength dipole elements for circular polarization. In order to achieve simultaneous dual circular polarization, it would be necessary to integrate, into the antenna feed structure, a network of hybrid components, which would introduce significant losses. The CCWA embodies an alternate approach that entails relatively low losses and affords the additional advantage of compactness. The CCWA includes a circular cylindrical cup, a circular disk subreflector, and a circular waveguide that serves as the excitation element. The components that make it possible to obtain simultaneous dual circular polarization are integrated into the circular waveguide. These components are a sixpost polarizer and an orthomode transducer (OMT) with two orthogonal coaxial ports. The overall length of the OMT and polarizer (for the nominal middle design frequency of 2.25 GHz) is about 11 in. (approximately equal to 28 cm), whereas the length of a commercially available OMT and polarizer for the same frequency is about 32 in. (approximately equal to 81 cm).

  19. Folded waveguide coupler

    DOEpatents

    Owens, Thomas L.

    1988-03-01

    A resonant cavity waveguide coupler for ICRH of a magnetically confined plasma. The coupler consists of a series of inter-leaved metallic vanes disposed withn an enclosure analogous to a very wide, simple rectangular waveguide that has been "folded" several times. At the mouth of the coupler, a polarizing plate is provided which has coupling apertures aligned with selected folds of the waveguide through which rf waves are launched with magnetic fields of the waves aligned in parallel with the magnetic fields confining the plasma being heated to provide coupling to the fast magnetosonic wave within the plasma in the frequency usage of from about 50-200 mHz. A shorting plate terminates the back of the cavity at a distance approximately equal to one-half the guide wavelength from the mouth of the coupler to ensure that the electric field of the waves launched through the polarizing plate apertures are small while the magnetic field is near a maximum. Power is fed into the coupler folded cavity by means of an input coaxial line feed arrangement at a point which provides an impedance match between the cavity and the coaxial input line.

  20. Loss mechanisms in polyimide waveguides

    SciTech Connect

    Kowalczyk, T.C.; Kosc, T.; Singer, K.D. ); Cahill, P.A.; Seager, C.H.; Meinhardt, M.B. ); Beuhler, A.J.; Wargowski, D.A. )

    1994-08-15

    Waveguide losses in thin film polyimides using waveguide loss spectroscopy and photothermal deflection spectroscopy as a function of cure cycle and structure were studied. Fluorinated sidegroups on the polyimide backbone lead to decreases in birefringence and absorption. The primary waveguide loss mechanism is absorption, not scattering. Waveguide losses as low as 0.4 dB/cm at 800 nm have been measured. Losses as low as 0.3 dB/cm at 1300 nm can be inferred from the photothermal deflection spectroscopy.

  1. Composite waveguide on a photorefractive crystal

    SciTech Connect

    Usievich, B A; Nurligareev, D Kh; Sychugov, V A; Ivleva, Lyudmila I

    2011-10-31

    A new waveguiding structure (composite waveguide) has been proposed, which has the form of a linear dielectric layer on the surface of a photorefractive crystal and supports spatially confined modes propagating along its surface. We demonstrate that the modal properties of the composite waveguide are determined by those of a Bragg waveguide and the properties of nonlinear surface waves and the leaky modes of the thin-film waveguide. Various schemes of mode excitation in the composite waveguide are examined.

  2. Photonic Waveguide Choke Joint with Absorptive Loading

    NASA Technical Reports Server (NTRS)

    Wollack, Edward J. (Inventor); U-Yen, Kongpop (Inventor); Chuss, David T. (Inventor)

    2016-01-01

    A photonic waveguide choke includes a first waveguide flange member having periodic metal tiling pillars, a dissipative dielectric material positioned within an area between the periodic metal tiling pillars and a second waveguide flange member disposed to be coupled with the first waveguide flange member and in spaced-apart relationship separated by a gap. The first waveguide flange member has a substantially smooth surface, and the second waveguide flange member has an array of two-dimensional pillar structures formed therein.

  3. Interacting single atoms with nanophotonics for chip-integrated quantum networks

    NASA Astrophysics Data System (ADS)

    Alton, Daniel James

    Underlying matter and light are their building blocks of tiny atoms and photons. The ability to control and utilize matter-light interactions down to the elementary single atom and photon level at the nano-scale opens up exciting studies at the frontiers of science with applications in medicine, energy, and information technology. Of these, an intriguing front is the development of quantum networks where N ≫ 1 single-atom nodes are coherently linked by single photons, forming a collective quantum entity potentially capable of performing quantum computations and simulations. Here, a promising approach is to use optical cavities within the setting of cavity quantum electrodynamics (QED). However, since its first realization in 1992 by Kimble et al., current proof-of-principle experiments have involved just one or two conventional cavities. To move beyond to N ≫ 1 nodes, in this thesis we investigate a platform born from the marriage of cavity QED and nanophotonics, where single atoms at ˜100 nm near the surfaces of lithographically fabricated dielectric photonic devices can strongly interact with single photons, on a chip. Particularly, we experimentally investigate three main types of devices: microtoroidal optical cavities, optical nanofibers, and nanophotonic crystal based structures. With a microtoroidal cavity, we realized a robust and efficient photon router where single photons are extracted from an incident coherent state of light and redirected to a separate output with high efficiency. We achieved strong single atom-photon coupling with atoms located ~100 nm near the surface of a microtoroid, which revealed important aspects in the atom dynamics and QED of these systems including atom-surface interaction effects. We present a method to achieve state-insensitive atom trapping near optical nanofibers, critical in nanophotonic systems where electromagnetic fields are tightly confined. We developed a system that fabricates high quality nanofibers with high

  4. New coplanar waveguide to rectangular waveguide end launcher

    NASA Technical Reports Server (NTRS)

    Simons, R. N.; Taub, S. R.

    1992-01-01

    A new coplanar waveguide to rectangular waveguide end launcher is experimentally demonstrated. The end launcher operates over the Ka-band frequencies that are designated for the NASA Advanced Communication Technology Satellite uplink. The measured insertion loss and return loss are better than 0.5 and -10 dB, respectively.

  5. Slab waveguide theory for general multi-slot waveguide

    NASA Astrophysics Data System (ADS)

    Le, ZiChun; Yin, LiXiang; Zou, Yu; Wu, Xiang

    2016-07-01

    Optical devices based on slot waveguide are of considerable interest in numerous applications due to the distinct feature of strong electric field confinement in a low-refractive index region. A theoretical model based on multi-slab waveguide theory is used to reveal the physical mechanism of the slot waveguide. The calculation results derived from the basic Helmholtz equation for the conventional single-slot waveguide with a ~2% validation of the effective refractive index are compared to the former experiment results by the Cornell University group. Moreover, we extend the theoretical model to a general multi-slot waveguide. Its electric field distribution and key properties such as optical power confinement factor and enhancement factor in slot are deduced theoretically and fully discussed.

  6. Hollow waveguide cavity ringdown spectroscopy

    NASA Technical Reports Server (NTRS)

    Dreyer, Chris (Inventor); Mungas, Greg S. (Inventor)

    2012-01-01

    Laser light is confined in a hollow waveguide between two highly reflective mirrors. This waveguide cavity is used to conduct Cavity Ringdown Absorption Spectroscopy of loss mechanisms in the cavity including absorption or scattering by gases, liquid, solids, and/or optical elements.

  7. 1D ferrimagnetism in homometallic chains

    NASA Astrophysics Data System (ADS)

    Coronado, E.; Gómez-García, C. J.; Borrás-Almenar, J. J.

    1990-05-01

    The magnetic properties of the cobalt zigzag chain Co(bpy)(NCS)2 (bpy=2,2'-bipyridine) are discussed on the basis of an Ising-chain model that takes into account alternating Landé factors. It is emphasized, for the first time, that a homometallic chain containing only one type of site can give rise to a 1D ferrimagneticlike behavior.

  8. DESIGN PACKAGE 1D SYSTEM SAFETY ANALYSIS

    SciTech Connect

    L.R. Eisler

    1995-02-02

    The purpose of this analysis is to systematically identify and evaluate hazards related to the Yucca Mountain Project Exploratory Studies Facility (ESF) Design Package 1D, Surface Facilities, (for a list of design items included in the package 1D system safety analysis see section 3). This process is an integral part of the systems engineering process; whereby safety is considered during planning, design, testing, and construction. A largely qualitative approach was used since a radiological System Safety analysis is not required. The risk assessment in this analysis characterizes the accident scenarios associated with the Design Package 1D structures/systems/components in terms of relative risk and includes recommendations for mitigating all identified risks. The priority for recommending and implementing mitigation control features is: (1) Incorporate measures to reduce risks and hazards into the structure/system/component (S/S/C) design, (2) add safety devices and capabilities to the designs that reduce risk, (3) provide devices that detect and warn personnel of hazardous conditions, and (4) develop procedures and conduct training to increase worker awareness of potential hazards, on methods to reduce exposure to hazards, and on the actions required to avoid accidents or correct hazardous conditions. The scope of this analysis is limited to the Design Package 1D structures/systems/components (S/S/Cs) during normal operations excluding hazards occurring during maintenance and ''off normal'' operations.

  9. Observation of Photon Echoes From Evanescently Coupled Rare-Earth Ions in a Planar Waveguide

    NASA Astrophysics Data System (ADS)

    Marzban, Sara; Bartholomew, John G.; Madden, Stephen; Vu, Khu; Sellars, Matthew J.

    2015-07-01

    We report the measurement of the inhomogeneous linewidth, homogeneous linewidth, and spin-state lifetime of Pr3 + ions in a novel waveguide architecture. The TeO2 slab waveguide deposited on a bulk Pr3 +∶Y2SiO5 crystal allows the 3H4↔1D2 transition of Pr3 + ions to be probed by the optical evanescent field that extends into the substrate. The 2-GHz inhomogeneous linewidth, the optical coherence time of 70 ±5 μ s , and the spin-state lifetime of 9.8 ±0.3 s indicate that the properties of ions interacting with the waveguide mode are consistent with those of bulk ions. This result establishes the foundation for large, integrated, and high performance rare-earth-ion quantum systems based on a waveguide platform.

  10. Observation of Photon Echoes From Evanescently Coupled Rare-Earth Ions in a Planar Waveguide.

    PubMed

    Marzban, Sara; Bartholomew, John G; Madden, Stephen; Vu, Khu; Sellars, Matthew J

    2015-07-01

    We report the measurement of the inhomogeneous linewidth, homogeneous linewidth, and spin-state lifetime of Pr3+ ions in a novel waveguide architecture. The TeO2 slab waveguide deposited on a bulk Pr3+∶Y2SiO5 crystal allows the 3H4↔1D2 transition of Pr3+ ions to be probed by the optical evanescent field that extends into the substrate. The 2-GHz inhomogeneous linewidth, the optical coherence time of 70±5  μs, and the spin-state lifetime of 9.8±0.3  s indicate that the properties of ions interacting with the waveguide mode are consistent with those of bulk ions. This result establishes the foundation for large, integrated, and high performance rare-earth-ion quantum systems based on a waveguide platform. PMID:26182097

  11. Low-loss chalcogenide waveguides for chemical sensing in the mid-infrared.

    PubMed

    Ma, Pan; Choi, Duk-Yong; Yu, Yi; Gai, Xin; Yang, Zhiyong; Debbarma, Sukanta; Madden, Steve; Luther-Davies, Barry

    2013-12-01

    We report the characteristics of low-loss chalcogenide waveguides for sensing in the mid-infrared (MIR). The waveguides consisted of a Ge₁₁.₅As₂₄Se₆₄.₅ rib waveguide core with a 10nm fluoropolymer coating on a Ge₁₁.₅As₂₄S₆₄.₅ bottom cladding and were fabricated by thermal evaporation, photolithography and ICP plasma etching. Over most of the functional group band from 1500 to 4000 cm⁻¹ the losses were < 1 dB/cm with a minimum of 0.3 dB/cm at 2000 cm⁻¹. The basic capabilities of these waveguides for spectroscopy were demonstrated by measuring the absorption spectrum of soluble Prussian blue in Dimethyl Sulphoxide. PMID:24514544

  12. Integrated optic waveguide devices

    NASA Technical Reports Server (NTRS)

    Ramer, O. G.

    1980-01-01

    Integrated optic waveguide circuits with a phase bias and modulator on the same chip were designed, fabricated, and tested for use in a fiber-optic rotation sensor (gyro) under development. Single mode fiber-optic pigtails were permanently coupled to the four ports of the chip. The switch format was based on coherent coupling between waveguides formed in Z-cut LiNbO3. The control of the coupling was achieved by electro-optically varying the phase propagation constants of each guide. Fiber-to-chip interfacing required the development of appropriate fixturing and manipulation techniques to achieve the close tolerance needed for high coupling efficiency between a fiber with an approximately 5 micron m core and a channel guide with a roughly 2 micron m by 5 micron m cross section. Switch and chip performance at 0.85 micron m is discussed as well as potential improvements related to insertion loss reduction, switching voltages, and suppression of Li2O out-diffusion.

  13. Förster resonance energy transfer rate in any dielectric nanophotonic medium with weak dispersion

    NASA Astrophysics Data System (ADS)

    Wubs, Martijn; Vos, Willem L.

    2016-05-01

    Motivated by the ongoing debate about nanophotonic control of Förster resonance energy transfer (FRET), notably by the local density of optical states (LDOS), we study FRET and spontaneous emission in arbitrary nanophotonic media with weak dispersion and weak absorption in the frequency overlap range of donor and acceptor. This system allows us to obtain the following two new insights. Firstly, we derive that the FRET rate only depends on the static part of the Green function. Hence, the FRET rate is independent of frequency, in contrast to spontaneous-emission rates and LDOS that are strongly frequency dependent in nanophotonic media. Therefore, the position-dependent FRET rate and the LDOS at the donor transition frequency are completely uncorrelated for any nondispersive medium. Secondly, we derive an exact expression for the FRET rate as a frequency integral of the imaginary part of the Green function. This leads to very accurate approximation for the FRET rate that features the LDOS that is integrated over a huge bandwidth ranging from zero frequency to far into the UV. We illustrate these general results for the analytic model system of a pair of ideal dipole emitters—donor and acceptor—in the vicinity of an ideal mirror. We find that the FRET rate is independent of the LDOS at the donor emission frequency. Moreover, we observe that the FRET rate hardly depends on the frequency-integrated LDOS. Nevertheless, the FRET is controlled between inhibition and 4×enhancement at distances close to the mirror, typically a few nm. Finally, we discuss the consequences of our results to applications of Förster resonance energy transfer, for instance in quantum information processing.

  14. Nanophotonic reservoir computing with photonic crystal cavities to generate periodic patterns.

    PubMed

    Fiers, Martin Andre Agnes; Van Vaerenbergh, Thomas; Wyffels, Francis; Verstraeten, David; Schrauwen, Benjamin; Dambre, Joni; Bienstman, Peter

    2014-02-01

    Reservoir computing (RC) is a technique in machine learning inspired by neural systems. RC has been used successfully to solve complex problems such as signal classification and signal generation. These systems are mainly implemented in software, and thereby they are limited in speed and power efficiency. Several optical and optoelectronic implementations have been demonstrated, in which the system has signals with an amplitude and phase. It is proven that these enrich the dynamics of the system, which is beneficial for the performance. In this paper, we introduce a novel optical architecture based on nanophotonic crystal cavities. This allows us to integrate many neurons on one chip, which, compared with other photonic solutions, closest resembles a classical neural network. Furthermore, the components are passive, which simplifies the design and reduces the power consumption. To assess the performance of this network, we train a photonic network to generate periodic patterns, using an alternative online learning rule called first-order reduced and corrected error. For this, we first train a classical hyperbolic tangent reservoir, but then we vary some of the properties to incorporate typical aspects of a photonics reservoir, such as the use of continuous-time versus discrete-time signals and the use of complex-valued versus real-valued signals. Then, the nanophotonic reservoir is simulated and we explore the role of relevant parameters such as the topology, the phases between the resonators, the number of nodes that are biased and the delay between the resonators. It is important that these parameters are chosen such that no strong self-oscillations occur. Finally, our results show that for a signal generation task a complex-valued, continuous-time nanophotonic reservoir outperforms a classical (i.e., discrete-time, real-valued) leaky hyperbolic tangent reservoir (normalized root-mean-square errors=0.030 versus NRMSE=0.127). PMID:24807033

  15. Preparation of 1D nanostructures using biomolecules

    NASA Astrophysics Data System (ADS)

    Pruneanu, Stela; Olenic, Liliana; Barbu Tudoran, Lucian; Kacso, Irina; Farha Al-Said, Said A.; Hassanien, Reda; Houlton, Andrew; Horrocks, Benjamin R.

    2009-08-01

    In this paper we have shown that one-dimensional (1D) particle arrays can be obtained using biomolecules, like DNA or amino-acids. Nano-arrays of silver and gold were prepared in a single-step synthesis, by exploiting the binding abilities of λ-DNA and L-Arginine. The morphology and optical properties of these nanostructures were investigated using AFM, TEM and UV-Vis absorption spectroscopy.

  16. Centrosome Positioning in 1D Cell Migration

    NASA Astrophysics Data System (ADS)

    Adlerz, Katrina; Aranda-Espinoza, Helim

    During cell migration, the positioning of the centrosome and nucleus define a cell's polarity. For a cell migrating on a two-dimensional substrate the centrosome is positioned in front of the nucleus. Under one-dimensional confinement, however, the centrosome is positioned behind the nucleus in 60% of cells. It is known that the centrosome is positioned by CDC42 and dynein for cells moving on a 2D substrate in a wound-healing assay. It is currently unknown, however, if this is also true for cells moving under 1D confinement, where the centrosome position is often reversed. Therefore, centrosome positioning was studied in cells migrating under 1D confinement, which mimics cells migrating through 3D matrices. 3 to 5 μm fibronectin lines were stamped onto a glass substrate and cells with fluorescently labeled nuclei and centrosomes migrated on the lines. Our results show that when a cell changes directions the centrosome position is maintained. That is, when the centrosome is between the nucleus and the cell's trailing edge and the cell changes direction, the centrosome will be translocated across the nucleus to the back of the cell again. A dynein inhibitor did have an influence on centrosome positioning in 1D migration and change of directions.

  17. Coalescence phenomena in 1D silver nanostructures

    NASA Astrophysics Data System (ADS)

    Gutiérrez-Wing, C.; Pérez-Alvarez, M.; Mondragón-Galicia, G.; Arenas-Alatorre, J.; Gutiérrez-Wing, M. T.; Henk, M. C.; Negulescu, I. I.; Rusch, K. A.

    2009-07-01

    Different coalescence processes on 1D silver nanostructures synthesized by a PVP assisted reaction in ethylene glycol at 160 °C were studied experimentally and theoretically. Analysis by TEM and HRTEM shows different defects found on the body of these materials, suggesting that they were induced by previous coalescence processes in the synthesis stage. TEM observations showed that irradiation with the electron beam eliminates the boundaries formed near the edges of the structures, suggesting that this process can be carried out by the application of other means of energy (i.e. thermal). These results were also confirmed by theoretical calculations by Monte Carlo simulations using a Sutton-Chen potential. A theoretical study by molecular dynamics simulation of the different coalescence processes on 1D silver nanostructures is presented, showing a surface energy driven sequence followed to form the final coalesced structure. Calculations were made at 1000-1300 K, which is near the melting temperature of silver (1234 K). Based on these results, it is proposed that 1D nanostructures can grow through a secondary mechanism based on coalescence, without losing their dimensionality.

  18. Broadband nanophotonic wireless links and networks using on-chip integrated plasmonic antennas.

    PubMed

    Yang, Yuanqing; Li, Qiang; Qiu, Min

    2016-01-01

    Owing to their high capacity and flexibility, broadband wireless communications have been widely employed in radio and microwave regimes, playing indispensable roles in our daily life. Their optical analogs, however, have not been demonstrated at the nanoscale. In this paper, by exploiting plasmonic nanoantennas, we demonstrate the complete design of broadband wireless links and networks in the realm of nanophotonics. With a 100-fold enhancement in power transfer superior to previous designs as well as an ultrawide bandwidth that covers the entire telecommunication wavelength range, such broadband nanolinks and networks are expected to pave the way for future optical integrated nanocircuits. PMID:26783033

  19. Broadband nanophotonic wireless links and networks using on-chip integrated plasmonic antennas

    NASA Astrophysics Data System (ADS)

    Yang, Yuanqing; Li, Qiang; Qiu, Min

    2016-01-01

    Owing to their high capacity and flexibility, broadband wireless communications have been widely employed in radio and microwave regimes, playing indispensable roles in our daily life. Their optical analogs, however, have not been demonstrated at the nanoscale. In this paper, by exploiting plasmonic nanoantennas, we demonstrate the complete design of broadband wireless links and networks in the realm of nanophotonics. With a 100-fold enhancement in power transfer superior to previous designs as well as an ultrawide bandwidth that covers the entire telecommunication wavelength range, such broadband nanolinks and networks are expected to pave the way for future optical integrated nanocircuits.

  20. Broadband nanophotonic wireless links and networks using on-chip integrated plasmonic antennas

    PubMed Central

    Yang, Yuanqing; Li, Qiang; Qiu, Min

    2016-01-01

    Owing to their high capacity and flexibility, broadband wireless communications have been widely employed in radio and microwave regimes, playing indispensable roles in our daily life. Their optical analogs, however, have not been demonstrated at the nanoscale. In this paper, by exploiting plasmonic nanoantennas, we demonstrate the complete design of broadband wireless links and networks in the realm of nanophotonics. With a 100-fold enhancement in power transfer superior to previous designs as well as an ultrawide bandwidth that covers the entire telecommunication wavelength range, such broadband nanolinks and networks are expected to pave the way for future optical integrated nanocircuits. PMID:26783033

  1. Origin of high strength and nanophotonic properties of crab shell (Paralithodes camtschaticus)

    SciTech Connect

    Aurognzeb, Deeder

    2009-03-01

    Understanding biomaterial is very important for superior material development. Here, we report structural and nanophotonic properties of crab shell. The fibrous shell is composed of nanocrystalline calcite, which gives the structure very high strength. Scanning electron microscope cross section and energy dispersive x-ray shows top surface (reddish) is fibrous with metal nanoparticle segregation, while the bottom layer is composed of layered nanohole array similar to air-dielectric photonic lattice structure. The air-dielectric nanohole arrays are disordered but correlated with fractal dimension >1 and able to block infrared. Nanocrystalline calcite and metal nanoparticles can also block extreme level of UV.

  2. Configurable silicon photonic crystal waveguides

    SciTech Connect

    Prorok, Stefan; Petrov, Alexander; Eich, Manfred; Luo, Jingdong; Jen, Alex K.-Y.

    2013-12-23

    In this Letter, we demonstrate that the mode cut off of a photonic crystal waveguide can be trimmed with high accuracy by electron beam bleaching of a chromophore doped polymer cladding. Using this method, configurable waveguides are realized, which allow for spatially resolved changes of the photonic crystal's effective lattice constant as small as 7.6 pm. We show three different examples how to take advantage of configurable photonic crystal waveguides: Shifting of the complete transmission spectrum, definition of cavities with high quality factor, and tuning of existing cavities.

  3. Configurable silicon photonic crystal waveguides

    NASA Astrophysics Data System (ADS)

    Prorok, Stefan; Petrov, Alexander; Eich, Manfred; Luo, Jingdong; Jen, Alex K.-Y.

    2013-12-01

    In this Letter, we demonstrate that the mode cut off of a photonic crystal waveguide can be trimmed with high accuracy by electron beam bleaching of a chromophore doped polymer cladding. Using this method, configurable waveguides are realized, which allow for spatially resolved changes of the photonic crystal's effective lattice constant as small as 7.6 pm. We show three different examples how to take advantage of configurable photonic crystal waveguides: Shifting of the complete transmission spectrum, definition of cavities with high quality factor, and tuning of existing cavities.

  4. Losses in polycrystalline silicon waveguides

    NASA Astrophysics Data System (ADS)

    Foresi, J. S.; Black, M. R.; Agarwal, A. M.; Kimerling, L. C.

    1996-04-01

    The losses of polycrystalline silicon (polySi) waveguides clad by SiO2 are measured by the cutback technique. We report losses of 34 dB/cm at a wavelength of 1.55 μm in waveguides fabricated from chemical mechanical polished polySi deposited at 625 °C. These losses are two orders of magnitude lower than reported absorption measurements for polySi. Waveguides fabricated from unpolished polySi deposited at 625 °C exhibit losses of 77 dB/cm. We find good agreement between calculated and measured losses due to surface scattering.

  5. Scintillator Waveguide For Sensing Radiation

    DOEpatents

    Bliss, Mary; Craig, Richard A.; Reeder; Paul L.

    2003-04-22

    The present invention is an apparatus for detecting ionizing radiation, having: a waveguide having a first end and a second end, the waveguide formed of a scintillator material wherein the therapeutic ionizing radiation isotropically generates scintillation light signals within the waveguide. This apparatus provides a measure of radiation dose. The apparatus may be modified to permit making a measure of location of radiation dose. Specifically, the scintillation material is segmented into a plurality of segments; and a connecting cable for each of the plurality of segments is used for conducting scintillation signals to a scintillation detector.

  6. Hollow waveguide for urology treatment

    NASA Astrophysics Data System (ADS)

    Jelínková, H.; Němec, M.; Koranda, P.; Pokorný, J.; Kőhler, O.; Drlík, P.; Miyagi, M.; Iwai, K.; Matsuura, Y.

    2010-02-01

    The aim of our work was the application of the special sealed hollow waveguide system for the urology treatment - In our experimental study we have compared the effects of Ho:YAG (wavelength 2100 nm) and Er:YAG (wavelength 2940 nm) laser radiation both on human urinary stones (or compressed plaster samples which serve as a model) fragmentation and soft ureter tissue incision in vitro. Cyclic Olefin Polymer - coated silver (COP/Ag) hollow glass waveguides with inner and outer diameters 700 and 850 μm, respectively, were used for the experiment. To prevent any liquid to diminish and stop the transmission, the waveguide termination was utilized.

  7. Variable temperature spectroscopy of as-grown and passivated CdS nanowire optical waveguide cavities.

    PubMed

    van Vugt, Lambert K; Piccione, Brian; Cho, Chang-Hee; Aspetti, Carlos; Wirshba, Aaron D; Agarwal, Ritesh

    2011-04-28

    Semiconductor nanowire waveguide cavities hold promise for nanophotonic applications such as lasers, waveguides, switches, and sensors due to the tight optical confinement in these structures. However, to realize their full potential, high quality nanowires, whose emission at low temperatures is dominated by free exciton emission, need to be synthesized. In addition, a proper understanding of their complex optical properties, including light-matter coupling in these subwavelength structures, is required. We have synthesized very high-quality wurztite CdS nanowires capped with a 5 nm SiO(2) conformal coating with diameters spanning 100-300 nm using physical vapor and atomic layer deposition techniques and characterized their spatially resolved photoluminescence over the 77-298 K temperature range. In addition to the Fabry-Pérot resonator modulated emission from the ends of the wires, the low temperature emission from the center of the wire shows clear free excitonic peaks and LO phonon replicas, persisting up to room-temperature in the passivated wires. From laser scanning measurements we determined the absorption in the vicinity of the excitonic resonances. In addition to demonstrating the high optical quality of the nanowire crystals, these results provide the fundamental parameters for strong light-matter coupling studies, potentially leading to low threshold polariton lasers, sensitive sensors and optical switches at the nanoscale. PMID:21214218

  8. Complete power concentration into a single waveguide in large-scale waveguide array lenses

    PubMed Central

    Catrysse, Peter B.; Liu, Victor; Fan, Shanhui

    2014-01-01

    Waveguide array lenses are waveguide arrays that focus light incident on all waveguides at the input side into a small number of waveguides at the output side. Ideal waveguide array lenses provide complete (100%) power concentration of incident light into a single waveguide. While of great interest for several applications, ideal waveguide array lenses have not been demonstrated for practical arrays with large numbers of waveguides. The only waveguide arrays that have sufficient degrees of freedom to allow for the design of an ideal waveguide array lens are those where both the propagation constants of the individual waveguides and the coupling constants between the waveguides vary as a function of space. Here, we use state-of-the-art numerical methods to demonstrate complete power transfer into a single waveguide for waveguide array lenses with large numbers of waveguides. We verify this capability for more than a thousand waveguides using a spatial coupled mode theory. We hereby extend the state-of-art by more than two orders of magnitude. We also demonstrate for the first time a physical design for an ideal waveguide array lens. The design is based on an aperiodic metallic waveguide array and focuses ~100% of the incident light into a deep-subwavelength focal spot. PMID:25319203

  9. Coplanar Waveguide Radial Line Stub

    NASA Technical Reports Server (NTRS)

    Simons, R. N.; Taub, S. R.

    1993-01-01

    A coplanar waveguide radial line stub resonator is experimentally characterized with respect to stub radius, sectoral angle, substrate thickness, and relative dielectric constant. A simple closed-form design equation which predicts the resonance radius of the stub is presented.

  10. Waveguides for performing enzymatic reactions

    DOEpatents

    Levene; Michael J. , Korlach; Jonas , Turner; Stephen W. , Craighead; Harold G. , Webb; Watt W.

    2007-11-06

    The present invention is directed to a method and an apparatus for analysis of an analyte. The method involves providing a zero-mode waveguide which includes a cladding surrounding a core where the cladding is configured to preclude propagation of electromagnetic energy of a frequency less than a cutoff frequency longitudinally through the core of the zero-mode waveguide. The analyte is positioned in the core of the zero-mode waveguide and is then subjected, in the core of the zero-mode wave guide, to activating electromagnetic radiation of a frequency less than the cut-off frequency under conditions effective to permit analysis of the analyte in an effective observation volume which is more compact than if the analysis were carried out in the absence of the zero-mode waveguide.

  11. Temporal waveguides for optical pulses

    DOE PAGESBeta

    Plansinis, Brent W.; Donaldson, William R.; Agrawal, Govind P.

    2016-05-12

    Here we discuss, temporal total internal reflection (TIR), in analogy to the conventional TIR of an optical beam at a dielectric interface, is the total reflection of an optical pulse inside a dispersive medium at a temporal boundary across which the refractive index changes. A pair of such boundaries separated in time acts as the temporal analog of planar dielectric waveguides. We study the propagation of optical pulses inside such temporal waveguides, both analytically and numerically, and show that the waveguide supports a finite number of temporal modes. We also discuss how a single-mode temporal waveguide can be created inmore » practice. In contrast with the spatial case, the confinement can occur even when the central region has a lower refractive index.« less

  12. 1-D EQUILIBRIUM DISCRETE DIFFUSION MONTE CARLO

    SciTech Connect

    T. EVANS; ET AL

    2000-08-01

    We present a new hybrid Monte Carlo method for 1-D equilibrium diffusion problems in which the radiation field coexists with matter in local thermodynamic equilibrium. This method, the Equilibrium Discrete Diffusion Monte Carlo (EqDDMC) method, combines Monte Carlo particles with spatially discrete diffusion solutions. We verify the EqDDMC method with computational results from three slab problems. The EqDDMC method represents an incremental step toward applying this hybrid methodology to non-equilibrium diffusion, where it could be simultaneously coupled to Monte Carlo transport.

  13. Atomic-scale photonic hybrids for mid-infrared and terahertz nanophotonics

    NASA Astrophysics Data System (ADS)

    Caldwell, Joshua D.; Vurgaftman, Igor; Tischler, Joseph G.; Glembocki, Orest J.; Owrutsky, Jeffrey C.; Reinecke, Thomas L.

    2016-01-01

    The field of nanophotonics focuses on the ability to confine light to nanoscale dimensions, typically much smaller than the wavelength of light. The goal is to develop light-based technologies that are impossible with traditional optics. Subdiffractional confinement can be achieved using either surface plasmon polaritons (SPPs) or surface phonon polaritons (SPhPs). SPPs can provide a gate-tunable, broad-bandwidth response, but suffer from high optical losses; whereas SPhPs offer a relatively low-loss, crystal-dependent optical response, but only over a narrow spectral range, with limited opportunities for active tunability. Here, motivated by the recent results from monolayer graphene and multilayer hexagonal boron nitride heterostructures, we discuss the potential of electromagnetic hybrids -- materials incorporating mixtures of SPPs and SPhPs -- for overcoming the limitations of the individual polaritons. Furthermore, we also propose a new type of atomic-scale hybrid the crystalline hybrid -- where mixtures of two or more atomic-scale (~3 nm or less) polar dielectric materials lead to the creation of a new material resulting from hybridized optic phonon behaviour of the constituents, potentially allowing direct control over the dielectric function. These atomic-scale hybrids expand the toolkit of materials for mid-infrared to terahertz nanophotonics and could enable the creation of novel actively tunable, yet low-loss optics at the nanoscale.

  14. Single mode acoustic fiber waveguide

    NASA Technical Reports Server (NTRS)

    Jackson, B. S.; May, R. G.; Claus, R. O.

    1984-01-01

    The single mode operation of a clad rod acoustic waveguide is described. Unlike conventional clad optical and acoustic waveguiding structures which use modes confined to a central core surrounded by a cladding, this guide supports neither core nor cladding modes but a single interface wave field on the core-cladding boundary. The propagation of this bound field and the potential improved freedom from spurious responses is discussed.

  15. A waveguide based microfluidic application

    NASA Astrophysics Data System (ADS)

    Taheri, Nooshin S.; Chan, Peggy; Friend, James R.; Yeo, Leslie

    2013-12-01

    Microfluidics is based on the performance of fluids in a microenvironment. As the microfluidics research advances in the cellular behaviour, the need for improved micro devices grows. This work introduces the design and fabrication of a micro ridge waveguide to be employed in fluids manipulations. Then it investigates the characteristics of the device in order to control the movement of the fluids on top of the ridge of the waveguide. The elastic vibration is excited along the ridge of the guide with the use of thickness poled lead zirconate titanate (PZT) elements attached to both sides of the waveguide. To excite anti-symmetric or flexural mode in the ridge of the guide, the propagation velocity has been kept significantly below the Rayleigh wave velocity. The velocity reduction of 15% is achieved with the high aspect ratio ridge (H/W =3) design. A three dimensional model of the micro waveguide has also been developed to determine the vibration characteristics; the natural frequency and the considered mode of the micro waveguide through finite element analysis using ANSYS. The travelling wave along the ridge of the guide is able to transmit strong vibration to the fluid atop of the substrate. The results represents a promising approach, through recasting the waveguide structure to be suitable in fluids and particle in fluids manipulations in one dimensional environment with the strong confined energy, at smaller scale with higher vibration displacement.

  16. MHD waveguides in space plasma

    SciTech Connect

    Mazur, N. G.; Fedorov, E. N.; Pilipenko, V. A.

    2010-07-15

    The waveguide properties of two characteristic formations in the Earth's magnetotail-the plasma sheet and the current (neutral) sheet-are considered. The question of how the domains of existence of different types of MHD waveguide modes (fast and slow, body and surface) in the (k, {omega}) plane and their dispersion properties depend on the waveguide parameters is studied. Investigation of the dispersion relation in a number of particular (limiting) cases makes it possible to obtain a fairly complete qualitative pattern of all the branches of the dispersion curve. Accounting for the finite size of perturbations across the wave propagation direction reveals new additional effects such as a change in the critical waveguide frequencies, the excitation of longitudinal current at the boundaries of the sheets, and a change in the symmetry of the fundamental mode. Knowledge of the waveguide properties of the plasma and current sheets can explain the occurrence of preferred frequencies in the low-frequency fluctuation spectra in the magnetotail. In satellite observations, the type of waveguide mode can be determined from the spectral properties, as well as from the phase relationships between plasma oscillations and magnetic field oscillations that are presented in this paper.

  17. A 1-D dusty plasma photonic crystal

    SciTech Connect

    Mitu, M. L.; Ticoş, C. M.; Toader, D.; Banu, N.; Scurtu, A.

    2013-09-21

    It is demonstrated numerically that a 1-D plasma crystal made of micron size cylindrical dust particles can, in principle, work as a photonic crystal for terahertz waves. The dust rods are parallel to each other and arranged in a linear string forming a periodic structure of dielectric-plasma regions. The dispersion equation is found by solving the waves equation with the boundary conditions at the dust-plasma interface and taking into account the dielectric permittivity of the dust material and plasma. The wavelength of the electromagnetic waves is in the range of a few hundred microns, close to the interparticle separation distance. The band gaps of the 1-D plasma crystal are numerically found for different types of dust materials, separation distances between the dust rods and rod diameters. The distance between levitated dust rods forming a string in rf plasma is shown experimentally to vary over a relatively wide range, from 650 μm to about 1350 μm, depending on the rf power fed into the discharge.

  18. Biocompatible silk step-index optical waveguides

    PubMed Central

    Applegate, Matthew B.; Perotto, Giovanni; Kaplan, David L.; Omenetto, Fiorenzo G.

    2015-01-01

    Biocompatible optical waveguides were constructed entirely of silk fibroin. A silk film (n=1.54) was encapsulated within a silk hydrogel (n=1.34) to form a robust and biocompatible waveguide. Such waveguides were made using only biologically and environmentally friendly materials without the use of harsh solvents. Light was coupled into the silk waveguides by direct incorporation of a glass optical fiber. These waveguides are extremely flexible, and strong enough to survive handling and manipulation. Cutback measurements showed propagation losses of approximately 2 dB/cm. The silk waveguides were found to be capable of guiding light through biological tissue. PMID:26600988

  19. Long range correlations by local dissipation in lattice waveguide QED

    NASA Astrophysics Data System (ADS)

    Royer, Baptiste; Grimsmo, Arne L.; Blais, Alexandre

    In waveguide QED, superconducting qubits acting as artificial atoms are coupled to 1D superconducting transmission lines playing the role of common bath for the qubits. By controlling their effective separation and coupling to the transmission line, it is possible to engineer various types of dissipation-induced interactions between the qubits. In this talk, we consider the situation where multiple superconducting qubits are coupled to a lattice of superconducting transmission lines. We show that this can lead to the creation of highly entangled dark states using local dissipation only. Using tensor networks techniques, we study such large-scale highly-correlated systems.

