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Sample records for all-optical switching devices

  1. All-optical switching of magnetoresistive devices using telecom-band femtosecond laser

    SciTech Connect

    He, Li; Chen, Jun-Yang; Wang, Jian-Ping E-mail: moli@umn.edu; Li, Mo E-mail: moli@umn.edu

    2015-09-07

    Ultrafast all-optical switching of the magnetization of various magnetic systems is an intriguing phenomenon that can have tremendous impact on information storage and processing. Here, we demonstrate all-optical switching of GdFeCo alloy films using a telecom-band femtosecond fiber laser. We further fabricate Hall cross devices and electrically readout all-optical switching by measuring anomalous Hall voltage changes. The use of a telecom laser and the demonstrated all-optical switching of magnetoresistive devices represent the first step toward integration of opto-magnetic devices with mainstream photonic devices to enable novel optical and spintronic functionalities.

  2. Fast all-optical switch

    NASA Technical Reports Server (NTRS)

    Shay, Thomas M. (Inventor); Poliakov, Evgeni Y. (Inventor); Hazzard, David A. (Inventor)

    2001-01-01

    An apparatus and method wherein polarization rotation in alkali vapors or other mediums is used for all-optical switching and digital logic and where the rate of operation is proportional to the amplitude of the pump field. High rates of speed are accomplished by Rabi flopping of the atomic states using a continuously operating monochromatic atomic beam as the pump.

  3. All-optical switching with 1-ps response time in a DDMEBT enabled silicon grating coupler/resonator hybrid device.

    PubMed

    Covey, John; Finke, Aaron D; Xu, Xiaochuan; Wu, Wenzhi; Wang, Yaguo; Diederich, François; Chen, Ray T

    2014-10-01

    An amorphous film of the third-order nonlinear optical material DDMEBT was spun onto silicon chips for the first time, filling 80 nm lithographic features. A 710 μm² device was designed, fabricated, and tested that acts both as a nonlinear resonator switch and as an input/output grating coupler to a perfectly vertical single mode fiber. Autocorrelation and spectral measurements indicate the device has <1 ps response time, 4 nm of switching bandwidth, and 4 dB of on/off contrast. With sufficient power, this all-optical device can potentially modulate a single optical carrier frequency in excess of 1 THz.

  4. Self-assembled InAs quantum dots within a vertical cavity structure for all-optical switching devices

    NASA Astrophysics Data System (ADS)

    Jin, C. Y.; Kojima, O.; Inoue, T.; Kita, T.; Wada, O.; Hopkinson, M.; Akahane, K.

    2010-02-01

    An all-optical switching device has been proposed by using self-assembled InAs/GaAs quantum dots (QDs) within a vertical cavity structure for ultrafast optical communications. This device has several desirable properties, such as the ultra-low power consumption, the micrometre size, and the polarization insensitive operation. Due to the threedimensional confined carrier state and the broad size distribution of self-assembled InAs/GaAs QDs, it is crucial to enhance the interaction between QDs and the cavity with appropriately designed 1D periodic structure. Significant QD/cavity nonlinearity is theoretically observed by increasing the GaAs/AlAs pair number of the bottom mirror. By this consideration, we have fabricated vertical-reflection type QD switches with 12 periods of GaAs/Al0.8Ga0.2As for the top mirror and 25 periods for the bottom mirror to give an asymmetric vertical cavity. Optical switching via the QD excited state exhibits a fast switching process with a time constant down to 23 ps, confirming that the fast intersubband relaxation of carriers inside QDs is an effective means to speed up the switching process. A technique by changing the light incident angle realizes wavelength tunability over 30 nm for the QD/cavity switch.

  5. All optical switching in henna thin film

    NASA Astrophysics Data System (ADS)

    Henari, Fryad Z.; Jasim, Khalil E.

    2013-08-01

    The optical nonlinearity in henna (Lawson (2- hydroxyl-1,4 naphthoquinone) film was utilized to demonstrate all optical switching. The nonlinear absorption of the henna film was calculated by measuring the transmission of the laser beam ( λ = 488 nm) as a function of incident light intensities. The observed nonlinear absorption is attributed to a two-photon absorption process. The pump and probe technique was used to demonstrate all optical switching. The switching characteristics can be utilized to generate all-optical logic gates such as simple inverter switches (NOT) NOR, AND NAND logic functions.

  6. Monolithically integrated nonlinear interferometers for all-optical switching

    SciTech Connect

    Jahn, E.; Agrawal, N.; Ehrke, H.J.; Pieper, W.; Franke, D.; Fuerst, W.; Weinert, C.M.

    1996-12-31

    All-optical switching devices are expected to play an important role in future optical communication networks. For example, nonlinear interferometer (NLI) arrangements consisting of one or two semiconductor laser amplifiers (SLA) are very attractive. Here, the cross-phase modulation due to the gain-saturation nonlinearity of SLAs could be used for switching in time, space, and wavelength domains. The first of such devices was configured as a nonlinear Sagnac interferometer (NSI) by using an SLA in a fiber loop mirror (SLALOM) for time domain switching. So far, these devices have been assembled using discrete SLA components. Other arrangements like Mach-Zehnder interferometer (MZI) with SLAs provide additional flexibility but require their realization as integrated devices for stable operation. In this paper the authors report on the development of monolithically integrated NLIs for all-optical signal processing in high bit-rate optical time division multiplexing systems. Both NSI and MZI configurations are considered.