  20. Femtosecond laser-written lithium niobate waveguide laser operating at 1085 nm

    NASA Astrophysics Data System (ADS)

    Tan, Yang; de Aldana, Javier R. Vázquez; Chen, Feng

    2014-10-01

    We report on the channel waveguide lasers at 1085 nm in femtosecond laser written Type II waveguides in an Nd:MgO:LiNbO3 crystal. The waveguide was constructed in a typical dual-line approach. In the geometry, we found that four vicinal regions of the track pair could guide light propagation. In addition, these guiding cores support polarization-dependent-guided modes. The propagation losses of the waveguides were measured to be as low as 1 dB/cm. Under an optical pump at 808 nm, the continuous-wave waveguide lasing at 1085 nm was generated, reaching a slope efficiency of 27% and maximum output power of 8 mW. The lasing threshold was 71 mW. Our results show that with the femtosecond laser written Nd:MgO:LiNbO3 waveguide as the miniature light source, it was possible to construct all-LiNbO3-based integrated devices for diverse photonic applications.

  1. Exceptional points and asymmetric mode conversion in quasi-guided dual-mode optical waveguides

    NASA Astrophysics Data System (ADS)

    Ghosh, S. N.; Chong, Y. D.

    2016-04-01

    Non-Hermitian systems host unconventional physical effects that be used to design new optical devices. We study a non-Hermitian system consisting of 1D planar optical waveguides with suitable amount of simultaneous gain and loss. The parameter space contains an exceptional point, which can be accessed by varying the transverse gain and loss profile. When light propagates through the waveguide structure, the output mode is independent of the choice of input mode. This “asymmetric mode conversion” phenomenon can be explained by the swapping of mode identities in the vicinity of the exceptional point, together with the failure of adiabatic evolution in non-Hermitian systems.

  2. Exceptional points and asymmetric mode conversion in quasi-guided dual-mode optical waveguides

    PubMed Central

    Ghosh, S. N.; Chong, Y. D.

    2016-01-01

    Non-Hermitian systems host unconventional physical effects that be used to design new optical devices. We study a non-Hermitian system consisting of 1D planar optical waveguides with suitable amount of simultaneous gain and loss. The parameter space contains an exceptional point, which can be accessed by varying the transverse gain and loss profile. When light propagates through the waveguide structure, the output mode is independent of the choice of input mode. This “asymmetric mode conversion” phenomenon can be explained by the swapping of mode identities in the vicinity of the exceptional point, together with the failure of adiabatic evolution in non-Hermitian systems. PMID:27101933

  3. Nonlinear diffusion model for annealed proton-exchanged waveguides in zirconium-doped lithium niobate.

    PubMed

    Langrock, Carsten; Roussev, Rostislav V; Nava, Giovanni; Minzioni, Paolo; Argiolas, Nicola; Sada, Cinzia; Fejer, Martin M

    2016-08-20

    Photorefractive-damage- (PRD) resistant zirconium-oxide-doped lithium niobate is investigated as a substrate for the realization of annealed proton-exchanged (APE) waveguides. Its advantages are a favorable distribution coefficient, PRD resistance comparable to magnesium-oxide-doped lithium niobate, and a proton-diffusion behavior resembling congruent lithium niobate. A 1D model for APE waveguides was developed based on a previous model for congruently melting lithium niobate. Evidence for a nonlinear index dependence on concentration was found. PMID:27556972

  4. 1D-VAR Retrieval Using Superchannels

    NASA Technical Reports Server (NTRS)

    Liu, Xu; Zhou, Daniel; Larar, Allen; Smith, William L.; Schluessel, Peter; Mango, Stephen; SaintGermain, Karen

    2008-01-01

    Since modern ultra-spectral remote sensors have thousands of channels, it is difficult to include all of them in a 1D-var retrieval system. We will describe a physical inversion algorithm, which includes all available channels for the atmospheric temperature, moisture, cloud, and surface parameter retrievals. Both the forward model and the inversion algorithm compress the channel radiances into super channels. These super channels are obtained by projecting the radiance spectra onto a set of pre-calculated eigenvectors. The forward model provides both super channel properties and jacobian in EOF space directly. For ultra-spectral sensors such as Infrared Atmospheric Sounding Interferometer (IASI) and the NPOESS Airborne Sounder Testbed Interferometer (NAST), a compression ratio of more than 80 can be achieved, leading to a significant reduction in computations involved in an inversion process. Results will be shown applying the algorithm to real IASI and NAST data.

  5. Simplified flangeless unisex waveguide coupler assembly

    DOEpatents

    Michelangelo, D.; Moeller, C.P.

    1993-05-04

    A unisex coupler assembly is disclosed capable of providing a leak tight coupling for waveguides with axial alignment of the waveguides and rotational capability. The sealing means of the coupler assembly are not exposed to RF energy, and the coupler assembly does not require the provision of external flanges on the waveguides. In a preferred embodiment, O ring seals are not used and the coupler assembly is, therefore, bakeable at a temperature up to about 150 C. The coupler assembly comprises a split collar which clamps around the waveguides and a second collar which fastens to the split collar. The split collar contains an inner annular groove. Each of the waveguides is provided with an external annular groove which receives a retaining ring. The split collar is clamped around one of the waveguides with the inner annular groove of the split collar engaging the retaining ring carried in the external annular groove in the waveguide. The second collar is then slipped over the second waveguide behind the annular groove and retaining ring therein and the second collar is coaxially secured by fastening means to the split collar to draw the respective waveguides together by coaxial force exerted by the second collar against the retaining ring on the second waveguide. A sealing ring is placed against an external sealing surface at a reduced external diameter end formed on one waveguide to sealingly engage a corresponding sealing surface on the other waveguide as the waveguides are urged toward each other.

  6. Simplified flangeless unisex waveguide coupler assembly

    DOEpatents

    Michelangelo, Dimartino; Moeller, Charles P.

    1993-01-01

    A unisex coupler assembly is disclosed capable of providing a leak tight coupling for waveguides with axial alignment of the waveguides and rotational capability. The sealing means of the coupler assembly are not exposed to RF energy, and the coupler assembly does not require the provision of external flanges on the waveguides. In a preferred embodiment, O ring seals are not used and the coupler assembly is, therefore, bakeable at a temperature up to about 150.degree. C. The coupler assembly comprises a split collar which clamps around the waveguides and a second collar which fastens to the split collar. The split collar contains an inner annular groove. Each of the waveguides is provided with an external annular groove which receives a retaining ring. The split collar is clamped around one of the waveguides with the inner annular groove of the split collar engaging the retaining ring carried in the external annular groove in the waveguide. The second collar is then slipped over the second waveguide behind the annular groove and retaining ring therein and the second collar is coaxially secured by fastening means to the split collar to draw the respective waveguides together by coaxial force exerted by the second collar against the retaining ring on the second waveguide. A sealing ring is placed against an external sealing surface at a reduced external diameter end formed on one waveguide to sealingly engage a corresponding sealing surface on the other waveguide as the waveguides are urged toward each other.

  7. Optical waveguide tamper sensor technology

    SciTech Connect

    Carson, R.F.; Butler, M.A.; Sinclair, M.B.

    1997-03-01

    Dielectric optical waveguides exhibit properties that are well suited to sensor applications. They have low refractive index and are transparent to a wide range of wavelengths. They can react with the surrounding environment in a variety of controllable ways. In certain sensor applications, it is advantageous to integrate the dielectric waveguide on a semiconductor substrate with active devices. In this work, we demonstrate a tamper sensor based on dielectric waveguides that connect epitaxial GaAs-GaAlAs sources and detectors. The tamper sensing function is realized by attaching particles of absorbing material with high refractive index to the surface of the waveguides. These absorbers are then attached to a lid or cover, as in an integrated circuit package or multi-chip module. The absorbers attenuate the light in the waveguides as a function of absorber interaction. In the tamper indicating mode, the absorbers are placed randomly on the waveguides, to form a unique attenuation pattern that is registered by the relative signal levels on the photodetectors. When the lid is moved, the pattern of absorbers changes, altering the photodetector signals. This dielectric waveguide arrangement is applicable to a variety of sensor functions, and specifically can be fabricated as a chemical sensor by the application of cladding layers that change their refractive index and/or optical absorption properties upon exposure to selected chemical species. An example is found in palladium claddings that are sensitive to hydrogen. A description of designs and a basic demonstration of the tamper sensing and chemical sensing functions is described herein.

  8. Graphene-enhanced waveguide-resonance gratings

    NASA Astrophysics Data System (ADS)

    Kumar, Mahesh; Tervo, Jani; Kaplas, Tommi; Svirko, Yuri

    2016-03-01

    We demonstrate that the integration of graphene strongly influences optical properties of the subwavelength gratings, opening a way toward nanophotonic devices. By using the Fourier-expansion modal method, we demonstrate that graphene-titanium dioxide nanostructures can be used for designing polarization-insensitive absorbers and biochemical sensors.

  9. Coaxial waveguide MRI.

    PubMed

    Alt, Stefan; Müller, Marco; Umathum, Reiner; Bolz, Armin; Bachert, Peter; Semmler, Wolfhard; Bock, Michael

    2012-04-01

    As ultrahigh-field MR imaging systems suffer from the standing wave problems of conventional coil designs, the use of antenna systems that generate travelling waves was suggested. As a modification to the original approach, we propose the use of a coaxial waveguide configuration with interrupted inner conductor. This concept can focus the radiofrequency energy to the desired imaging region in the human body and can operate at different Larmor frequencies without hardware modifications, as it is not limited by a lower cut-off frequency. We assessed the potential of the method with a hardware prototype setup that was loaded with a tissue equivalent phantom and operated with imaging areas of different size. Signal and flip angle distributions within the phantom were analyzed, and imaging at different Larmor frequencies was performed. Results were compared to a finite difference time domain simulation of the setup that additionally provides information on the spatial distribution of the specific absorption rate load. Furthermore, simulation results with a human model (virtual family) are presented. It was found that the proposed method can be used for MRI at multiple frequencies, achieving transmission efficiencies similar to other travelling wave approaches but still suffers from several limitations due to the used mode of wave propagation. PMID:22021117

  10. Integration of a waveguide self-electrooptic effect device and a vertically coupled interconnect waveguide

    DOEpatents

    Vawter, G. Allen

    2008-02-26

    A self-electrooptic effect device ("SEED") is integrated with waveguide interconnects through the use of vertical directional couplers. Light initially propagating in the interconnect waveguide is vertically coupled to the active waveguide layer of the SEED and, if the SEED is in the transparent state, the light is coupled back to the interconnect waveguide.

  11. Phased waveguide array with fixed tuning elements

    SciTech Connect

    Motley, R.W.; Bernabei, S.; Hooke, W.M.; Paoloni, F.J.

    1980-04-01

    The waveguide grill excites both penetrating lower hybrid waves and surface plasma waves. Quarter wavelength tuning elements attached to the sides of a twin waveguide are shown to reduce the surface wave component by a factor of approx. 3..

  12. Slotted Polyimide-Aerogel-Filled-Waveguide Arrays

    NASA Technical Reports Server (NTRS)

    Rodriguez-Solis, Rafael A.; Pacheco, Hector L.; Miranda, Felix A.; Meador, Mary Ann B.

    2013-01-01

    Polyimide aerogels were considered to serve as a filling for millimeter-wave waveguides. While these waveguides present a slightly higher loss than hollow waveguides, they have less losses than Duroid substrate integrated waveguides (less than 0.15 dB at Ka-band, in a 20 mm section), and exhibit an order of magnitude of mass reduction when compared to commercial waveguides. A Ka-band slotted aerogel-filled-waveguide array was designed, which provided the same gain (9 dBi) as its standard waveguide counterpart, and a slotted aerogel-filled-waveguide array using folded-slots was designed for comparison, obtaining a gain of 9 dB and a bandwidth of 590 MHz.

  13. Optical panel system including stackable waveguides

    DOEpatents

    DeSanto, Leonard; Veligdan, James T.

    2007-11-20

    An optical panel system including stackable waveguides is provided. The optical panel system displays a projected light image and comprises a plurality of planar optical waveguides in a stacked state. The optical panel system further comprises a support system that aligns and supports the waveguides in the stacked state. In one embodiment, the support system comprises at least one rod, wherein each waveguide contains at least one hole, and wherein each rod is positioned through a corresponding hole in each waveguide. In another embodiment, the support system comprises at least two opposing edge structures having the waveguides positioned therebetween, wherein each opposing edge structure contains a mating surface, wherein opposite edges of each waveguide contain mating surfaces which are complementary to the mating surfaces of the opposing edge structures, and wherein each mating surface of the opposing edge structures engages a corresponding complementary mating surface of the opposite edges of each waveguide.

  14. Optical panel system including stackable waveguides

    DOEpatents

    DeSanto, Leonard; Veligdan, James T.

    2007-03-06

    An optical panel system including stackable waveguides is provided. The optical panel system displays a projected light image and comprises a plurality of planar optical waveguides in a stacked state. The optical panel system further comprises a support system that aligns and supports the waveguides in the stacked state. In one embodiment, the support system comprises at least one rod, wherein each waveguide contains at least one hole, and wherein each rod is positioned through a corresponding hole in each waveguide. In another embodiment, the support system comprises at least two opposing edge structures having the waveguides positioned therebetween, wherein each opposing edge structure contains a mating surface, wherein opposite edges of each waveguide contain mating surfaces which are complementary to the mating surfaces of the opposing edge structures, and wherein each mating surface of the opposing edge structures engages a corresponding complementary mating surface of the opposite edges of each waveguide.

  15. Planar waveguide sensor of ammonia

    NASA Astrophysics Data System (ADS)

    Rogoziński, Roman; Tyszkiewicz, Cuma; Karasiński, Paweł; Izydorczyk, Weronika

    2015-12-01

    The paper presents the concept of forming ammonia sensor based on a planar waveguide structure. It is an amplitude sensor produced on the basis of the multimode waveguide. The technological base for this kind of structure is the ion exchange method and the sol-gel method. The planar multimode waveguide of channel type is produced in glass substrate (soda-lime glass of Menzel-Glaser company) by the selective Ag+↔Na+ ion exchange. On the surface of the glass substrate a porous (~40%) silica layer is produced by the sol-gel method. This layer is sensitized to the presence of ammonia in the surrounding atmosphere by impregnation with Bromocresol Purple (BCP) dye. Therefore it constitutes a sensor layer. Spectrophotometric tests carried out showed about 50% reduction of cross-transmission changes of such sensor layer for a wave λ=593 nm caused by the presence of 25% ammonia water vapor in its ambience. The radiation source used in this type of sensor structure is a light emitting diode LED. The gradient channel waveguide is designed for frontal connection (optical glue) with a standard multimode telecommunications waveguide 62.5/125μm.

  16. Slotted Polyimide-Aerogel-Filled-Waveguide Arrays

    NASA Technical Reports Server (NTRS)

    Rodriguez-Solis, Rafael A.; Pacheco, Hector L.; Miranda, Felix A.; Meador, Mary Ann B.

    2013-01-01

    This presentation discussed the potential advantages of developing Slotted Waveguide Arrays using polyimide aerogels. Polyimide (PI) aerogels offer great promise as an enabling technology for lightweight aerospace antenna systems. PI aerogels are highly porous solids possessing low density and low dielectric permittivity combined with good mechanical properties. For slotted waveguide array applications, there are significant advantages in mass that more than compensate for the slightly higher loss of the aerogel filled waveguide when compared to state of practice commercial waveguide.

  17. Silicon waveguide based TE mode converter.

    PubMed

    Zhang, Jing; Liow, Tsung-Yang; Yu, Mingbin; Lo, Guo-Qiang; Kwong, Dim-Lee

    2010-11-22

    A silicon waveguide based TE mode converter was designed for the mode conversion between a horizontal waveguide and vertical waveguide in the two-layer structure waveguide based polarization diversity circuit. The TE mode converter's performance was studied. The polarization mode converter with minimum length of 5 μm was demonstrated to provide the TE mode conversion while maintaining the polarization status. The insertion loss at the transition region was less than 2 dB. PMID:21164874

  18. Applications of gradient index metamaterials in waveguides

    PubMed Central

    Fu, Yangyang; Xu, Yadong; Chen, Huanyang

    2015-01-01

    In this letter, we find that gradient index metamaterials (GIMs) could be utilized to manipulate wave propagation in waveguides. Through manipulating the conversion between propagating wave and surface wave, we can design some interesting applications in waveguides, such as controlling transmission effect, realizing bending waveguide and achieving waveguide splitting effect. These devices not only work for both transverse electric and magnetic polarized waves, but also function for a broadband of spectra. Numerical simulations are performed to verify our findings. PMID:26656558

  19. Low loss etchless silicon photonic waveguides.

    PubMed

    Cardenas, Jaime; Poitras, Carl B; Robinson, Jacob T; Preston, Kyle; Chen, Long; Lipson, Michal

    2009-03-16

    We demonstrate low loss silicon waveguides fabricated without any silicon etching. We define the waveguides by selective oxidation which produces ultra-smooth sidewalls with width variations of 0.3 nm. The waveguides have a propagation loss of 0.3 dB/cm at 1.55 microm. The waveguide geometry enables low bending loss of approximately 0.007 dB/bend for a 90 degrees bend with a 50 microm bending radius. PMID:19293905

  20. Investigation of semiconductor clad optical waveguides

    NASA Technical Reports Server (NTRS)

    Batchman, T. E.; Carson, R. F.

    1985-01-01

    A variety of techniques have been proposed for fabricating integrated optical devices using semiconductors, lithium niobate, and glasses as waveguides and substrates. The use of glass waveguides and their interaction with thin semiconductor cladding layers was studied. Though the interactions of these multilayer waveguide structures have been analyzed here using glass, they may be applicable to other types of materials as well. The primary reason for using glass is that it provides a simple, inexpensive way to construct waveguides and devices.

  1. Nano-photonic phenomena in van der Waals heterostructures (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Basov, Dmitri N.

    2015-09-01

    van der Waals (vdW) crystals consist of individual atomic planes coupled by vdW interaction, similar to graphene monolayers in bulk graphite. We investigated van der Waals heterostructures assembled from atomically thin layers of graphene and hexagonal boron nitride (hBN). We launched, detected and imaged plasmonic, phonon polaritonic and hybrid plasmon-phonon polariton waves in a setting of an antenna based nano-infrared apparatus. Hyperbolic phonon polaritons in hBN enabled sub-diffractional focusing in infrared frequencies. Because electronic, plasmonic and phonon polaritonic properties in van der Waals heterstructures are intertwined, gate voltage and/or details of layer assembly enable efficient control of nano-photonic effects.

  2. Direct Bandgap Light Emission from Strained Germanium Nanowires Coupled with High-Q Nanophotonic Cavities.

    PubMed

    Petykiewicz, Jan; Nam, Donguk; Sukhdeo, David S; Gupta, Shashank; Buckley, Sonia; Piggott, Alexander Y; Vučković, Jelena; Saraswat, Krishna C

    2016-04-13

    A silicon-compatible light source is the final missing piece for completing high-speed, low-power on-chip optical interconnects. In this paper, we present a germanium nanowire light emitter that encompasses all the aspects of potential low-threshold lasers: highly strained germanium gain medium, strain-induced pseudoheterostructure, and high-Q nanophotonic cavity. Our nanowire structure presents greatly enhanced photoluminescence into cavity modes with measured quality factors of up to 2000. By varying the dimensions of the germanium nanowire, we tune the emission wavelength over more than 400 nm with a single lithography step. We find reduced optical loss in optical cavities formed with germanium under high (>2.3%) tensile strain. Our compact, high-strain cavities open up new possibilities for low-threshold germanium-based lasers for on-chip optical interconnects. PMID:26907359

  3. Geometrical shape design of nanophotonic surfaces for thin film solar cells.

    PubMed

    Nam, W I; Yoo, Y J; Song, Y M

    2016-07-11

    We present the effect of geometrical parameters, particularly shape, on optical absorption enhancement for thin film solar cells based on crystalline silicon (c-Si) and gallium arsenide (GaAs) using a rigorous coupled wave analysis (RCWA) method. It is discovered that the "sweet spot" that maximizes efficiency of solar cells exists for the design of nanophotonic surfaces. For the case of ultrathin, rod array is practical due to the effective optical resonances resulted from the optimum geometry whereas parabola array is viable for relatively thicker cells owing to the effective graded index profile. A specific value of thickness, which is the median value of other two devices tailored by rod and paraboloid, is optimized by truncated shape structure. It is therefore worth scanning the optimum shape of nanostructures in a given thickness in order to achieve high performance. PMID:27410892

  4. Open-geometry Fourier modal method: modeling nanophotonic structures in infinite domains.

    PubMed

    Häyrynen, Teppo; de Lasson, Jakob Rosenkrantz; Gregersen, Niels

    2016-07-01

    We present an open-geometry Fourier modal method based on a new combination of open boundary conditions and an efficient k-space discretization. The open boundary of the computational domain is obtained using basis functions that expand the whole space, and the integrals subsequently appearing due to the continuous nature of the radiation modes are handled using a discretization based on nonuniform sampling of the k space. We apply the method to a variety of photonic structures and demonstrate that our method leads to significantly improved convergence with respect to the number of degrees of freedom, which may pave the way for more accurate and efficient modeling of open nanophotonic structures. PMID:27409686

  5. Programmable nanoengineering templates for fabrication of three-dimensional nanophotonic structures

    PubMed Central

    2013-01-01

    Porous anodic alumina membranes (AAMs) have attracted great amount of attention due to their potential application as templates for nanoengineering. Template-guided fabrication and assembly of nanomaterials based on AAMs are cost-effective and scalable methods to program and engineer the shape and morphology of nanostructures and nanomaterials. In this work, perfectly ordered AAMs with the record large pitch up to 3 μm have been fabricated by properly controlling the anodization conditions and utilization of nanoimprint technique. Due to the capability of programmable structural design and fabrication, a variety of nanostructures, including nanopillar arrays, nanotower arrays, and nanocone arrays, have been successfully fabricated using nanoengineered AAM templates. Particularly, amorphous Si nanocones have been fabricated as three-dimensional nanophotonic structures with the characterization of their intriguing optical anti-reflection property. These results directly indicate the potential application of the reported approach for photonics and optoelectronics. PMID:23742170

  6. Open-geometry Fourier modal method: modeling nanophotonic structures in infinite domains

    NASA Astrophysics Data System (ADS)

    Häyrynen, Teppo; de Lasson, Jakob Rosenkrantz; Gregersen, Niels

    2016-07-01

    We present an open geometry Fourier modal method based on a new combination of open boundary conditions and an efficient $k$-space discretization. The open boundary of the computational domain is obtained using basis functions that expand the whole space, and the integrals subsequently appearing due to the continuous nature of the radiation modes are handled using a discretization based on non-uniform sampling of the $k$-space. We apply the method to a variety of photonic structures and demonstrate that our method leads to significantly improved convergence with respect to the number of degrees of freedom, which may pave the way for more accurate and efficient modeling of open nanophotonic structures.

  7. High-Aspect-Ratio Nanophotonic Components Fabricated by Cl(2) RIBE

    SciTech Connect

    Zubrzycki, W.J.; Vawter, G.A.; Wendt, J.R.

    1999-07-08

    We describe highly anisotropic reactive ion beam etching of nanophotonic structures in AlGaAs based on the ion beam divergence angle and chamber pressure. The divergence angle is shown to influence the shape of the upper portion of the etch while the chamber pressure controls the shape of the lower portion. This predictable region of parameter space resulted in highly anisotropic nanostructures. Deeply etched distributed Bragg reflectors are etched to an aspect ratio of 8:1 with 100 nm trench widths. The profile of the grating etch is straight with smooth sidewalls, flat bottoms, and squared corners. Two-dimensional photonic crystal post arrays are fabricated with smooth and vertical sidewalls, with structures as small as 180 nm in diameter and 2.0 {micro}m in height.

  8. Programmable nanoengineering templates for fabrication of three-dimensional nanophotonic structures

    NASA Astrophysics Data System (ADS)

    Lin, Qingfeng; Leung, Siu-Fung; Tsui, Kwong-Hoi; Hua, Bo; Fan, Zhiyong

    2013-06-01

    Porous anodic alumina membranes (AAMs) have attracted great amount of attention due to their potential application as templates for nanoengineering. Template-guided fabrication and assembly of nanomaterials based on AAMs are cost-effective and scalable methods to program and engineer the shape and morphology of nanostructures and nanomaterials. In this work, perfectly ordered AAMs with the record large pitch up to 3 μm have been fabricated by properly controlling the anodization conditions and utilization of nanoimprint technique. Due to the capability of programmable structural design and fabrication, a variety of nanostructures, including nanopillar arrays, nanotower arrays, and nanocone arrays, have been successfully fabricated using nanoengineered AAM templates. Particularly, amorphous Si nanocones have been fabricated as three-dimensional nanophotonic structures with the characterization of their intriguing optical anti-reflection property. These results directly indicate the potential application of the reported approach for photonics and optoelectronics.

  9. Refractive Index Sensor Based on a 1D Photonic Crystal in a Microfluidic Channel

    PubMed Central

    Nunes, Pedro S.; Mortensen, Niels Asger; Kutter, Jörg P.; Mogensen, Klaus B.

    2010-01-01

    A refractive index sensor has been fabricated in silicon oxynitride by standard UV lithography and dry etching processes. The refractive index sensor consists of a 1D photonic crystal (PhC) embedded in a microfluidic channel addressed by fiber-terminated planar waveguides. Experimental demonstrations performed with several ethanol solutions ranging from a purity of 96.00% (n = 1.36356) to 95.04% (n = 1.36377) yielded a sensitivity (Δλ/Δn) of 836 nm/RIU and a limit of detection (LOD) of 6 × 10−5 RIU, which is, however, still one order of magnitude higher than the theoretical lower limit of the limit of detection 1.3 × 10−6 RIU. PMID:22294930

  10. Detecting different correlation regimes in a 1D Bose gas using in-situ absorption imaging

    NASA Astrophysics Data System (ADS)

    Salces-Carcoba, Francisco; Sugawa, Seiji; Yue, Yuchen; Putra, Andika; Spielman, Ian

    2016-05-01

    We present the realization of a single 1D Bose gas (1DBG) using a tightly focused Laguerre-Gauss beam as a waveguide for a 87Rb cloud. Axial confinement is provided by a weak trap that also sets the final density profile. A homogeneous 1DBG at T = 0 can be fully described by the dimensionless interaction parameter γ ~ 1/n, where n is the linear density; at sufficiently low densities the system becomes strongly interacting. An inhomogeneous (trapped) system can enter this description within the local density approximation (LDA) where the interaction parameter becomes position dependent γ(x) ~ 1/n(x). The system then displays different correlation regimes over its extension which can be detected by measuring its equation of state (EoS) or the density density correlations in real space using in-situ absorption imaging.

  11. Laser acceleration with open waveguides

    SciTech Connect

    Xie, Ming

    1999-03-01

    A unified framework based on solid-state open waveguides is developed to overcome all three major limitations on acceleration distance and hence on the feasibility of two classes of laser acceleration. The three limitations are due to laser diffraction, acceleration phase slippage, and damage of waveguide structure by high power laser. The two classes of laser acceleration are direct-field acceleration and ponderomotive-driven acceleration. Thus the solutions provided here encompass all mainstream approaches for laser acceleration, either in vacuum, gases or plasmas.

  12. Band gap control in a line-defect magnonic crystal waveguide

    SciTech Connect

    Morozova, M. A. Grishin, S. V.; Sadovnikov, A. V.; Romanenko, D. V.; Sharaevskii, Yu. P.; Nikitov, S. A.

    2015-12-14

    We report on the experimental observation of the spin wave spectrum control in a line-defect magnonic crystal (MC) waveguide. We demonstrate the possibility to control the forbidden frequency band (band gap) for spin waves tuning the line-defect width. In particular, this frequency may be greater or lower than the one of 1D MC waveguide without line-defect. By means of space-resolved Brillouin light scattering technique, we study the localization of magnetization amplitude in the line-defect area. We show that the length of this localization region depends on the line-defect width. These results agree well with theoretical calculations of spin wave spectrum using the proposed model of two coupled magnonic crystal waveguides. The proposed simple geometry of MC with line-defect can be used as a logic and multiplexing block for application in the novel field of magnonic devices.

  13. Densely packed waveguide array (DPWA) on a silicon chip for mode division multiplexing.

    PubMed

    Liu, Liu

    2015-05-01

    A densely packed waveguide array (DPWA) structure for mode division multiplexing on a silicon chip is proposed. The DPWA consists of several narrow waveguides with different widths, which are densely packed with gaps of 100nm. The lateral dimension of the DPWA is comparable to the conventional multimode waveguide used for mode division multiplexing on silicon. An efficient and parallel (de)multiplexing structure is proposed. For a three-mode DPWA with a 15μm-long (de)multiplexing structure, insertion losses of -0.05dB and cross-talks of -20dB are achievable for all the modes in a wide wavelength range. The present DPWA favors a compact direct bending. In a 45μm-radius 90° bend, insertion losses of -0.1dB and cross-talks of -20dB are obtained. The proposed DPWA structure also shows a large fabrication tolerance. PMID:25969301

  14. Systematic modeling study of channel waveguide fabrication by thermal silver ion exchange.

    PubMed

    Li, Guangyu; Winick, Kim A; Griffin, Henry C; Hayden, Joseph S

    2006-03-10

    A systematic study of thermal silver ion exchange used for the fabrication of optical channel waveguides is reported in a single-alkali glass. The diffusion equilibrium and diffusion dynamics are experimentally studied, and the concentration-dependent diffusion coefficients are determined. The relationship between the fabrication conditions, i.e., time, temperature, and melt concentration, and the induced waveguide refractive index profile is established. It is demonstrated that the diffusion equation can be solved, without use of any free parameters, to predict the refractive index profiles of both planar and channel waveguides. A 1.6 cm diameter integrated optic ring resonator, with a propagation loss of 0.1 dB/cm, is fabricated in a glass by thermal silver ion exchange. The induced refractive index profile is related to the optical characteristics of the functional device. PMID:16572690

  15. Polymer optical waveguide composed of europium-aluminum-acrylate composite core for compact optical amplifier and laser

    NASA Astrophysics Data System (ADS)

    Mitani, Marina; Yamashita, Kenichi; Fukui, Toshimi; Ishigure, Takaaki

    2015-02-01

    We successfully fabricate polymer waveguides with Europium-Aluminum (Eu-Al) polymer composite core using the Mosquito method that utilizes a microdispenser for realizing a compact waveguide optical amplifiers and lasers. Rareearth (RE) ions are widely used as the gain medium for fiber lasers and optical fiber amplifiers. However, high concentration doping of rare-earth-ion leads to the concentration quenching resulting in observing less gain in optical amplification. For addressing the concentration quenching problem, a rare-earth metal (RE-M) polymer composite has been proposed by KRI, Inc. to be a waveguide core material. Actually, 10-wt% RE doping into organic polymer materials was already achieved. Hence, realization of compact and high-efficiency waveguide amplifiers and lasers have been anticipated using the RE-M polymer composite. In this paper, a microdispenser is adopted to fabricate a Eu-doped polymer waveguide. Then, it is experimentally confirmed that the low-loss waveguides are fabricated with a high reproducibility. Optical gain is estimated by measuring the amplified spontaneous emission using the variable stripe length method. The fabricated waveguide exhibits an optical gain as high as 7.1 dB/cm at 616-nm wavelength.

  16. Optical loss coefficient in plastic waveguides

    NASA Astrophysics Data System (ADS)

    Geetha, K.; Gopinath, Pramod; Unnikrishnan, K. P.; Lee, S. T.; Vallabhan, C. P. G.; Nampoori, V. P. N.; Radhakrishnan, Periasamy

    2002-09-01

    We report the position dependent tuning of fluorescence emission from Rhodamine 6G doped plastic waveguide using side illumination technique . The transmitted fluorescence as a function of the distance from the point of illumination is measured by translating the waveguide horizontally across a monochromatic light source. This technique has proved to be a useful method for characterizing the light propagation properties of dye-doped waveguides. An important finding of the present studies is the nonlinear behavior of the loss coefficient as a function of propagation distance through the waveguide. It is also found that this type of nonlinear nature depends on the dye concentration and thickness of the waveguide.

  17. 1D-1D Coulomb drag in a 6 Million Mobility Bi-layer Heterostructure

    NASA Astrophysics Data System (ADS)

    Bilodeau, Simon; Laroche, Dominique; Xia, Jian-Sheng; Lilly, Mike; Reno, John; Pfeiffer, Loren; West, Ken; Gervais, Guillaume

    We report Coulomb drag measurements in vertically-coupled quantum wires. The wires are fabricated in GaAs/AlGaAs bilayer heterostructures grown from two different MBE chambers: one at Sandia National Laboratories (1.2M mobility), and the other at Princeton University (6M mobility). The previously observed positive and negative drag signals are seen in both types of devices, demonstrating the robustness of the result. However, attempts to determine the temperature dependence of the drag signal in the 1D regime proved challenging in the higher mobility heterostructure (Princeton), in part because of difficulties in aligning the wires within the same transverse subband configuration. Nevertheless, this work, performed at the Microkelvin laboratory of the University of Florida, is an important proof-of-concept for future investigations of the temperature dependence of the 1D-1D drag signal down to a few mK. Such an experiment could confirm the Luttinger charge density wave interlocking predicted to occur in the wires. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL8500.

  18. Folded waveguide cavity coupler for ICRF heating

    SciTech Connect

    Owens, T.L.

    1986-01-01

    This paper introduces a new type of waveguide coupler for ion cyclotron range of frequencies (ICRF) heating which is an adaptation of a concept known as a ''folded waveguide'' reported by Barrow and Schaevitz in connection with low-frequency waveguide transmission systems. The basic idea involves ''folding'' a simple rectangular waveguide to form a more compact structure. Cutoff for the folded waveguide occurs when one-half of a free-space wavelength equals the path length around the ''folds'' of the structure. By adding a large number of folds, the path length around the folds can be made large, leading to very low cutoff frequencies relative to those for simple rectangular waveguides having comparable outside dimensions. Folded waveguide couplers are practical for frequencies as low as 60 MHz for some ports found on present-day experients.

  19. Cutoff frequency of toroidal plasma waveguide

    SciTech Connect

    Zakeri-Khatir, H.; Aghamir, F. M.

    2015-02-15

    The cutoff frequencies of E and H-modes of empty and plasma filled toroidal waveguides are evaluated. The effects of space curvature and plasma density on cutoff frequencies for both modes are investigated. Using a suitable variable change, a scalar wave equation in the direction of propagation was obtained. The study indicates that the curvature in the direction of wave propagation in toroidal waveguide has an analogous effect as a straight waveguide filled with anisotropic media. The Rayleigh-Schrodinger perturbation method was employed to solve for cutoff frequencies in the first order of approximation. In the limit of small space curvature, the toroidal waveguide cutoff frequencies for both E and H-modes approach those of TM and TE modes of empty cylindrical waveguide with a radius equal to toroidal waveguide minor radius. The analysis shows that the curvature in the direction of propagation in toroidal waveguides leads to the removal of the degeneracy between E and H-modes.

  20. Understanding 1D Electrostatic Dust Levitation

    NASA Astrophysics Data System (ADS)

    Hartzell, C. M.; Scheeres, D. J.

    2011-12-01

    Electrostatically-dominated dust motion has been hypothesized since the Lunar Horizon Glow was observed by the Surveyor spacecraft. The hypothesized occurence of this phenomenon was naturally extended to asteroids due to their small gravities. Additionally, it has been suggested that the dust ponds observed on Eros by the NEAR mission may be created by electrostatically-dominated dust transport. Previous attempts to numerically model dust motion on the Moon and Eros have been stymied by poorly understood dust launching mechanisms. As a result, the initial velocity and charge of dust particles used in numerical simulations may or may not have any relevance to the actual conditions occurring in situ. It has been seen that properly tuned initial states (velocity and charge) result in dust particles levitating above the surface in both 1D and 2D simulations. Levitation is of interest to planetary scientists since it provides a way to quickly redistribute the surface dust particles over a body. However, there is currently no method to predict whether or not a certain initial state will result in levitation. We have developed a method to provide constraints on the initial states that result in levitation as a function of dust particle size and central body gravity. Additionally, our method can be applied to several models of the plasma sheath. Thus, we limit the guesswork involved in determining which initial conditions result in levitation. We provide a more detailed understanding of levitation phenomena couched in terms of the commonly recognized spring-mass system. This method of understanding dust motion removes the dependency on the launching mechanism, which remains fraught with controversy. Once a feasible dust launching mechanism is identified (be it micrometeoroid bombardment or electrostatic lofting), our method will allow the community to quickly ascertain if dust levitation will occur in situ or if it is simply a numerical artifact. In addition to

  1. Parabolic tapers for overmoded waveguides

    DOEpatents

    Doane, J.L.

    1983-11-25

    A waveguide taper with a parabolic profile, in which the distance along the taper axis varies as the square of the tapered dimension, provides less mode conversion than equal length linear tapers and is easier to fabricate than other non-linear tapers.

  2. A Truncated Waveguide Phase Shifter

    NASA Technical Reports Server (NTRS)

    Lourie, Nathan P.; Chuss, D. T.; Henry, R.; Wollack, E. J.

    2011-01-01

    The design, fabrication and performance of a simple phase shifter based upon truncated circular and square waveguides is presented. An emphasis is placed upon validation of simple analytical formulae that describe the propagation properties of the structure. A test device is prototyped at approximately 40GHz; however, the concepts explored can be directly extended to millimeter and submillimeter applications.

  3. Hybrid graphene plasmonic waveguide modulators.

    PubMed

    Ansell, D; Radko, I P; Han, Z; Rodriguez, F J; Bozhevolnyi, S I; Grigorenko, A N

    2015-01-01

    The unique optical and electronic properties of graphene make possible the fabrication of novel optoelectronic devices. One of the most exciting graphene characteristics is the tunability by gating which allows one to realize active optical devices. While several types of graphene-based photonic modulators have already been demonstrated, the potential of combining the versatility of graphene with subwavelength field confinement of plasmonic waveguides remains largely unexplored. Here we report fabrication and study of hybrid graphene-plasmonic waveguide modulators. We consider several types of modulators and identify the most promising one for telecom applications. The modulator working at the telecom range is demonstrated, showing a modulation depth of >0.03 dB μm(-1) at low gating voltages for an active device area of just 10 μm(2), characteristics which are already comparable to those of silicon-based waveguide modulators while retaining the benefit of further device miniaturization. Our proof-of-concept results pave the way towards on-chip realization of efficient graphene-based active plasmonic waveguide devices for optical communications. PMID:26554944

  4. Hybrid graphene plasmonic waveguide modulators

    NASA Astrophysics Data System (ADS)

    Ansell, D.; Radko, I. P.; Han, Z.; Rodriguez, F. J.; Bozhevolnyi, S. I.; Grigorenko, A. N.

    2015-11-01

    The unique optical and electronic properties of graphene make possible the fabrication of novel optoelectronic devices. One of the most exciting graphene characteristics is the tunability by gating which allows one to realize active optical devices. While several types of graphene-based photonic modulators have already been demonstrated, the potential of combining the versatility of graphene with subwavelength field confinement of plasmonic waveguides remains largely unexplored. Here we report fabrication and study of hybrid graphene-plasmonic waveguide modulators. We consider several types of modulators and identify the most promising one for telecom applications. The modulator working at the telecom range is demonstrated, showing a modulation depth of >0.03 dB μm-1 at low gating voltages for an active device area of just 10 μm2, characteristics which are already comparable to those of silicon-based waveguide modulators while retaining the benefit of further device miniaturization. Our proof-of-concept results pave the way towards on-chip realization of efficient graphene-based active plasmonic waveguide devices for optical communications.

  5. Optical properties of titanium-diffused LiNbO3 strip waveguides and their coupling-to-a-fiber characteristics

    NASA Astrophysics Data System (ADS)

    Fukuma, M.; Noda, J.

    1980-02-01

    Optical propagation losses and coupling losses in Ti-diffused strip waveguides, fabricated in y-plate and z-plate LiNbO3, have been examined at 1.15 microns wavelength. Propagation losses for y-plate and z-plate waveguides are about 0.5 dB/cm. Coupling losses in the y-plate and z-plate waveguides for a single-mode fiber are 2.5 and 1 dB, respectively. This difference is due to the large surface diffusion anisotropy; it is expressed by near-field pattern overlap calculations.

  6. Optical properties of titanium-diffused LiNbO(3) strip waveguides and their coupling-to-a-fiber characteristics.

    PubMed

    Fukuma, M; Noda, J

    1980-02-15

    Optical propagation losses and coupling losses in Ti-diffused strip waveguides, fabricated in y-plate and z-plate LiNbO(3), have been examined at 1.15-,microm wavelength. Propagation losses for y-plate and z-plate waveguides are ~0.5 dB/cm. Coupling losses in the y-plate and z-plate waveguides for a single-mode fiber are 2.5 and 1 dB, respectively. This difference is due to the large surface diffusion anisotropy; it is expressed by near-field pattern overlap calculations. PMID:20216898

  7. Novel Waveguide Architectures for Light Sources in Silicon Photonics

    NASA Astrophysics Data System (ADS)

    Tummidi, Ravi Sekhar

    Of the many challenges which are threatening to derail the success trend set by Moore's Law, perhaps the most prominent one is the "Interconnect Bottleneck". The metallic interconnections which carry inter-chip and intra-chip signals are increasingly proving to be inadequate to carry the enormous amount of data due to band-width limitations, cross talk and increased latency. A silicon based optical interconnect is showing enormous promise to address this issue in a cost effective manner by leveraging the extremely matured CMOS fabrication infrastructure. An optical interconnect system consists of a low loss waveguide, modulator, photo detector and a light source. Of these the only component yet to be demonstrated in silicon is a CMOS compatible electrically pumped silicon based laser. The present work is our endeavor towards the goal of a practical light source in silicon. To this end we have focused our efforts on horizontal slot waveguide which consists of a nm thin low index silica layer sandwiched between two high index silicon layers. Such a structure provides an exceptionally high confinement for the TM-like mode in the thin silica slot. The shallow ridge profile of the waveguide allows in principle for lateral electrical access to the core of the waveguide for excitation of the slot embedded gain material like erbium or nano-crystal sensitized erbium using tunneling, polarization transfer or transport. Low losses in the proposed structure are paramount due to the low gain expectation (˜1dB/cm) from CMOS compatible gain media. This dissertation details the novel techniques conceived to mitigate the severe lateral radiation leakage loss of the TM-like mode in these waveguides and resonators using "Magic Widths" and "Magic Radii" designs. New fabrication techniques are discussed which were developed to achieve ultra-smooth waveguide surfaces to substantially reduce the scattering induced losses in the Silicon-on-Insulator (SOI) high index contrast system. This

  8. Numerical investigation of silicon nitride trench waveguide

    NASA Astrophysics Data System (ADS)

    Zhao, Qiancheng; Huang, Yuewang; Torun, Rasul; Rahman, Shah; Atasever, Tuva C.; Boyraz, Ozdal

    2015-08-01

    We numerically investigated optical properties, including evanescent intensity ratio (EIR), effective refractive index (Neff), dispersion coefficient (D), and mode area (Aeff) of the silicon nitride trench waveguides fabricated by using conventional lithography. The waveguides are etched 3 μm deep with potassium hydroxide for triangle and trapezoidal waveguides, which is then followed by 3 μm thermal oxidation and 725 nm silicon nitride deposition. The waveguide with 725 nm thickness has an EIR peak of 0.025 when its bottom width Wbtm equals 0.65 μm. A thinner waveguide has higher evanescent intensity ratio, which can be used in sensing applications. The locations of EIR peaks correspond to the quasi-TM and TE mode boundary. Narrower waveguides mainly support quasi-TM modes, whereas wider waveguides can support only TE modes. As the waveguide width increases, higher orders of TE modes emerge. In addition, a boundary of TE single mode and multimode can also be linearly curve fitted, according to the starting points of TE higher modes, in order to provide the single mode condition of the waveguide. The waveguide dispersion can be engineered to be in the anomalous region while at the same time remain close to zero. The waveguide with 725 nm thickness and 0.2 μm bottom width has its anomalous dispersion region between the wavelength of 1356 nm and 1462 nm. The mode area decreases with increasing waveguide width. This is the first time we have studied the mode properties of trench waveguides systematically. The waveguide will find more applications in sensing and nonlinear fields with the help of this mode analysis.

  9. Nanophotonic light trapping in polycrystalline silicon thin-film solar cells using periodically nanoimprint-structured glass substrates

    NASA Astrophysics Data System (ADS)

    Becker, Christiane; Xavier, Jolly; Preidel, Veit; Wyss, Philippe; Sontheimer, Tobias; Rech, Bernd; Probst, Jürgen; Hülsen, Christoph; Löchel, Bernd; Erko, Alexei; Burger, Sven; Schmidt, Frank; Back, Franziska; Rudigier-Voigt, Eveline

    2013-09-01

    A smart light trapping scheme is essential to tap the full potential of polycrystalline silicon (poly-Si) thin-film solar cells. Periodic nanophotonic structures are of particular interest as they allow to substantially surpass the Lambertian limit from ray optics in selected spectral ranges. We use nanoimprint-lithography for the periodic patterning of sol-gel coated glass substrates, ensuring a cost-effective, large-area production of thin-film solar cell devices. Periodic crystalline silicon nanoarchitectures are prepared on these textured substrates by high-rate silicon film evaporation, solid phase crystallization and chemical etching. Poly-Si microhole arrays in square lattice geometry with an effective thickness of about 2μm and with comparatively large pitch (2 μm) exhibit a large absorption enhancement (A900nm = 52%) compared to a planar film (A900nm ~ 7%). For the optimization of light trapping in the desired spectral region, the geometry of the nanophotonic structures with varying pitch from 600 nm to 800 nm is tailored and investigated for the cases of poly-Si nanopillar arrays of hexagonal lattice geometry, exhibiting an increase in absorption in comparison to planar film attributed to nanophotonic wave optic effects. These structures inspire the design of prospective applications such as highly-efficient nanostructured poly-Si thin-film solar cells and large-area photonic crystals.

  10. Toward large-area roll-to-roll printed nanophotonic sensors

    NASA Astrophysics Data System (ADS)

    Karioja, Pentti; Hiltunen, Jussi; Aikio, Sanna M.; Alajoki, Teemu; Tuominen, Jarkko; Hiltunen, Marianne; Siitonen, Samuli; Kontturi, Ville; Böhlen, Karl; Hauser, Rene; Charlton, Martin; Boersma, Arjen; Lieberzeit, Peter; Felder, Thorsten; Eustace, David; Haskal, Eliav

    2014-05-01

    Polymers have become an important material group in fabricating discrete photonic components and integrated optical devices. This is due to their good properties: high optical transmittance, versatile processability at relative low temperatures and potential for low-cost production. Recently, nanoimprinting or nanoimprint lithography (NIL) has obtained a plenty of research interest. In NIL, a mould is pressed against a substrate coated with a moldable material. After deformation of the material, the mold is separated and a replica of the mold is formed. Compared with conventional lithographic methods, imprinting is simple to carry out, requires less-complicated equipment and can provide high-resolution with high throughput. Nanoimprint lithography has shown potential to become a method for low-cost and high-throughput fabrication of nanostructures. We show the development process of nano-structured, large-area multi-parameter sensors using Photonic Crystal (PC) and Surface Enhanced Raman Scattering (SERS) methodologies for environmental and pharmaceutical applications. We address these challenges by developing roll-to-roll (R2R) UV-nanoimprint fabrication methods. Our development steps are the following: Firstly, the proof of concept structures are fabricated by the use of wafer-level processes in Si-based materials. Secondly, the master molds of successful designs are fabricated, and they are used to transfer the nanophotonic structures into polymer materials using sheet-level UV-nanoimprinting. Thirdly, the sheet-level nanoimprinting processes are transferred to roll-to-roll fabrication. In order to enhance roll-to-roll manufacturing capabilities, silicone-based polymer material development was carried out. In the different development phases, Photonic Crystal and SERS sensor structures with increasing complexities were fabricated using polymer materials in order to enhance sheet-level and roll-to-roll manufacturing processes. In addition, chemical and molecular

  11. Human serotonin 1D receptor is encoded by a subfamily of two distinct genes: 5-HT1D alpha and 5-HT1D beta.

    PubMed Central

    Weinshank, R L; Zgombick, J M; Macchi, M J; Branchek, T A; Hartig, P R

    1992-01-01

    The serotonin 1D (5-HT1D) receptor is a pharmacologically defined binding site and functional receptor site. Observed variations in the properties of 5-HT1D receptors in different tissues have led to the speculation that multiple receptor proteins with slightly different properties may exist. We report here the cloning, deduced amino acid sequences, pharmacological properties, and second-messenger coupling of a pair of human 5-HT1D receptor genes, which we have designated 5-HT1D alpha and 5-HT1D beta due to their strong similarities in sequence, pharmacological properties, and second-messenger coupling. Both genes are free of introns in their coding regions, are expressed in the human cerebral cortex, and can couple to inhibition of adenylate cyclase activity. The pharmacological binding properties of these two human receptors are very similar, and match closely the pharmacological properties of human, bovine, and guinea pig 5-HT1D sites. Both receptors exhibit high-affinity binding of sumatriptan, a new anti-migraine medication, and thus are candidates for the pharmacological site of action of this drug. Images PMID:1565658

  12. High-performance polymeric materials for waveguide applications

    NASA Astrophysics Data System (ADS)

    Glukh, Konstantin; Lipian, John-Henry; Mimna, Richard; Neal, Phillip S.; Ravikiran, R.; Rhodes, Larry F.; Shick, Robert A.; Zhao, Xiao-Mei

    2000-11-01

    The ever-increasing need for economical, reliable, and high- performance optical interconnects for telecommunication and data communication markets demands new innovative solutions. Polymer technology being developed at BFGoodrich is focused on satisfying this demand. It is based on proprietary polynorbornene polymers that exhibit excellent optical, thermal and mechanical properties essential for fabrication of reliable components for integrated optics. Typical polymer waveguide systems exhibit a tradeoff between thermal and optical performance. The uniqueness of the polynorbornene system is that these tradeoffs are minimized. The intrinsic properties of the polynorbornene system include low transmission loss (<0.1 dB/cm at 820 nm), wide spectral range (<0.4 dB/cm at 450 nm and <0.1 dB/cm at 515-870nm), low birefringence ((Delta) n(in plane)<10-5, (Delta) n(out of plane) <10-3 at 820 nm, consistent difference in index over a wide temperature range, long-term thermal stability (>2000 hours at 125 degree(s)C), high glass transition temperature (>280 degree(s)C), and low moisture absorption (<0.1%). The combination of these characteristics offers advantages over existing plastic materials for visible and near IR applications such as those used in the datacom market. Candidate materials have been identified as core and cladding components for optical waveguides. The refractive index of a typical core material is 1.53, and of a typical clad material, 1.50 at 820 nm. The difference in index between core and cladding is approximately 0.03 over a broad range of wavelength (515-870nm). Preliminary results indicate that the difference in index between core and cladding tracks with temperature, which is in line with out expectation since these polymers have similar structures at the molecular level. Fabrication of functional waveguides has been demonstrated using a conventional cast and cure process at the lab scale. Optical performance of the constituent materials and the

  13. Wideband unbalanced waveguide power dividers and combiners

    DOEpatents

    Halligan, Matthew; McDonald, Jacob Jeremiah; Strassner, II, Bernd H.

    2016-05-17

    The various technologies presented herein relate to waveguide dividers and waveguide combiners for application in radar systems, wireless communications, etc. Waveguide dividers-combiners can be manufactured in accordance with custom dimensions, as well as in accordance with waveguide standards such that the input and output ports are of a defined dimension and have a common impedance. Various embodiments are presented which can incorporate one or more septum(s), one or more pairs of septums, an iris, an input matching region, a notch located on the input waveguide arm, waveguide arms having stepped transformer regions, etc. The various divider configurations presented herein can be utilized in high fractional bandwidth applications, e.g., a fractional bandwidth of about 30%, and RF applications in the Ka frequency band (e.g., 26.5-40 GHz).

  14. Waveguide-based antireflection structure

    NASA Astrophysics Data System (ADS)

    Zhu, Zhongshu; Li, Xun

    2016-04-01

    A waveguide-based antireflection structure is proposed. The device consists of two polarization rotators (PRs), two polarization-distinguished 90-deg phase delay units (PDUs), and a polarization beam combiner (PBC). The PR and PDU, providing the same function as a quarter wave plate in free-space optics, convert a linearly polarized light into a circularly polarized light. Upon reflection from an isotropic homogenous interface, the returned light is converted back into a linearly polarized light in its perpendicular direction. Through the PBC placed at the input port, the returned light is then redirected into a different port for further use or discard. Our three-dimensional mode-matching method-based simulation shows that, on the silicon-on-insulator waveguide platform, the total device length can be made as short as 10.5 μm.

  15. Radar clutter via waveguide methods

    NASA Astrophysics Data System (ADS)

    Pappert, R. A.

    1989-12-01

    Recent backscatter results generated by Tappert, using parabolic equation and Monte Carlo methods, afford an excellent opportunity to assess the adequacy of concepts such as shadowing and surface tilting often used in concert with ray concepts for line of sight backscatter calculations. In this study, results of first order scatter from rough surfaces are used in conjunction with waveguide formalism to calculate clutter from distant ranges in tropospheric waveguide environments. Comparisons are made with Tappert's results at 9.6 GHz for the standard atmosphere, and for 14 and 28 m evaporation ducts. Results apply to wind speeds of 10, 20, 30 and 40 knots. Averaged backscattered signals calculated by the two methods, for a transmitter altitude of 25 m, agree to within about + or - 10 dB. This is considered surprisingly good agreement in view of the many uncertainties and approximations involved in the calculations.

  16. Bandwidth characteristics of monopulse slotted waveguide antennas

    NASA Astrophysics Data System (ADS)

    Derneryd, A.; Peterson, R.

    Slotted waveguide antennas are of resonant and nonresonant type; the former generate a beam normal to the aperture, rendering them suitable for monopulse antenna applications. Attention is presently given to the improvement of resonant antenna impedance matching through a process of waveguide overloading. The combination of an overloaded waveguide and a transformer will generally have a broader impedance match than the antenna matched by itself; this phenomenon is discussed from both impedance-match and sidelobe level viewpoints.

  17. Neodymium-doped glasses for waveguide lasers

    NASA Astrophysics Data System (ADS)

    Church, Kenneth H.; Zanoni, Raymond; Sapak, David L.; Hayden, Joseph S.

    1994-10-01

    We report recent results from our work on the fabrication of neodymium waveguide lasers. Several neodymium doped glasses. APG-1, LG-680, BK 7 and S 3 made by Schott Glass Technologies, Inc. were studied as candidates for use as waveguide lasers. It was found that S 3, a standard ophthalmic glass, had the best ion-exchange properties of any of the glasses studied. A waveguide laser was successfully made using the neodymium doped S 3 glass.

  18. Optical fiber having wave-guiding rings

    DOEpatents

    Messerly, Michael J.; Dawson, Jay W.; Beach, Raymond J.; Barty, Christopher P. J.

    2011-03-15

    A waveguide includes a cladding region that has a refractive index that is substantially uniform and surrounds a wave-guiding region that has an average index that is close to the index of the cladding. The wave-guiding region also contains a thin ring or series of rings that have an index or indices that differ significantly from the index of the cladding. The ring or rings enable the structure to guide light.

  19. The functional nanostructures based on the bipolymers fragments with unidirect excitations energy transfer for nanophotonics

    NASA Astrophysics Data System (ADS)

    Yashchuk, V. M.; Kudrya, V. Yu.; Dubey, I. Ya.; Fedorovich, R. D.; Suga, H.; Savchenko, I. O.; Golovach, G. P.

    2007-06-01

    The results of the design, synthesis and investigations of the compounds (possessing predicted unidirect excitations conductivity) containing several π-electron systems (including nucleotides - the short DNA-fragments) are reported. The predicted processes of unidirect triplet excitations transfer in all investigated compounds were proved. The nature of electronic excitations traps in the compounds investigated is discussed. For the molecular systems composed from the DNA-fragments spectral investigations show the adenosine-thymidine-sequences are such traps in these compounds as well as the DNA [1]. The energy levels lowering existence from chromophore to chromophore along the molecular system gives the ground to predict not only unidirect neutral excitation transfer but unidirect charge carrier current. Really the "diode" I(U) characteristic for metal-organic system of gold islands connected by π-electron-containing molecules was observed. This gives the possibility to propose these compounds to be used for nanoelectronic devices design. Computer simulations of electronic excitations passing through the oligomer functional macromolecule taking into account reverse exciton currents show such type macromolecules are perspective for applying in nanophotonics.

  20. Efficient and low-noise single-photon-level frequency conversion interfaces using silicon nanophotonics

    NASA Astrophysics Data System (ADS)

    Li, Qing; Davanço, Marcelo; Srinivasan, Kartik

    2016-06-01

    Optical frequency conversion has applications ranging from tunable light sources to telecommunications-band interfaces for quantum information science. Here, we demonstrate efficient, low-noise frequency conversion on a nanophotonic chip through four-wave-mixing Bragg scattering in compact (footprint <0.5 × 10–4 cm2) Si3N4 microring resonators. We investigate three frequency conversion configurations: spectral translation over a few nanometres within the 980 nm band; upconversion from 1,550 nm to 980 nm and downconversion from 980 nm to 1,550 nm. With conversion efficiencies ranging from 25% for the first process to >60% for the last two processes, a signal conversion bandwidth of >1 GHz, a required continuous-wave pump power of <60 mW and background noise levels between a few femtowatts and a few picowatts, these devices are suitable for quantum frequency conversion of single-photon states from InAs/GaAs quantum dots. Simulations based on coupled mode equations and the Lugiato–Lefever equation are used to model device performance, and show quantitative agreement with measurements.

  1. Nanophotonic detection of freely interacting molecules on a single influenza virus.

    PubMed

    Kang, Pilgyu; Schein, Perry; Serey, Xavier; O'Dell, Dakota; Erickson, David

    2015-01-01

    Biomolecular interactions, such as antibody-antigen binding, are fundamental to many biological processes. At present, most techniques for analyzing these interactions require immobilizing one or both of the interacting molecules on an assay plate or a sensor surface. This is convenient experimentally but can constrain the natural binding affinity and capacity of the molecules, resulting in data that can deviate from the natural free-solution behavior. Here we demonstrate a label-free method for analyzing free-solution interactions between a single influenza virus and specific antibodies at the single particle level using near-field optical trapping and light-scattering techniques. We determine the number of specific antibodies binding to an optically trapped influenza virus by analyzing the change of the Brownian fluctuations of the virus. We develop an analytical model that determines the increased size of the virus resulting from antibodies binding to the virus membrane with uncertainty of ± 1-2 nm. We present stoichiometric results of 26 ± 4 (6.8 ± 1.1 attogram) anti-influenza antibodies binding to an H1N1 influenza virus. Our technique can be applied to a wide range of molecular interactions because the nanophotonic tweezer can handle molecules from tens to thousands of nanometers in diameter. PMID:26160194

  2. Photonics and Nanophotonics and Information and Communication Technologies in Modern Food Packaging

    NASA Astrophysics Data System (ADS)

    Sarapulova, Olha; Sherstiuk, Valentyn; Shvalagin, Vitaliy; Kukhta, Aleksander

    2015-05-01

    The analysis of the problem of conjunction of information and communication technologies (ICT) with packaging industry and food production was made. The perspective of combining the latest advances of nanotechnology, including nanophotonics, and ICT for creating modern smart packaging was shown. There were investigated luminescent films with zinc oxide nanoparticles, which change luminescence intensity as nano-ZnO interacts with decay compounds of food products, for active and intelligent packaging. High luminescent transparent films were obtained from colloidal suspension of ZnO and polyvinylpyrrolidone (PVP). The influence of molecular mass, concentration of nano-ZnO, and film thickness on luminescent properties of films was studied in order to optimize the content of the compositions. The possibility of covering the obtained films with polyvinyl alcohol was considered for eliminating water soluble properties of PVP. The luminescent properties of films with different covers were studied. The insoluble in water composition based on ZnO stabilized with colloidal silicon dioxide and PVP in polymethylmethacrylate was developed, and the luminescent properties of films were investigated. The compositions are non-toxic, safe, and suitable for applying to the inner surface of active and intelligent packaging by printing techniques, such as screen printing, flexography, inkjet, and pad printing.

  3. Nanophotonic detection of freely interacting molecules on a single influenza virus

    PubMed Central

    Kang, Pilgyu; Schein, Perry; Serey, Xavier; O’Dell, Dakota; Erickson, David

    2015-01-01

    Biomolecular interactions, such as antibody-antigen binding, are fundamental to many biological processes. At present, most techniques for analyzing these interactions require immobilizing one or both of the interacting molecules on an assay plate or a sensor surface. This is convenient experimentally but can constrain the natural binding affinity and capacity of the molecules, resulting in data that can deviate from the natural free-solution behavior. Here we demonstrate a label-free method for analyzing free-solution interactions between a single influenza virus and specific antibodies at the single particle level using near-field optical trapping and light-scattering techniques. We determine the number of specific antibodies binding to an optically trapped influenza virus by analyzing the change of the Brownian fluctuations of the virus. We develop an analytical model that determines the increased size of the virus resulting from antibodies binding to the virus membrane with uncertainty of ±1–2 nm. We present stoichiometric results of 26 ± 4 (6.8 ± 1.1 attogram) anti-influenza antibodies binding to an H1N1 influenza virus. Our technique can be applied to a wide range of molecular interactions because the nanophotonic tweezer can handle molecules from tens to thousands of nanometers in diameter. PMID:26160194

  4. Nanophotonic detection of freely interacting molecules on a single influenza virus

    NASA Astrophysics Data System (ADS)

    Kang, Pilgyu; Schein, Perry; Serey, Xavier; O'Dell, Dakota; Erickson, David

    2015-07-01

    Biomolecular interactions, such as antibody-antigen binding, are fundamental to many biological processes. At present, most techniques for analyzing these interactions require immobilizing one or both of the interacting molecules on an assay plate or a sensor surface. This is convenient experimentally but can constrain the natural binding affinity and capacity of the molecules, resulting in data that can deviate from the natural free-solution behavior. Here we demonstrate a label-free method for analyzing free-solution interactions between a single influenza virus and specific antibodies at the single particle level using near-field optical trapping and light-scattering techniques. We determine the number of specific antibodies binding to an optically trapped influenza virus by analyzing the change of the Brownian fluctuations of the virus. We develop an analytical model that determines the increased size of the virus resulting from antibodies binding to the virus membrane with uncertainty of ±1-2 nm. We present stoichiometric results of 26 ± 4 (6.8 ± 1.1 attogram) anti-influenza antibodies binding to an H1N1 influenza virus. Our technique can be applied to a wide range of molecular interactions because the nanophotonic tweezer can handle molecules from tens to thousands of nanometers in diameter.

  5. Nanophotonic photon echo memory based on rare-earth-doped crystals

    NASA Astrophysics Data System (ADS)

    Zhong, Tian; Kindem, Jonathan; Miyazono, Evan; Faraon, Andrei; Caltech nano quantum optics Team

    2015-03-01

    Rare earth ions (REIs) are promising candidates for implementing solid-state quantum memories and quantum repeater devices. Their high spectral stability and long coherence times make REIs a good choice for integration in an on-chip quantum nano-photonic platform. We report the coupling of the 883 nm transition of Neodymium (Nd) to a Yttrium orthosilicate (YSO) photonic crystal nano-beam resonator, achieving Purcell enhanced spontaneous emission by 21 times and increased optical absorption. Photon echoes were observed in nano-beams of different doping concentrations, yielding optical coherence times T2 up to 80 μs that are comparable to unprocessed bulk samples. This indicates the remarkable coherence properties of Nd are preserved during nanofabrication, therefore opening the possibility of efficient on-chip optical quantum memories. The nano-resonator with mode volume of 1 . 6(λ / n) 3 was fabricated using focused ion beam, and a quality factor of 3200 was measured. Purcell enhanced absorption of 80% by an ensemble of ~ 1 × 106 ions in the resonator was measured, which fulfills the cavity impedance matching condition that is necessary to achieve quantum storage of photons with unity efficiency.

  6. Advanced in-situ electron-beam lithography for deterministic nanophotonic device processing.

    PubMed

    Kaganskiy, Arsenty; Gschrey, Manuel; Schlehahn, Alexander; Schmidt, Ronny; Schulze, Jan-Hindrik; Heindel, Tobias; Strittmatter, André; Rodt, Sven; Reitzenstein, Stephan

    2015-07-01

    We report on an advanced in-situ electron-beam lithography technique based on high-resolution cathodoluminescence (CL) spectroscopy at low temperatures. The technique has been developed for the deterministic fabrication and quantitative evaluation of nanophotonic structures. It is of particular interest for the realization and optimization of non-classical light sources which require the pre-selection of single quantum dots (QDs) with very specific emission features. The two-step electron-beam lithography process comprises (a) the detailed optical study and selection of target QDs by means of CL-spectroscopy and (b) the precise retrieval of the locations and integration of target QDs into lithographically defined nanostructures. Our technology platform allows for a detailed pre-process determination of important optical and quantum optical properties of the QDs, such as the emission energies of excitonic complexes, the excitonic fine-structure splitting, the carrier dynamics, and the quantum nature of emission. In addition, it enables a direct and precise comparison of the optical properties of a single QD before and after integration which is very beneficial for the quantitative evaluation of cavity-enhanced quantum devices. PMID:26233395

  7. Advanced in-situ electron-beam lithography for deterministic nanophotonic device processing

    NASA Astrophysics Data System (ADS)

    Kaganskiy, Arsenty; Gschrey, Manuel; Schlehahn, Alexander; Schmidt, Ronny; Schulze, Jan-Hindrik; Heindel, Tobias; Strittmatter, André; Rodt, Sven; Reitzenstein, Stephan

    2015-07-01

    We report on an advanced in-situ electron-beam lithography technique based on high-resolution cathodoluminescence (CL) spectroscopy at low temperatures. The technique has been developed for the deterministic fabrication and quantitative evaluation of nanophotonic structures. It is of particular interest for the realization and optimization of non-classical light sources which require the pre-selection of single quantum dots (QDs) with very specific emission features. The two-step electron-beam lithography process comprises (a) the detailed optical study and selection of target QDs by means of CL-spectroscopy and (b) the precise retrieval of the locations and integration of target QDs into lithographically defined nanostructures. Our technology platform allows for a detailed pre-process determination of important optical and quantum optical properties of the QDs, such as the emission energies of excitonic complexes, the excitonic fine-structure splitting, the carrier dynamics, and the quantum nature of emission. In addition, it enables a direct and precise comparison of the optical properties of a single QD before and after integration which is very beneficial for the quantitative evaluation of cavity-enhanced quantum devices.

  8. Advanced in-situ electron-beam lithography for deterministic nanophotonic device processing

    SciTech Connect

    Kaganskiy, Arsenty; Gschrey, Manuel; Schlehahn, Alexander; Schmidt, Ronny; Schulze, Jan-Hindrik; Heindel, Tobias; Rodt, Sven Reitzenstein, Stephan; Strittmatter, André

    2015-07-15

    We report on an advanced in-situ electron-beam lithography technique based on high-resolution cathodoluminescence (CL) spectroscopy at low temperatures. The technique has been developed for the deterministic fabrication and quantitative evaluation of nanophotonic structures. It is of particular interest for the realization and optimization of non-classical light sources which require the pre-selection of single quantum dots (QDs) with very specific emission features. The two-step electron-beam lithography process comprises (a) the detailed optical study and selection of target QDs by means of CL-spectroscopy and (b) the precise retrieval of the locations and integration of target QDs into lithographically defined nanostructures. Our technology platform allows for a detailed pre-process determination of important optical and quantum optical properties of the QDs, such as the emission energies of excitonic complexes, the excitonic fine-structure splitting, the carrier dynamics, and the quantum nature of emission. In addition, it enables a direct and precise comparison of the optical properties of a single QD before and after integration which is very beneficial for the quantitative evaluation of cavity-enhanced quantum devices.

  9. Self-induced back-action optical trapping in nanophotonic systems

    NASA Astrophysics Data System (ADS)

    Neumeier, Lukas; Quidant, Romain; Chang, Darrick E.

    2015-12-01

    Optical trapping is an indispensable tool in physics and the life sciences. However, there is a clear trade off between the size of a particle to be trapped, its spatial confinement, and the intensities required. This is due to the decrease in optical response of smaller particles and the diffraction limit that governs the spatial variation of optical fields. It is thus highly desirable to find techniques that surpass these bounds. Recently, a number of experiments using nanophotonic cavities have observed a qualitatively different trapping mechanism described as ‘self-induced back-action trapping’ (SIBA). In these systems, the particle motion couples to the resonance frequency of the cavity, which results in a strong interplay between the intra-cavity field intensity and the forces exerted. Here, we provide a theoretical description that for the first time captures the remarkable range of consequences. In particular, we show that SIBA can be exploited to yield dynamic reshaping of trap potentials, strongly sub-wavelength trap features, and significant reduction of intensities seen by the particle, which should have important implications for future trapping technologies.

  10. Photonics and nanophotonics and information and communication technologies in modern food packaging.

    PubMed

    Sarapulova, Olha; Sherstiuk, Valentyn; Shvalagin, Vitaliy; Kukhta, Aleksander

    2015-01-01

    The analysis of the problem of conjunction of information and communication technologies (ICT) with packaging industry and food production was made. The perspective of combining the latest advances of nanotechnology, including nanophotonics, and ICT for creating modern smart packaging was shown. There were investigated luminescent films with zinc oxide nanoparticles, which change luminescence intensity as nano-ZnO interacts with decay compounds of food products, for active and intelligent packaging. High luminescent transparent films were obtained from colloidal suspension of ZnO and polyvinylpyrrolidone (PVP). The influence of molecular mass, concentration of nano-ZnO, and film thickness on luminescent properties of films was studied in order to optimize the content of the compositions. The possibility of covering the obtained films with polyvinyl alcohol was considered for eliminating water soluble properties of PVP. The luminescent properties of films with different covers were studied. The insoluble in water composition based on ZnO stabilized with colloidal silicon dioxide and PVP in polymethylmethacrylate was developed, and the luminescent properties of films were investigated. The compositions are non-toxic, safe, and suitable for applying to the inner surface of active and intelligent packaging by printing techniques, such as screen printing, flexography, inkjet, and pad printing. PMID:26034421

  11. Interacting Photons in Waveguide-QED and Applications in Quantum Information Processing

    NASA Astrophysics Data System (ADS)

    Zheng, Huaixiu

    Strong coupling between light and matter has been demonstrated both in classical cavity quantum electrodynamics (QED) systems and in more recent circuit-QED experiments. This enables the generation of strong nonlinear photon-photon interactions at the single-photon level, which is of great interest for the observation of quantum nonlinear optical phenomena, the control of light quanta in quantum information protocols such as quantum networking, as well as the study of strongly correlated quantum many-body systems using light. Recently, strong coupling has also been realized in a variety of one-dimensional (1D) waveguide- QED experimental systems, which in turn makes them promising candidates for quantum information processing. Compared to cavity-QED systems, there are two new features in waveguide-QED: the existence of a continuum of states and the restricted 1D phase space, which together bring in new physical effects, such as the bound-state effects. This thesis consists of two parts: 1) understanding the fundamental interaction between local quantum objects, such as two-level systems and four-level systems, and photons confined in the waveguide; 2) exploring its implications in quantum information processing, in particular photonic quantum computation and quantum key distribution. First, we demonstrate that by coupling a two-level system (TLS) or three/four-level system to a 1D continuum, strongly-correlated photons can be generated inside the waveguide. Photon-photon bound states, which decay exponentially as a function of the relative coordinates of photons, appear in multiphoton scattering processes. As a result, photon bunching and antibunching can be observed in the photon-photon correlation function, and nonclassical light source can be generated on demand. In the case of an N-type four-level system, we show that the effective photon-photon interaction mediated by the four-level system, gives rise to a variety of nonlinear optical phenomena, including

  12. Computing Scattering Matrices For Circular Waveguides

    NASA Technical Reports Server (NTRS)

    Hoppe, Daniel J.

    1990-01-01

    Scattering Matrix Program for Circular Waveguide Junctions computes scattering matrix for series of circular waveguide sections. Sections must have same axis, but radius and length of each section completely arbitrary. Devices analyzed include simple waveguide step discontinuity like that used in a dual-mode horn, stepped matching section, or corrugated waveguide section with constant or varying slot depth. Certain types of corrugated horns also analyzed with program. Mathematical model used in program accurately predicts reflection and transmission characteristics of such devices, taking into account excitation of modes of higher order as well as multiple reflections and energy stored at each discontinuity. Written in FORTRAN 77.

  13. RF window assembly comprising a ceramic disk disposed within a cylindrical waveguide which is connected to rectangular waveguides through elliptical joints

    DOEpatents

    Tantawi, Sami G.; Dolgashev, Valery A.; Yeremian, Anahid D.

    2016-03-15

    A high-power microwave RF window is provided that includes a cylindrical waveguide, where the cylindrical waveguide includes a ceramic disk concentrically housed in a central region of the cylindrical waveguide, a first rectangular waveguide, where the first rectangular waveguide is connected by a first elliptical joint to a proximal end of the cylindrical waveguide, and a second rectangular waveguide, where the second rectangular waveguide is connected by a second elliptical joint to a distal end of the cylindrical waveguide.

  14. Facile synthesis of single-crystalline microwires based on anthracene derivative and their efficient optical waveguides and linearly polarized emission

    NASA Astrophysics Data System (ADS)

    Peng, Hong-Dan; Wang, Juan-Ye; Liu, Zheng-Hui; Pan, Ge-Bo

    2016-05-01

    The well-defined single-crystalline microwires of a solid-emissive organic functional molecule, 2-(anthracen-9-yl)-4, 5-diphenyl-1H-imidozole (ADPI) were successfully prepared by a facile solution process without the use of surfactant or additional templates. In addition, the optical loss coefficient is as low as 0.1 dB μm-1 for the as-prepared ADPI microwires, which is lower than most previous reported organic optical waveguides. Meanwhile, these microwires also show optically uniaxial properties as demonstrated by the linearly polarized emission, providing potentially orientation-sensitive applications as optical waveguides with low optical loss.