  7. Design of all-optical, hot-electron current-direction-switching device based on geometrical asymmetry.

    PubMed

    Kumarasinghe, Chathurangi S; Premaratne, Malin; Gunapala, Sarath D; Agrawal, Govind P

    2016-01-01

    We propose a nano-scale current-direction-switching device(CDSD) that operates based on the novel phenomenon of geometrical asymmetry between two hot-electron generating plasmonic nanostructures. The proposed device is easy to fabricate and economical to develop compared to most other existing designs. It also has the ability to function without external wiring in nano or molecular circuitry since it is powered and controlled optically. We consider a such CDSD made of two dissimilar nanorods separated by a thin but finite potential barrier and theoretically derive the frequency-dependent electron/current flow rate. Our analysis takes in to account the quantum dynamics of electrons inside the nanorods under a periodic optical perturbation that are confined by nanorod boundaries, modelled as finite cylindrical potential wells. The influence of design parameters, such as geometric difference between the two nanorods, their volumes and the barrier width on quality parameters such as frequency-sensitivity of the current flow direction, magnitude of the current flow, positive to negative current ratio, and the energy conversion efficiency is discussed by considering a device made of Ag/TiO2/Ag. Theoretical insight and design guidelines presented here are useful for customizing our proposed CDSD for applications such as self-powered logic gates, power supplies, and sensors. PMID:26887286

  8. Design of all-optical, hot-electron current-direction-switching device based on geometrical asymmetry

    PubMed Central

    Kumarasinghe, Chathurangi S.; Premaratne, Malin; Gunapala, Sarath D.; Agrawal, Govind P.

    2016-01-01

    We propose a nano-scale current-direction-switching device(CDSD) that operates based on the novel phenomenon of geometrical asymmetry between two hot-electron generating plasmonic nanostructures. The proposed device is easy to fabricate and economical to develop compared to most other existing designs. It also has the ability to function without external wiring in nano or molecular circuitry since it is powered and controlled optically. We consider a such CDSD made of two dissimilar nanorods separated by a thin but finite potential barrier and theoretically derive the frequency-dependent electron/current flow rate. Our analysis takes in to account the quantum dynamics of electrons inside the nanorods under a periodic optical perturbation that are confined by nanorod boundaries, modelled as finite cylindrical potential wells. The influence of design parameters, such as geometric difference between the two nanorods, their volumes and the barrier width on quality parameters such as frequency-sensitivity of the current flow direction, magnitude of the current flow, positive to negative current ratio, and the energy conversion efficiency is discussed by considering a device made of Ag/TiO2/Ag. Theoretical insight and design guidelines presented here are useful for customizing our proposed CDSD for applications such as self-powered logic gates, power supplies, and sensors. PMID:26887286

  9. Design of all-optical, hot-electron current-direction-switching device based on geometrical asymmetry

    NASA Astrophysics Data System (ADS)

    Kumarasinghe, Chathurangi S.; Premaratne, Malin; Gunapala, Sarath D.; Agrawal, Govind P.

    2016-02-01

    We propose a nano-scale current-direction-switching device(CDSD) that operates based on the novel phenomenon of geometrical asymmetry between two hot-electron generating plasmonic nanostructures. The proposed device is easy to fabricate and economical to develop compared to most other existing designs. It also has the ability to function without external wiring in nano or molecular circuitry since it is powered and controlled optically. We consider a such CDSD made of two dissimilar nanorods separated by a thin but finite potential barrier and theoretically derive the frequency-dependent electron/current flow rate. Our analysis takes in to account the quantum dynamics of electrons inside the nanorods under a periodic optical perturbation that are confined by nanorod boundaries, modelled as finite cylindrical potential wells. The influence of design parameters, such as geometric difference between the two nanorods, their volumes and the barrier width on quality parameters such as frequency-sensitivity of the current flow direction, magnitude of the current flow, positive to negative current ratio, and the energy conversion efficiency is discussed by considering a device made of Ag/TiO2/Ag. Theoretical insight and design guidelines presented here are useful for customizing our proposed CDSD for applications such as self-powered logic gates, power supplies, and sensors.

  10. All-optical nonlinear switching cell made of photonic crystal.

    PubMed

    Wirth Lima, A; da Silva, Marcio G; Ferreira, A C; Sombra, A S B

    2009-07-01

    We analyze and propose a directional optical coupler embedded in photonic crystal, which is driven by an external command signal. Therefore, this switching cell can work in an all-optical switch. The switching method uses a low-power external command signal, inserted in the central coupling region, which acts as another waveguide. The switching process is based on the change from the bar state to the cross state due to the external command signal. In our simulations we used the plane wave expansion method, finite-difference time-domain method, and our own binary propagation method.

  11. All-optical switching in optically induced nonlinear waveguide couplers

    SciTech Connect

    Diebel, Falko Boguslawski, Martin; Rose, Patrick; Denz, Cornelia; Leykam, Daniel; Desyatnikov, Anton S.

    2014-06-30

    We experimentally demonstrate all-optical vortex switching in nonlinear coupled waveguide arrays optically induced in photorefractive media. Our technique is based on multiplexing of nondiffracting Bessel beams to induce various types of waveguide configurations. Using double- and quadruple-well potentials, we demonstrate precise control over the coupling strength between waveguides, the linear and nonlinear dynamics and symmetry-breaking bifurcations of guided light, and a power-controlled optical vortex switch.

  12. Bandwidth analysis of all-optical turbo-switch

    NASA Astrophysics Data System (ADS)

    Zhou, Peng; Yang, Xuelin; Hu, Xiaonan; Hu, Weisheng

    2015-01-01

    We propose and develop a frequency-domain model to analyze the bandwidth of all-optical turbo-switch. The model has taken the spatial inhomogeneity of semiconductor optical amplifier (SOA) into consideration for the first time. The simulations based on the model show that the 3-dB bandwidth of turbo-switch could reach up to ~270 GHz when the second SOA is oversaturated. However, the overshoot will be higher, which may result in the distortion of the output signal. There is a trade-off between the bandwidth and the flatness of frequency response characteristics for turbo-switch operation. In addition, the optimum position of the delay-interferometer (DI) is investigated, showing that the level of the overshoot is relatively lower if the DI is placed between the two SOAs.

  13. Enhanced all-optical switching with double slow light pulses

    NASA Astrophysics Data System (ADS)

    Lin, Chi-Ching; Wu, Meng-Chang; Shiau, Bor-Wen; Chen, Yi-Hsin; Yu, Ite A.; Chen, Yong-Fan; Chen, Ying-Cheng

    2012-12-01

    We experimentally demonstrate an all-optical switching (AOS) scheme based on double slow light (DSL) pulses, in which one pulse is switched by another due to the cross-Kerr nonlinearity. The interaction time is prolonged by optically dense atomic media and matched group velocities. The interaction strength is maintained at a high level by keeping both fields at their electromagnetically-induced-transparency resonances to minimize the linear loss. In the AOS without the DSL scheme, the group velocity mismatch sets an upper limit on the switching efficiency of two photons per atomic cross section as discussed by Harris and Hau [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.82.4611 82, 4611 (1999)]. Compared to that limit, we have obtained an enhanced switching efficiency by a factor of 3 with our DSL scheme. The nonlinear efficiency can be further improved by increasing the optical depth of the medium. Our work advances low-light-level nonlinear optics and provides essential ingredients for quantum many-body physics using strongly interacting photons.

  14. Resource allocation in circuit-switched all-optical networks

    NASA Astrophysics Data System (ADS)

    Marquis, Douglas; Barry, Richard A.; Finn, Steven G.; Parikh, Salil A.; Swanson, Eric A.; Thomas, Robert E.

    1996-03-01

    We describe an all-optical network testbed deployed in the Boston area, and research surrounding the allocation of optical resources -- frequencies and time slots -- within the network. The network was developed by a consortium of AT&T Bell Laboratories, Digital Equipment Corporation, and Massachusetts Institute of Technology under a grant from ARPA. The network is organized as a hierarchy consisting of local, metropolitan, and wide area nodes tea support optical broadcast and routing modes. Frequencies are shared and reused to enhance network scalability. Electronic access is provided through optical terminals that support multiple services having data rates between 10 Mbps/user and 10 Gbps/user. Of particular interest for this work is the 'B-service,' which simultaneously hops frequency and time slots on each optical terminal to allow frequency sharing within the AON. B-service provides 1.244 Gbps per optical terminal, with bandwidth for individual connections divided in increments as small as 10 Mbps. We have created interfaces between the AON and commercially available electronic circuit-switched and packet-switched networks. The packet switches provide FDDI (datacomm), T3 (telecomm), and ATM/SONET switching at backplane rates of over 3 Gbps. We show results on network applications that dynamically allocate optical bandwidth between electronic packet-switches based on the offered load presented by users. Bandwidth allocation granularity is proportional to B-Service slots (10-1244 Mbps), and switching times are on the order of one second. We have also studied the effects of wavelength changers upon the network capacity and blocking probabilities in wide area all-optical networks. Wavelength changers allow a change in the carrier frequency (within the network) without disturbing the data modulation. The study includes both a theoretical model of blocking probabilities based on network design parameters, and a computer simulation of blocking in networks with and

  15. All-optical transistor action with bistable switching in a photonic crystal cross-waveguide geometry.

    PubMed

    Yanik, Mehmet Fatih; Fan, Shanhui; Soljacić, Marin; Joannopoulos, J D

    2003-12-15

    We demonstrate all-optical switching action in a nonlinear photonic crystal cross-waveguide geometry with instantaneous Kerr nonlinearity, in which the transmission of a signal can be reversibly switched on and off by a control input. Our geometry accomplishes both spatial and spectral separation between the signal and the control in the nonlinear regime. The device occupies a small footprint of a few micrometers squared and requires only a few milliwatts of power at a 10-Gbit/s switching rate by use of Kerr nonlinearity in AlGaAs below half the electronic bandgap. We also show that the switching dynamics, as revealed by both coupled-mode theory and finite-difference time domain simulations, exhibits collective behavior that can be exploited to generate high-contrast logic levels and all-optical memory.

  16. Passive all-optical polarization switch, binary logic gates, and digital processor.

    PubMed

    Zaghloul, Y A; Zaghloul, A R M; Adibi, A

    2011-10-10

    We introduce the passive all-optical polarization switch, which modulates light with light. That switch is used to construct all the binary logic gates of two or more inputs. We discuss the design concepts and the operation of the AND, OR, NAND, and NOR gates as examples. The rest of the 16 logic gates are similarly designed. Cascading of such gates is straightforward as we show and discuss. Cascading in itself does not require a power source, but feedback at this stage of development does. The design and operation of an SR Latch is presented as one of the popular basic sequential devices used for memory cells. That completes the essential components of an all-optical polarization digital processor. The speed of such devices is well above 10 GHz for bulk implementations and is much higher for chip-size implementations. In addition, the presented devices do have the four essential characteristics previously thought unique to the microelectronic ones.