  15. Nano-photonics in III-V semiconductors for integrated quantum optical circuits

    NASA Astrophysics Data System (ADS)

    Wasley, Nicholas Andrew

    This thesis describes the optical spectroscopic measurements of III-V semiconductors used to investigate a number of issues related to the development of integrated quantum optical circuits. The disorder-limited propagation of photons in photonic crystal waveguides in the slow-light regime is investigated. The analysis of Fabry-Perot resonances is used to map the mode dispersion and extract the photon localisation length. Andersonlocalised modes are observed at high group indices, when the localisation lengths are shorter than the waveguide lengths, consistent with the Fabry-Perot analysis. A spin-photon interface based on two orthogonal waveguides is introduced, where the polarisation emitted by a quantum dot is mapped to a path-encoded photon. Operation is demonstrated by deducing the spin using the interference of in-plane photons. A second device directly maps right and left circular polarisations to anti-parallel waveguides, surprising for a non-chiral structure but consistent with an off-centre dot. Two dimensional photonic crystal cavities in GaInP and full control over the spontaneous emission rate of InP quantum dots is demonstrated by spectrally tuning the exciton emission energy into resonance with the fundamental cavity mode. Fourier transform spectroscopy is used to investigate the short coherence times of InP quantum dots in GaInP photonic crystal cavities. Additional technological developments are also presented including a quantum dot registration technique, electrical tuning of quantum dot emission and uniaxial strain tuning of H1 cavity modes.

  16. Stability of spinor Fermi gases in tight waveguides

    SciTech Connect

    Campo, A. del; Muga, J. G.; Girardeau, M. D.

    2007-07-15

    The two- and three-body correlation functions of the ground state of an optically trapped ultracold spin-(1/2) Fermi gas (SFG) in a tight waveguide [one-dimensional (1D) regime] are calculated in the plane of even- and odd-wave coupling constants, assuming a 1D attractive zero-range odd-wave interaction induced by a 3D p-wave Feshbach resonance, as well as the usual repulsive zero-range even-wave interaction stemming from 3D s-wave scattering. The calculations are based on the exact mapping from the SFG to a 'Lieb-Liniger-Heisenberg' model with delta-function repulsions depending on isotropic Heisenberg spin-spin interactions, and indicate that the SFG should be stable against three-body recombination in a large region of the coupling constant plane encompassing parts of both the ferromagnetic and antiferromagnetic phases. However, the limiting case of the fermionic Tonks-Girardeau gas, a spin-aligned 1D Fermi gas with infinitely attractive p-wave interactions, is unstable in this sense. Effects due to the dipolar interaction and a Zeeman term due to a resonance-generating magnetic field do not lead to shrinkage of the region of stability of the SFG.

  17. Enhancement of second-harmonic generation in nonlinear nanolaminate metamaterials by nanophotonic resonances.

    PubMed

    Hsiao, Hui-Hsin; Abass, Aimi; Fischer, Johannes; Alaee, Rasoul; Wickberg, Andreas; Wegener, Martin; Rockstuhl, Carsten

    2016-05-01

    Nanolaminate metamaterials recently attracted a lot of attention as a novel second-order nonlinear material that can be used in integrated photonic circuits. Here, we explore theoretically and numerically the opportunity to enhance the nonlinear response from such nanolaminates by exploiting Fano resonances supported in grating-coupled waveguides. The enhancement factor of the radiated second harmonic signal compared to a flat nanolaminate can reach values as large as 35 for gold gratings and even 7000 for MgF2 gratings. For the MgF2 grating, extremely high-Q Fano resonances are excited in such all-dielectric system that result in strong local fields in the nonlinear waveguide layer to boost the nonlinear conversion. A significant portion of the nonlinear signal is also strongly coupled to a dark waveguide mode, which remains guided in the nanolaminate. The strong excitation of a dark mode at the second harmonic frequency provides a viable method for utilizing second-order nonlinearities for light generation and manipulation in integrated photonic circuits. PMID:27137578

  18. Terahertz spin-wave waveguides and optical magnonics in one-dimensional NiO nanorods

    NASA Astrophysics Data System (ADS)

    Patil, Ranjit A.; Su, Chiung-Wu; Chuang, Chin-Jung; Lai, Chien-Chih; Liou, Yung; Ma, Yuan-Ron

    2016-06-01

    The two-magnon (2M) spin waves with a magnon frequency of 43 THz, generated by a polarized laser, were first observed in one-dimensional (1D) NiO nanorods. The 1D NiO nanorods of ~700 nm length, which have perfectly in-plane antiferromagnetic spins lying on the (200) and (100) faces, are the smallest spin-wave waveguides. Due to the magneto-optical Faraday effect (MOFE), the significant change in the Faraday intensity can show the 2M information in the NiO nanorods. There are only two 2M-on and 2M-off states at various applied alternating-current magnetic fields and laser-incident angles, which make the 1D NiO nanorods excellent optical nanomagnonics.The two-magnon (2M) spin waves with a magnon frequency of 43 THz, generated by a polarized laser, were first observed in one-dimensional (1D) NiO nanorods. The 1D NiO nanorods of ~700 nm length, which have perfectly in-plane antiferromagnetic spins lying on the (200) and (100) faces, are the smallest spin-wave waveguides. Due to the magneto-optical Faraday effect (MOFE), the significant change in the Faraday intensity can show the 2M information in the NiO nanorods. There are only two 2M-on and 2M-off states at various applied alternating-current magnetic fields and laser-incident angles, which make the 1D NiO nanorods excellent optical nanomagnonics. Electronic supplementary information (ESI) available: Cubic crystal structure and Raman scattering of 1D NiO nanorods. See DOI: 10.1039/c6nr02531e

  19. Brady 1D seismic velocity model ambient noise prelim

    DOE Data Explorer

    Mellors, Robert J.

    2013-10-25

    Preliminary 1D seismic velocity model derived from ambient noise correlation. 28 Green's functions filtered between 4-10 Hz for Vp, Vs, and Qs were calculated. 1D model estimated for each path. The final model is a median of the individual models. Resolution is best for the top 1 km. Poorly constrained with increasing depth.

  20. Multi-scale soft-lithographic lift-off and grafting (MS-SLLOG) process for active polymer nanophotonic device fabrication

    NASA Astrophysics Data System (ADS)

    Tung, Yi-Chung; Truxal, Steven C.; Kurabayashi, Katsuo

    2005-12-01

    This paper reports a new microfabrication process named "Multi-Scale Soft-Lithographic Lift-Off and Grafting (MS-SLLOG)" used to construct active nanophotonic devices. MS-SLLOG is a low-temperature (less than 150°C) microfabrication technique that allows soft lithographically molded polymer micro-structures to be integrated together with silicon-based microelectromechanical systems (MEMS) structures to perform active control. Moreover, MS-SLLOG process allows us to achieve a hierarchical device structure seamlessly accommodating feature sizes ranging from tens of nanometer to sub-millimeters on a single chip for nanophotonic structure integration. To demonstrate the MS-SLLOG process capability, a strain-controlled micro-optical grating device is fabricated and experimentally characterized. The experimental results successfully show the operation of an active polymer nanophotonic device fabricated by the MS-SLLOG process.

  1. Grating assisted optical waveguide coupler to excite individual modes of a multi-mode waveguide

    NASA Astrophysics Data System (ADS)

    Bremer, K.; Lochmann, S.; Roth, B.

    2015-12-01

    Spatial division multiplexing (SDM) in the form of mode division multiplexing (MDM) in multi-mode (MM) waveguides is currently explored to overcome the capacity limitation of single-mode (SM) waveguides in data transmission technology. In this work a new approach towards mode selective optical waveguide couplers to multiplex and demultiplex individual modes of MM waveguides is presented. We discuss a grating assisted mode selective optical waveguide coupler and evaluate numerically its coupling efficiency. The approach relies on a grating structure in a SM waveguide which is used to excite individual modes of an adjacent unmodified MM waveguide via evanescent field coupling. The simulations verify that by using the grating structure and tailoring the grating period, light from the SM waveguide can be coupled selectively into the fundamental mode or any higher-order mode of a MM waveguide with high efficiency and low crosstalk to adjacent mode-channels. The results indicate the potential of the grating assisted waveguide coupler approach for future applications in on-chip photonic networks and the (de)multiplexing of individual modes of MM waveguides.

  2. Scalar Product in the Space of Waveguide Modes of an Open Planar Waveguide

    NASA Astrophysics Data System (ADS)

    Sevastianov, A. L.; Sevastianov, L. A.; Tiutiunnik, A. A.; Nikolaev, N. E.

    2016-02-01

    To implement the method of adiabatic waveguide modes for modeling the propagation of polarized monochromatic electromagnetic radiation in irregular integrated optics structures it is necessary to expand the desired solution in basic adiabatic waveguide modes. This expansion requires the use of the scalar product in the space of waveguide vector fields of integrated optics waveguide. This work solves the first stage of this problem - the construction of the scalar product in the space of vector solutions of the eigenmode problem (classical and generalized) waveguide modes of an open planar waveguide. In constructing the mentioned sesquilinear form, we used the Lorentz reciprocity principle of waveguide modes and tensor form of the Ostrogradsky-Gauss theorem.

  3. Dielectric-loaded waveguide circulator for cryogenically cooled and cascaded maser waveguide structures

    NASA Technical Reports Server (NTRS)

    Clauss, R. C.; Quinn, R. B. (Inventor)

    1980-01-01

    A dielectrically loaded four port waveguide circulator is used with a reflected wave maser connected to a second port between first and third ports to form one of a plurality of cascaded maser waveguide structures. The fourth port is connected to a waveguide loaded with microwave energy absorbing material. The third (output signal) port of one maser waveguide structure is connected by a waveguide loaded with dielectric material to the first (input) port of an adjacent maser waveguide structure, and the second port is connected to a reflected wave maser by a matching transformer which passes the signal to be amplified into and out of the reflected wavemaser and blocks pumping energy in the reflected wave maser from entering the circulator. A number of cascaded maser waveguide structures are thus housed in a relatively small volume of conductive material placed within a cryogenically cooled magnet assembly.

  4. Dielectric matrices with air cavities as a waveguide photonic crystal

    NASA Astrophysics Data System (ADS)

    Usanov, D. A.; Skripal', A. V.; Merdanov, M. K.; Gorlitskii, V. O.

    2016-02-01

    Frequency dependences of the transmission coefficient of a microwave photonic crystal that represents a structure containing alternating layers of ceramic material (Al2O3) with a relatively large number of cavities and foam plastic are studied in the presence and absence of distortions of the periodicity of a photonic structure. The frequency dependences of the transmission coefficient can be analyzed using a model of effective medium that makes it possible to consider the interaction of electromagnetic wave and photonic crystal using a transfer matrix of a 1D photonic crystal. The band character of the frequency dependence of the transmission coefficient of the photonic crystal related to the periodicity of the photonic crystal in the transverse plane for the waveguide with a standard cross section is not manifested in a certain range of material permittivities.

  5. High temperature pressure coupled ultrasonic waveguide

    SciTech Connect

    Caines, M.J.

    1983-07-12

    A pressure coupled ultrasonic waveguide is provided to which one end may be attached a transducer and at the other end a high temperature material for continuous ultrasonic testing of the material. The ultrasonic signal is coupled from the waveguide into the material through a thin, dry copper foil.

  6. High temperature pressure coupled ultrasonic waveguide

    DOEpatents

    Caines, Michael J.

    1983-01-01

    A pressure coupled ultrasonic waveguide is provided to which one end may be attached a transducer and at the other end a high temperature material for continuous ultrasonic testing of the material. The ultrasonic signal is coupled from the waveguide into the material through a thin, dry copper foil.

  7. Standing sausage waves in photospheric magnetic waveguides

    NASA Astrophysics Data System (ADS)

    Dorotovič, I.; Erdélyi, R.; Freij, N.; Karlovský, V.; Márquez, I.

    2014-03-01

    Aims: By focussing on the oscillations of the cross-sectional area and the total intensity of magnetic waveguides located in the lower solar atmosphere, we aim to detect and identify magnetohydrodynamic (MHD) sausage waves. Methods: Capturing several high-resolution time series of magnetic waveguides and employing a wavelet analysis, in conjunction with empirical mode decomposition (EMD), makes the MHD wave analysis possible. For this paper, two sunspots and one pore (with a light bridge) were chosen as examples of MHD waveguides in the lower solar atmosphere. Results: The waveguides display a range of periods from 4 to 65 min. These structures display in-phase behaviour between the area and intensity, presenting mounting evidence for sausage modes within these waveguides. The detected periods point towards standing oscillations. Conclusions: The presence of fast and slow MHD sausage waves has been detected in three different magnetic waveguides in the solar photosphere. Furthermore, these oscillations are potentially standing harmonics supported in the waveguides that are sandwiched vertically between the temperature minimum in the lower solar atmosphere and the transition region. The relevance of standing harmonic oscillations is that their exploitation by means of solar magneto-seismology may allow insight into the sub-pixel resolution structure of photospheric MHD waveguides.

  8. Nanophotonics and nanochemistry: controlling the excitation dynamics for frequency up- and down-conversion in lanthanide-doped nanoparticles.

    PubMed

    Chen, Guanying; Yang, Chunhui; Prasad, Paras N

    2013-07-16

    Nanophotonics is an emerging science dealing with the interaction of light and matter on a nanometer scale and holds promise to produce new generation nanophosphors with highly efficient frequency conversion of infrared (IR) light. Scientists can control the excitation dynamics by using nanochemistry to produce hierarchically built nanostructures and tailor their interfaces. These nanophosphors can either perform frequency up-conversion from IR to visible or ultraviolet (UV) or down-conversion, which results in the IR light being further red shifted. Nanophotonics and nanochemistry open up numerous opportunities for these photon converters, including in high contrast bioimaging, photodynamic therapy, drug release and gene delivery, nanothermometry, and solar cells. Applications of these nanophosphors in these directions derive from three main stimuli. Light excitation and emission within the near-infrared (NIR) "optical transparency window" of tissues is ideal for high contrast in vitro and in vivo imaging. This is due to low natural florescence, reduced scattering background, and deep penetration in tissues. Secondly, the naked eye is highly sensitive in the visible range, but it has no response to IR light. Therefore, many scientists have interest in the frequency up-conversion of IR wavelengths for security and display applications. Lastly, frequency up-conversion can convert IR photons to higher energy photons, which can then readily be absorbed by solar materials. Current solar devices do not use abundant IR light that comprises almost half of solar energy. In this Account, we present our recent work on nanophotonic control of frequency up- and down-conversion in fluoride nanophosphors, and their biophotonic and nanophotonic applications. Through nanoscopic control of phonon dynamics, electronic energy transfer, local crystal field, and surface-induced non-radiative processes, we were able to produce new generation nanophosphors with highly efficient frequency

  9. Hybrid Group IV Nanophotonic Structures Incorporating Diamond Silicon-Vacancy Color Centers.

    PubMed

    Zhang, Jingyuan Linda; Ishiwata, Hitoshi; Babinec, Thomas M; Radulaski, Marina; Müller, Kai; Lagoudakis, Konstantinos G; Dory, Constantin; Dahl, Jeremy; Edgington, Robert; Soulière, Veronique; Ferro, Gabriel; Fokin, Andrey A; Schreiner, Peter R; Shen, Zhi-Xun; Melosh, Nicholas A; Vučković, Jelena

    2016-01-13

    We demonstrate a new approach for engineering group IV semiconductor-based quantum photonic structures containing negatively charged silicon-vacancy (SiV(-)) color centers in diamond as quantum emitters. Hybrid diamond-SiC structures are realized by combining the growth of nano- and microdiamonds on silicon carbide (3C or 4H polytype) substrates, with the subsequent use of these diamond crystals as a hard mask for pattern transfer. SiV(-) color centers are incorporated in diamond during its synthesis from molecular diamond seeds (diamondoids), with no need for ion-implantation or annealing. We show that the same growth technique can be used to grow a diamond layer controllably doped with SiV(-) on top of a high purity bulk diamond, in which we subsequently fabricate nanopillar arrays containing high quality SiV(-) centers. Scanning confocal photoluminescence measurements reveal optically active SiV(-) lines both at room temperature and low temperature (5 K) from all fabricated structures, and, in particular, very narrow line widths and small inhomogeneous broadening of SiV(-) lines from all-diamond nanopillar arrays, which is a critical requirement for quantum computation. At low temperatures (5 K) we observe in these structures the signature typical of SiV(-) centers in bulk diamond, consistent with a double lambda. These results indicate that high quality color centers can be incorporated into nanophotonic structures synthetically with properties equivalent to those in bulk diamond, thereby opening opportunities for applications in classical and quantum information processing. PMID:26695059

  10. An innovative nanophotonic information processing concept implementing cogent micro/nanosensors for space robotics

    NASA Astrophysics Data System (ADS)

    Santoli, Salvatore

    2013-02-01

    Cogent sensors, defined as sensors that are capable of performing the transformation of raw data into information, are shown to be of the essence for realization of the long sought-after autonomous robots for space applications. A strongly miniaturized integration of sensing and information processing systems is needed for cogent sensors designed for autonomous sensing—information processing (IP)—actuating behavior. It is shown that the recently developed field of quantum holography (QH), stemming from geometric quantization of any holographic processes through the Heisenberg Group (G) and deeply different, as stressed in detail, from other meanings of "quantum holography" in the literature, supplies the nanophotonic tools for designing and assembling an associative memory (AM) as the brain implementing such strong cogency. An AM is designed through a free-space interconnected large planar multilayer architecture of quantum well-based two-port neurons implementing a shift register on the manifold of G, and whose input consists of photonic holograms from high frequency pulsed microlasers in the infrared band of em or em-transduced outside signals. The optoelectronics as relative, integrated into a hybrid chip involving photonic detectors, microlasers and electronic components for the clock control system, would allow cycle times as short as 30 ns with the large spatial bandwidth available in photonics. IP through QH concerns the encoding and decoding of holographic interference patterns, not of mere binary digital logical (syntactic) information. Accordingly, QH defines on the G's manifold an IP paradigm where information as experimental knowledge is processed; i.e., IP concerns both syntax and semantics. It is shown that such QH-neural brain would cogently deal with spurious signals as random noise that would be caused to die out on the way to the intended target through parallel massive and real-time IP.

  11. Crystal phase-dependent nanophotonic resonances in InAs nanowire arrays.

    PubMed

    Anttu, Nicklas; Lehmann, Sebastian; Storm, Kristian; Dick, Kimberly A; Samuelson, Lars; Wu, Phillip M; Pistol, Mats-Erik

    2014-10-01

    Nanostructures have many material, electronic, and optical properties that are not found in bulk systems and that are relevant for technological applications. For example, nanowires realized from III-V semiconductors can be grown into a wurtzite crystal structure. This crystal structure does not naturally exist in bulk where these materials form the zinc-blende counterpart. Being able to concomitantly grow these nanowires in the zinc-blende and/or wurtzite crystal structure provides an important degree of control for the design and optimization of optoelectronic applications based on these semiconductor nanostructures. However, the refractive indices of this new crystallographic phase have so far not been elucidated. This shortcoming makes it impossible to predict and utilize the full potential of these new nanostructured materials for optoelectronics applications: a careful design and optimization of optical resonances by tuning the nanostructure geometry is needed to achieve optimal performance. Here, we report and analyze striking differences in the optical response of nanophotonic resonances in wurtzite and zinc-blende InAs nanowire arrays. Specifically, through reflectance measurements we find that the resonance can be tuned down to λ ≈ 380 nm in wurtzite nanowires by decreasing the nanowire diameter. In stark contrast, a similar tuning to below λ ≈ 500 nm is not possible in the zinc-blende nanowires. Furthermore, we find that the wurtzite nanowires can absorb twice as strongly as the zinc-blende nanowires. We attribute these strikingly large differences in resonant behavior to large differences between the refractive indices of the two crystallographic phases realized in these nanostructures. We anticipate our findings to be relevant for other III-V materials as well as for all material systems that manifest polytypism. Taken together, our results demonstrate crystal phase engineering as a potentially new design dimension for optoelectronics

  12. On-chip plasmonic waveguide optical waveplate

    PubMed Central

    Gao, Linfei; Huo, Yijie; Zang, Kai; Paik, Seonghyun; Chen, Yusi; Harris, James S.; Zhou, Zhiping

    2015-01-01

    Polarization manipulation is essential in almost every photonic system ranging from telecommunications to bio-sensing to quantum information. This is traditionally achieved using bulk waveplates. With the developing trend of photonic systems towards integration and miniaturization, the need for an on-chip waveguide type waveplate becomes extremely urgent. However, this is very challenging using conventional dielectric waveguides, which usually require complex 3D geometries to alter the waveguide symmetry and are also difficult to create an arbitrary optical axis. Recently, a waveguide waveplate was realized using femtosecond laser writing, but the device length is in millimeter range. Here, for the first time we propose and experimentally demonstrate an ultracompact, on-chip waveplate using an asymmetric hybrid plasmonic waveguide to create an arbitrary optical axis. The device is only in several microns length and produced in a flexible integratable IC compatible format, thus opening up the potential for integration into a broad range of systems. PMID:26507563

  13. Folded waveguide coupler for ion cyclotron heating

    SciTech Connect

    Owens, T.L.; Chen, G.L.

    1986-01-01

    A new type of waveguide coupler for plasma heating in the ion cyclotron range of frequencies is described. The coupler consists of a series of interleaved metallic vanes within a rectangular enclosure analogous to a wide rectangular waveguide that has been ''folded'' several times. At the mouth of the coupler, a plate is attached which contains coupling apertures in each fold or every other fold of the waveguide, depending upon the wavenumber spectrum desired. This plate serves primarily as a wave field polarizer that converts coupler fields to the polarization of the fast magnetosonic wave within the plasma. Theoretical estimates indicate that the folded waveguide is capable of high-efficiency, multimegawatt operation into a plasma. Bench tests have verified the predicted field structure within the waveguide in preparation for high-power tests on the Radio Frequency Test Facility at the Oak Ridge National Laboratory.

  14. Analysis of waveguiding properties of VCSEL structures

    SciTech Connect

    Erteza, I.A.

    1996-09-01

    In this paper, the authors explore the feasibility of using the distributed Bragg reflector, grown on the substrate for a VCSEL (Vertical Cavity Surface Emitting Laser), to provide waveguiding within the substrate. This waveguiding could serve as an interconnection among VCSELs in an array. Before determining the feasibility of waveguide interconnected VCSELs, two analysis methods are presented and evaluated for their applicability to this problem. The implementations in Mathematica of both these methods are included. Results of the analysis show that waveguiding in VCSEL structures is feasible. Some of the many possible uses of waveguide interconnected VCSELs are also briefly discussed. The tools and analysis presented in this report can be used to evaluate such system concepts and to do detailed design calculations.

  15. Perturbation measurement of waveguides for acoustic thermometry

    NASA Astrophysics Data System (ADS)

    Lin, H.; Feng, X. J.; Zhang, J. T.

    2013-09-01

    Acoustic thermometers normally embed small acoustic transducers in the wall bounding a gas-filled cavity resonator. At high temperature, insulators of transducers loss electrical insulation and degrade the signal-to-noise ratio. One essential solution to this technical trouble is to couple sound by acoustic waveguides between resonator and transducers. But waveguide will break the ideal acoustic surface and bring perturbations(Δf+ig) to the ideal resonance frequency. The perturbation model for waveguides was developed based on the first-order acoustic theory in this paper. The frequency shift Δf and half-width change g caused by the position, length and radius of waveguides were analyzed using this model. Six different length of waveguides (52˜1763 mm) were settled on the cylinder resonator and the perturbation (Δf+ig) were measured at T=332 K and p=250˜500 kPa. The experiment results agreed with the theoretical prediction very well.

  16. Interaction of environmental contaminants with zebrafish organic anion transporting polypeptide, Oatp1d1 (Slco1d1)

    SciTech Connect

    Popovic, Marta; Zaja, Roko; Fent, Karl; Smital, Tvrtko

    2014-10-01

    Polyspecific transporters from the organic anion transporting polypeptide (OATP/Oatp) superfamily mediate the uptake of a wide range of compounds. In zebrafish, Oatp1d1 transports conjugated steroid hormones and cortisol. It is predominantly expressed in the liver, brain and testes. In this study we have characterized the transport of xenobiotics by the zebrafish Oatp1d1 transporter. We developed a novel assay for assessing Oatp1d1 interactors using the fluorescent probe Lucifer yellow and transient transfection in HEK293 cells. Our data showed that numerous environmental contaminants interact with zebrafish Oatp1d1. Oatp1d1 mediated the transport of diclofenac with very high affinity, followed by high affinity towards perfluorooctanesulfonic acid (PFOS), nonylphenol, gemfibrozil and 17α-ethinylestradiol; moderate affinity towards carbaryl, diazinon and caffeine; and low affinity towards metolachlor. Importantly, many environmental chemicals acted as strong inhibitors of Oatp1d1. A strong inhibition of Oatp1d1 transport activity was found by perfluorooctanoic acid (PFOA), chlorpyrifos-methyl, estrone (E1) and 17β-estradiol (E2), followed by moderate to low inhibition by diethyl phthalate, bisphenol A, 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4 tetrahydronapthalene and clofibrate. In this study we identified Oatp1d1 as a first Solute Carrier (SLC) transporter involved in the transport of a wide range of xenobiotics in fish. Considering that Oatps in zebrafish have not been characterized before, our work on zebrafish Oatp1d1 offers important new insights on the understanding of uptake processes of environmental contaminants, and contributes to the better characterization of zebrafish as a model species. - Highlights: • We optimized a novel assay for determination of Oatp1d1 interactors • Oatp1d1 is the first SLC characterized fish xenobiotic transporter • PFOS, nonylphenol, diclofenac, EE2, caffeine are high affinity Oatp1d1substrates • PFOA, chlorpyrifos

  17. High-bandwidth and low-loss multimode polymer waveguides and waveguide components for high-speed board-level optical interconnects

    NASA Astrophysics Data System (ADS)

    Bamiedakis, N.; Chen, J.; Penty, R. V.; White, I. H.

    2016-03-01

    Multimode polymer waveguides are being increasingly considered for use in short-reach board-level optical interconnects as they exhibit favourable optical properties and allow direct integration onto standard PCBs with conventional methods of the electronics industry. Siloxane-based multimode waveguides have been demonstrated with excellent optical transmission performance, while a wide range of passive waveguide components that offer routing flexibility and enable the implementation of complex on-board interconnection architectures has been reported. In recent work, we have demonstrated that these polymer waveguides can exhibit very high bandwidth-length products in excess of 30 GHz×m despite their highly-multimoded nature, while it has been shown that even larger values of > 60 GHz×m can be achieved by adjusting their refractive index profile. Furthermore, the combination of refractive index engineering and launch conditioning schemes can ensure high bandwidth (> 100 GHz×m) and high coupling efficiency (<1 dB) with standard multimode fibre inputs with relatively large alignment tolerances (~17×15 μm2). In the work presented here, we investigate the effects of refractive index engineering on the performance of passive waveguide components (crossings, bends) and provide suitable design rules for their on-board use. It is shown that, depending on the interconnection layout and link requirements, appropriate choice of refractive index profile can provide enhanced component performance, ensuring low loss interconnection and adequate link bandwidth. The results highlight the strong potential of this versatile optical technology for the formation of high-performance board-level optical interconnects with high routing flexibility.

  18. Hybrid grapheme plasmonic waveguide modulators

    NASA Astrophysics Data System (ADS)

    Ansell, D.; Thackray, B. D.; Aznakayeva, D. E.; Thomas, P.; Auton, G. H.; Marshall, O. P.; Rodriguez, F. J.; Radko, I. P.; Han, Z.; Bozhevolnyi, S. I.; Grigorenko, A. N.

    2016-03-01

    The unique optical and electronic properties of graphene allow one to realize active optical devices. While several types of graphene-based photonic modulators have already been demonstrated, the potential of combining the versatility of graphene with sub-wavelength field confinement of plasmonic/metallic structures is not fully realized. Here we report fabrication and study of hybrid graphene-plasmonic modulators. We consider several types of modulators and identify the most promising one for light modulation at telecom and near-infrared. Our proof-of-concept results pave the way towards on-chip realization of efficient graphene-based active plasmonic waveguide devices for optical communications.

  19. Phosphorylation and desensitization of alpha1d-adrenergic receptors.

    PubMed Central

    García-Sáinz, J A; Vázquez-Cuevas, F G; Romero-Avila, M T

    2001-01-01

    In rat-1 fibroblasts stably expressing rat alpha(1d)-adrenoceptors, noradrenaline and PMA markedly decreased alpha(1d)-adrenoceptor function (noradrenaline-elicited increases in calcium in whole cells and [(35)S]guanosine 5'-[gamma-thio]triphosphate binding in membranes), suggesting homologous and heterologous desensitizations. Photoaffinity labelling, Western blotting and immunoprecipitation identified alpha(1d)-adrenoceptors as a broad band of 70-80 kDa. alpha(1d)-Adrenoceptors were phosphorylated in the basal state and noradrenaline and PMA increased it. The effect of noradrenaline was concentration-dependent (EC(50) 75 nM), rapid (maximum at 1 min) and transient. Phorbol ester-induced phosphorylation was concentration-dependent (EC(50) 25 nM), slightly slower (maximum at 5 min) and stable for at least 60 min. Inhibitors of protein kinase C decreased the effect of phorbol esters but not that of noradrenaline. Evidence of cross-talk of alpha(1d)-adrenoceptors with receptors endogenously expressed in rat-1 fibroblasts was given by the ability of endothelin, lysophosphatidic acid and bradykinin to induce alpha(1d)-adrenoceptor phosphorylation. In summary, it is shown for the first time here that alpha(1d)-adrenoceptors are phosphoproteins and that receptor phosphorylation is increased by the natural ligand, noradrenaline, by direct activation of protein kinase C and via cross-talk with other receptors endogenously expressed in rat-1 fibroblasts. Receptor phosphorylation has functional repercussions. PMID:11171057

  20. Terahertz spin-wave waveguides and optical magnonics in one-dimensional NiO nanorods.

    PubMed

    Patil, Ranjit A; Su, Chiung-Wu; Chuang, Chin-Jung; Lai, Chien-Chih; Liou, Yung; Ma, Yuan-Ron

    2016-07-14

    The two-magnon (2M) spin waves with a magnon frequency of 43 THz, generated by a polarized laser, were first observed in one-dimensional (1D) NiO nanorods. The 1D NiO nanorods of ∼700 nm length, which have perfectly in-plane antiferromagnetic spins lying on the (200) and (100) faces, are the smallest spin-wave waveguides. Due to the magneto-optical Faraday effect (MOFE), the significant change in the Faraday intensity can show the 2M information in the NiO nanorods. There are only two 2M-on and 2M-off states at various applied alternating-current magnetic fields and laser-incident angles, which make the 1D NiO nanorods excellent optical nanomagnonics. PMID:27304863

  1. Optical ridge waveguides in Yb:YAG laser crystal produced by combination of swift carbon ion irradiation and femtosecond laser ablation

    NASA Astrophysics Data System (ADS)

    Cheng, Yazhou; Lv, Jinman; Akhmadaliev, Shavkat; Hernández-Palmero, Irene; Romero, Carolina; Vázquez de Aldana, Javier R.; Zhou, Shengqiang; Chen, Feng

    2015-09-01

    We report on the fabrication of optical ridge waveguides in ytterbium-doped yttrium aluminum garnet (Yb:YAG) single crystal by applying swift C5+ ion irradiation and the followed femtosecond laser ablation. The planar waveguide layer is first produced by C5+ ion irradiation and the laser ablation is used to microstructure the planar waveguide surface to construct ridge structures. The lowest propagation loss of the ridge waveguide has been determined to be ~2.1 dB/cm. From the confocal micro-fluorescence and micro-Raman spectra obtained from the waveguide regions, the intensities, positions and widths of the emission-line peaks had no obvious changes with respect to those from the bulks, which indicate that C5+ ion irradiation does not affect the bulk-related properties of the Yb:YAG crystal significantly in the waveguide regions. The results obtained in this work suggest potential applications of the Yb:YAG ridge waveguides as integrated laser sources.

  2. Nano-photonic organic solar cell architecture for advanced light management utilizing dual photonic crystals

    NASA Astrophysics Data System (ADS)

    Peer, Akshit; Biswas, Rana

    2015-09-01

    Organic solar cells have rapidly increasing efficiencies, but typically absorb less than half of the incident solar spectrum. To increase broadband light absorption, we rigorously design experimentally realizable solar cell architectures based on dual photonic crystals. Our optimized architecture consists of a polymer microlens at the air-glass interface, coupled with a photonic-plasmonic crystal at the metal cathode. The microlens focuses light on the periodic nanostructure that generates strong light diffraction. Waveguiding modes and surface plasmon modes together enhance long wavelength absorption in P3HT-PCBM. The architecture has a period of 500 nm, with absorption and photocurrent enhancement of 49% and 58%, respectively.

  3. Spatial Solitons in Algaas Waveguides

    NASA Astrophysics Data System (ADS)

    Kang, Jin Ung

    In this work, by measuring the two-, three-photon absorption, and the nonlinear refractive index coefficients, a useful bandwidth for an all-optical switching applications in the AlGaAs below half the band gap is identified. Operating in this material system, several types of spatial solitons such as fundamental bright solitons, Vector solitons, and Manakov solitons are experimentally demonstrated. The propagation and the interaction behaviors of these solitons are studied experimentally and numerically. The distinct properties of each soliton are discussed along with some possible applications. Some applications, such as all -optical switching based on spatial soliton dragging and the efficient guiding of orthogonally polarized femtosecond pulses by a bright spatial soliton, are experimentally demonstrated. The signal gain due to an ultrafast polarization coupling, better known as Four Wave Mixing (FWM) is demonstrated in a channel waveguide. The effects of FWM are studied experimentally and numerically. This effect is also used to demonstrate polarization switching. The linear and nonlinear properties of AlGaAs/GaAs multiple quantum well waveguides are measured. Anisotropic two photon absorption and nonlinear refractive indices near half the band gap are measured along with the linear birefringence for several different quantum well structures. The usefulness of multiple quantum well structures for an all -optical switching because of anisotropic nature of this material system is discussed.

  4. Potassium Titanyl Phosphate Thin Films for Optical Waveguide Applications.

    NASA Astrophysics Data System (ADS)

    Hagerman, Michael Eugene

    1995-11-01

    waveguides with propagation losses of less than 1 dB/cm. Research continues on the optimization of thin film properties, the investigation of the relation between thin film microstructure and NLO response, and the development of two photonic devices, an optical switch (bistable directional coupler) and a microscopic frequency doubler (hybrid integration of mesa -type diode laser and KTP waveguide).

  5. Severe Hypertriglyceridemia in Glut1D on Ketogenic Diet.

    PubMed

    Klepper, Joerg; Leiendecker, Baerbel; Heussinger, Nicole; Lausch, Ekkehart; Bosch, Friedrich

    2016-04-01

    High-fat ketogenic diets are the only treatment available for Glut1 deficiency (Glut1D). Here, we describe an 8-year-old girl with classical Glut1D responsive to a 3:1 ketogenic diet and ethosuximide. After 3 years on the diet a gradual increase of blood lipids was followed by rapid, severe asymptomatic hypertriglyceridemia (1,910 mg/dL). Serum lipid apheresis was required to determine liver, renal, and pancreatic function. A combination of medium chain triglyceride-oil and a reduction of the ketogenic diet to 1:1 ratio normalized triglyceride levels within days but triggered severe myoclonic seizures requiring comedication with sultiam. Severe hypertriglyceridemia in children with Glut1D on ketogenic diets may be underdiagnosed and harmful. In contrast to congenital hypertriglyceridemias, children with Glut1D may be treated effectively by dietary adjustments alone. PMID:26902182

  6. 1D Nanostructures: Controlled Fabrication and Energy Applications

    SciTech Connect

    Hu, Michael Z.

    2013-01-01

    Jian Wei, Xuchun Song, Chunli Yang, and Michael Z. Hu, 1D Nanostructures: Controlled Fabrication and Energy Applications, Journal of Nanomaterials, published special issue (http://www.hindawi.com/journals/jnm/si/197254/) (2013).

  7. 60. BOILER CHAMBER No. 1, D LOOP STEAM GENERATOR AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    60. BOILER CHAMBER No. 1, D LOOP STEAM GENERATOR AND MAIN COOLANT PUMP LOOKING NORTHEAST (LOCATION OOO) - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

  8. Ultralow loss cavities and waveguides scattering loss cancellation

    SciTech Connect

    Rakich, Peter T

    2014-01-07

    A waveguide system includes a first waveguide having surface roughness along at least one surface and a second waveguide substantially identical to the first waveguide and having substantially identical surface roughness along a corresponding side. The first and second waveguides are separated from each other by a predermined distance and are configured to receive respective first and second light signals having antisymmetric modes. The predetermined distance between the first and second waveguide tends to cause cancellation of at least far-field polarization radiation emanating from the first and second waveguides and resulting from surface roughness.