  17. Ultrafast, broadband, and configurable midinfrared all-optical switching in nonlinear graphene plasmonic waveguides

    NASA Astrophysics Data System (ADS)

    Ooi, Kelvin J. A.; Cheng, J. L.; Sipe, J. E.; Ang, L. K.; Tan, Dawn T. H.

    2016-07-01

    Graphene plasmonics provides a unique and excellent platform for nonlinear all-optical switching, owing to its high nonlinear conductivity and tight optical confinement. In this paper, we show that impressive switching performance on graphene plasmonic waveguides could be obtained for both phase and extinction modulations at sub-MW/cm2 optical pump intensities. Additionally, we find that the large surface-induced nonlinearity enhancement that comes from the tight confinement effect can potentially drive the propagating plasmon pump power down to the pW range. The graphene plasmonic waveguides have highly configurable Fermi-levels through electrostatic-gating, allowing for versatility in device design and a broadband optical response. The high capabilities of nonlinear graphene plasmonics would eventually pave the way for the adoption of the graphene plasmonics platform in future all-optical nanocircuitry.

  18. Software Defined Networking (SDN) controlled all optical switching networks with multi-dimensional switching architecture

    NASA Astrophysics Data System (ADS)

    Zhao, Yongli; Ji, Yuefeng; Zhang, Jie; Li, Hui; Xiong, Qianjin; Qiu, Shaofeng

    2014-08-01

    Ultrahigh throughout capacity requirement is challenging the current optical switching nodes with the fast development of data center networks. Pbit/s level all optical switching networks need to be deployed soon, which will cause the high complexity of node architecture. How to control the future network and node equipment together will become a new problem. An enhanced Software Defined Networking (eSDN) control architecture is proposed in the paper, which consists of Provider NOX (P-NOX) and Node NOX (N-NOX). With the cooperation of P-NOX and N-NOX, the flexible control of the entire network can be achieved. All optical switching network testbed has been experimentally demonstrated with efficient control of enhanced Software Defined Networking (eSDN). Pbit/s level all optical switching nodes in the testbed are implemented based on multi-dimensional switching architecture, i.e. multi-level and multi-planar. Due to the space and cost limitation, each optical switching node is only equipped with four input line boxes and four output line boxes respectively. Experimental results are given to verify the performance of our proposed control and switching architecture.

  19. All-optical swapping of spectral amplitude code labels for packet-switched networks

    NASA Astrophysics Data System (ADS)

    Chen, Lawrence R.

    2008-08-01

    Packet-switched networks have attracted considerable attention as a basis for next-generation optical networks due to their advantages in terms of flexibility and network efficiency over traditional circuit-switched networks. Optical code multi-protocol label switching (OC-MPLS) promises fast, flexible, power-efficient switching by keeping signals in the optical domain and avoiding costly conversions to the electrical domain. In this paper, we review the use of spectral amplitude codes (SACs) for implementing OC-MPLS labels. We discuss the principles and features, as well as key enabling technologies required for their processing. In particular, we compare three different approaches for low cost all-optical swapping of SAC labels. All approaches are based on semiconductor fiber lasers and exploit nonlinearity in a semiconductor device: the first uses cross-absorption modulation in an electroabsorption modulator, the second uses cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA), and the third makes use of XGM in an SOA as well as injection locking in a Fabry-Pérot laser. We present the static and dynamic responses of each for swapping a multi-wavelength input label to a multi-wavelength output label. The benefits and limitations of each approach as well as future improvements are discussed. We also present the results of systems experiments which demonstrate error-free all-optical label swapping, recognition, and switching of multi-rate packets in packet-switched networks using multi-wavelength labels.

  20. ZnO nanowire-based all-optical switch with Reset-Set flip-flop function

    NASA Astrophysics Data System (ADS)

    Mu, L. X.; Shi, W. S.; Zhang, T. P.; Zhang, H. Y.; Wang, Y.; She, G. W.; Gao, Y. H.; Wang, P. F.; Chang, J. C.; Lee, S. T.

    2011-04-01

    An all-optical switch with Reset-Set (RS) flip-flop function has been developed by attaching a derivative of spiropyran on the surface of zinc oxide (ZnO) Nanowire. Using UV/visible irradiation and the fluorescence of spiropyran-modified ZnO nanowire as inputs—set/reset and output, RS flip-flop function can be performed on a single ZnO nanowire or a nanowire array. The configuration of the current all-optical switch represents a potential for developing small-sized all-optical devices, which could be further exploited at higher level of integration.

  1. Electrical characterization of all-optical helicity-dependent switching in ferromagnetic Hall crosses

    NASA Astrophysics Data System (ADS)

    El Hadri, M. S.; Pirro, P.; Lambert, C.-H.; Bergeard, N.; Petit-Watelot, S.; Hehn, M.; Malinowski, G.; Montaigne, F.; Quessab, Y.; Medapalli, R.; Fullerton, E. E.; Mangin, S.

    2016-02-01

    We present an experimental study of all-optical helicity-dependent switching (AO-HDS) of ferromagnetic Pt/Co/Pt heterostructures with perpendicular magnetic anisotropy. The sample is patterned into a Hall cross and the AO-HDS is measured via the anomalous Hall effect. This all-electrical probing of the magnetization during AO-HDS enables a statistical quantification of the switching ratio for different laser parameters, such as the threshold power to achieve AO-HDS and the exposure time needed to reach complete switching at a given laser power. We find that the AO-HDS is a cumulative process, a certain number of optical pulses is needed to obtain a full and reproducible helicity-dependent switching. The deterministic switching of the ferromagnetic Pt/Co/Pt Hall cross provides a full "opto-spintronic device," where the remanent magnetization can be all-optically and reproducibly written and erased without the need of an external magnetic field.

  2. All-optical 2-bit header recognition and packet switching using polarization bistable VCSELs.

    PubMed

    Hayashi, Daisuke; Nakao, Kazuya; Katayama, Takeo; Kawaguchi, Hitoshi

    2015-04-01

    We propose and evaluate an all-optical 2-bit header recognition and packet switching method using two 1.55-µm polarization bistable vertical-cavity surface-emitting lasers (VCSELs) and three optical switches. Polarization bistable VCSELs acted as flip-flop devices by using AND-gate operations of the header and set pulses, together with the reset pulses. Optical packets including 40-Gb/s non-return-to-zero pseudo-random bit-sequence payloads were successfully sent to one of four ports according to the state of two bits in the headers with a 4-bit 500-Mb/s return-to-zero format. The input pulse powers were 17.2 to 31.8 dB lower than the VCSEL output power. We also examined an extension of this method to multi-bit header recognition and packet switching.

  3. Energy-bandwidth trade-off in all-optical photonic crystal microcavity switches.

    PubMed

    Heuck, Mikkel; Kristensen, Philip Trøst; Mørk, Jesper

    2011-09-12

    The performance of all-optical switches is a compromise between the achievable bandwidth of the switched signal and the energy requirement of the switching operation. In this work we consider a system consisting of a photonic crystal cavity coupled to two input and two output waveguides. As a specific example of a switching application, we investigate the demultiplexing of an optical time division multiplexed signal. To quantify the energy-bandwidth trade-off, we introduce a figure of merit for the detection of the demultiplexed signal. In such investigations it is crucial to consider patterning effects, which occur on time scales that are longer than the bit period. Our analysis is based on a coupled mode theory, which allows for an extensive investigation of the influence of the system parameters on the switching dynamics. The analysis is shown to provide new insights into the ultrafast dynamics of the switching operation, and the results show optimum parameter ranges that may serve as design guidelines in device fabrication.

  4. On the size-dependent magnetism and all-optical magnetization switching of transition-metal silicide nanostructures

    SciTech Connect

    Glushkov, G. I.; Tuchin, A. V.; Popov, S. V.; Bityutskaya, L. A.

    2015-12-15

    Theoretical investigations of the electronic structure, synthesis, and all-optical magnetization switching of transition-metal silicide nanostructures are reported. The magnetic moment of the nanostructures is studied as a function of the silicide cluster size and configuration. The experimentally demonstrated magnetization switching of nanostructured nickel silicide by circularly polarized light makes it possible to create high-speed storage devices with high density data recording.

  5. All-optical switching in a symmetric three-waveguide coupler with phase-mismatched absorptive central waveguide.

    PubMed

    Chen, Yijing; Ho, Seng-Tiong; Krishnamurthy, Vivek

    2013-12-20

    All-optical switching operation based on manipulation of absorption in a three-waveguide directional coupler is theoretically investigated. The proposed structure consists of one absorptive central waveguide and two identical passive side waveguides. Optically induced absorption change in the central waveguide effectively controls the coupling of light between the two side waveguides, leading to optical switching action. The proposed architecture alleviates the fabrication challenges and waveguide index matching conditions that limit previous demonstrations of similar switching schemes based on a two-waveguide directional coupler. The proposed device accommodates large modal index difference between absorptive and passive waveguides without compromising the switching extinction ratio.

  6. Integration of photonic nanojets and semiconductor nanoparticles for enhanced all-optical switching

    PubMed Central

    Born, Brandon; Krupa, Jeffrey D. A.; Geoffroy-Gagnon, Simon; Holzman, Jonathan F.

    2015-01-01

    All-optical switching is the foundation of emerging all-optical (terabit-per-second) networks and processors. All-optical switching has attracted considerable attention, but it must ultimately support operation with femtojoule switching energies and femtosecond switching times to be effective. Here we introduce an all-optical switch architecture in the form of a dielectric sphere that focuses a high-intensity photonic nanojet into a peripheral coating of semiconductor nanoparticles. Milli-scale spheres coated with Si and SiC nanoparticles yield switching energies of 200 and 100 fJ with switching times of 10 ps and 350 fs, respectively. Micro-scale spheres coated with Si and SiC nanoparticles yield switching energies of 1 pJ and 20 fJ with switching times of 2 ps and 270 fs, respectively. We show that femtojoule switching energies are enabled by localized photoinjection from the photonic nanojets and that femtosecond switching times are enabled by localized recombination within the semiconductor nanoparticles. PMID:26314911

  7. Effect of pH on all-optical switching with bR films

    NASA Astrophysics Data System (ADS)

    Fimia, A.; Gomariz, M.; Murciano, A.; Acebal, P.; Madrigal, R.; Blaya, S.; Carretero, L.; Alemañ, R.; Meseguer, I.