  9. Interaction of environmental contaminants with zebrafish organic anion transporting polypeptide, Oatp1d1 (Slco1d1).

    PubMed

    Popovic, Marta; Zaja, Roko; Fent, Karl; Smital, Tvrtko

    2014-10-01

    Polyspecific transporters from the organic anion transporting polypeptide (OATP/Oatp) superfamily mediate the uptake of a wide range of compounds. In zebrafish, Oatp1d1 transports conjugated steroid hormones and cortisol. It is predominantly expressed in the liver, brain and testes. In this study we have characterized the transport of xenobiotics by the zebrafish Oatp1d1 transporter. We developed a novel assay for assessing Oatp1d1 interactors using the fluorescent probe Lucifer yellow and transient transfection in HEK293 cells. Our data showed that numerous environmental contaminants interact with zebrafish Oatp1d1. Oatp1d1 mediated the transport of diclofenac with very high affinity, followed by high affinity towards perfluorooctanesulfonic acid (PFOS), nonylphenol, gemfibrozil and 17α-ethinylestradiol; moderate affinity towards carbaryl, diazinon and caffeine; and low affinity towards metolachlor. Importantly, many environmental chemicals acted as strong inhibitors of Oatp1d1. A strong inhibition of Oatp1d1 transport activity was found by perfluorooctanoic acid (PFOA), chlorpyrifos-methyl, estrone (E1) and 17β-estradiol (E2), followed by moderate to low inhibition by diethyl phthalate, bisphenol A, 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4 tetrahydronapthalene and clofibrate. In this study we identified Oatp1d1 as a first Solute Carrier (SLC) transporter involved in the transport of a wide range of xenobiotics in fish. Considering that Oatps in zebrafish have not been characterized before, our work on zebrafish Oatp1d1 offers important new insights on the understanding of uptake processes of environmental contaminants, and contributes to the better characterization of zebrafish as a model species. PMID:25088042

  10. TBC1D24 genotype–phenotype correlation

    PubMed Central

    Balestrini, Simona; Milh, Mathieu; Castiglioni, Claudia; Lüthy, Kevin; Finelli, Mattea J.; Verstreken, Patrik; Cardon, Aaron; Stražišar, Barbara Gnidovec; Holder, J. Lloyd; Lesca, Gaetan; Mancardi, Maria M.; Poulat, Anne L.; Repetto, Gabriela M.; Banka, Siddharth; Bilo, Leonilda; Birkeland, Laura E.; Bosch, Friedrich; Brockmann, Knut; Cross, J. Helen; Doummar, Diane; Félix, Temis M.; Giuliano, Fabienne; Hori, Mutsuki; Hüning, Irina; Kayserili, Hulia; Kini, Usha; Lees, Melissa M.; Meenakshi, Girish; Mewasingh, Leena; Pagnamenta, Alistair T.; Peluso, Silvio; Mey, Antje; Rice, Gregory M.; Rosenfeld, Jill A.; Taylor, Jenny C.; Troester, Matthew M.; Stanley, Christine M.; Ville, Dorothee; Walkiewicz, Magdalena; Falace, Antonio; Fassio, Anna; Lemke, Johannes R.; Biskup, Saskia; Tardif, Jessica; Ajeawung, Norbert F.; Tolun, Aslihan; Corbett, Mark; Gecz, Jozef; Afawi, Zaid; Howell, Katherine B.; Oliver, Karen L.; Berkovic, Samuel F.; Scheffer, Ingrid E.; de Falco, Fabrizio A.; Oliver, Peter L.; Striano, Pasquale; Zara, Federico

    2016-01-01

    Objective: To evaluate the phenotypic spectrum associated with mutations in TBC1D24. Methods: We acquired new clinical, EEG, and neuroimaging data of 11 previously unreported and 37 published patients. TBC1D24 mutations, identified through various sequencing methods, can be found online (http://lovd.nl/TBC1D24). Results: Forty-eight patients were included (28 men, 20 women, average age 21 years) from 30 independent families. Eighteen patients (38%) had myoclonic epilepsies. The other patients carried diagnoses of focal (25%), multifocal (2%), generalized (4%), and unclassified epilepsy (6%), and early-onset epileptic encephalopathy (25%). Most patients had drug-resistant epilepsy. We detail EEG, neuroimaging, developmental, and cognitive features, treatment responsiveness, and physical examination. In silico evaluation revealed 7 different highly conserved motifs, with the most common pathogenic mutation located in the first. Neuronal outgrowth assays showed that some TBC1D24 mutations, associated with the most severe TBC1D24-associated disorders, are not necessarily the most disruptive to this gene function. Conclusions: TBC1D24-related epilepsy syndromes show marked phenotypic pleiotropy, with multisystem involvement and severity spectrum ranging from isolated deafness (not studied here), benign myoclonic epilepsy restricted to childhood with complete seizure control and normal intellect, to early-onset epileptic encephalopathy with severe developmental delay and early death. There is no distinct correlation with mutation type or location yet, but patterns are emerging. Given the phenotypic breadth observed, TBC1D24 mutation screening is indicated in a wide variety of epilepsies. A TBC1D24 consortium was formed to develop further research on this gene and its associated phenotypes. PMID:27281533

  11. Towards low-loss, infrared and THz nanophotonics and metamaterials: surface phonon polariton modes in polar dielectric crystals (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Caldwell, Joshua D.; Lindsey, Lucas; Giannini, Vincenzo; Vurgaftman, Igor; Reinecke, Thomas L.; Maier, Stefan A.; Glembocki, Orest J.

    2015-09-01

    The field of nanophotonics is based on the ability to confine light to sub-diffractional dimensions. Up until recently, research in this field has been primarily focused on the use of plasmonic metals. However, the high optical losses inherent in such metal-based surface plasmon materials has led to an ever-expanding effort to identify, low-loss alternative materials capable of supporting sub-diffractional confinement. One highly promising alternative are polar dielectric crystals whereby sub-diffraction confinement of light can be achieved through the stimulation of surface phonon polaritons within an all-dielectric, and thus low loss material system. Both SiC and hexagonal BN are two exemplary SPhP systems, which along with a whole host of alternative materials promise to transform nanophotonics and metamaterials in the mid-IR to THz spectral range. In addition to the lower losses, these materials offer novel opportunities not available with traditional plasmonics, for instance hyperbolic optical behavior in natural materials such as hBN, enabling super-resolution imaging without the need for complex fabrication. This talk will provide an overview of the SPhP phenomenon, a discussion of what makes a `good' SPhP material and recent results from SiC and the naturally hyperbolic material, hBN from our research group.

  12. Effect of effective mass mismatch in CdS/CdTe heterojunctions on the fundamental design parameters of nanophotonic devices

    NASA Astrophysics Data System (ADS)

    Villa-Angulo, José R.; Villa-Angulo, Rafael; Solorio-Ferrales, Karina; Ahumada-Valdez, Silvia E.; Villa-Angulo, Carlos

    2014-01-01

    Single- and multiple-quantum well (QW) nanophotonic devices, such as detectors and solar cells, are often fabricated by the concatenation of low-dimensional heterojunctions of different semiconductors. Quantum effects dominate the well structure, with dimensions of the order of several nanometers. At this width regime, even small variations in the fundamental material properties, such as band gap, dielectric constant, lattice constant, and effective mass of the materials, may give rise to errors in determining the fundamental design parameters. This, in turn, can significantly affect the device performance. In cadmium-sulfide/cadmium-telluride (CdS/CdTe) material system, the failure to include the mismatch of electronic effective masses can lead to >30% shift from the real position of the eigenstate energy levels, and >40% shift from the real position of quasi-Fermi levels E and E. In addition, depending on the width of the QW active layer, the absorption coefficient value can lead to >12% shift from its real value. These results prompt the need for accurate estimation of such errors in the precise analysis and design of CdS/CdTe heterojunction-based nanophotonic devices.

  13. Understanding the nanophotonic light-trapping structure of diatom frustule for enhanced solar energy conversion: a theoretical and experimental study

    NASA Astrophysics Data System (ADS)

    Chen, Xiangfan; Wang, Chen; Baker, Evan; Wang, Jane; Sun, Cheng

    2014-03-01

    Recent designs in nanophotonic light-trapping technologies offer promising potential to develop high-efficiency thin-film solar cell at dramatically reduced cost. However, the lack of a cost effective scalable nanomanufacturing technique remains the main road-block. In nature, diatoms exhibit high solar energy harvesting efficiency due to their frustules (i.e., hard porous cell wall made of silica) possessing remarkable hierarchical nano-features optimized for the photosynthetic process through millions of years evolution. To explore this unique light trapping effect, different species of diatoms (Coscinodiscus sp. and Coscinodiscus wailesii) are cultured and characterized by Scanning electron microscope (SEM). Rigorous Coupled Wave Analysis (RCWA) and Finite-difference time-domain (FDTD) method are employed to numerically study the nanophotonic light-trapping effect. The absorption efficiency is significantly enhanced over the spectrum region centered on 450nm and 700nm where the electric fields are found strongly confined within the active layer. The transmission and reflection spectra are also measured by optical spectroscopy and the experimental results are in good agreement with numerical simulations.

  14. Waveguide-Based Biosensors for Pathogen Detection

    PubMed Central

    Mukundan, Harshini; Anderson, Aaron S.; Grace, W. Kevin; Grace, Karen M.; Hartman, Nile; Martinez, Jennifer S.; Swanson, Basil I.

    2009-01-01

    Optical phenomena such as fluorescence, phosphorescence, polarization, interference and non-linearity have been extensively used for biosensing applications. Optical waveguides (both planar and fiber-optic) are comprised of a material with high permittivity/high refractive index surrounded on all sides by materials with lower refractive indices, such as a substrate and the media to be sensed. This arrangement allows coupled light to propagate through the high refractive index waveguide by total internal reflection and generates an electromagnetic wave—the evanescent field—whose amplitude decreases exponentially as the distance from the surface increases. Excitation of fluorophores within the evanescent wave allows for sensitive detection while minimizing background fluorescence from complex, “dirty” biological samples. In this review, we will describe the basic principles, advantages and disadvantages of planar optical waveguide-based biodetection technologies. This discussion will include already commercialized technologies (e.g., Corning’s EPIC® Ô, SRU Biosystems’ BIND™, Zeptosense®, etc.) and new technologies that are under research and development. We will also review differing assay approaches for the detection of various biomolecules, as well as the thin-film coatings that are often required for waveguide functionalization and effective detection. Finally, we will discuss reverse-symmetry waveguides, resonant waveguide grating sensors and metal-clad leaky waveguides as alternative signal transducers in optical biosensing. PMID:22346727

  15. Long-range hybrid wedge plasmonic waveguide.

    PubMed

    Zhang, Zhonglai; Wang, Jian

    2014-01-01

    We design a novel long-range hybrid wedge plasmonic (LRHWP) waveguide composed of two identical dielectric nanowires symmetrically placed on two opposed wedges of a diamond shaped metal wire. With strong coupling between the dielectric nanowire mode and long-range surface plasmon polariton (SPP) mode, both deep subwavelength mode confinement and low propagation loss are achieved. On one hand, when compared to the previous long-range hybrid SPP waveguide, LRHWP waveguide can achieve smaller mode size with similar propagation length; on the other hand, when compared to the previous hybrid wedge SPP waveguide, LRHWP waveguide can provide an order of magnitude longer propagation length with similar level of mode confinement. The designed LRHWP waveguide also features an overall advantage of one-order improvement of Figure of Merit. We further evaluate in detail the impacts of possible practical fabrication imperfections on the mode properties. The obtained results of mode properties show that the proposed LRHWP waveguide with an optimized wedge tip angle of 140 degree is fairly tolerant to practical fabrication errors in geometry parameters such as misalignment in the horizontal direction, asymmetry in the vertical direction, variation of wedge tip angle, tilt or rotation of metal wire, and variation of wedge tip curvature radius. PMID:25362900

  16. Characterization of passive polymer optical waveguides

    NASA Astrophysics Data System (ADS)

    Joehnck, Matthias; Kalveram, Stefan; Lehmacher, Stefan; Pompe, Guido; Rudolph, Stefan; Neyer, Andreas; Hofstraat, Johannes W.

    1999-05-01

    The characterization of monomode passive polymer optical devices fabricated according to the POPCORN technology by methods originated from electron, ion and optical spectroscopy is summarized. Impacts of observed waveguide perturbations on the optical characteristics of the waveguide are evaluated. In the POPCORN approach optical components for telecommunication applications are fabricated by photo-curing of liquid halogenated (meth)acrylates which have been applied on moulded thermoplastic substrates. For tuning of waveguide material refractive indices with respect to the substrate refractive index frequently comonomer mixtures are used. The polymerization characteristics, especially the polymerization kinetics of individual monomers, determine the formation of copolymers. Therefore the unsaturation as function of UV-illumination time in the formation of halogenated homo- and copolymers has been examined. From different suitable copolymer system, after characterization of their glass transition temperatures, their curing behavior and their refractive indices as function of the monomer ratios, monomode waveguides applying PMMA substrates have been fabricated. To examine the materials composition also in the 6 X 6 micrometers 2 waveguides they have been visualized by transmission electron microscopy. With this method e.g. segregation phenomena could be observed in the waveguide cross section characterization as well. The optical losses in monomode waveguides caused by segregation and other materials induce defects like micro bubbles formed as a result of shrinkage have been quantized by return loss measurements. Defects causing scattering could be observed by convocal laser scanning microscopy and by conventional light microscopy.

  17. Long-range hybrid wedge plasmonic waveguide

    PubMed Central

    Zhang, Zhonglai; Wang, Jian

    2014-01-01

    We design a novel long-range hybrid wedge plasmonic (LRHWP) waveguide composed of two identical dielectric nanowires symmetrically placed on two opposed wedges of a diamond shaped metal wire. With strong coupling between the dielectric nanowire mode and long-range surface plasmon polariton (SPP) mode, both deep subwavelength mode confinement and low propagation loss are achieved. On one hand, when compared to the previous long-range hybrid SPP waveguide, LRHWP waveguide can achieve smaller mode size with similar propagation length; on the other hand, when compared to the previous hybrid wedge SPP waveguide, LRHWP waveguide can provide an order of magnitude longer propagation length with similar level of mode confinement. The designed LRHWP waveguide also features an overall advantage of one-order improvement of Figure of Merit. We further evaluate in detail the impacts of possible practical fabrication imperfections on the mode properties. The obtained results of mode properties show that the proposed LRHWP waveguide with an optimized wedge tip angle of 140 degree is fairly tolerant to practical fabrication errors in geometry parameters such as misalignment in the horizontal direction, asymmetry in the vertical direction, variation of wedge tip angle, tilt or rotation of metal wire, and variation of wedge tip curvature radius. PMID:25362900

  18. Cascaded two-photon nonlinearity in a one-dimensional waveguide with multiple two-level emitters

    PubMed Central

    Roy, Dibyendu

    2013-01-01

    We propose and theoretically investigate a model to realize cascaded optical nonlinearity with few atoms and photons in one-dimension (1D). The optical nonlinearity in our system is mediated by resonant interactions of photons with two-level emitters, such as atoms or quantum dots in a 1D photonic waveguide. Multi-photon transmission in the waveguide is nonreciprocal when the emitters have different transition energies. Our theory provides a clear physical understanding of the origin of nonreciprocity in the presence of cascaded nonlinearity. We show how various two-photon nonlinear effects including spatial attraction and repulsion between photons, background fluorescence can be tuned by changing the number of emitters and the coupling between emitters (controlled by the separation). PMID:23948782

  19. Surface and waveguide collection of Raman emission in waveguide-enhanced Raman spectroscopy.

    PubMed

    Wang, Zilong; Zervas, Michalis N; Bartlett, Philip N; Wilkinson, James S

    2016-09-01

    We demonstrate Raman spectroscopy on a high index thin film tantalum pentoxide waveguide and compare collection of Raman emission from the waveguide end with that from the waveguide surface. Toluene was used as a convenient model analyte, and a 40-fold greater signal was collected from the waveguide end. Simulations of angular and spatial Raman emission distributions showed good agreement with experiments, with the enhancement resulting from efficient collection of power from dipoles near the surface into the high-index waveguide film and substrate, combined with long interaction length. The waveguide employed was optimized at the excitation wavelength but not at emission wavelengths, and full optimization is expected to lead to enhancements comparable to surface-enhanced Raman spectroscopy in robust low-cost metal-free and nanostructure-free chips. PMID:27607994

  20. Carbon-implanted monomode waveguides in magneto-optical glasses for waveguide isolators

    NASA Astrophysics Data System (ADS)

    Liu, Chun-Xiao; Fu, Li-Li; Zhang, Liao-Lin; Guo, Hai-Tao; Li, Wei-Nan; Lin, She-Bao; Wei, Wei

    2016-02-01

    Tb3+-doped aluminum borosilicate glasses are important magneto-optical materials for optical isolators. Optical waveguides are basic components in integrated photonics. By using the ion implantation technique, optical guiding structures can be produced in Tb3+-doped aluminum borosilicate glasses, and miniaturized waveguide isolators can be realized. In this paper, planar waveguides have been fabricated in Tb3+-doped aluminum borosilicate glasses by (6.0 + 5.5) MeV carbon ion implantation at doses of (8.0 + 4.0) × 1013 ions/cm2. The optical properties of optical waveguides are measured by equipments of prism coupling and end-face coupling systems. They are also analyzed by simulation programs of intensity calculation method and beam propagation method. The waveguides with good optical performances suggest potential applications on fabrication of waveguide isolators in Tb3+-doped aluminum borosilicate glasses.

  1. Method of making a scintillator waveguide

    DOEpatents

    Bliss, Mary; Craig, Richard A.; Reeder, Paul L.

    2000-01-01

    The present invention is an apparatus for detecting ionizing radiation, having: a waveguide having a first end and a second end, the waveguide formed of a scintillator material wherein the therapeutic ionizing radiation isotropically generates scintillation light signals within the waveguide. This apparatus provides a measure of radiation dose. The apparatus may be modified to permit making a measure of location of radiation dose. Specifically, the scintillation material is segmented into a plurality of segments; and a connecting cable for each of the plurality of segments is used for conducting scintillation signals to a scintillation detector.

  2. Waveguide device and method for making same

    DOEpatents

    Forman, Michael A.

    2007-08-14

    A monolithic micromachined waveguide device or devices with low-loss, high-power handling, and near-optical frequency ranges is set forth. The waveguide and integrated devices are capable of transmitting near-optical frequencies due to optical-quality sidewall roughness. The device or devices are fabricated in parallel, may be mass produced using a LIGA manufacturing process, and may include a passive component such as a diplexer and/or an active capping layer capable of particularized signal processing of the waveforms propagated by the waveguide.

  3. Waveguide-based optical chemical sensor

    DOEpatents

    Grace, Karen M.; Swanson, Basil I.; Honkanen, Seppo

    2007-03-13

    The invention provides an apparatus and method for highly selective and sensitive chemical sensing. Two modes of laser light are transmitted through a waveguide, refracted by a thin film host reagent coating on the waveguide, and analyzed in a phase sensitive detector for changes in effective refractive index. Sensor specificity is based on the particular species selective thin films of host reagents which are attached to the surface of the planar optical waveguide. The thin film of host reagents refracts laser light at different refractive indices according to what species are forming inclusion complexes with the host reagents.

  4. Optical planar waveguide for cell counting

    PubMed Central

    LeBlanc, John; Mueller, Andrew J.; Prinz, Adrian; Butte, Manish J.

    2012-01-01

    Low cost counting of cells has medical applications in screening, military medicine, disaster medicine, and rural healthcare. In this report, we present a shallow, buried, planar waveguide fabricated by potassium ion exchange in glass that enables low-cost and rapid counting of metal-tagged objects that lie in the evanescent field of the waveguide. Laser light transmitted through the waveguide was attenuated proportionately to the presence of metal-coated microstructures fabricated from photoresist. This technology enables the low-cost enumeration of cells from blood, urine, or other biofluids. PMID:22331960

  5. Multiport waveguide couplers with periodic energy exchange.

    PubMed

    Petrovic, Jovana

    2015-01-15

    In this Letter, a multiport directional optical coupler based on periodic energy exchange in a linear waveguide array is proposed. The periodic power transfer is achieved by choosing waveguide separations that render commensurate eigenvalues of the array coupling matrix. This is a general solution and offers a plethora of possibilities. Particularly interesting is an array that can be used to realize different couplers by simply choosing a different input waveguide. The proposed design principle is validated by full numerical simulations of realistic devices and the required fabrication precision is estimated. The proposed couplers are of interest for quantum optics, biosensing, and communications. PMID:25679828

  6. Hybrid nano ridge plasmonic polaritons waveguides

    NASA Astrophysics Data System (ADS)

    Mu, Jianwei; Chen, Lin; Li, Xun; Huang, Wei-Ping; Kimerling, Lionel C.; Michel, Jurgen

    2013-09-01

    We demonstrate an ultra-subwavelength surface plasmonic polaritons waveguide, which can confine light in the nano-scale region with comparable low propagation loss. The mode can be squeezed to one thousandth of the diffraction spot size with micro-meter scale propagation distance and is highly sensitive to the buffer layer materials and geometric parameters. This design improves the performance of previous surface plasmonic polaritons waveguides and lends itself to complementary metal-oxide-semiconductor compatible fabrication. These waveguides can be used as a platform for active devices as well as for nano-sensing applications.

  7. Proposal for a IR waveguide SASE FEL at the PEGASUS injector

    NASA Astrophysics Data System (ADS)

    Reiche, S.; Rosenzweig, J.; Telfer, S.

    2001-12-01

    Free Electron Lasers up to the visible regime are dominated by diffraction effects, resulting in a radiation size much larger than the electron beam. Thus the effective field amplitude at the location of the electron beam, driving the FEL process, is reduced. By using a waveguide, the radiation field is confined within a smaller aperture and an enhancement of the FEL performance can be expected. The PEGASUS injector at UCLA will be capable to provide the brilliance needed for an IR SASE FEL. The experiment Power Enhanced Radiation Source Experiment Using Structures (PERSEUS) is proposed to study the physics of a waveguide SASE FEL in a quasi 1D environment, where diffraction effects are strongly reduced as it is the case only for future FELs operating in the VUV and X-ray regime. The expected FEL performance is given by this presentation.

  8. Second harmonic generation of diamond-blade diced KTiOPO4 ridge waveguides.

    PubMed

    Chen, Chen; Rüter, Christian E; Volk, Martin F; Chen, Cheng; Shang, Zhen; Lu, Qingming; Akhmadaliev, Shavkat; Zhou, Shengqiang; Chen, Feng; Kip, Detlef

    2016-07-25

    We report on the fabrication of ridge waveguides in KTiOPO4 nonlinear optical crystals through carbon ion irradiation followed by precise diamond blade dicing. The diced side-walls have low roughness, which allows for low propagation loss of ~1dB/cm in fabricated of ridges. The waveguide property investigation has been performed at 1064 nm as well as 532 nm, showing good guidance at both TE and TM polarizations. Based on type II phase matching configuration, efficient second harmonic generation of green light at room temperature has been realized. High conversion efficiencies of ~1.12%W-1 and ~12.4% have been obtained for frequency doubling under the pump of continuous-wave (CW) and pulsed fundamental waves at 1064 nm, respectively. PMID:27464095

  9. Ultra-low-loss high-aspect-ratio Si3N4 waveguides.

    PubMed

    Bauters, Jared F; Heck, Martijn J R; John, Demis; Dai, Daoxin; Tien, Ming-Chun; Barton, Jonathon S; Leinse, Arne; Heideman, René G; Blumenthal, Daniel J; Bowers, John E

    2011-02-14

    We characterize an approach to make ultra-low-loss waveguides using stable and reproducible stoichiometric Si3N4 deposited with low-pressure chemical vapor deposition. Using a high-aspect-ratio core geometry, record low losses of 8-9 dB/m for a 0.5 mm bend radius down to 3 dB/m for a 2 mm bend radius are measured with ring resonator and optical frequency domain reflectometry techniques. From a waveguide loss model that agrees well with experimental results, we project that 0.1 dB/m total propagation loss is achievable at a 7 mm bend radius with this approach. PMID:21369138

  10. Extremely low-loss terahertz waveguide based on silicon photonic-crystal slab.

    PubMed

    Tsuruda, Kazuisao; Fujita, Masayuki; Nagatsuma, Tadao

    2015-12-14

    We pursued the extremely low loss of photonic-crystal waveguides composed of a silicon slab with high resistivity (20 kΩ-cm) in the terahertz region. Propagation and bending losses as small as <0.1 dB/cm (0.326-0.331 THz) and 0.2 dB/bend (0.323-0.331 THz), respectively, were achieved in the 0.3-THz band. We also developed 1.5-Gbit/s terahertz links and demonstrated an error-free uncompressed high-definition video transmission by using a photonic-crystal waveguide with a length of as long as 50 cm and up to 28 bends thanks to the low-loss properties. Our results show the potential of photonic crystals for application as terahertz integration platforms. PMID:26698989

  11. Dual-mode waveguides for variably polarised slotted waveguide array antennas

    NASA Astrophysics Data System (ADS)

    Sangster, A. J.; Lyon, R. W.

    1980-10-01

    The polarization selection mechanism in dual-mode slotted waveguide arrays requires that the exciting modes of the waveguide exhibit essentially identical phase and group velocities. This generally implies using an even and an odd mode of the structure, in an arrangement which provides useable current distributions in the slotted wall. This paper describes the results of a study of some waveguide configurations aimed at meeting these requirements in an array which was additionally intended to be frequency scanned.

  12. Analysis of coupling between two-dimensional photonic crystal waveguide and external waveguide

    NASA Astrophysics Data System (ADS)

    Miyai, Eiji; Okano, Makoto; Mochizuki, Masamitsu; Noda, Susumu

    2002-11-01

    Coupling between conventional wire waveguide and two-dimensional photonic crystal waveguide was analyzed by means of a three-dimensional finite difference time domain method. We evaluated the transmittance corresponding to the coupling efficiency between two waveguides. By using SiO2 clad below the wire and setting the width of the wire to be an appropriate value, we obtained single mode guiding and a coupling efficiency over 80% for the wave length around 1.55 mum.

  13. Nanophotonics of vertically aligned carbon nanotubes: Two-dimensional photonic crystals and optical dipole antennas

    NASA Astrophysics Data System (ADS)

    Wang, Yang

    Carbon nanotubes (CNTs) and related nanostructures represent a novel class of condensed matters with intriguing properties due to their unique atomic structures and nanoscale morphologies. It is of particular interest to examine the interaction behavior and mechanism between the free electron gas within carbon nanotubes and the external electromagnetic wave, which may greatly facilitate the understanding of the physics of nanophotonics at the fundamental level. This dissertation is committed to investigate the optical responses of arrays of vertically aligned CNTs in different configurations, based on their fabrication by Plasma-Enhanced Chemical Vapor Deposition (PECVD) and other techniques involved therein. The mechanisms of the photonic results are categorized into inter-CNT and intra-CNT contributions through data analysis on periodic and random CNT arrays, which then give rise to practical applications in photonic crystals and optical antennas. The growth and fabrication procedure of vertically aligned CNTs with optimized morphology and well-defined arrangement is first elaborated in this dissertation, owing to the tremendous difficulties encountered and efforts paid during the sample fabrication and optimization process, and the dominant effect of sample quality on the final results at the optical characterization stage. To fabricate periodic CNT arrays, a microsphere self-assembly technique is first adopted for catalyst patterning and a parametric study is carried out systematically for CNT growth by PECVD method. For random CNT arrays, the growth conditions are also modified so that small diameter CNTs can be grown and an IC industry-compatible procedure can be developed for practical application purposes. The inter-scatterer optical responses are studied by using hexagonal lattices of vertically aligned CNTs with various lattice constants and CNT morphologies. The diffraction patterns of theses CNT arrays are recorded and compared to theoretical

  14. Dynamically tunable plasmon induced transparency in a graphene-based nanoribbon waveguide coupled with graphene rectangular resonators structure on sapphire substrate.

    PubMed

    Han, Xu; Wang, Tao; Li, Xiaoming; Xiao, Shuyuan; Zhu, Youjiang

    2015-12-14

    In this paper, we propose dynamically tunable plasmon induced transparency (PIT) in a graphene-based nanoribbon waveguide coupled with graphene rectangular resonators structure on sapphire substrate by shifting the Fermi energy level of the graphene. Two different methods are employed to obtain the PIT effect: one is based on the direct destructive interference between a radiative state and a dark state, the other is based on the indirect coupling through a graphene nanoribbon waveguide. Our numerical results reveal that high tunability in the PIT transparency window can be obtained by altering the Fermi energy levels of the graphene rectangular resonators. Moreover, double PITs are also numerically predicted in this ultracompact structure, comprising series of graphene rectangular resonators. Compared with previously proposed graphene-based PIT effects, our proposed scheme is much easier to design and fabricate. This work not only paves a new way towards the realization of graphene-based integrated nanophotonic devices, but also has important applications in multi-channel-selective filters, sensors, and slow light. PMID:26698986

  15. Polymer taper bridge for silicon waveguide to single mode waveguide coupling

    NASA Astrophysics Data System (ADS)

    Kruse, Kevin; Middlebrook, Christopher T.

    2016-03-01

    Coupling of optical power from high-density silicon waveguides to silica optical fibers for signal routing can incur high losses and often requires complex end-face preparation/processing. Novel coupling device taper structures are proposed for low coupling loss between silicon photonic waveguides and single mode fibers are proposed and devices are fabricated and measured in terms of performance. Theoretical mode conversion models for waveguide tapers are derived for optimal device structure design and performance. Commercially viable vertical and multi-layer taper designs using polymer waveguide materials are proposed as innovative, cost-efficient, and mass-manufacturable optical coupling devices. The coupling efficiency for both designs is determined to evaluate optimal device dimensions and alignment tolerances with both silicon rib waveguides and silicon nanowire waveguides. Propagation loss as a function of waveguide roughness and metallic loss are determined and correlated to waveguide dimensions to obtain total insertion loss for the proposed taper designs. Multi-layer tapers on gold-sputtered substrates are fabricated through photolithography as proof-of-concept devices and evaluated for device loss optimization. Tapered waveguide coupling loss with Si WGs (2.74 dB) was experimentally measured with high correlation to theoretical results.

  16. Acoustically driven arrayed waveguide grating.

    PubMed

    Crespo-Poveda, A; Hernández-Mínguez, A; Gargallo, B; Biermann, K; Tahraoui, A; Santos, P V; Muñoz, P; Cantarero, A; de Lima, M M

    2015-08-10

    We demonstrate compact tunable phased-array wavelength-division multiplexers driven by surface acoustic waves (SAWs) in the low GHz range. The devices comprise two couplers, which respectively split and combine the optical signal, linked by an array of single-mode waveguides (WGs). Two different layouts are presented, in which multi-mode interference couplers or free propagating regions were separately employed as couplers. The multiplexers operate on five equally distributed wavelength channels, with a spectral separation of 2 nm. A standing SAW modulates the refractive index of the arrayed WGs. Each wavelength component periodically switches paths between the output channel previously asigned by the design and the adjacent channels, at a fixed applied acoustic power. The devices were monolithically fabricated on (Al,Ga)As. A good agreement between theory and experiment is achieved. PMID:26367971

  17. Multimode waveguide based directional coupler

    NASA Astrophysics Data System (ADS)

    Ahmed, Rajib; Rifat, Ahmmed A.; Sabouri, Aydin; Al-Qattan, Bader; Essa, Khamis; Butt, Haider

    2016-07-01

    The Silicon-on-Insulator (SOI) based platform overcomes limitations of the previous copper and fiber based technologies. Due to its high index difference, SOI waveguide (WG) and directional couplers (DC) are widely used for high speed optical networks and hybrid Electro-Optical inter-connections; TE00-TE01, TE00-TE00 and TM00-TM00 SOI direction couplers are designed with symmetrical and asymmetrical configurations to couple with TE00, TE01 and TM00 in a multi-mode semi-triangular ring-resonator configuration which will be applicable for multi-analyte sensing. Couplers are designed with effective index method and their structural parameters are optimized with consideration to coupler length, wavelength and polarization dependence. Lastly, performance of the couplers are analyzed in terms of cross-talk, mode overlap factor, coupling length and coupling efficiency.

  18. Slotted antenna waveguide plasma source

    NASA Technical Reports Server (NTRS)

    Foster, John (Inventor)

    2007-01-01

    A high density plasma generated by microwave injection using a windowless electrodeless rectangular slotted antenna waveguide plasma source has been demonstrated. Plasma probe measurements indicate that the source could be applicable for low power ion thruster applications, ion implantation, and related applications. This slotted antenna plasma source invention operates on the principle of electron cyclotron resonance (ECR). It employs no window and it is completely electrodeless and therefore its operation lifetime is long, being limited only by either the microwave generator itself or charged particle extraction grids if used. The high density plasma source can also be used to extract an electron beam that can be used as a plasma cathode neutralizer for ion source beam neutralization applications.

  19. Waveguides having patterned, flattened modes

    DOEpatents

    Messerly, Michael J.; Pax, Paul H.; Dawson, Jay W.

    2015-10-27

    Field-flattening strands may be added to and arbitrarily positioned within a field-flattening shell to create a waveguide that supports a patterned, flattened mode. Patterning does not alter the effective index or flattened nature of the mode, but does alter the characteristics of other modes. Compared to a telecom fiber, a hexagonal pattern of strands allows for a three-fold increase in the flattened mode's area without reducing the separation between its effective index and that of its bend-coupled mode. Hexagonal strand and shell elements prove to be a reasonable approximation, and, thus, to be of practical benefit vis-a-vis fabrication, to those of circular cross section. Patterned flattened modes offer a new and valuable path to power scaling.

  20. Polar discontinuities and 1D interfaces in monolayered materials

    NASA Astrophysics Data System (ADS)

    Martinez-Gordillo, Rafael; Pruneda, Miguel

    2015-12-01

    Interfaces are the birthplace of a multitude of fascinating discoveries in fundamental science, and have enabled modern electronic devices, from transistors, to lasers, capacitors or solar cells. These interfaces between bulk materials are always bi-dimensional (2D) 'surfaces'. However the advent of graphene and other 2D crystals opened up a world of possibilities, as in this case the interfaces become one-dimensional (1D) lines. Although the properties of 1D nanoribbons have been extensively discussed in the last few years, 1D interfaces within infinite 2D systems had remained mostly unexplored until very recently. These include grain boundaries in polycrystalline samples, or interfaces in hybrid 2D sheets composed by segregated domains of different materials (as for example graphene/BN hybrids, or chemically different transition metal dichalcogenides). As for their 2D counterparts, some of these 1D interfaces exhibit polar characteristics, and can give rise to fascinating new physical properties. Here, recent experimental discoveries and theoretical predictions on the polar discontinuities that arise at these 1D interfaces will be reviewed, and the perspectives of this new research topic, discussed.

  1. Multistaged stokes injected Raman capillary waveguide amplifier

    DOEpatents

    Kurnit, Norman A.

    1980-01-01

    A multistaged Stokes injected Raman capillary waveguide amplifier for providing a high gain Stokes output signal. The amplifier uses a plurality of optically coupled capillary waveguide amplifiers and one or more regenerative amplifiers to increase Stokes gain to a level sufficient for power amplification. Power amplification is provided by a multifocused Raman gain cell or a large diameter capillary waveguide. An external source of CO.sub.2 laser radiation can be injected into each of the capillary waveguide amplifier stages to increase Raman gain. Devices for injecting external sources of CO.sub.2 radiation include: dichroic mirrors, prisms, gratings and Ge Brewster plates. Alternatively, the CO.sub.2 input radiation to the first stage can be coupled and amplified between successive stages.

  2. Wideband waveguide polarizer development for SETI

    NASA Technical Reports Server (NTRS)

    Lee, P.; Stanton, P.

    1991-01-01

    A wideband polarizer for the Deep Space Network (DSN) 34 meter beam waveguide antenna is needed for the Search for Extraterrestrial Intelligence (SETI) project. The results of a computer analysis of a wideband polarizer are presented.

  3. Analysis of Open TEM-Waveguide Structures

    NASA Astrophysics Data System (ADS)

    Rambousky, R.; Garbe, H.

    This work belongs to a research project on the analysis and characterization of higher order modes occurring in open TEM-waveguide structures. An open TEM waveguide, derived from a conventional GTEM cell by removing the sidewalls, is investigated. The intrinsic resonances of the electromagnetic field occurring in the test volume of the waveguide are analyzed in frequency domain by computer simulation and measurement. This resonance behavior is compared to that of more simplified wire models, describing just the planar septum of the original TEM waveguide. The influence of the number of wires used in the wire model is investigated with respect to the resonant behavior. The use of wire structures is a prerequisite for application of transmission-line super theory (TLST) for further analysis.

  4. Dispersion and luminescence measurements of optical waveguides

    NASA Astrophysics Data System (ADS)

    Faik, A.; Allen, L.; Eicher, C.; Gagola, A.; Townsend, P. D.; Pitt, C. W.

    1983-05-01

    The results of measurements are presented for the dispersion curves in the visible wavelength range of a variety of optical waveguides which were formed in LiNbO3 and LiTaO3 by the implantation of helium ions. It is found that the radiation damage reduces the refractive index in both materials by about 12 percent throughout the visible region, probably resulting from amorphization of the lattice. Waveguides formed by impurity enhancement of the refractive index were measured in soda lime glass which had been doped by ion exchange of Li, K, Rb, Cs, or Ag; and it was found that in each case the percentage increase in index was wavelength dependent. The Ag ion exchange waveguides were found to have features which could be attributed to colloidal silver metal. The metal colloids give dispersion anomalies as well as a red luminescence which was used to measure the losses in the waveguide.

  5. Radiation from Axisymmetric Waveguide Fed Horns

    NASA Technical Reports Server (NTRS)

    Chinn, G. C.; Hoppe, D. J.; Epp, L. W.

    1995-01-01

    Return losses and radiation patterns for axisymmetric waveguide fed horns are calculated with the finite element method (FEM) in conjunction with the method of moments (MoM) and the mode matching technique (MM).

  6. Optical Waveguide Output Couplers Fabricated in Polymers

    NASA Technical Reports Server (NTRS)

    Watson, Michael D.; Abushagur, Mustafa A. G.; Ashley, Paul R.; Johnson-Cole, Helen

    1998-01-01

    Waveguide output couplers fabricated in Norland Optical Adhesive (NOA) #81 and AMOCO Ultradel 9020D polyimide are investigated. The output couplers are implemented using periodic relief gratings on a planar waveguide. Design theory of the couplers is based on the perturbation approach. Coupling of light from waveguide propagation modes to output radiation modes is described by coupled mode theory and the transmission line approximation of the perturbed area (grating structure). Using these concepts, gratings can be accurately designed to output a minimum number of modes at desired output angles. Waveguide couplers were designed using these concepts. These couplers were fabricated and analyzed for structural accuracy, output beam accuracy, and output efficiency. The results for the two different materials are compared.

  7. Waveguide-slot antenna with controlled polarization

    NASA Astrophysics Data System (ADS)

    Kamardinova, V. I.; Kapitanov, V. A.; Nikolaev, A. G.