    2012-06-01

    Protein Bacteriorhodopsin (bR) is one of the most promising and widely studied biomaterials for photonic applications like optical storage, modulation devices and photosynthetic light energy transduction. In this paper, we present the corresponding experimental results when pH-controlled modifications of bR doped polymeric films are realized in order to apply these systems to all-optical switching processes and technologies. In this work, the performance of wild type bR processed in polymeric films with different pH was tested in several series of experiments by varying the pump beam (532 nm) period of ON and OFF and analyzing the amplitude contrast and switching time of the probe beam (633 nm). The influence of pH values on contrast ratio and switching time were also discussed and the optimal value was found by defining a new parameter called "switching speed". As a result, the variation of pH can be used to obtain different time of response and speed of modulation. Concretely, we find that, in function of pH, variations of a magnitude order in contrast ratio and time response can be obtained. So, at the red region of the probe beam, high pH values produce high transmission with flat response in the contrast ratio and a magnitude order variation in switching time. On the other hand, at medium pH values and when high intensities are used, the switching time and contrast ratio are better. Moreover, it is demonstrated that as a function of the wavelength of the probe beam the transmission response curve changes. Absorption response is very important and depends on relaxation time processes of intermediate species which are function of pH values. Therefore, these results bring the possibility for controlling the contrast ratio and the switching time in a specific way which could be useful for different applications.

  8. Numerical investigation of an all-optical switch in a graded nonlinear plasmonic grating.

    PubMed

    Wang, Guoxi; Lu, Hua; Liu, Xueming; Gong, Yongkang

    2012-11-01

    We have proposed and numerically investigated an all-optical switch based on a metal-insulator-metal waveguide with graded nonlinear plasmonic gratings. The influences of grating depth and refractive index of a Kerr nonlinear medium on the transmission of the switch are exactly analyzed by utilizing transmission line theory. The finite-difference time-domain simulation results show that the highly compact structure possesses excellent switch function by tuning the incident electric field intensity. In addition, the simulation results show that this all-optical switch has an ultrawide operating frequency regime and femtosecond-scale response time (~130 fs). Such a switch can find potential applications for all-optical signal processing and optical communication.

  9. Two types of all-optical magnetization switching mechanisms using femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    El Hadri, M. S.; Pirro, P.; Lambert, C.-H.; Petit-Watelot, S.; Quessab, Y.; Hehn, M.; Montaigne, F.; Malinowski, G.; Mangin, S.

    2016-08-01

    Using a time-dependent electrical investigation of the all-optical switching in ferrimagnetic and ferromagnetic Hall crosses via the anomalous Hall effect, intriguing insights into the rich physics underlying the all-optical switching are provided. We demonstrate that two different all-optical magnetization switching mechanisms can be distinguished; a "single pulse" switching for ferrimagnetic GdFeCo alloys, and a "two regimes" switching process for both ferrimagnetic TbCo alloys and ferromagnetic Pt/Co multilayers. We show that the latter takes place at two different time scales, and consists of a steplike helicity-independent multiple-domain formation within the first 1 ms followed by a helicity-dependent remagnetization on several tens of milliseconds.

  10. Study on all-optical switching characteristics of ethyl orange-doped polymer film

    NASA Astrophysics Data System (ADS)

    Xu, Tang; Zhang, Chunping; Lin, Yu; Qi, Shengwen

    2008-10-01

    The all-optical switching polymer thin films with azobenzene dye ethyl orange as the guest material and polyvinyl alcohol (PVA) as the host material were prepared by adulteration and spin-coating methods. The all-optical switching characteristics of the samples were measured at different intensities and modulation frequencies of the pump beam (532 nm, CW); the influence of doping concentration on the all-optical switching effect of the films was studied. It is shown that, under room temperature conditions and with a low pump power of 6 mW, the all-optical switch has a response time of about 2 ms and a modulation depth of 45%, and the maximal modulation depth reaches 90%. In addition, it is found that samples with higher doping concentration show a stronger all-optical switching effect but a larger background signal, and good switching performance is obtained by choosing the doping concentrations from 0.8% to 2% of the sample.

  11. On the fly all-optical packet switching based on hybrid WDM/OCDMA labeling scheme

    NASA Astrophysics Data System (ADS)

    Brahmi, Houssem; Giannoulis, Giannis; Menif, Mourad; Katopodis, Vasilis; Kalavrouziotis, Dimitrios; Kouloumentas, Christos; Groumas, Panos; Kanakis, Giannis; Stamatiadis, Christos; Avramopoulos, Hercules; Erasme, Didier

    2014-02-01

    We introduce a novel design of an all-optical packet routing node that allows for the selection and forwarding of optical packets based on the routing information contained in hybrid wavelength division multiplexing/optical code division multiple access (WDM/OCDMA) labels. A stripping paradigm of optical code-label is adopted. The router is built around an optical-code gate that consists in an optical flip-flop controlled by two fiber Bragg grating correlators and is combined with a Mach-Zehnder interferometer (MZI)-based forwarding gate. We experimentally verify the proof-of-principle operation of the proposed self-routing node under NRZ and OCDMA packet traffic conditions. The successful switching of elastic NRZ payload at 40 Gb/s controlled by DS-OCDMA coded labels and the forwarding operation of encoded data using EQC codes are presented. Proper auto-correlation functions are obtained with higher than 8.1 dB contrast ratio, suitable to efficiently trigger the latching device with a contrast ratio of 11.6 dB and switching times below 3.8 ns. Error-free operation is achieved with 1.5 dB penalty for 40 Gb/s NRZ data and with 2.1 dB penalty for DS-OCDMA packets. The scheme can further be applied to large-scale optical packet switching networks by exploiting efficient optical coders allocated at different WDM channels.