    A theoretical study, based on experimental data obtained for a waveguide-slot antenna with controlled polarization, is conducted, prompted by the necessity of developing airborne side-looking radars whose antenna is extended in one dimension (along the aircraft fuselage) and has controlled polarization. Emission by an inclined slot in a waveguide of circular cross section is examined; computations and experimental verification of results are carried out for two counterinclined slots. Results of testing of a waveguide with slots at 45 deg to the waveguide generatrix at a wavelength of 3 cm yielded a gain factor of 1300 and radiation pattern width of 1 deg 10 arcmin in the horizontal plane and 5 deg in the vertical. The level of the sidelobe was 13 dB, while that of the following lobes did not exceed 20 dB.

  8. Light-emitting waveguide-plasmon polaritons.

    PubMed

    Rodriguez, S R K; Murai, S; Verschuuren, M A; Rivas, J Gómez

    2012-10-19

    We demonstrate the generation of light in an optical waveguide strongly coupled to a periodic array of metallic nanoantennas. This coupling gives rise to hybrid waveguide-plasmon polaritons (WPPs), which undergo a transmutation from plasmon to waveguide mode and vice versa as the eigenfrequency detuning of the bare states transits through zero. Near zero detuning, the structure is nearly transparent in the far-field but sustains strong local field enhancements inside the waveguide. Consequently, light-emitting WPPs are strongly enhanced at energies and in-plane momenta for which WPPs minimize light extinction. We elucidate the unusual properties of these polaritons through a classical model of coupled harmonic oscillators. PMID:23215111

  9. Entangling two distant nanocavities via a waveguide

    SciTech Connect

    Tan, Hua-Tang; Zhang Weimin; Li Gaoxiang

    2011-06-15

    In this paper, we present a scheme for generating continuous-variable entanglement between two spatially separated nanocavities in photonic crystals, which are mediated by a coupled-resonator optical waveguide. The entanglement degree and purity of the generated states are investigated as varying the cavity frequencies, the cavity-waveguide coupling strength, and the location of the second cavity. It is shown that a steady and pure entanglement between separated nanocavities can be generated only with a weak cavity-waveguide coupling when the cavities are resonant with the band center of the waveguide. Various cases with different cavity frequencies and coupling strengths, which affect the degree of entanglement, are also investigated, and interestingly sudden death and sudden birth of entanglement occur for strong couplings.

  10. Flexible parylene-film optical waveguide arrays

    NASA Astrophysics Data System (ADS)

    Yamagiwa, S.; Ishida, M.; Kawano, T.

    2015-08-01

    Modulation of neuronal activities by light [e.g., laser or light-emitting diode] using optogenetics is a powerful tool for studies on neuronal functions in a brain. Herein, flexible thin-film optical waveguide arrays based on a highly biocompatible material of parylene are reported. Parylene-C and -N thin layers with the different refractive indices form the clad and the core of the waveguide, respectively, and neural recording microelectrodes are integrated to record optical stimuli and electrical recordings simultaneously using the same alignment. Both theoretical and experimental investigations confirm that light intensities of more than 90% can propagate in a bent waveguide with a curvature radius of >5 mm. The proposed flexible thin-film waveguide arrays with microelectrodes can be used for numerous spherical bio-tissues, including brain and spinal cord samples.

  11. Waveguide-mode sensors as aptasensors.

    PubMed

    Gopinath, Subash C B; Awazu, Koichi; Fujimaki, Makoto

    2012-01-01

    Aptamers are artificial nucleic acid ligands that can be generated by in vitro selection through partition and amplification. Aptamers can be generated against a wide range of biomolecules through the formation of versatile stem-loop structures. Because aptamers are potential substitutes for antibodies and drugs, the development of an aptamer-based sensor (aptasensor) is mandatory for diagnosis. We previously reported that waveguide-mode sensors are useful in the analysis of a wide range of biomolecular interactions, including aptamers. The advantages of the waveguide-mode sensor that we developed include physical and chemical stability and that higher sensitivity can be achieved with ease by perforating the waveguide layer or using colored materials such as dyes or metal nanoparticles as labels. Herein, we provide an overview of the strategies and applications for aptamer-based analyses using waveguide-mode sensors. PMID:22438756

  12. A Multi-Waveguide Implantable Probe for Light Delivery to Sets of Distributed Brain Targets

    PubMed Central

    Zorzos, Anthony N.; Boyden, Edward S.; Fonstad, Clifton G.

    2010-01-01

    Optical fibers are commonly inserted into living tissues such as the brain in order to deliver light to deep targets for neuroscientific and neuroengineering applications such as optogenetics, in which light is used to activate or silence neurons expressing specific photosensitive proteins. However, an optical fiber is limited to delivering light to a single target within the three-dimensional structure of the brain. We here demonstrate a multi-waveguide probe capable of independently delivering light to multiple targets along the probe axis, thus enabling versatile optical control of sets of distributed brain targets. The 1.45 cm long probe is microfabricated in the form of a 360 micron-wide array of 12 parallel silicon oxynitride (SiON) multi-mode wave-guides clad with SiO2 and coated with aluminum; probes of custom dimensions are easily created as well. The waveguide array accepts light from a set of sources at the input end, and guides the light down each waveguide to an aluminum corner mirror that efficiently deflects light away from the probe axis. Light losses at each stage are small (input coupling loss, 0.4 ± 0.3 dB; bend loss, negligible; propagation loss, 3.1 ± 1 dB/cm using the out-scattering method and 3.2 ± 0.4 dB/cm using the cut-back method; corner mirror loss, 1.5 ± 0.4 dB); a waveguide coupled, for example, to a 5 mW source will deliver over 1.5 mW to a target at a depth of 1 cm. PMID:21165114

  13. Novel spot size converter for coupling standard single mode fibers to SOI waveguides

    NASA Astrophysics Data System (ADS)

    Sisto, Marco Michele; Fisette, Bruno; Paultre, Jacques-Edmond; Paquet, Alex; Desroches, Yan

    2016-03-01

    We have designed and numerically simulated a novel spot size converter for coupling standard single mode fibers with 10.4μm mode field diameter to 500nm × 220nm SOI waveguides. Simulations based on the eigenmode expansion method show a coupling loss of 0.4dB at 1550nm for the TE mode at perfect alignment. The alignment tolerance on the plane normal to the fiber axis is evaluated at +/-2.2μm for <=1dB excess loss, which is comparable to the alignment tolerance between two butt-coupled standard single mode fibers. The converter is based on a cross-like arrangement of SiOxNy waveguides immersed in a 12μm-thick SiO2 cladding region deposited on top of the SOI chip. The waveguides are designed to collectively support a single degenerate mode for TE and TM polarizations. This guided mode features a large overlap to the LP01 mode of standard telecom fibers. Along the spot size converter length (450μm), the mode is first gradually confined in a single SiOxNy waveguide by tapering its width. Then, the mode is adiabatically coupled to a SOI waveguide underneath the structure through a SOI inverted taper. The shapes of SiOxNy and SOI tapers are optimized to minimize coupling loss and structure length, and to ensure adiabatic mode evolution along the structure, thus improving the design robustness to fabrication process errors. A tolerance analysis based on conservative microfabrication capabilities suggests that coupling loss penalty from fabrication errors can be maintained below 0.3dB. The proposed spot size converter is fully compliant to industry standard microfabrication processes available at INO.

  14. Ultra-thin low loss Si3N4 optical waveguides at 1310 nm

    NASA Astrophysics Data System (ADS)

    Lim, Soon Thor; Gandhi, Alagappan; Png, Ching Eng; Lu, Ding; Ang, Norman Soo Seng; Teo, Ee Jin; Teng, Jinghua

    2014-03-01

    Recent advances in optical waveguides have brought long-awaited technologies closer to practical realization. Although the concept of a single-mode (SM) waveguide has been around for a while, SM condition usually posed very stringent conditions in fabrication for small waveguides. Researchers have developed low loss silicon nitride (Si3N4) at 1550nm wavelength, the developments in specific application have down converted to 1310nm (O-band) so they do not have to compete with internet data for bandwidth and could share the existing optical fiber infrastructure. However, wavelengthdemultiplexer technology at this band is not readily commercial available. Custom-made O-band optical devices for wavelength-demultiplexing have typical losses. Such high losses deplete more than 75% of the already-scarce photons. We studied Si3N4 channel waveguide with ultra-thin slab for (SM) condition at 1310nm wavelength using finite element method (FEM) and 3-D imaginary beam propagation method (IDBPM). We have shown that SM condition is possible for ultra-thin slab with wide waveguide width; such condition can ease the constraint of photolithography, allowing deposition of thin Si3N4 layer to be accomplished in minutes. Studies show that for ultra-thin layer, for example, at 60nm, we can achieve a wide range of widths that fulfilled the SM condition, ranging from 2μm to 5μm. SM condition becomes more stringent when the Si3N4 layer increases. Substrate losses are estimated at 0.001 dB/cm, 0.003 dB/cm, and 0.1 dB/cm for slab height at 100nm, 80nm, and 60nm respectively.

  15. Quantum diffusion of ultra-cold neutrons in a rough waveguide in a gravity field

    NASA Astrophysics Data System (ADS)

    Escobar, Mauricio

    We report the results of our study of propagation of gravitationally quantized ultracold neutrons in rough waveguides in conjunction with GRANIT experiments (ILL, Grenoble). Our theoretical study is done within the frame of the general theory of transport in systems with random rough boundaries developed by Meyerovich et al. We present a theoretical description of GRANIT experiments in the biased diffusion approximation for waveguides with one- and two-dimensional (1Dd and 2D) roughness. All system parameters collapse into a single constant (phi) which determines the depletion times for the gravitational quantum states and the exit neutron count. phi is determined by a complicated integral of the correlation function (CF) of surface roughness. For waveguides with 1D roughness most of the calculations can be performed analytically for the main common types of CF. For waveguides with 2D roughness the final calculations are mostly numerical. We also developed useful scaling equations for phi which can allow experimentalists to accommodate our results to different experimental setups. The reliable identification of the CF is always hindered by the presence of long fluctuation-driven correlation tails in finite-size samples. In order to deal with this issue, we perform numerical experiments relevant for the identification of the roughness CF. We generate surfaces with predetermined CF using rotation of uncorrelated surfaces or using Monte Carlo simulations based on the Ising model. These numerical experiments show how to circumvent the difficulties that arise in extracting the correlation properties of surface roughness using the data on the surface profile obtained in STM-like experiments. This experience helps us to analyze the new rough mirror and make theoretical predictions for ongoing GRANIT experiments. We also propose an alternative waveguide design which can improve the accuracy of experimental results.

  16. Acoustic waveguides: Applications to oceanic science

    SciTech Connect

    Boyles, C.A.

    1984-01-01

    This book provides a systematic, detailed introduction, including original research, on the mathematical theory of acoustic propagation in oceanic waveguides. Emphasis is on introducing the mathematical techniques of theory of differential equations necessary for solving the wave equations. It also describes that an exact numerical solution for the wave equation has been obtained for an oceanic waveguide with a depth and range dependent sound speed and randomly rough sea surface.

  17. Antiresonant decoupling of parallel dielectric waveguides.

    PubMed

    Someda, C G

    1991-08-15

    Two open waveguides with finite spacing can be decoupled, if the index between them is a suitable function of the transverse coordinates. An analytical proof is provided that makes use of vector properties of electromagnetic waves. On the contrary, decoupling is shown to be impossible for scalar waves and thus incompatible with the weakly guiding assumption. Decoupling can be interpreted as a distributed antiresonance in the region between the waveguides. PMID:19776931

  18. Fluorescence Spectroscopy with Metal-Dielectric Waveguides

    PubMed Central

    Badugu, Ramachandram; Szmacinski, Henryk; Ray, Krishanu; Descrovi, Emiliano; Ricciardi, Serena; Zhang, Douguo; Chen, Junxue; Huo, Yiping; Lakowicz, Joseph R.

    2015-01-01

    We describe a hybrid metal-dielectric waveguide structures (MDWs) with numerous potential applications in the biosciences. These structures consist of a thin metal film coated with a dielectric layer. Depending on the thickness of the dielectric layer, the modes can be localized near the metal, within the dielectric, or at the top surface of the dielectric. The optical modes in a metal-dielectric waveguide can have either S (TE) or P (TM) polarization. The dielectric spacer avoids the quenching, which usually occurs for fluorophores within about 5 nm from the metal. Additionally, the resonances display a sharp angular dependence and can exhibit several hundred-fold increases in intensity (E2) at the silica-air interface relative to the incident intensity. Fluorophores placed on top of the silica layer couple efficiently with the metal, resulting in a sharp angular distribution of emission through the metal and down from the bottom of the structure. This coupling occurs over large distances to several hundred nm away from the metal and was found to be consistent with simulations of the reflectivity of the metal-dielectric waveguides. Remarkably, for some silica thicknesses, the emission is almost completely coupled through the structure with little free-space emission away from the metal-dielectric waveguide. The efficiency of fluorophore coupling is related to the quality of the resonant modes sustained by the metal-dielectric waveguide, resulting in coupling of most of the emission through the metal into the underlying glass substrates. Metal-dielectric waveguides also provide a method to resolve the emission from surface-bound fluorophores from the bulk-phase fluorophores. Metal-dielectric waveguides are simple to fabricate for large surface areas, the resonance wavelength can be adjusted by the dielectric thickness, and the silica surface is suitable for coupling to biomolecules. Metal-dielectric waveguides can have numerous applications in diagnostics and high

  19. Unexpected light behaviour in periodic segmented waveguides

    NASA Astrophysics Data System (ADS)

    Aschiéri, Pierre; Doya, Valérie

    2011-12-01

    In this article, it is shown that multimode periodic segmented waveguides (PSW) are versatile optical systems in which properties of wave chaos can be highlighted. Numerical wave analysis reveals that structures of quantum phase space of PSW are similar to Poincaré sections which display a mixed phase space where stability islands are surrounded by a chaotic sea. Then, unexpected light behavior can occur such as, input gaussian beams do not diverge during the propagation in a highly multimode waveguide.

  20. Subwavelength grating waveguides for integrated photonics

    NASA Astrophysics Data System (ADS)

    Nikkhah, Hamdam; Hall, Trevor J.

    2016-04-01

    Subwavelength waveguide gratings (SWG) are locally periodic structures with parameters that may vary slowly on the scale of a wavelength. Here the implementation of a Lüneburg lens as a SWG to provide Fourier optics on a chip and the design of the adiabatic structures that must be provided to interface SWG structures to conventional waveguides are considered. Preliminary findings are reported on the dispersion engineering of multimode interference couples towards the ideal port phase relations needed in coherent applications.

  1. Probing 1D super-strongly correlated dipolar quantum gases

    NASA Astrophysics Data System (ADS)

    Citro, R.; de Palo, S.; Orignac, E.; Pedri, P.; Chiofalo, M.-L.

    2009-04-01

    One-dimensional (1D) dipolar quantum gases are characterized by a very special condition where super-strong correlations occur to significantly affect the static and dynamical low-energy behavior. This behavior is accurately described by the Luttinger Liquid theory with parameter K < 1. Dipolar Bose gases are routinely studied in laboratory with Chromium atoms. On the other hand, 1D realizations with molecular quantum gases can be at reach of current experimental expertises, allowing to explore such extreme quantum degenerate conditions which are the bottom line for designing technological devices. Aim of the present contribution is to focus on the possible probes expected to signal the reach of Luttinger-Liquid behavior in 1D dipolar gases.

  2. PC-1D installation manual and user's guide

    SciTech Connect

    Basore, P.A.

    1991-05-01

    PC-1D is a software package for personal computers that uses finite-element analysis to solve the fully-coupled two-carrier semiconductor transport equations in one dimension. This program is particularly useful for analyzing the performance of optoelectronic devices such as solar cells, but can be applied to any bipolar device whose carrier flows are primarily one-dimensional. This User's Guide provides the information necessary to install PC-1D, define a problem for solution, solve the problem, and examine the results. Example problems are presented which illustrate these steps. The physical models and numerical methods utilized are presented in detail. This document supports version 3.1 of PC-1D, which incorporates faster numerical algorithms with better convergence properties than previous versions of the program. 51 refs., 17 figs., 5 tabs.

  3. The GIRAFFE Archive: 1D and 3D Spectra

    NASA Astrophysics Data System (ADS)

    Royer, F.; Jégouzo, I.; Tajahmady, F.; Normand, J.; Chilingarian, I.

    2013-10-01

    The GIRAFFE Archive (http://giraffe-archive.obspm.fr) contains the reduced spectra observed with the intermediate and high resolution multi-fiber spectrograph installed at VLT/UT2 (ESO). In its multi-object configuration and the different integral field unit configurations, GIRAFFE produces 1D spectra and 3D spectra. We present here the status of the archive and the different functionalities to select and download both 1D and 3D data products, as well as the present content. The two collections are available in the VO: the 1D spectra (summed in the case of integral field observations) and the 3D field observations. These latter products can be explored using the VO Paris Euro3D Client (http://voplus.obspm.fr/ chil/Euro3D).

  4. Nanodamage and Nanofailure of 1d Zno Nanomaterials and Nanodevices

    NASA Astrophysics Data System (ADS)

    Li, Peifeng; Yang, Ya; Huang, Yunhua; Zhang, Yue

    2012-08-01

    One-dimensional (1D) ZnO nanomaterials include nanowires, nanobelts, and nanorods etc. The extensive applied fields and excellent properties of 1D ZnO nanomaterials can meet the requests of the electronic and electromechanical devices for "smaller, faster and colder", and would be applied in new energy convention, environmental protection, information science and technology, biomedical, security and defense fields. While micro porous, etching pits nanodamage and brittle fracture, dissolving, functional failure nanofailure phenomena of 1D ZnO nanomaterials and nanodevices are observed in some practical working environments like illumination, currents or electric fields, external forces, and some chemical gases or solvents. The more important thing is to discuss the mechanism and reduce or prohibit their generation.

  5. Resonant indirect exchange in 1D semiconductor nanostructures

    NASA Astrophysics Data System (ADS)

    Rozhansky, I. V.; Krainov, I. V.; Averkiev, N. S.; Lähderanta, E.

    2015-06-01

    We consider resonant indirect exchange interaction between magnetic centers in 1D nanostructures. The magnetic centers are assumed to be coupled to the 1D conducting channel by the quantum tunneling which can be of resonant character. The indirect exchange between the centers is mediated by the free carriers of the channel. The two cases of quadratic and linear energy dispersion of the 1D free carriers are considered. The former case is attributed to conventional semiconductor (InGaAs based to be concrete) nanowires or nanowhiskers, while the latter case is associated with carbon nanotubes with magnetic adatoms. We demonstrate that whenever the energy of a bound state at the magnetic center lies within the continuum energy spectra of the delocalized carriers in the channel the indirect exchange is strongly enhanced due to effective tunnel hybridization of the bound states with the continuum.

  6. Optical waveguide device with an adiabatically-varying width

    DOEpatents

    Watts; Michael R. , Nielson; Gregory N.

    2011-05-10

    Optical waveguide devices are disclosed which utilize an optical waveguide having a waveguide bend therein with a width that varies adiabatically between a minimum value and a maximum value of the width. One or more connecting members can be attached to the waveguide bend near the maximum value of the width thereof to support the waveguide bend or to supply electrical power to an impurity-doped region located within the waveguide bend near the maximum value of the width. The impurity-doped region can form an electrical heater or a semiconductor junction which can be activated with a voltage to provide a variable optical path length in the optical waveguide. The optical waveguide devices can be used to form a tunable interferometer (e.g. a Mach-Zehnder interferometer) which can be used for optical modulation or switching. The optical waveguide devices can also be used to form an optical delay line.

  7. Towards new applications using capillary waveguides

    PubMed Central

    Stasio, Nicolino; Shibukawa, Atsushi; Papadopoulos, Ioannis N.; Farahi, Salma; Simandoux, Olivier; Huignard, Jean-Pierre; Bossy, Emmanuel; Moser, Christophe; Psaltis, Demetri

    2015-01-01

    In this paper we demonstrate the enhancement of the sensing capabilities of glass capillaries. We exploit their properties as optical and acoustic waveguides to transform them potentially into high resolution minimally invasive endoscopic devices. We show two possible applications of silica capillary waveguides demonstrating fluorescence and optical-resolution photoacoustic imaging using a single 330 μm-thick silica capillary. A nanosecond pulsed laser is focused and scanned in front of a capillary by digital phase conjugation through the silica annular ring of the capillary, used as an optical waveguide. We demonstrate optical-resolution photoacoustic images of a 30 μm-thick nylon thread using the water-filled core of the same capillary as an acoustic waveguide, resulting in a fully passive endoscopic device. Moreover, fluorescence images of 1.5 μm beads are obtained collecting the fluorescence signal through the optical waveguide. This kind of silica-capillary waveguide together with wavefront shaping techniques such as digital phase conjugation, paves the way to minimally invasive multi-modal endoscopy. PMID:26713182

  8. Towards new applications using capillary waveguides.

    PubMed

    Stasio, Nicolino; Shibukawa, Atsushi; Papadopoulos, Ioannis N; Farahi, Salma; Simandoux, Olivier; Huignard, Jean-Pierre; Bossy, Emmanuel; Moser, Christophe; Psaltis, Demetri

    2015-12-01

    In this paper we demonstrate the enhancement of the sensing capabilities of glass capillaries. We exploit their properties as optical and acoustic waveguides to transform them potentially into high resolution minimally invasive endoscopic devices. We show two possible applications of silica capillary waveguides demonstrating fluorescence and optical-resolution photoacoustic imaging using a single 330 μm-thick silica capillary. A nanosecond pulsed laser is focused and scanned in front of a capillary by digital phase conjugation through the silica annular ring of the capillary, used as an optical waveguide. We demonstrate optical-resolution photoacoustic images of a 30 μm-thick nylon thread using the water-filled core of the same capillary as an acoustic waveguide, resulting in a fully passive endoscopic device. Moreover, fluorescence images of 1.5 μm beads are obtained collecting the fluorescence signal through the optical waveguide. This kind of silica-capillary waveguide together with wavefront shaping techniques such as digital phase conjugation, paves the way to minimally invasive multi-modal endoscopy. PMID:26713182

  9. GIS-BASED 1-D DIFFUSIVE WAVE OVERLAND FLOW MODEL

    SciTech Connect

    KALYANAPU, ALFRED; MCPHERSON, TIMOTHY N.; BURIAN, STEVEN J.

    2007-01-17

    This paper presents a GIS-based 1-d distributed overland flow model and summarizes an application to simulate a flood event. The model estimates infiltration using the Green-Ampt approach and routes excess rainfall using the 1-d diffusive wave approximation. The model was designed to use readily available topographic, soils, and land use/land cover data and rainfall predictions from a meteorological model. An assessment of model performance was performed for a small catchment and a large watershed, both in urban environments. Simulated runoff hydrographs were compared to observations for a selected set of validation events. Results confirmed the model provides reasonable predictions in a short period of time.

  10. Passive estimation of the waveguide invariant per pair of modes.

    PubMed

    Le Gall, Yann; Bonnel, Julien

    2013-08-01

    In many oceanic waveguides, acoustic propagation is characterized by a parameter called waveguide invariant. This property is used in many passive and active sonar applications where knowledge of the waveguide invariant value is required. The waveguide invariant is classically considered as scalar but several studies show that it is better modeled by a distribution because of its dependence on frequency and mode pairs. This paper presents a new method for estimating the waveguide invariant distribution. Using the noise radiated by a distant ship and a single hydrophone, the proposed methodology allows estimating the waveguide invariant for each pair of modes in shallow water. Performance is evaluated on simulated data. PMID:23927230

  11. Compact polarization rotators for integrated polarization diversity in InP-based waveguides.

    PubMed

    Beggs, Daryl M; Midrio, Michele; Krauss, Thomas F

    2007-08-01

    We present the design, fabrication, and operation of a polarization converter based on angled waveguides in the InP/InGaAsP material system. By combining design elements from mode evolution and birefringent devices, the total device length is kept short (less than 50 microm) and the insertion efficiency high at 81%+/-19%, which corresponds to an insertion loss of 1 dB. Devices operate broadband, i.e., the polarization conversion exceeds 15 dB over a 100 nm wavelength range. A polarization rotator with these specifications is a prime candidate for use in an integrated polarization diversity scheme. PMID:17671575

  12. Compact polarization rotators for integrated polarization diversity in InP-based waveguides

    NASA Astrophysics Data System (ADS)

    Beggs, Daryl M.; Midrio, Michele; Krauss, Thomas F.

    2007-08-01

    We present the design, fabrication, and operation of a polarization converter based on angled waveguides in the InP/InGaAsP material system. By combining design elements from mode evolution and birefringent devices, the total device length is kept short (less than 50μm) and the insertion efficiency high at 81%+/-19%, which corresponds to an insertion loss of 1dB. Devices operate broadband, i.e., the polarization conversion exceeds 15dB over a 100nm wavelength range. A polarization rotator with these specifications is a prime candidate for use in an integrated polarization diversity scheme.

  13. 2-D simulation of a waveguide free electron laser having a helical undulator

    SciTech Connect

    Kim, S.K.; Lee, B.C.; Jeong, Y.U.

    1995-12-31

    We have developed a 2-D simulation code for the calculation of output power from an FEL oscillator having a helical undulator and a cylindrical waveguide. In the simulation, the current and the energy of the electron beam is 2 A and 400 keV, respectively. The parameters of the permanent-magnet helical undulator are : period = 32 mm, number of periods = 20, magnetic field = 1.3 kG. The gain per pass is 10 and the output power is calculated to be higher than 10 kW The results of the 2-D simulation are compared with those of 1-D simulation.

  14. An Inline Microstrip-to-Waveguide Transition Operating in the Full W-Band

    NASA Astrophysics Data System (ADS)

    Rebollo, Ainara; Gonzalo, Ramón; Ederra, Iñigo

    2015-08-01

    An inline microstrip-to-waveguide transition covering the full W-Band is presented in this article. The verification of the simulation results has been carried out by means of a back-to-back transition measurement. Experimental results show good return losses above 15 dB in the entire W-Band and also low insertion losses. Specifically, the measured insertion losses are 0.71 dB at the central frequency of W-Band, i.e., 92.5 GHz, and below 1.1 dB in the full W-band.

  15. Atmospheric refraction correction for Ka-band blind pointing on the DSS-13 beam waveguide antenna

    NASA Technical Reports Server (NTRS)

    Perez-Borroto, I. M.; Alvarez, L. S.

    1992-01-01

    An analysis of the atmospheric refraction corrections at the DSS-13 34-m diameter beam waveguide (BWG) antenna for the period Jul. - Dec. 1990 is presented. The current Deep Space Network (DSN) atmospheric refraction model and its sensitivity with respect to sensor accuracy are reviewed. Refraction corrections based on actual atmospheric parameters are compared with the DSS-13 station default corrections for the six-month period. Average blind-pointing improvement during the worst month would have amounted to 5 mdeg at 10 deg elevation using actual surface weather values. This would have resulted in an average gain improvement of 1.1 dB.

  16. Hollow glass waveguides with multilayer polystyrene and metal sulfide thin film coatings for improved infrared transmission

    NASA Astrophysics Data System (ADS)

    Johnson, Valencia S.

    2007-12-01

    The overall goal of this project was to improve transmission of infrared radiation in hollow waveguides. First, polystyrene was studied as a new dielectric material for silver-coated hollow glass waveguides. The deposition and performance of polystyrene, as a single dielectric layer, were investigated. The potential of polystyrene as the low index of refraction material in a multilayer coating was also demonstrated. Cadmium sulfide and lead sulfide were each considered as the high index material in the multilayer stack. Multilayer silver coated hollow glass waveguides can be formed using polystyrene and either cadmium sulfide or lead sulfide. These material pairs are interesting because they form a multilayer structure with high index contrast, which can significantly lower the loss of a waveguide. The deposition of lead sulfide was also optimized in this project. Lead sulfide, as a single layer dielectric coating, is an attractive material for transmission of longer wavelength radiation, especially 10.6 mum. It is also of interest for emerging applications such as metals processing by lasers because hollow waveguides with silver and lead sulfide can make a low loss waveguide. Losses as low as 0.1dB/m were achieved. The deposition of zinc sulfide and zinc selenide was also investigated in this project. They are of interest because of their small extinction coefficients at longer wavelengths and potential for use in waveguides used for materials processing. The numerous simultaneous chemical reactions occurring during deposition of these materials makes obtaining pure films difficult. Gold was evaluated as a replacement for silver as the highly reflecting metallic layer. It was considered an attractive alternative because it has greater resistance to degradation in high temperature and corrosive environments. All samples were made using an electroless process. Characterization of the samples was performed using the optical techniques of FTIR and UV

  17. Monolithic integration of active and second-order nonlinear functionality in Bragg reflection waveguides

    NASA Astrophysics Data System (ADS)

    Bijlani, Bhavin J.

    2011-07-01

    This thesis explored the theory, design, fabrication and characterization of AlGaAs Bragg reflection waveguides (BRW) towards the goal of a platform for monolithic integration of active and optically nonlinear devices. Through integration of a diode laser and nonlinear phase-matched cavity, the possibility of on-chip nonlinear frequency generation was explored. Such integrated devices would be highly useful as a robust, alignment free, small footprint and electrically injected alternative to bulk optic systems. A theoretical framework for modal analysis of arbitrary 1-D photonic crystal defect waveguides is developed. This method relies on the transverse resonance condition. It is then demonstrated in the context of several types of Bragg reflection waveguides. The framework is then extended to phase-match second-order nonlinearities and incorporating quantum-wells for diode lasers. Experiments within a slab and ridge waveguide demonstrated phase-matched Type-I second harmonic generation at fundamental wavelength of 1587 and 1600 nm, respectively; a first for this type of waveguide. For the slab waveguide, conversion efficiency was 0.1 %/W. In the more strongly confined ridge waveguides, efficiency increased to 8.6 %/W owing to the increased intensity. The normalized conversion efficiency was estimated to be at 600 %/Wcm2. Diode lasers emitting at 980 nm in the BRW mode were also fabricated. Verification of the Bragg mode was performed through imaging the near- field of the mode. Propagation loss of this type of mode was measured directly for the first time at ≈ 14 cm-1. The lasers were found to be very insensitive with characteristic temperature at 215 K. Two designs incorporating both laser and phase-matched nonlinearity within the same cavity were fabricated, for degenerate and non-degenerate down-conversion. Though the lasers were sub-optimal, a parametric fluorescence signal was readily detected. Fluorescence power as high as 4 nW for the degenerate design

  18. Atomic layer deposited second-order nonlinear optical metamaterial for back-end integration with CMOS-compatible nanophotonic circuitry.

    PubMed

    Clemmen, Stéphane; Hermans, Artur; Solano, Eduardo; Dendooven, Jolien; Koskinen, Kalle; Kauranen, Martti; Brainis, Edouard; Detavernier, Christophe; Baets, Roel

    2015-11-15

    We report the fabrication of artificial unidimensional crystals exhibiting an effective bulk second-order nonlinearity. The crystals are created by cycling atomic layer deposition of three dielectric materials such that the resulting metamaterial is noncentrosymmetric in the direction of the deposition. Characterization of the structures by second-harmonic generation Maker-fringe measurements shows that the main component of their nonlinear susceptibility tensor is about 5 pm/V, which is comparable to well-established materials and more than an order of magnitude greater than reported for a similar crystal [Appl. Phys. Lett.107, 121903 (2015)APPLAB0003-695110.1063/1.4931492]. Our demonstration opens new possibilities for second-order nonlinear effects on CMOS-compatible nanophotonic platforms. PMID:26565877

  19. Optical properties of LEDs with patterned 1D photonic crystal

    NASA Astrophysics Data System (ADS)

    Hronec, P.; Kuzma, A.; Å kriniarová, J.; Kováč, J.; Benčurová, A.; Haščík, Å.; Nemec, P.

    2015-08-01

    In this paper we focus on the application of the one-dimensional photonic crystal (1D PhC) structures on the top of Al0.295Ga0.705As/GaAs multi-quantum well light emitting diode (MQW LED). 1D PhC structures with periods of 600 nm, 700 nm, 800 nm, and 900 nm were fabricated by the E-Beam Direct Write (EBDW) Lithography. Effect of 1D PhC period on the light extraction enhancement was studied. 1D PhC LED radiation profiles were obtained from Near Surface Light Emission Images (NSLEI). Measurements showed the strongest light extraction enhancement using 800 nm period of PhC. Investigation of PhC LED radiation profiles showed strong light decoupling when light reaches PhC structure. Achieved LEE was from 22.6% for 600 nm PhC LED to 47.0% for 800 nm PhC LED. LED with PhC structure at its surface was simulated by FDTD simulation method under excitation of appropriate launch field.

  20. NEW FEATURES OF HYDRUS-1D, VERSION 3.0

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper briefly summarizes new features in version 3.0 of HYDRUS-1D, released in May 2005, as compared to version 2.1. The new features are a) new approaches to simulate preferential and nonequilibrium water flow and solute transport, b) a new hysteresis module that avoids the effects of pumpin...

  1. A 1D wavelet filtering for ultrasound images despeckling

    NASA Astrophysics Data System (ADS)

    Dahdouh, Sonia; Dubois, Mathieu; Frenoux, Emmanuelle; Osorio, Angel

    2010-03-01

    Ultrasound images appearance is characterized by speckle, shadows, signal dropout and low contrast which make them really difficult to process and leads to a very poor signal to noise ratio. Therefore, for main imaging applications, a denoising step is necessary to apply successfully medical imaging algorithms on such images. However, due to speckle statistics, denoising and enhancing edges on these images without inducing additional blurring is a real challenging problem on which usual filters often fail. To deal with such problems, a large number of papers are working on B-mode images considering that the noise is purely multiplicative. Making such an assertion could be misleading, because of internal pre-processing such as log compression which are done in the ultrasound device. To address those questions, we designed a novel filtering method based on 1D Radiofrequency signal. Indeed, since B-mode images are initially composed of 1D signals and since the log compression made by ultrasound devices modifies noise statistics, we decided to filter directly the 1D Radiofrequency signal envelope before log compression and image reconstitution, in order to conserve as much information as possible. A bi-orthogonal wavelet transform is applied to the log transform of each signal and an adaptive 1D split and merge like algorithm is used to denoise wavelet coefficients. Experiments were carried out on synthetic data sets simulated with Field II simulator and results show that our filter outperforms classical speckle filtering methods like Lee, non-linear means or SRAD filters.

  2. Non-cooperative Brownian donkeys: A solvable 1D model

    NASA Astrophysics Data System (ADS)

    Jiménez de Cisneros, B.; Reimann, P.; Parrondo, J. M. R.

    2003-12-01

    A paradigmatic 1D model for Brownian motion in a spatially symmetric, periodic system is tackled analytically. Upon application of an external static force F the system's response is an average current which is positive for F < 0 and negative for F > 0 (absolute negative mobility). Under suitable conditions, the system approaches 100% efficiency when working against the external force F.

  3. Coaxial waveguides as primary feeds for reflector antennas and their comparison with circular waveguides

    NASA Astrophysics Data System (ADS)

    Shafai, L.; Kishk, A. A.

    1985-02-01

    The radiation characteristics of a coaxial waveguide with a TE(11) mode excitation are numerically studied using the moment method. It is shown that since a coaxial waveguide has an additional dimensional parameter, the radius of the inner conductor, varieties of radiation patterns can be generated by selecting different conductor radii. In particular, the computed patterns indicate that for any given ratio of conductor radii, an outer conductor radius can be found to equalize the E and H plane patterns. This property allows symmetric radiation patterns to be obtained without any corrugation over the waveguides inner wall or on the surface of the end flange. This results in a very small feed diameter, which reduces the central blockage when used as a feed for a paraboloid reflector. The performance of circular waveguides is studied and is shown to be nearly the same as that of coaxial waveguides as long as the outer diameters are the same.

  4. 1D design style implications for mask making and CEBL

    NASA Astrophysics Data System (ADS)

    Smayling, Michael C.

    2013-09-01

    At advanced nodes, CMOS logic is being designed in a highly regular design style because of the resolution limitations of optical lithography equipment. Logic and memory layouts using 1D Gridded Design Rules (GDR) have been demonstrated to nodes beyond 12nm.[1-4] Smaller nodes will require the same regular layout style but with multiple patterning for critical layers. One of the significant advantages of 1D GDR is the ease of splitting layouts into lines and cuts. A lines and cuts approach has been used to achieve good pattern fidelity and process margin to below 12nm.[4] Line scaling with excellent line-edge roughness (LER) has been demonstrated with self-aligned spacer processing.[5] This change in design style has important implications for mask making: • The complexity of the masks will be greatly reduced from what would be required for 2D designs with very complex OPC or inverse lithography corrections. • The number of masks will initially increase, as for conventional multiple patterning. But in the case of 1D design, there are future options for mask count reduction. • The line masks will remain simple, with little or no OPC, at pitches (1x) above 80nm. This provides an excellent opportunity for continual improvement of line CD and LER. The line pattern will be processed through a self-aligned pitch division sequence to divide pitch by 2 or by 4. • The cut masks can be done with "simple OPC" as demonstrated to beyond 12nm.[6] Multiple simple cut masks may be required at advanced nodes. "Coloring" has been demonstrated to below 12nm for two colors and to 8nm for three colors. • Cut/hole masks will eventually be replaced by e-beam direct write using complementary e-beam lithography (CEBL).[7-11] This transition is gated by the availability of multiple column e-beam systems with throughput adequate for high- volume manufacturing. A brief description of 1D and 2D design styles will be presented, followed by examples of 1D layouts. Mask complexity for 1

  5. Ultralow-loss waveguide crossings for the integration of microfluidics and optical waveguide sensors

    NASA Astrophysics Data System (ADS)

    Wang, Zheng; Yan, Hai; Wang, Zongxing; Zou, Yi; Yang, Chun-Ju; Chakravarty, Swapnajit; Subbaraman, Harish; Tang, Naimei; Xu, Xiaochuan; Fan, D. L.; Wang, Alan X.; Chen, Ray T.

    2015-03-01

    Integrating photonic waveguide sensors with microfluidics is promising in achieving high-sensitivity and cost-effective biological and chemical sensing applications. One challenge in the integration is that an air gap would exist between the microfluidic channel and the photonic waveguide when the micro-channel and the waveguide intersect. The air gap creates a path for the fluid to leak out of the micro-channel. Potential solutions, such as oxide deposition followed by surface planarization, would introduce additional fabrication steps and thus are ineffective in cost. Here we propose a reliable and efficient approach for achieving closed microfluidic channels on a waveguide sensing chip. The core of the employed technique is to add waveguide crossings, i.e., perpendicularly intersecting waveguides, to block the etched trenches and prevent the fluid from leaking through the air gap. The waveguide crossings offer a smooth interface for microfluidic channel bonding while bring negligible additional propagation loss (0.024 dB/crossing based on simulation). They are also efficient in fabrication, which are patterned and fabricated in the same step with waveguides. We experimentally integrated microfluidic channels with photonic crystal (PC) microcavity sensor chips on silicon-on-insulator substrate and demonstrated leak-free sensing measurement with waveguide crossings. The microfluidic channel was made from polydimethylsiloxane (PDMS) and pressure bonded to the silicon chip. The tested flow rates can be varied from 0.2 μL/min to 200 μL/min. Strong resonances from the PC cavity were observed from the transmission spectra. The spectra also show that the waveguide crossings did not induce any significant additional loss or alter the resonances.

  6. Fabrication of hollow optical waveguides on planar substrates

    NASA Astrophysics Data System (ADS)

    Barber, John P.

    This dissertation presents the fabrication of hollow optical waveguides integrated on planar substrates. Similar in principle to Bragg waveguides and other photonic crystal waveguides, the antiresonant reflecting optical waveguide (ARROW) is used to guide light in hollow cores filled with liquids or gases. Waveguides with liquid or gas cores are an important new building block for integrated optical sensors. The fabrication method developed for hollow ARROW waveguides makes use of standard microfabrication processes and materials. Dielectric layers are deposited on a silicon wafer using plasma-enhanced chemical vapor deposition (PECVD) to form the bottom layers of the ARROW waveguide. A sacrificial core material is then deposited and patterned. Core materials used include aluminum, SU-8 and reflowed photoresist, each resulting in a different core geometry. Additional dielectric layers are then deposited, forming the top and sides of the waveguide. The sacrificial core is then removed in an acid solution, resulting in a hollow ARROW waveguide. Experiments investigating the mechanical strength of the hollow waveguides and the etching characteristics of the sacrificial core suggest design rules for the different core types. Integration of solid-core waveguides is accomplished by etching a ridge into the top dielectric layer of the ARROW structure. Improved optical performance can be obtained by forming the waveguides on top of a raised pedestal on the silicon substrate. Loss measurements on hollow ARROW waveguides fabricated in this manner gave loss coefficients of 0.26 cm-1 for liquid-core waveguides and 2.6 cm-1 for air-core waveguides. Fluorescence measurements in liquid-core ARROW waveguides have achieved single-molecule detection sensitivity. Integrated optical filters based on ARROW waveguides were fabricated, and preliminary results of a capillary electrophoresis separation device using a hollow ARROW indicate the feasibility of such devices for future

  7. Untangled modes in multimode waveguides

    NASA Astrophysics Data System (ADS)

    Plöschner, Martin; Tyc, TomáÅ.¡; Čižmár, TomáÅ.¡

    2016-03-01

    Small, fibre-based endoscopes have already improved our ability to image deep within the human body. A novel approach introduced recently utilised disordered light within a standard multimode optical fibre for lensless imaging. Importantly, this approach brought very significant reduction of the instruments footprint to dimensions below 100 μm. The most important limitations of this exciting technology is the lack of bending flexibility - imaging is only possible as long as the fibre remains stationary. The only route to allow flexibility of such endoscopes is in trading-in all the knowledge about the optical system we have, particularly the cylindrical symmetry of refractive index distribution. In perfect straight step-index cylindrical waveguides we can find optical modes that do not change their spatial distribution as they propagate through. In this paper we present a theoretical background that provides description of such modes in more realistic model of real-life step-index multimode fibre taking into account common deviations in distribution of the refractive index from its ideal step-index profile. Separately, we discuss how to include the influence of fibre bending.

  8. Numerical simulations of heavily polluted fine-grained sediment remobilization using 1D, 1D+, and 2D channel schematization.

    PubMed

    Kaiglová, Jana; Langhammer, Jakub; Jiřinec, Petr; Janský, Bohumír; Chalupová, Dagmar

    2015-03-01

    This article used various hydrodynamic and sediment transport models to analyze the potential and the limits of different channel schematizations. The main aim was to select and evaluate the most suitable simulation method for fine-grained sediment remobilization assessment. Three types of channel schematization were selected to study the flow potential for remobilizing fine-grained sediment in artificially modified channels. Schematization with a 1D cross-sectional horizontal plan, a 1D+ approach, splitting the riverbed into different functional zones, and full 2D mesh, adopted in MIKE by the DHI modeling suite, was applied to the study. For the case study, a 55-km stretch of the Bílina River, in the Czech Republic, Central Europe, which has been heavily polluted by the chemical and coal mining industry since the mid-twentieth century, was selected. Long-term exposure to direct emissions of toxic pollutants including heavy metals and persistent organic pollutants (POPs) resulted in deposits of pollutants in fine-grained sediments in the riverbed. Simulations, based on three hydrodynamic model schematizations, proved that for events not exceeding the extent of the riverbed profile, the 1D schematization can provide comparable results to a 2D model. The 1D+ schematization can improve accuracy while keeping the benefits of high-speed simulation and low requirements of input DEM data, but the method's suitability is limited by the channel properties. PMID:25687259

  9. Optimizing polarization-diversity couplers for Si-photonics: reaching the -1dB coupling efficiency threshold.

    PubMed

    Carroll, Lee; Gerace, Dario; Cristiani, Ilaria; Andreani, Lucio C

    2014-06-16

    Polarization-diversity couplers are low-cost industrially-scalable passive devices that can couple light of unknown polarization from a telecom fiber-mode to a pair of TE-polarized wave-guided modes in the Silicon-on-Insulator platform. These couplers offer significantly more relaxed alignment tolerances than edge-coupling schemes, which is advantageous for commercial fiber-packaging of Si-photonic circuits. However, until now, polarization-diversity couplers have not offered sufficient coupling efficiency to motivate serious commercial consideration. Using 3D finite difference time domain calculations for device optimization, we identify Silicon-on-Insulator polarization-diversity couplers with 1,550 nm coupling efficiencies of -0.95 dB and -1.9 dB, for designs with and without bottom-reflector elements, respectively. These designs offer a significant improvement over state-of-the-art performance, and effectively bridge the "performance gap" between polarization-diversity couplers and 1D-grating couplers. Our best polarization-diversity coupler design goes beyond the -1dB efficiency limit that is typically accepted as the minimum needed for industrial adoption of coupler devices in the telecoms market. PMID:24977572

  10. Quasi-optical equivalent of waveguide slide screw tuner

    NASA Technical Reports Server (NTRS)

    Kurpis, G. P.

    1970-01-01

    Tuner utilizes a metal plated dielectric grid inserted into the cross sectional plane of an oversized waveguide. It provides both variable susceptance and variable longitudinal position along the waveguide to provide a wide matching range.

  11. Improved cooling design for high power waveguide system

    NASA Technical Reports Server (NTRS)

    Chen, W. C. J.; Hartop, R.

    1981-01-01

    Testing of X band high power components in a traveling wave resonator indicates that this improved cooling design reduces temperature in the waveguide and flange. The waveguide power handling capability and power transmission reliability is increased substantially.

  12. Electro-optic switching based on a waveguide-ring resonator made of dielectric-loaded graphene plasmon waveguides

    NASA Astrophysics Data System (ADS)

    Qi, Zhe; Zhu, Zhi Hong; Xu, Wei; Zhang, Jian Fa; Cai Guo, Chu; Liu, Ken; Yuan, Xiao Dong; Qiao Qin, Shi

    2016-09-01

    We numerically demonstrate that electro-optic switching in the mid-infrared range can be realized using a waveguide-ring resonator made of dielectric-loaded graphene plasmon waveguides (DLGPWs). The numerical results are in good agreement with the results of physical analysis. The switching mechanism is based on dynamic modification of the resonant wavelengths of the ring resonator, achieved by varying the Fermi energy of a graphene sheet. The results reveal that a switching ratio of ∼24 dB can be achieved with only a 0.01 eV change in the Fermi energy. Such electrically controlled switching operation may find use in actively tunable integrated photonic circuits.

  13. A waveguide-typed plasmonic mode converter.

    PubMed

    Park, Hae-Ryeong; Park, Jong-Moon; Kim, Min-Su; Lee, Myung-Hyun

    2012-08-13

    Waveguide-typed plasmonic mode converters (WPMCs) at a wavelength of 1.55 μm are presented. The WPMC is composed of an insulator-metal-insulator waveguide (IMI-W), a 1st reversely tapered insulator-metal-insulator-metal-insulator waveguide (RT-IMIMI-W), an insulator-metal-insulator-metal-insulator waveguide (IMIMI-W), a 2nd RT-IMIMI-W with lateral silver mirrors (LSMs), and a metal-insulator-metal waveguide (MIM-W) in series. The mode sizes for the IMI-W, IMIMI-W, and MIM-W via the IMIMI-W with LSMs were not only calculated using a finite element method but were also experimentally measured. The input mode size of 10.3 μm × 10.3 μm from a polarization-maintaining single-mode fiber was squeezed to the mode size of ~2.9 μm × 2.9 μm in measurement by converting an s0 mode to an Sa0 mode via an Ss0 mode. The WPMC may be potentially useful for bridging micro- to nano-plasmonic integrated circuits. PMID:23038504

  14. Recent progress on polymer optical waveguides

    NASA Astrophysics Data System (ADS)

    Kobayashi, Junya

    2008-02-01

    Intensive research on optical interconnection over flexible optical circuit boards has been undertaken for such applications as high-end routers, servers and cellular phones. And these flexible optical circuit boards are expected to be used for polymer optical waveguides. This paper reports recent progress on polymer optical waveguides. It also describes a flexible stamping method, which employs a flexible film stamp made of polymeric materials. Unlike conventional hard stamps, the flexible film stamp does not require either the stamp or its substrate to be perfectly flat, which means large area stamping is easy to achieve at reduced cost. We confirmed this by replicating 50 μm multi-mode optical polymer waveguides. The propagation loss of the waveguide is fairly low at 0.06 dB/cm at a wavelength of 850 nm. This loss is sufficiently small to meet the basic requirement for optical circuit boards, and the waveguide was used to fabricate a flexible optical circuit board with MT connectors.

  15. Waveguide switches using asymmetric coupled quantum wells

    NASA Astrophysics Data System (ADS)

    Ritter, Kenneth J.; Horst, Scott C.

    1994-07-01

    This report contains the results of a three-year effort to investigate the use of Asymmetric Coupled Quantum Well in optical waveguide cross bar switches. The two types of devices investigated are the standard delta beta switch and the delta alpha switch. The delta alpha switch uses the imaginary part of the refractive index to modulate the intensity along different waveguide paths in the switch structure. Both types of switch were fabricated and tested. The delta beta switches produced are suitable as 1-input 2-output devices. The delta alpha switches were demonstrated as 2 by 2 cross bar switches with up to 40% throughput. To compensate for losses in the switches the use of amplifying elements was investigated. To provide gain at a longer wavelength than that of the excitons in the modulation waveguides, the quantum wells in the modulation waveguides were blue shifted using vacancy induced disordering (VID). The VID shifted quantum wells showed less Stark shift than the unshifted quantum wells. This effect is explained by the nearly parabolic shape of the disordered wells. Coupled quantum wells can be used to create a structure that will maintain a strongly Stark shifted spatially indirect transition even after VID. Modeling of the various waveguide structures used is also discussed.

  16. Waveguides in Thin Film Polymeric Materials

    NASA Technical Reports Server (NTRS)

    Sakisov, Sergey; Abdeldayem, Hossin; Venkateswarlu, Putcha; Teague, Zedric

    1996-01-01

    Results on the fabrication of integrated optical components in polymeric materials using photo printing methods will be presented. Optical waveguides were fabricated by spin coating preoxidized silicon wafers with organic dye/polymer solution followed by soft baking. The waveguide modes were studied using prism coupling technique. Propagation losses were measured by collecting light scattered from the trace of a propagation mode by either scanning photodetector or CCD camera. We observed the formation of graded index waveguides in photosensitive polyimides after exposure of UV light from a mercury arc lamp. By using a theoretical model, an index profile was reconstructed which is in agreement with the profile reconstructed by the Wentzel-Kramers-Brillouin calculation technique using a modal spectrum of the waveguides. Proposed mechanism for the formation of the graded index includes photocrosslinking followed by UV curing accompanied with optical absorption increase. We also developed the prototype of a novel single-arm double-mode interferometric sensor based on our waveguides. It demonstrates high sensitivity to the chance of ambient temperature. The device can find possible applications in aeropropulsion control systems.

  17. Simple Broadband Circular Polarizer in Oversized Waveguide

    NASA Astrophysics Data System (ADS)

    Stange, Torsten

    2016-02-01

    In this paper, a possibility is shown to realize a simple waveguide polarizer producing nearly the same circular polarization over a broad frequency range up to an octave. It is based upon the combination of two smoothly squeezed oversized waveguides with different diameters. The principle is similar to an achromatic lens in optics, where two counteracting lenses with differently sloped wavelength dependencies of the refractive index are combined to compensate the dispersion in the desired wavelength range. Consequently, two different wavelengths of light are brought into focus at the same plane. A waveguide for the transmission of microwaves has a similar frequency dependence of the refractive index resulting in a frequency-dependent phase shift between two propagating waves polarized along the symmetry axes of a waveguide with an elliptical cross section. For this reason, an incident wave with a linear polarization between the axes of symmetry can be only converted into a circularly polarized wave over a limited frequency range. However, the diameter and the shape along two counteracting squeezed waveguides can be adjusted in such a way that the frequency dependence of the resultant phase shift is finally canceled out.

  18. MMICs with Radial Probe Transitions to Waveguides

    NASA Technical Reports Server (NTRS)

    Samoska, Lorene; Chattopadhyay, Goutam; Pukala, David; Soria, Mary; Fung, King Man; Gaier, Todd; Radisic, Vesna; Lai, Richard

    2009-01-01

    A document presents an update on the innovation reported in Integrated Radial Probe Transition From MMIC to Waveguide (NPO-43957), NASA Tech Briefs Vol. 31, No. 5 (May 2007), page 38. To recapitulate: To enable operation or testing of a monolithic microwave integrated circuit (MMIC), it is necessary to mount the MMIC in a waveguide package that typically has cross-sectional waveguide dimensions of the order of a few hundred microns. A radial probe transition between an MMIC operating at 340 GHz and a waveguide had been designed (but not yet built and tested) to be fabricated as part of a monolithic unit that would include the MMIC. The radial probe could readily be integrated with an MMIC amplifier because the design provided for fabrication of the transition on a substrate of the same material (InP) and thickness (50 m) typical of substrates of MMICs that can operate above 300 GHz. As illustrated in the updated document by drawings, photographs, and plots of test data, the concept has now been realized by designing, fabricating, and testing several MMIC/radial- probe integrated-circuit chips and designing and fabricating a waveguide package to contain each chip.

  19. Compact transverse-magnetic-pass polarizer based on one-dimensional photonic crystal waveguide

    NASA Astrophysics Data System (ADS)

    Kim, Dong Wook; Lee, Moon Hyeok; Kim, Yudeuk; Kim, Kyong Hon

    2016-03-01

    We propose a compactly integrated transverse-magnetic (TM)-pass polarizer based on rectangular-shape onedimensional photonic-crystal silicon waveguide with an extremely high polarization extinction ratio of >30 dB and low insertion loss (~1 dB) over a broad wavelength range of 210 nm from 1,460 nm to 1,670 nm. The polarizer has been numerically simulated using three-dimensional finite-difference time-domain (3D FDTD) method. The optimum length of the proposed TM-pass polarizer is about 4 μm. At the 1,550 nm wavelength, the simulated polarization extinction ratio of the polarizer is 36 dB, and its corresponding insertion loss is about 1 dB.

  20. Mode size converter between high-index-contrast waveguide and cleaved single mode fiber using SiON as intermediate material.

    PubMed

    Jia, Lianxi; Song, Junfeng; Liow, Tsung-Yang; Luo, Xianshu; Tu, Xiaoguang; Fang, Qing; Koh, Sing-Chee; Yu, Mingbin; Lo, Guoqiang

    2014-09-22

    High-index-contrast (HIC) waveguide such as Si and Si3N4 has small mode size enabling compact integration. However, the coupling loss with single mode fiber is also remarkable owning to the mode mismatching. Therefore, mode size converter, as the interface between HIC waveguide and optical fiber, takes an important role in the field of integrated optics. The material with refractive index (RI) between HIC waveguide and optical fiber can be used as a bridge to reduce the mode mismatching loss. In this letter, we employ silicon oxynitride (SiON) with RI about 1.50 as the intermediate material and optimize the structure of the SiON waveguide to match with cleaved single mode fiber and HIC waveguide separately. Combined with inverse taper and suspended structure, the mismatching loss is reduced and the dependence to the dimension of the structure is also released. The coupling loss is 1.2 and 1.4 dB/facet for TE and TM mode, respectively, with 3 dB alignment tolerance of ± 3.5 μm for Si(3)N(4) waveguide with just 200 nm-wide tip. While for Si waveguide, a critical dimension of 150 nm is applied due to the higher index contrast than Si(3)N(4) waveguide. Similar alignment tolerance is realized with coupling loss about 1.8 and 2.1 dB/facet for TE and TM mode. The polarization dependence loss (PDL) for both platforms is within 0.5 dB. PMID:25321831

  1. Position dependent spin wave spectrum in nanostrip magnonic waveguides

    SciTech Connect

    Wang, Qi; Zhang, Huaiwu; Ma, Guokun; Liao, Yulong; Zhong, Zhiyong; Zheng, Yun

    2014-04-07

    The dispersion curves of propagating spin wave along different positions in nanostrip magnonic waveguides were studied by micromagnetic simulation. The results show that the modes of spin wave in the nanostrip magnonic waveguide are dependent on the position and the weak even modes of spin wave are excited even by symmetric excitation fields in a nanostrip magnonic waveguide. The reasons of the position dependent dispersion curve are explained by associating with geometrical confinement in the nanostrip magnonic waveguide.

  2. Control of light diffusion in a disordered photonic waveguide

    SciTech Connect

    Sarma, Raktim; Cao, Hui; Golubev, Timofey; Yamilov, Alexey

    2014-07-28

    We control the diffusion of light in a disordered photonic waveguide by modulating the waveguide geometry. In a single waveguide of varying cross-section, the diffusion coefficient changes spatially in two dimensions due to localization effects. The intensity distribution inside the waveguide agrees with the prediction of the self-consistent theory of localization. Our work shows that wave diffusion can be efficiently manipulated without modifying the structural disorder.

  3. 1D Josephson quantum interference grids: diffraction patterns and dynamics

    NASA Astrophysics Data System (ADS)

    Lucci, M.; Badoni, D.; Corato, V.; Merlo, V.; Ottaviani, I.; Salina, G.; Cirillo, M.; Ustinov, A. V.; Winkler, D.

    2016-02-01

    We investigate the magnetic response of transmission lines with embedded Josephson junctions and thus generating a 1D underdamped array. The measured multi-junction interference patterns are compared with the theoretical predictions for Josephson supercurrent modulations when an external magnetic field couples both to the inter-junction loops and to the junctions themselves. The results provide a striking example of the analogy between Josephson phase modulation and 1D optical diffraction grid. The Fiske resonances in the current-voltage characteristics with voltage spacing {Φ0}≤ft(\\frac{{\\bar{c}}}{2L}\\right) , where L is the total physical length of the array, {Φ0} the magnetic flux quantum and \\bar{c} the speed of light in the transmission line, demonstrate that the discrete line supports stable dynamic patterns generated by the ac Josephson effect interacting with the cavity modes of the line.

  4. A Bayesian Algorithm for Reading 1D Barcodes

    PubMed Central

    Tekin, Ender; Coughlan, James

    2010-01-01

    The 1D barcode is a ubiquitous labeling technology, with symbologies such as UPC used to label approximately 99% of all packaged goods in the US. It would be very convenient for consumers to be able to read these barcodes using portable cameras (e.g. mobile phones), but the limited quality and resolution of images taken by these cameras often make it difficult to read the barcodes accurately. We propose a Bayesian framework for reading 1D barcodes that models the shape and appearance of barcodes, allowing for geometric distortions and image noise, and exploiting the redundant information contained in the parity digit. An important feature of our framework is that it doesn’t require that every barcode edge be detected in the image. Experiments on a publicly available dataset of barcode images explore the range of images that are readable, and comparisons with two commercial readers demonstrate the superior performance of our algorithm. PMID:20428491

  5. Morphodynamics and sediment tracers in 1-D (MAST-1D): 1-D sediment transport that includes exchange with an off-channel sediment reservoir

    NASA Astrophysics Data System (ADS)

    Lauer, J. Wesley; Viparelli, Enrica; Piégay, Hervé

    2016-07-01

    Bed material transported in geomorphically active gravel bed rivers often has a local source at nearby eroding banks and ends up sequestered in bars not far downstream. However, most 1-D numerical models for gravel transport assume that gravel originates from and deposits on the channel bed. In this paper, we present a 1-D framework for simulating morphodynamic evolution of bed elevation and size distribution in a gravel-bed river that actively exchanges sediment with its floodplain, which is represented as an off-channel sediment reservoir. The model is based on the idea that sediment enters the channel at eroding banks whose elevation depends on total floodplain sediment storage and on the average elevation of the floodplain relative to the channel bed. Lateral erosion of these banks occurs at a specified rate that can represent either net channel migration or channel widening. Transfer of material out of the channel depends on a typical bar thickness and a specified lateral exchange rate due either to net channel migration or narrowing. The model is implemented using an object oriented framework that allows users to explore relationships between bank supply, bed structure, and lateral change rates. It is applied to a ∼50-km reach of the Ain River, France, that experienced significant reduction in sediment supply due to dam construction during the 20th century. Results are strongly sensitive to lateral exchange rates, showing that in this reach, the supply of sand and gravel at eroding banks and the sequestration of gravel in point bars can have strong influence on overall reach-scale sediment budgets.

  6. Demonstration of integrated polarization rotator based on an asymmetric silicon waveguide with a trench

    NASA Astrophysics Data System (ADS)

    Kim, Yudeuk; Kim, Dong Wook; Lee, Moon-Hyeok; Lee, Min Hee; Yoo, Dong Eun; Kim, Ki Nam; Jeon, Sang Chul; Kim, Kyong Hon

    2016-09-01

    An integrated polarization rotator is demonstrated experimentally by forming a strip waveguide with an asymmetric trench on a silicon-on-insulator wafer. The trench is located asymmetrically in the strip waveguide. It induces the evolution of an orthogonal polarization mode upon a linearly polarized beam input, and thus causes polarization rotation. The device is fabricated using a conventional complementary metal oxide semiconductor process with a single dry etching step. The fabricated device shows a maximum transverse electric (TE)-to-transverse magnetic (TM) polarization conversion efficiency of 21.3 dB and an insertion loss of ‑0.95 dB at a 1550 nm wavelength with a device length of 67 μm. The device exhibits a polarization conversion efficiency and insertion loss of 21.1 dB and ‑2.12 dB, respectively, for the TM-to-TE polarization conversion. The optimum parameters for the waveguide size and trench size are investigated by performing numerical simulations, and by demonstrating experimental fabrication and measurement.

  7. Efficient active waveguiding properties of Mo6 nano-cluster-doped polymer nanotubes

    NASA Astrophysics Data System (ADS)

    Bigeon, J.; Huby, N.; Amela-Cortes, M.; Molard, Y.; Garreau, A.; Cordier, S.; Bêche, B.; Duvail, J.-L.

    2016-06-01

    We investigate 1D nanostructures based on a Mo6@SU8 hybrid nanocomposite in which photoluminescent Mo6 clusters are embedded in the photosensitive SU8 resist. Tens of micrometers long Mo6@SU8-based tubular nanostructures were fabricated by the wetting template method, enabling the control of the inner and outer diameter to about 190 nm and 240 nm respectively, as supported by structural and optical characterizations. The image plane optical study of these nanotubes under optical pumping highlights the efficient waveguiding phenomenon of the red luminescence emitted by the clusters. Moreover, the wave vector distribution in the Fourier plane determined by leakage radiation microscopy gives additional features of the emission and waveguiding. First, the anisotropic red luminescence of the whole system can be attributed to the guided mode along the nanotube. Then, a low-loss propagation behavior is evidenced in the Mo6@SU8-based nanotubes. This result contrasts with the weaker waveguiding signature in the case of UV210-based nanotubes embedding PFO (poly(9,9-di-n-octylfluorenyl-2,7-diyl)). It is attributed to the strong reabsorption phenomenon, owing to overlapping between absorption and emission bands in the semi-conducting conjugated polymer PFO. These results make this Mo6@SU8 original class of nanocomposite a promising candidate as nanosources for submicronic photonic integration.

  8. Efficient active waveguiding properties of Mo6 nano-cluster-doped polymer nanotubes.

    PubMed

    Bigeon, J; Huby, N; Amela-Cortes, M; Molard, Y; Garreau, A; Cordier, S; Bêche, B; Duvail, J-L

    2016-06-24

    We investigate 1D nanostructures based on a Mo6@SU8 hybrid nanocomposite in which photoluminescent Mo6 clusters are embedded in the photosensitive SU8 resist. Tens of micrometers long Mo6@SU8-based tubular nanostructures were fabricated by the wetting template method, enabling the control of the inner and outer diameter to about 190 nm and 240 nm respectively, as supported by structural and optical characterizations. The image plane optical study of these nanotubes under optical pumping highlights the efficient waveguiding phenomenon of the red luminescence emitted by the clusters. Moreover, the wave vector distribution in the Fourier plane determined by leakage radiation microscopy gives additional features of the emission and waveguiding. First, the anisotropic red luminescence of the whole system can be attributed to the guided mode along the nanotube. Then, a low-loss propagation behavior is evidenced in the Mo6@SU8-based nanotubes. This result contrasts with the weaker waveguiding signature in the case of UV210-based nanotubes embedding PFO (poly(9,9-di-n-octylfluorenyl-2,7-diyl)). It is attributed to the strong reabsorption phenomenon, owing to overlapping between absorption and emission bands in the semi-conducting conjugated polymer PFO. These results make this Mo6@SU8 original class of nanocomposite a promising candidate as nanosources for submicronic photonic integration. PMID:27171341

  9. Waves in a 1D electrorheological dusty plasma lattice

    NASA Astrophysics Data System (ADS)

    Rosenberg, M.

    2015-08-01

    The behavior of waves in a one-dimensional (1D) dusty plasma lattice where the dust interacts via Yukawa and electric dipole interactions is discussed theoretically. This study is motivated by recent reports on electrorheological dusty plasmas (e.g. Ivlev et al. 2008 Phys. Rev. Lett. 100, 095003) where the dipole interaction arises due to an external uniaxial AC electric field that distorts the Debye sphere surrounding each grain. Application to possible dusty plasma experimental parameters is discussed.

  10. Nonreciprocity of edge modes in 1D magnonic crystal

    NASA Astrophysics Data System (ADS)

    Lisenkov, I.; Kalyabin, D.; Osokin, S.; Klos, J. W.; Krawczyk, M.; Nikitov, S.

    2015-03-01

    Spin waves propagation in 1D magnonic crystals is investigated theoretically. Mathematical model based on plane wave expansion method is applied to different types of magnonic crystals, namely bi-component magnonic crystal with symmetric/asymmetric boundaries and ferromagnetic film with periodically corrugated top surface. It is shown that edge modes in magnonic crystals may exhibit nonreciprocal behaviour at much lower frequencies than in homogeneous films.

  11. Excitation of a Parallel Plate Waveguide by an Array of Rectangular Waveguides

    NASA Technical Reports Server (NTRS)

    Rengarajan, Sembiam

    2011-01-01

    This work addresses the problem of excitation of a parallel plate waveguide by an array of rectangular waveguides that arises in applications such as the continuous transverse stub (CTS) antenna and dual-polarized parabolic cylindrical reflector antennas excited by a scanning line source. In order to design the junction region between the parallel plate waveguide and the linear array of rectangular waveguides, waveguide sizes have to be chosen so that the input match is adequate for the range of scan angles for both polarizations. Electromagnetic wave scattered by the junction of a parallel plate waveguide by an array of rectangular waveguides is analyzed by formulating coupled integral equations for the aperture electric field at the junction. The integral equations are solved by the method of moments. In order to make the computational process efficient and accurate, the method of weighted averaging was used to evaluate rapidly oscillating integrals encountered in the moment matrix. In addition, the real axis spectral integral is evaluated in a deformed contour for speed and accuracy. The MoM results for a large finite array have been validated by comparing its reflection coefficients with corresponding results for an infinite array generated by the commercial finite element code, HFSS. Once the aperture electric field is determined by MoM, the input reflection coefficients at each waveguide port, and coupling for each polarization over the range of useful scan angles, are easily obtained. Results for the input impedance and coupling characteristics for both the vertical and horizontal polarizations are presented over a range of scan angles. It is shown that the scan range is limited to about 35 for both polarizations and therefore the optimum waveguide is a square of size equal to about 0.62 free space wavelength.

  12. EEsoF MICAD and ACADEMY macro files for coplanar waveguide and finite ground plan coplanar waveguide

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.

    1995-01-01

    A collection of macro files is presented which when appended to either the EEsoF MICAD.ELE or EEsoF ACADEMY.ELE file permits the layout of coplanar waveguide and finite ground plane coplanar waveguide circuits.

  13. Constructing 3D interaction maps from 1D epigenomes

    PubMed Central

    Zhu, Yun; Chen, Zhao; Zhang, Kai; Wang, Mengchi; Medovoy, David; Whitaker, John W.; Ding, Bo; Li, Nan; Zheng, Lina; Wang, Wei

    2016-01-01

    The human genome is tightly packaged into chromatin whose functional output depends on both one-dimensional (1D) local chromatin states and three-dimensional (3D) genome organization. Currently, chromatin modifications and 3D genome organization are measured by distinct assays. An emerging question is whether it is possible to deduce 3D interactions by integrative analysis of 1D epigenomic data and associate 3D contacts to functionality of the interacting loci. Here we present EpiTensor, an algorithm to identify 3D spatial associations within topologically associating domains (TADs) from 1D maps of histone modifications, chromatin accessibility and RNA-seq. We demonstrate that active promoter–promoter, promoter–enhancer and enhancer–enhancer associations identified by EpiTensor are highly concordant with those detected by Hi-C, ChIA-PET and eQTL analyses at 200 bp resolution. Moreover, EpiTensor has identified a set of interaction hotspots, characterized by higher chromatin and transcriptional activity as well as enriched TF and ncRNA binding across diverse cell types, which may be critical for stabilizing the local 3D interactions. PMID:26960733

  14. Development of 1D Liner Compression Code for IDL

    NASA Astrophysics Data System (ADS)

    Shimazu, Akihisa; Slough, John; Pancotti, Anthony

    2015-11-01

    A 1D liner compression code is developed to model liner implosion dynamics in the Inductively Driven Liner Experiment (IDL) where FRC plasmoid is compressed via inductively-driven metal liners. The driver circuit, magnetic field, joule heating, and liner dynamics calculations are performed at each time step in sequence to couple these effects in the code. To obtain more realistic magnetic field results for a given drive coil geometry, 2D and 3D effects are incorporated into the 1D field calculation through use of correction factor table lookup approach. Commercial low-frequency electromagnetic fields solver, ANSYS Maxwell 3D, is used to solve the magnetic field profile for static liner condition at various liner radius in order to derive correction factors for the 1D field calculation in the code. The liner dynamics results from the code is verified to be in good agreement with the results from commercial explicit dynamics solver, ANSYS Explicit Dynamics, and previous liner experiment. The developed code is used to optimize the capacitor bank and driver coil design for better energy transfer and coupling. FRC gain calculations are also performed using the liner compression data from the code for the conceptual design of the reactor sized system for fusion energy gains.

  15. Enhancing Solar Cell Efficiencies through 1-D Nanostructures

    PubMed Central

    2009-01-01

    The current global energy problem can be attributed to insufficient fossil fuel supplies and excessive greenhouse gas emissions resulting from increasing fossil fuel consumption. The huge demand for clean energy potentially can be met by solar-to-electricity conversions. The large-scale use of solar energy is not occurring due to the high cost and inadequate efficiencies of existing solar cells. Nanostructured materials have offered new opportunities to design more efficient solar cells, particularly one-dimensional (1-D) nanomaterials for enhancing solar cell efficiencies. These 1-D nanostructures, including nanotubes, nanowires, and nanorods, offer significant opportunities to improve efficiencies of solar cells by facilitating photon absorption, electron transport, and electron collection; however, tremendous challenges must be conquered before the large-scale commercialization of such cells. This review specifically focuses on the use of 1-D nanostructures for enhancing solar cell efficiencies. Other nanostructured solar cells or solar cells based on bulk materials are not covered in this review. Major topics addressed include dye-sensitized solar cells, quantum-dot-sensitized solar cells, and p-n junction solar cells.

  16. Examining Prebiotic Chemistry Using O(^1D) Insertion Reactions

    NASA Astrophysics Data System (ADS)

    Hays, Brian M.; Laas, Jacob C.; Weaver, Susanna L. Widicus

    2013-06-01

    Aminomethanol, methanediol, and methoxymethanol are all prebiotic molecules expected to form via photo-driven grain surface chemistry in the interstellar medium (ISM). These molecules are expected to be precursors for larger, biologically-relevant molecules in the ISM such as sugars and amino acids. These three molecules have not yet been detected in the ISM because of the lack of available rotational spectra. A high resolution (sub)millimeter spectrometer coupled to a molecular source is being used to study these molecules using O(^1D) insertion reactions. The O(^1D) chemistry is initiated using an excimer laser, and the products of the insertion reactions are adiabatically cooled using a supersonic expansion. Experimental parameters are being optimized by examination of methanol formed from O(^1D) insertion into methane. Theoretical studies of the structure and reaction energies for aminomethanol, methanediol, and methoxymethanol have been conducted to guide the laboratory studies once the methanol experiment has been optimized. The results of the calculations and initial experimental results will be presented.

  17. Optical bullets in (2+1)D photonic structures and their interaction with localized defects

    NASA Astrophysics Data System (ADS)

    Dohnal, Tomas

    2005-11-01

    This dissertation studies light propagation in Kerr-nonlinear two dimensional waveguides with a Bragg resonant, periodic structure in the propagation direction. The model describing evolution of the electric field envelopes is the system of 2D Nonlinear Coupled Mode Equations (2D CME). The periodic structure induces a range of frequencies (frequency gap) in which linear waves do not propagate. It is shown that, similarly to the ID case of a fiber grating, the 2D nonlinear system supports localized solitary wave solutions, referred to as 2D gap solitons, which have frequencies inside the linear gap and can travel at, any speed smaller than or equal to the speed of light in the corresponding homogeneous medium. Such solutions are constructed numerically via Newton's iteration. Convergence is obtained only near the upper edge of the gap. Gap solitons with a nonzero velocity are constructed by numerically following a bifurcation curve parameterized by the velocity v. It is shown that gap solitons are saddle points of the corresponding Hamiltonian functional and that no (constrained) local minima of the Hamiltonian exist. The linear stability problem is formulated and reasons for the failure of the standard Hamiltonian PDE approach for determining linear stability are discussed. In the second part of the dissertation interaction of 2D gap solitons with localized defects is studied and trapping of slow enough 2D gap solitons is demonstrated. This study builds on [JOSA B 19, 1635 (2002)], where such trapping of 1D gap solitons is considered. Analogously to this 1D problem trapping in the 2D model is explained as a resonant energy transfer into one or more defect modes existent for the particular defect. For special localized defects exact linear modes are found explicitly via the separation of variables. Numerical computation of linear defect modes is used for more general defects. Corresponding nonlinear modes are then constructed via Newton's iteration by following a

  18. Nonreciprocal acousto-optical effect in planar waveguides

    SciTech Connect

    Nanii, Oleg E

    2000-03-31

    The amplitude nonreciprocal effect in planar waveguides during the interaction of waveguide optical modes with a travelling surface acoustic wave was calculated. The possibility of constructing an optical isolator (circulator) by using collinear acousto-optical diffraction with conversion of the type of waveguide mode is demonstrated. (laser applications and other topics in quantum electronics)

  19. Tunneling through a quantum dot in a quantum waveguide

    NASA Astrophysics Data System (ADS)

    Arsen'ev, A. A.

    2010-07-01

    The problem is considered of scattering in a system consisting of a quantum waveguide and a quantum dot weakly coupled to the waveguide. It is assumed that the quantum waveguide is described by the Pauli equations, and the Rashba spin-orbit interaction is taken into account. The possibility of tunneling through the quantum dot is proved.