  12. All-optical switching based on nonradiative effects in doped fibers

    NASA Astrophysics Data System (ADS)

    Davis, Monica Karin

    1999-10-01

    Doped fibers are used for many purposes in fiber-optic communications and fiber sensors. These applications rely on the stimulated electronic transitions of dopant ions to produce a desired effect, such as gain (erbium doped fiber amplifiers and fiber lasers), refractive index modulation (switching) or absorption (fiber attenuators). In most devices it is advantageous to use short doped fiber lengths containing large numbers of dopant ions. However, high dopant concentrations are often accompanied by significant nonradiative decay processes that produce other effects, either beneficial or undesirable. The understanding of these nonradiative processes is critical to most doped fiber devices. In this dissertation we report the first comprehensive study of the effects of nonradiative processes in optically pumped, highly doped fibers. We have developed a new method to measure the size and relative abundance of clusters in rare-earth-doped fibers. This enables us to predict the extent of nonradiative, heat-producing processes in these fibers. We have also developed analytical and numerical models to quantify the dynamic evolution of the temperature profile in the fiber and to predict the thermal phase modulation in the fiber due to this temperature increase. Ours is the first analysis to fully describe the thermal effects created in doped fibers in both the single short pump pulse regime and the continuous pumping regime, as well as in intermediate modes of operation. We have designed methods to determine the presence and extent of nonradiative decay mechanisms and to differentiate them from nonlinear optical effects. We present this analysis and experimental verification of our model using high concentration cobalt- and vanadium- doped fibers. Finally, we have expanded the number of configurations available for all-optical switching by developing both the analysis of the pumped nonlinear directional coupler (PNLDC) and the analysis of the self- terminating Sagnac loop

  13. Ultrafast defect dynamics: A new approach to all optical broadband switching employing amorphous selenium thin films

    SciTech Connect

    Sharma, Rituraj; Adarsh, K. V. E-mail: adarsh@iiserb.ac.in; Prasai, Kiran; Drabold, D. A. E-mail: adarsh@iiserb.ac.in

    2015-07-15

    Optical switches offer higher switching speeds than electronics, however, in most cases utilizing the interband transitions of the active medium for switching. As a result, the signal suffers heavy losses. In this article, we demonstrate a simple and yet efficient ultrafast broadband all-optical switching on ps timescale in the sub-bandgap region of the a-Se thin film, where the intrinsic absorption is very weak. The optical switching is attributed to short-lived transient defects that form localized states in the bandgap and possess a large electron-phonon coupling. We model these processes through first principles simulation that are in agreement with the experiments.

  14. A 2*4 all optical decoder switch based on photonic crystal ring resonators

    NASA Astrophysics Data System (ADS)

    Alipour-Banaei, Hamed; Mehdizadeh, Farhad; Serajmohammadi, Somaye; Hassangholizadeh-Kashtiban, Mahdi

    2015-03-01

    Based on photonic crystal ring resonators and nonlinear Kerr effect in this paper, we proposed a 2*4 all optical decoder switch. Our proposed structure has two logic input ports and one bias input port. This decoder switch has four output ports. Via these two logic input ports, we control the bias signal to transfer toward which output port. We employed numerical methods such as plane wave expansion and finite difference time domain methods for analyzing the proposed structure.

  15. Carrier transport in an InGaAs(P)/InP all-optical switching structure

    SciTech Connect

    Knorr, C.; Wilhelm, U.; Ottenwaelder, D.; Scholz, F.; Hangleiter, A.

    1996-12-31

    All-optical switches play a central role in optical computing and optical data processing. SEEDs (self electro-optic effect devices) are one class of devices, which work at low optical power, but need an external electrical feedback. The authors presented a specially designed SCMQW structure, where hole transport is controlled by an additional large heterobarrier. This barrier gives access to steady state escape times by measuring the charge carrier induced field change in the MWQ region. The authors get a minimum value for the hole extraction time over the barrier of several {micro}s at 77 K. At a temperature of 200 K the measured time constants lie below the values, which their rate equation model and the semi-classical model predict, and show a stronger field dependence. This could be accounted for thermally assisted tunneling and contribution of light hole transport, which both reduce the effective barrier height and show a stronger field dependence. Further investigations of the transport times are currently in progress by changing the thickness of the InP barrier and the barrier height of the quaternary material.

  16. Nanoresonator Enabled Ultrafast All-optical Terahertz Switching Based on Vanadium Dioxide Thin Film

    NASA Astrophysics Data System (ADS)

    Kyoung, J. S.; Choi, S. B.; Kim, H. S.; Kim, B. J.; Ahn, Y. H.; Kim, H. T.; Kim, D. S.

    2011-12-01

    We demonstrate nanoresonator enabled ultrafast all-optical switching of terahertz transmission based on phase transition of vanadium dioxide (VO2) thin film. Nanoresonators, nm-width slot antenna patterns on the gold layer, are fabricated on the VO2 films. Without nanoresonators, THz wave shows negligible change through bare VO2 film even though optical pumping exists, while about 20 percents switching ratio is clearly seen with nanoresonator patterns on the VO2. The switching time is in a few hundreds femtosecond time scales.