  20. Strip loaded waveguide on lithium niobate thin films

    NASA Astrophysics Data System (ADS)

    Roussey, Matthieu; Karvinen, Petri; Häyrinen, Markus; Honkanen, Seppo; Kuittinen, Markku

    2016-02-01

    We present the experimental demonstration of a strip loaded waveguide on crystalline lithium niobate thin film. The structure consists in a 1 μm-wide and 200 nm-thick titanium dioxide strip waveguide on a 700 nm lithium niobate slab waveguide. It operates at the telecom wavelength for a TE-polarized light.

  1. Microminiature optical waveguide structure and method for fabrication

    DOEpatents

    Strand, Oliver T.; Deri, Robert J.; Pocha, Michael D.

    1998-01-01

    A method for manufacturing low-cost, nearly circular cross section waveguides comprises starting with a substrate material that a molten waveguide material can not wet or coat. A thin layer is deposited of an opposite material that the molten waveguide material will wet and is patterned to describe the desired surface-contact path pedestals for a waveguide. A waveguide material, e.g., polymer or doped silica, is deposited. A resist material is deposited and unwanted excess is removed to form pattern masks. The waveguide material is etched away to form waveguide precursors and the masks are removed. Heat is applied to reflow the waveguide precursors into near-circular cross-section waveguides that sit atop the pedestals. The waveguide material naturally forms nearly circular cross sections due to the surface tension effects. After cooling, the waveguides will maintain the round shape. If the width and length are the same, then spherical ball lenses are formed. Alternatively, the pedestals can be patterned to taper along their lengths on the surface of the substrate. This will cause the waveguides to assume a conical taper after reflowing by heat.

  2. Microminiature optical waveguide structure and method for fabrication

    DOEpatents

    Strand, O.T.; Deri, R.J.; Pocha, M.D.

    1998-12-08

    A method for manufacturing low-cost, nearly circular cross section waveguides comprises starting with a substrate material that a molten waveguide material can not wet or coat. A thin layer is deposited of an opposite material that the molten waveguide material will wet and is patterned to describe the desired surface-contact path pedestals for a waveguide. A waveguide material, e.g., polymer or doped silica, is deposited. A resist material is deposited and unwanted excess is removed to form pattern masks. The waveguide material is etched away to form waveguide precursors and the masks are removed. Heat is applied to reflow the waveguide precursors into near-circular cross-section waveguides that sit atop the pedestals. The waveguide material naturally forms nearly circular cross sections due to the surface tension effects. After cooling, the waveguides will maintain the round shape. If the width and length are the same, then spherical ball lenses are formed. Alternatively, the pedestals can be patterned to taper along their lengths on the surface of the substrate. This will cause the waveguides to assume a conical taper after reflowing by heat. 32 figs.

  3. Elliptic cylindrical silicon nanowire hybrid surface plasmon polariton waveguide.

    PubMed

    Zhang, Li; Xiong, Qiulin; Li, Xiaopeng; Ma, Junxian

    2015-08-10

    We researched an elliptic cylindrical silicon nanowire hybrid surface plasmon polariton waveguide and evaluated its mode characteristics using the finite element method software COMSOL. The waveguide consists of three parts: an elliptic cylindrical silicon nanowire, a silver film layer, and a silica covering layer between them. All of the components are surrounded by air. After optimizing the geometrical parameters of the waveguide, we can achieve the waveguide's strong field confinement (ranging from λ2/270 to λ2/27) and long propagation distances (119-485 μm). In order to further understand the impact of the waveguide's architecture on its performance, we also studied the ridge hybrid waveguide. The results show that the ridge waveguide has moderate local field confinement ranging from λ2/190 to λ2/20 and its maximum propagation distance is about 340 μm. We compared the elliptic cylindrical and ridge nanowire hybrid waveguides with the cylindrical hybrid waveguide that we studied before. The elliptic cylindrical waveguide achieves a better trade-off between reasonable mode confinement and maximum propagation length in the three waveguides. The researched hybrid surface plasmon polaritons waveguides are useful to construct devices such as a directional coupler and may find potential applications in photonic integrated circuits or other novel SPP devices. PMID:26368373

  4. High-Performance Flexible Waveguiding Photovoltaics

    PubMed Central

    Chou, Chun-Hsien; Chuang, Jui-Kang; Chen, Fang-Chung

    2013-01-01

    The use of flat-plane solar concentrators is an effective approach toward collecting sunlight economically and without sun trackers. The optical concentrators are, however, usually made of rigid glass or plastics having limited flexibility, potentially restricting their applicability. In this communication, we describe flexible waveguiding photovoltaics (FWPVs) that exhibit high optical efficiencies and great mechanical flexibility. We constructed these FWPVs by integrating poly-Si solar cells, a soft polydimethylsiloxane (PDMS) waveguide, and a TiO2-doped backside reflector. Optical microstructures that increase the light harvesting ability of the FWPVs can be fabricated readily, through soft lithography, on the top surface of the PDMS waveguide. Our optimized structure displayed an optical efficiency of greater than 42% and a certified power conversion efficiency (PCE) of 5.57%, with a projected PCE as high as approximately 18%. This approach might open new avenues for the harvesting of solar energy at low cost with efficient, mechanically flexible photovoltaics. PMID:23873225

  5. Temperature-independent silicon subwavelength grating waveguides.

    PubMed

    Schmid, J H; Ibrahim, M; Cheben, P; Lapointe, J; Janz, S; Bock, P J; Densmore, A; Lamontagne, B; Ma, R; Ye, W N; Xu, D-X

    2011-06-01

    We demonstrate, by experiment and numerical calculations, temperature-independent subwavelength grating waveguides with a periodic composite core composed of alternating regions of silicon and SU-8 polymer. The polymer has a negative thermo-optic (TO) material coefficient that cancels the large positive TO effect of the silicon. Measurements and Bloch mode calculations were carried out over a range of silicon-polymer duty ratios. The lowest measured TO coefficient at a wavelength of 1550 nm is 1.8×10(-6) K(-1); 2 orders of magnitude smaller than a conventional silicon photonic wire waveguide. Calculations predict the possibility of complete cancellation of the silicon waveguide temperature dependence. PMID:21633465

  6. Hybrid layered polymer slot waveguide Young interferometer.

    PubMed

    Ahmadi, Leila; Hiltunen, Marianne; Stenberg, Petri; Hiltunen, Jussi; Aikio, Sanna; Roussey, Matthieu; Saarinen, Jyrki; Honkanen, Seppo

    2016-05-16

    We demonstrate a polymer slot waveguide Young interferometer coated with a bilayer of Al2O3/TiO2. The approach enables relaxed dimensions of the polymer waveguide which simplifies the fabrication of the structure with a resolution of 50 nm. The layers were coated by an atomic layer deposition technique. The feasibility of the device was investigated by exploiting the interferometric structure as a bulk refractive index sensor operating at 975 nm wavelength for detection of an ethanol-water solution. A refractive index change of 1 × 10-6 RIU with a sensing length of only 800 µm was detected. The approach confirms the possibility of realizing a low cost device with a small footprint and enhanced sensitivity by employing the TiO2 rails in the sides of the slot waveguide. PMID:27409852

  7. Self-referenced waveguide grating sensor.

    PubMed

    Kehl, Florian; Follonier, Stephane

    2016-04-01

    Like any other sensor system, performances of waveguide grating couplers are affected by adverse effects such as noise and drift, mainly limiting the devices' resolution and long-term stability. It is therefore often required to reference the measurement with a secondary, parallel sensor to decrease these undesired influences. Here we present a simple but effective method to self-reference a label-free waveguide grating coupler by partially coating and thereby passivating the sensitive area with an inert layer. The presented waveguide grating chip design offers the advantage of internal self-referencing for adverse effects, such as inherent system instabilities, mechanical disturbance, or temperature drift, without the need of a sacrificial reference channel. PMID:27192258

  8. Beam waveguides in the Deep Space Network

    NASA Technical Reports Server (NTRS)

    Clauss, R. C.; Smith, J. G.

    1987-01-01

    A beam waveguide is a mechanism for guiding electromagnetic radiation from one part of an antenna to another through a series of reflectors. Appropriate placement of reflectors on an antenna allows a beam to be guided around the elevation axis and/or below the alidade. The beam waveguide permits placement of all electronics in a room on the alidade below the elevation axis, or below the alidade; feed horn covers to be protected from the weather; and feed electronics to be in spacious rooms rather than in crowded cones, and always level rather than tipping with change in elevation angle. These factors can lead to lower costs in implementation such as Ka-band, better antenna performance at X-band, more efficient and stable performance of transmitters and receivers, and lower maintenance and operating costs. Studies are underway to determine methods for converting the major antennas of the Deep Space Network (DSN) to beam waveguide operations by 1995.

  9. Assembly and performance of silicone polymer waveguides

    NASA Astrophysics Data System (ADS)

    Lostutter, Calob K.; Hodge, Malcolm H.; Marrapode, Thomas R.; Swatowski, Brandon W.; Weidner, W. Ken

    2016-03-01

    We report on the functionality and key performance properties of 50 μm x 50 μm flexible graded index silicone polymer waveguides. The materials show low optical propagation losses of < 0.04 dB/cm @ 850 nm over 1 m lengths as well as stability to 2000 hours 85°C/85% relative humidity and 5 cycles of 260°C solder wave reflow testing. Methods to fabricate large area panels are demonstrated for scaled manufacturing of polymer based optical printed wiring boards. The polymer waveguides are terminated with a passive direct fiber attach method. Fully MPO connectorized waveguide panels are realized and their optical performance properties assessed.

  10. Waveguide BEC Interferometry with Painted Potentials

    NASA Astrophysics Data System (ADS)

    Boshier, Malcolm; Lebedev, Vyacheslav; Samson, Carlo; Ryu, Changhyun

    2015-05-01

    Waveguide atom interferometers offer the possibility of long measurement times in a compact geometry, which can be an advantage over free space interferometers if the dephasing due to interatomic interactions can be controlled. We are investigating waveguide BEC interferometers created with the painted potential, a technique which allows for the creation and manipulation of BECs in arbitrary 2D potentials. The goal is to measure a linear acceleration of the device. The painted potential allows new approaches to the initial splitting of the BEC. For example, instead of smoothly deforming a single well potential into a double well, it is possible instead to gradually remove a weak link coupling two initially separated waveguides. This strategy should reduce excitations created in the splitting process. We are currently implementing such schemes and measuring the coherence time of the BEC after division. We will present the results of these measurements, and report progress towards measuring linear accelerations. Supported by LANL/LDRD.

  11. Rethinking the surface of optical waveguides

    NASA Astrophysics Data System (ADS)

    Melati, D.; Morichetti, F.; Grillanda, S.; Annoni, A.; Melloni, A.

    2015-05-01

    The interface between the core and the cladding of optical waveguides exhibits a number of physical phenomena that do not occur in the bulk of the material. For this reason, the behavior of nanoscale devices is expected to be conditioned, or even dominated, by the nature of their surfaces. Roughness-induced losses, backscattering and crosstalk between adjacent waveguides, together with surface states absorption impact on the optical and electrical properties of the waveguides must be considered in the design of any integrated optoelectronic device. The detrimental effects and the possibility of their exploitation are carefully reviewed, presenting in particular the ContacLess Integrated Photonic Probe to be used as transparent power monitor.

  12. Lithium niobate integrated photonic crystal and waveguides

    NASA Astrophysics Data System (ADS)

    Lim, Soon Thor; Ang, Thomas Y.-L.; Png, Ching Eng; Deng, Jun; Danner, Aaron J.

    2016-02-01

    In this work we successfully fabricated and measured PhCs patterned on a LiNbO3 APE waveguide. SIMS data indicate that after 5 hours exchange time a PE layer of 3μm can be obtained. The depth of holes was 2μm by applying a large milling current. We presented experimental characterization of the PhC waveguide and a well-defined PBG was observed from the transmission spectra. An extinction ratio was estimated to be approximately 15dB. Optical transmission results indicate that deep air holes can lead to a sharp band edge. This PhC waveguide is a good candidate for further development of an ultra-compact, low-voltage LiNbO3 modulator.

  13. Experimental investigations on channelized coplanar waveguide

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Ponchak, George E.; Martzaklis, Konstantinas S.; Romanofsky, Robert R.

    1990-01-01

    A new variant of coplanar waveguide (CPW) which was termed channelized coplanar waveguide (CCPW) is presented. Measured propagation characteristics for CCPW such as epsilon(eff) and unloaded Q as a function of geometrical parameters and frequency are presented. The measured and modeled epsilon(eff) are also compared. Equivalent circuit model element values are presented for a CCPW open circuit and a CCPW right angle bend. A CCPW matched T-junction, matched 1:3 junction, and a novel coax-to-CCPW in-phase, N-way, radial power divider are also demonstrated.

  14. Numerical modeling of waveguide heated microwave plasmas

    SciTech Connect

    Venkateswaran, S.; Schwer, D.A.; Merkle, C.L.

    1993-12-01

    Waveguide-heated microwave plasmas for space propulsion applications are analyzed by a two-dimensional numerical solution of the combined Navier-Stokes and Maxwell equations. Two waveguide configurations -- one purely transmitting and the other with a reflecting end wall -- are considered. Plasma stability and absorption characteristics are studied and contrasted with the characteristic of resonant cavity heated plasmas. In addition, preliminary estimates of the overall efficiency and the thrust and specific impulse of the propulsion system are also made. The computational results are used to explain experimental trends and to better understand the working of these devices.

  15. Solitonic optical waveguides in PR crystals

    NASA Astrophysics Data System (ADS)

    Klotz, Matthew Jason

    This dissertation describes a new technique for creating permanent, two-dimensional optical circuitry in bulk ferroelectric photorefractive crystals. This method utilizes steady state photorefractive screening spatial solitons to produce a localized space charge field capable of modulating the spontaneous polarization of the ferroelectric crystal. This localized change in the spontaneous polarization results in a permanent index change within the material that is capable of guiding optical waves. Individual waveguides were formed in the crystal by fixing single screening solitons. The waveguides were found to be identical in size to the soliton responsible for their formation and were observed to efficiently guide light for periods of continuous illumination in excess of 12 hours without degradation. In addition, arrays of waveguides were formed using binary optics to form several solitons in the material at the same time. It was determined that waveguides formed by extraordinarily polarized solitons were single mode and that those formed by ordinarily polarized solitons were multimode, due to the difference in the magnitude of the nonlinear optical properties of the crystal for the different polarization states. Thus the size and mode guiding properties of the fixed waveguides can be controlled by changing the input solitons properties. In addition to single waveguides formed by a single screening soliton, coherent collisions of two screening solitons were used to form a permanent y-junction in the crystal. The screening soliton collision results in two initially independent solitons fusing into a single soliton. After fixing, the resulting waveguide structure allows signals from two distinct inputs to be combined into a single output. It was demonstrated that this fixed structure was bidirectional, i.e. that light sent into the output would exit the original input branches with an even division of power. Again, the size and mode guiding properties were found to

  16. A slotted waveguide antenna with adjustable polarisation

    NASA Astrophysics Data System (ADS)

    Blommendaal, R.; Westerman, B. E.

    A new slotted waveguide antenna has been developed which has adjustable polarization, as well as good control of azimuth patterns, a light weight, and low windage. The design of the antenna is based on three slotted waveguides in a symmetrical configuration, which generate two orthogonal polarizations in a parallel plate region. Two arrays with matched inclined/displaced slots are used for the transverse polarization, while one array with matched edge slots is used for the longitudinal polarization. A corrugated horn is used to obtain equal vertical patterns. A prototype antenna with a 0.5 deg beamwidth and a weight of about 100 kg is presently under construction.

  17. Soft tissue cutting with ultrasonic mechanical waveguides

    NASA Astrophysics Data System (ADS)

    Wylie, Mark. P.; McGuinness, Garrett; Gavin, Graham P.

    2012-05-01

    The use of ultrasonic vibrations transmitted via small diameter wire waveguides represents a technology that has potential for minimally invasive procedures in surgery. This form of energy delivery results in distal tip mechanical vibrations with amplitudes of vibration of up to 50 μm and at frequencies between 20-50 kHz commonly reported. This energy can then be used by micro-cutting surgical tools and end effectors for a range of applications such as bone cutting, cement removal in joint revision surgery and soft tissue cutting. One particular application which has gained regulatory approval in recent years is in the area of cardiovascular surgery in the removal of calcified atherosclerotic plaques and chronic total occlusions. This paper builds on previous work that was focused on the ultrasonic perforation of soft vascular tissue using ultrasonically activated mechanical waveguides and the applied force required to initiate failure in soft tissue when compared with non-ultrasonic waveguides. An ultrasonic device and experimental rig was developed that can deliver ultrasonic vibrations to the distal tip of 1.0 mm diameter nickel-titanium waveguides. The operation of the ultrasonic device has been characterized at 22.5 kHz with achievable amplitudes of vibration in the range of 16 - 40μm. The experimental rig allows the ultrasonically activated waveguide to be advanced through a tissue sample over a range of feedrates and the waveguide-tissue interaction force can be measured during perforation into the tissue. Preliminary studies into the effects of feedrate on porcine aortic arterial tissue perforation forces are presented as part of this work. A range of amplitudes of vibration at the wire waveguide distal tip were examined. The resulting temperature increase when perforating artery wall when using the energized wire waveguides is also examined. Results show a clear multistage failure of the tissue. The first stage involves a rise in force up to some

  18. DIELECTRIC-LOADED WAVE-GUIDES

    DOEpatents

    Robertson-Shersby-Harvie, R.B.; Mullett, L.B.

    1957-04-23

    This patent presents a particular arrangement for delectric loading of a wave-guide carrying an electromagnetic wave in the E or TM mode of at least the second order, to reduce the power dissipated as the result of conduction loss in the wave-guide walls. To achieve this desirabie result, the effective dielectric constants in the radial direction of adjacent coaxial tubular regions bounded approximateiy by successive nodai surfaces within the electromagnetic field are of two different values alternating in the radial direction, the intermost and outermost regions being of the lower value, and the dielectric constants between nodes are uniform.

  19. Null-broadening in a waveguide.

    PubMed

    Kim, J S; Hodgkiss, W S; Kuperman, W A; Song, H C

    2002-07-01

    Null-broadening, introduced in plane wave beamforming, is extended to an ocean waveguide in the context of matched field processing. The method is based on the minimum variance processor with white noise constraint and the distribution of fictitious sources using the theory of waveguide invariants. The proposed method is demonstrated in simulation as well as with data collected during the SWellEx-96 experiment. As another application, it is shown that the width of a null can be controlled in an adaptive time reversal mirror with a source-receive array. PMID:12141344

  20. Nonlinear waves in an Alfven waveguide

    SciTech Connect

    Dmitrienko, I.S.

    1992-06-01

    A nonlinear Schroedinger equation is derived for the envelopes of weakly nonlinear quasilongitudinal (k{sub 1}<{radical}{omega}/{omega}{sub i}k{sub {parallel}}) Alfven waves in a waveguide, the existence of which is ensured by the presence of ion inertia (m{sub i}{ne}0) in a plasma with a transverse density gradient. It is shown that the nonlinear properties of such waves are associated with the presence of transverse structure in the waveguide modes. Estimates show that weakly nonlinear processes can have a significant effect on the dynamics of Pc 1 geomagnetic pulsations. 7 refs.

  1. Forecast analysis of optical waveguide bus performance

    NASA Technical Reports Server (NTRS)

    Ledesma, R.; Rourke, M. D.

    1979-01-01

    Elements to be considered in the design of a data bus include: architecture; data rate; modulation, encoding, detection; power distribution requirements; protocol, work structure; bus reliability, maintainability; interterminal transmission medium; cost; and others specific to application. Fiber- optic data bus considerations for a 32 port transmissive star architecture, are discussed in a tutorial format. General optical-waveguide bus concepts, are reviewed. The electrical and optical performance of a 32 port transmissive star bus, and the effects of temperature on the performance of optical-waveguide buses are examined. A bibliography of pertinent references and the bus receiver test results are included.

  2. Low-Loss Waveguides for Terahertz Frequencies

    NASA Technical Reports Server (NTRS)

    Siegel, Peter; Yeh, Cavour; Shimabukuro, Fred; Fraser, Scott

    2008-01-01

    Hollow-core, periodic bandgap (HCPBG) flexible waveguides have been proposed as a means of low-loss transmission of electromagnetic signals in the frequency range from about 300 GHz to 30 THz. This frequency range has been called the "terahertz gap" because it has been little utilized: Heretofore, there has been no way of low-loss guiding of terahertz beams other than by use of fixed-path optical beam guides with lenses and mirrors or multimode waveguides that cannot maintain mode purity around bends or modest discontinuities.

  3. Waveguide-QED-Based Photonic Quantum Computation

    NASA Astrophysics Data System (ADS)

    Zheng, Huaixiu; Gauthier, Daniel J.; Baranger, Harold U.

    2013-08-01

    We propose a new scheme for quantum computation using flying qubits—propagating photons in a one-dimensional waveguide interacting with matter qubits. Photon-photon interactions are mediated by the coupling to a four-level system, based on which photon-photon π-phase gates (controlled-not) can be implemented for universal quantum computation. We show that high gate fidelity is possible, given recent dramatic experimental progress in superconducting circuits and photonic-crystal waveguides. The proposed system can be an important building block for future on-chip quantum networks.

  4. Bidirectional waveguide coupling with plasmonic Fano nanoantennas

    SciTech Connect

    Guo, Rui; Decker, Manuel Staude, Isabelle; Neshev, Dragomir N.; Kivshar, Yuri S.

    2014-08-04

    We introduce the concept of a bidirectional, compact single-element Fano nanoantenna that allows for directional coupling of light in opposite directions of a high-index dielectric waveguide for two different operation wavelengths. We utilize a Fano resonance to tailor the radiation phases of a gold nanodisk and a nanoslit that is inscribed into the nanodisk to realize bidirectional scattering. We show that this Fano nanoantenna operates as a bidirectional waveguide coupler at telecommunication wavelengths and, thus, is ideally suitable for integrated wavelength-selective light demultiplexing.

  5. Titanium dioxide slot waveguides for visible wavelengths.

    PubMed

    Häyrinen, Markus; Roussey, Matthieu; Säynätjoki, Antti; Kuittinen, Markku; Honkanen, Seppo

    2015-04-01

    We present the first, to our knowledge, experimental demonstration of a titanium dioxide slot waveguide operating in the visible range of light. Ring resonators based on slot waveguides were designed, fabricated, and characterized for λ≃650  nm. The fabrication method includes atomic layer deposition, electron beam lithography, and reactive ion etching. The required narrow slot widths of a few tens of nanometers were achieved by using a conformal atomic layer re-coating technique. This unique feature-size-reduction technique was applied after the final etching step. PMID:25967172

  6. Integrated optical tamper sensor with planar waveguide

    DOEpatents

    Carson, Richard F.; Casalnuovo, Stephen A.

    1993-01-01

    A monolithic optical tamper sensor, comprising an optical emitter and detector, connected by an optical waveguide and placed into the critical entry plane of an enclosed sensitive region, the tamper sensor having a myriad of scraps of a material optically absorbent at the wavelength of interest, such that when the absorbent material is in place on the waveguide, an unique optical signature can be recorded, but when entry is attempted into the enclosed sensitive region, the scraps of absorbent material will be displaced and the optical/electrical signature of the tamper sensor will change and that change can be recorded.

  7. Integrated optical tamper sensor with planar waveguide

    DOEpatents

    Carson, R.F.; Casalnuovo, S.A.

    1993-01-05

    A monolithic optical tamper sensor, comprising an optical emitter and detector, connected by an optical waveguide and placed into the critical entry plane of an enclosed sensitive region, the tamper sensor having a myriad of scraps of a material optically absorbent at the wavelength of interest, such that when the absorbent material is in place on the waveguide, an unique optical signature can be recorded, but when entry is attempted into the enclosed sensitive region, the scraps of absorbent material will be displaced and the optical/electrical signature of the tamper sensor will change and that change can be recorded.

  8. Propagation losses and gain measurements in erbium-doped fluoride glass channel waveguides by use of a double-pass technique.

    PubMed

    Vasilief, Ion; Guy, Stéphan; Jacquier, Bernard; Boulard, Brigitte; Gao, You Ping; Duverger, Claire; Haquin, Hervé; Nazabal, Virginie; Adam, Jean-Luc; Couchaud, Maurice; Fulbert, Laurent; Cassagnettes, Cédric; Rooms, Frédéric; Barbier, Denis

    2005-08-01

    We have studied Er3+, Yb3+, and Ce3+ codoped microchannel waveguides that were developed by two methods: ionic exchange for heavy metal fluoride glasses [ZrF4-BaF2-AlF3-CeF3 (ZBAC)] and vapor phase deposition for transition metal fluoride glasses [PbF2-ZnF2-GaF3 (PZG)] by using a double-pass technique. For the first time to our knowledge, the measurement of propagation losses and amplification tests were carried out by use of the same experimental setup, leading to complete characterization of the waveguides. Net gains higher than 1 dB/cm were achieved in ZBAC Er/Ce single-mode fluoride glass waveguides. PMID:16078378

  9. Nonlinear evolution equations for surface plasmons for nano-focusing at a Kerr/metallic interface and tapered waveguide

    NASA Astrophysics Data System (ADS)

    Crutcher, Sihon H.; Osei, Albert; Biswas, Anjan

    2012-06-01

    Maxwell's equations for a metallic and nonlinear Kerr interface waveguide at the nanoscale can be approximated to a (1+1) D Nonlinear Schrodinger type model equation (NLSE) with appropriate assumptions and approximations. Theoretically, without losses or perturbations spatial plasmon solitons profiles are easily produced. However, with losses, the amplitude or beam profile is no longer stationary and adiabatic parameters have to be considered to understand propagation. For this model, adiabatic parameters are calculated considering losses resulting in linear differential coupled integral equations with constant definite integral coefficients not dependent on the transverse and longitudinal coordinates. Furthermore, by considering another configuration, a waveguide that is an M-NL-M (metal-nonlinear Kerr-metal) that tapers, the tapering can balance the loss experienced at a non-tapered metal/nonlinear Kerr interface causing attenuation of the beam profile, so these spatial plasmon solitons can be produced. In this paper taking into consideration the (1+1)D NLSE model for a tapered waveguide, we derive a one soliton solution based on He's Semi-Inverse Variational Principle (HPV).

  10. Single rolled-up InGaAs/GaAs quantum dot microtubes integrated with silicon-on-insulator waveguides.

    PubMed

    Tian, Zhaobing; Veerasubramanian, Venkat; Bianucci, Pablo; Mukherjee, Shouvik; Mi, Zetian; Kirk, Andrew G; Plant, David V

    2011-06-20

    We report on single rolled-up microtubes integrated with silicon-on-insulator waveguides. Microtubes with diameters of ~7 μm, wall thicknesses of ~250 nm, and lengths greater than 100 μm are fabricated by selectively releasing a coherently strained InGaAs/GaAs quantum dot layer from the handling GaAs substrate. The microtubes are then transferred from their host substrate to silicon-on-insulator waveguides by an optical fiber abrupt taper. The Q-factor of the waveguide coupled microtube is measured to be 1.5×10(5), the highest recorded for a semiconductor microtube cavity to date. The insertion loss and extinction ratio of the microtube are 1 dB and 34 dB respectively. By pumping the microtube with a 635 nm laser, the resonance wavelength is shifted by 0.7 nm. The integration of InGaAs/GaAs microtubes with silicon-on-insulator waveguides provides a simple, low loss, high extinction passive filter solution in the C+L band communication regime. PMID:21716453

  11. GPR waveguide and full-waveform inversion for the hydrogeophysical characterization of soils and aquifers

    NASA Astrophysics Data System (ADS)

    Van Der Kruk, J.; Mangel, A. R.; Gueting, N.; Busch, S.; Klotzsche, A.; Moysey, S. M.; Huisman, J. A.; Vereecken, H.

    2015-12-01

    Ground-penetrating radar (GPR) is a powerful tool for characterizing hydrologic processes. Coupled hydrogeophysical inversion can be used to invert time-lapse GPR data to obtain soil hydraulic properties. However, the inversion will fail if the hydrological model is not appropriately conceptualized, or when the ray-based methods that are often used to limit the computation time are not appropriate. Ray-based approaches cannot be used in the case of wetting fronts in the vadose zone due to precipitation/infiltration or thawing events, where low-velocity layers with high water content can trap the GPR waves and act as a waveguide such that multiple internal reflections cause dispersion. Utilizing the dispersion, manifested as a singled appearance of arrivals on multi-offset data, we can invert for waveguide properties. Single- or two-layer waveguide inversion approaches return average water contents but are incapable of representing the gradational nature of the water content distribution of the shallow subsurface. Recently, a shuffled complex evolution algorithm was implemented that used a piece-wise linear function to closely match the shallow gradational water content profile present for early-time infiltration events for different n-parameter values of the Mualem-van Genuchten equation using HYDRUS-1D. Similar waveguide phenomena can arise in the presence of high porosity layers in saturated aquifers for crosshole GPR. These high porosity layers result in significant late arrival high-amplitude elongated wave trains that were detected in crosshole data from the Widen, Boise and Krauthausen aquifers. Full-waveform inversion of these data that uses an accurate forward model to explain the measured data is able to return decimeter scale resolution of the porosity based on the GPR velocity. With increasing computer power, it is expected that these advanced processing can be soon included in the coupled inversion approaches.

  12. Transversal Anderson localization of sound in acoustic waveguide arrays.

    PubMed

    Ye, Yangtao; Ke, Manzhu; Feng, Junheng; Wang, Mudi; Qiu, Chunyin; Liu, Zhengyou

    2015-04-22

    We present designs of one-dimensional acoustic waveguide arrays and investigate wave propagation inside. Under the condition of single identical waveguide mode and weak coupling, the acoustic wave motion in waveguide arrays can be modeled with a discrete mode-coupling theory. The coupling constants can be retrieved from simulations or experiments as the function of neighboring waveguide separations. Sound injected into periodic arrays gives rise to the discrete diffraction, exhibiting ballistic or extended transport in transversal direction. But sound injected into randomized waveguide arrays readily leads to Anderson localization transversally. The experimental results show good agreement with simulations and theoretical predictions. PMID:25812602

  13. Linear-array ultrasonic waveguide transducer for under sodium viewing.

    SciTech Connect

    Sheen, S. H.; Chien, H. T.; Wang, K.; Lawrence, W. P.; Engel, D.; Nuclear Engineering Division

    2010-09-01

    In this report, we first present the basic design of a low-noise waveguide and its performance followed by a review of the array transducer technology. The report then presents the concept and basic designs of arrayed waveguide transducers that can apply to under-sodium viewing for in-service inspection of fast reactors. Depending on applications, the basic waveguide arrays consist of designs for sideway and downward viewing. For each viewing application, two array geometries, linear and circular, are included in design analysis. Methods to scan a 2-D target using a linear array waveguide transducer are discussed. Future plan to develop a laboratory array waveguide prototype is also presented.

  14. Waveguide Power-Amplifier Module for 80 to 150 GHz

    NASA Technical Reports Server (NTRS)

    Samoska, Lorene; Weinreb, Sander; Peralta, Alejandro

    2006-01-01

    A waveguide power-amplifier module capable of operating over the frequency range from 80 to 150 GHz has been constructed. The module comprises a previously reported power amplifier packaged in a waveguide housing that is compatible with WR-8 waveguides. (WR- 8 is a standard waveguide size for the nominal frequency range from 90 to 140 GHz.) The waveguide power-amplifier module is robust and can be bolted to test equipment and to other electronic circuits with which the amplifier must be connected for normal operation.

  15. Mode imaging and loss evaluation of semiconductor waveguides

    SciTech Connect

    Mochizuki, Toshimitsu; Kim, Changsu; Yoshita, Masahiro; Nakamura, Takahiro; Akiyama, Hidefumi; Pfeiffer, Loren N.; West, Ken W.

    2014-05-15

    An imaging and loss evaluation method for semiconductor waveguides coupled with non-doped quantum wells is presented. Using the internal emission of the wells as a probe light source, the numbers and widths of the modes of waveguides with various ridge sizes were evaluated by CCD imaging, and the obtained values were consistent with effective index method calculation. Waveguide internal losses were obtained from analyses of the Fabry-Pérot fringes of waveguide emission spectra. We quantified the quality of 29 single-mode waveguide samples as an internal loss and variation of 10.2 ± 0.6  cm{sup −1}.

  16. Compact waveguide power divider with multiple isolated outputs

    DOEpatents

    Moeller, Charles P.

    1987-01-01

    A waveguide power divider (10) for splitting electromagnetic microwave power and directionally coupling the divided power includes an input waveguide (21) and reduced height output waveguides (23) interconnected by axial slots (22) and matched loads (25) and (26) positioned at the unused ends of input and output guides (21) and (23) respectively. The axial slots are of a length such that the wave in the input waveguide (21) is directionally coupled to the output waveguides (23). The widths of input guide (21) and output guides (23) are equal and the width of axial slots (22) is one half of the width of the input guide (21).

  17. Polarization rotation and coupling between silicon waveguide and hybrid plasmonic waveguide

    PubMed Central

    Kim, Sangsik; Qi, Minghao

    2015-01-01

    We present a polarization rotation and coupling scheme that rotates a TE0 mode in a silicon waveguide and simultaneously couples the rotated mode to a hybrid plasmonic (HP0) waveguide mode. Such a polarization rotation can be realized with a partially etched asymmetric hybrid plasmonic waveguide consisting of a silicon strip waveguide, a thin oxide spacer, and a metal cap made from copper, gold, silver or aluminum. Two implementations, one with and one without the tapering of the metal cap are presented, and different taper shapes (linear and exponential) are also analyzed. The devices have large 3 dB conversion bandwidths (over 200 nm at near infrared) and short length (< 5 μm), and achieve a maximum coupling factor of ∼ 78% with a linearly tapered silver metal cap. PMID:25969038

  18. Extended-Range Ultrarefractive 1D Photonic Crystal Prisms

    NASA Technical Reports Server (NTRS)

    Ting, David Z.

    2007-01-01

    A proposal has been made to exploit the special wavelength-dispersive characteristics of devices of the type described in One-Dimensional Photonic Crystal Superprisms (NPO-30232) NASA Tech Briefs, Vol. 29, No. 4 (April 2005), page 10a. A photonic crystal is an optical component that has a periodic structure comprising two dielectric materials with high dielectric contrast (e.g., a semiconductor and air), with geometrical feature sizes comparable to or smaller than light wavelengths of interest. Experimental superprisms have been realized as photonic crystals having three-dimensional (3D) structures comprising regions of amorphous Si alternating with regions of SiO2, fabricated in a complex process that included sputtering. A photonic crystal of the type to be exploited according to the present proposal is said to be one-dimensional (1D) because its contrasting dielectric materials would be stacked in parallel planar layers; in other words, there would be spatial periodicity in one dimension only. The processes of designing and fabricating 1D photonic crystal superprisms would be simpler and, hence, would cost less than do those for 3D photonic crystal superprisms. As in 3D structures, 1D photonic crystals may be used in applications such as wavelength-division multiplexing. In the extended-range configuration, it is also suitable for spectrometry applications. As an engineered structure or artificially engineered material, a photonic crystal can exhibit optical properties not commonly found in natural substances. Prior research had revealed several classes of photonic crystal structures for which the propagation of electromagnetic radiation is forbidden in certain frequency ranges, denoted photonic bandgaps. It had also been found that in narrow frequency bands just outside the photonic bandgaps, the angular wavelength dispersion of electromagnetic waves propagating in photonic crystal superprisms is much stronger than is the angular wavelength dispersion obtained

  19. Non-linearity in Bayesian 1-D magnetotelluric inversion

    NASA Astrophysics Data System (ADS)

    Guo, Rongwen; Dosso, Stan E.; Liu, Jianxin; Dettmer, Jan; Tong, Xiaozhong

    2011-05-01

    This paper applies a Bayesian approach to examine non-linearity for the 1-D magnetotelluric (MT) inverse problem. In a Bayesian formulation the posterior probability density (PPD), which combines data and prior information, is interpreted in terms of parameter estimates and uncertainties, which requires optimizing and integrating the PPD. Much work on 1-D MT inversion has been based on (approximate) linearized solutions, but more recently fully non-linear (numerical) approaches have been applied. This paper directly compares results of linearized and non-linear uncertainty estimation for 1-D MT inversion; to do so, advanced methods for both approaches are applied. In the non-linear formulation used here, numerical optimization is carried out using an adaptive-hybrid algorithm. Numerical integration applies Metropolis-Hastings sampling, rotated to a principal-component parameter space for efficient sampling of correlated parameters, and employing non-unity sampling temperatures to ensure global sampling. Since appropriate model parametrizations are generally not known a priori, both under- and overparametrized approaches are considered. For underparametrization, the Bayesian information criterion is applied to determine the number of layers consistent with the resolving power of the data. For overparametrization, prior information is included which favours simple structure in a manner similar to regularized inversion. The data variance and/or trade-off parameter regulating data and prior information are treated in several ways, including applying fixed optimal estimates (an empirical Bayesian approach) or including them as hyperparameters in the sampling (hierarchical Bayesian). The latter approach has the benefit of accounting for the uncertainty in the hyperparameters in estimating model parameter uncertainties. Non-linear and linearized inversion results are compared for synthetic test cases and for the measured COPROD1 MT data by considering marginal probability

  20. Spatial coherence of polaritons in a 1D channel

    SciTech Connect

    Savenko, I. G.; Iorsh, I. V.; Kaliteevski, M. A.; Shelykh, I. A.

    2013-01-15

    We analyze time evolution of spatial coherence of a polariton ensemble in a quantum wire (1D channel) under constant uniform resonant pumping. Using the theoretical approach based on the Lindblad equation for a one-particle density matrix, which takes into account the polariton-phonon and excitonexciton interactions, we study the behavior of the first-order coherence function g{sup 1} for various pump intensities and temperatures in the range of 1-20 K. Bistability and hysteresis in the dependence of the first-order coherence function on the pump intensity is demonstrated.