  17. Model for multishot all-thermal all-optical switching in ferromagnets

    NASA Astrophysics Data System (ADS)

    Gorchon, J.; Yang, Y.; Bokor, J.

    2016-07-01

    All-optical magnetic switching (AOS) is a recently observed rich and puzzling phenomenon that offers promising technological applications. However, a fundamental understanding of the underlying mechanisms remains elusive. Here we present a model for multishot helicity-dependent AOS in ferromagnetic materials based on a purely heat-driven mechanism in the presence of magnetic circular dichroism (MCD). We predict that AOS should be possible with as little as 0.5% of MCD, after a minimum number of laser shots heat the sample close to the Curie temperature. Finally, we qualitatively reproduce the all-optically switched domain patterns observed experimentally by numerically simulating the result of multiple laser shots on an FePtC granular ferromagnetic film.

  18. Realization of all-optical switch and diode via Raman gain process using a Kerr field

    NASA Astrophysics Data System (ADS)

    Abbas, Muqaddar; Qamar, Sajid; Qamar, Shahid

    2016-08-01

    The idea of optical photonic crystal, which is generated using two counter-propagating fields, is revisited to study gain-assisted all-optical switch and diode using Kerr field. Two counter-propagating fields with relative detuning Δ ν generate standing-wave field pattern which interacts with a four-level atomic system. The standing-wave field pattern acts like a static photonic crystal for Δ ν =0 , however, it behaves as a moving photonic crystal for Δ ν \

  19. Nanoscale Confinement of All-Optical Magnetic Switching in TbFeCo

    NASA Astrophysics Data System (ADS)

    Liu, Tianmin; Wang, Tianhan; Reid, Alexander; Savoini, Matteo; Wu, Xiaofei; Konene, Benny; Granitzka, Patrick; Graves, Catherine; Higley, Daniel; Chen, Zhao; Razinskas, Gary; Hantschmann, Markus; Scherz, Andreas; Stohr, Joachim; Tsukamoto, Arata; Hecht, Bert; Kimel, Alexey; Kirilyuk, Andrei; Rasing, Theo; Durr, Hermann; Durr/Stohr Team; Theo Rasing Team; Arata Tsukamoto Team; Bert Hecht Team

    Gold two-wire antennas structures are placed upon the surface of the all-optical switching film TbFeCo. They resonate with the optical field and create a field enhancement in its vicinity, which is used to confine the area where optical switching can occur. It is demonstrated that single femtosecond optical laser pulses can reverse magnetization in a controllable fashion by such confinement. The magnetic states are imaged using resonant X-ray holography and magnetic circular dichroism. The results not only show the feasibility of controllable switching with antenna assistance but also demonstrate the highly inhomogeneous nature of the switching process, which is attributed to the material's heterogeneity. Research is supported by U.S. DOE, Office of Basic Energy Sciences, Materials Sciences and Engineering Division.

  20. Quantum optics. All-optical routing of single photons by a one-atom switch controlled by a single photon.

    PubMed

    Shomroni, Itay; Rosenblum, Serge; Lovsky, Yulia; Bechler, Orel; Guendelman, Gabriel; Dayan, Barak

    2014-08-22

    The prospect of quantum networks, in which quantum information is carried by single photons in photonic circuits, has long been the driving force behind the effort to achieve all-optical routing of single photons. We realized a single-photon-activated switch capable of routing a photon from any of its two inputs to any of its two outputs. Our device is based on a single atom coupled to a fiber-coupled, chip-based microresonator. A single reflected control photon toggles the switch from high reflection (R ~ 65%) to high transmission (T ~ 90%), with an average of ~1.5 control photons per switching event (~3, including linear losses). No additional control fields are required. The control and target photons are both in-fiber and practically identical, making this scheme compatible with scalable architectures for quantum information processing.

  1. Design of SOA-MZI based all-optical programmable logic device (PLD)

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Tanay; Roy, Jitendra Nath

    2010-06-01

    Photon being the ultimate unit of information with unmatched speed and with data package in a signal of zero mass, the techniques of computing with light may provide a way out of the limitations of computational speed and complexity inherent in electronics computing. Information processing with photon as information carrying signal has shown a high level potentiality through the researches in last few decades. The driving force behind this evolution has been the utilization of interferometric configurations that employ a semiconductor optical amplifier (SOA) as the nonlinear element in combination with cross-phase modulation to achieve switching by means of light. Here, in this paper we present an all-optical circuit of programmable logic device (PLD) with the help of SOA-MZI (Mach-Zehnder interferometer) based optical tree-structured splitter. Numerical simulation result confirming described method is reported here. This paper also explains the applicability of this scheme to perform logical and arithmetic operations in all-optical domain.

  2. Free-carrier contribution to all-optical switching in Mie-resonant hydrogenated amorphous silicon nanodisks

    NASA Astrophysics Data System (ADS)

    Vabishchevich, Polina P.; Shorokhov, Alexander S.; Shcherbakov, Maxim R.; Fedyanin, Andrey A.

    2016-03-01

    Conventionally, all-optical switching devices made out from bulk silicon and other semiconductors are limited by free-carrier relaxation time which spans from picoseconds to microseconds. In this work, we discuss the possibility to suppress the undesired long free-carrier relaxation in subwavelength dielectric nanostructures exhibiting localized magnetic Mie resonances. Numerical calculations show the unsymmetrical modification of the transmittance spectra of the nanodisks due the free carriers photo-injection. Such a spectral dependance allows to control temporal response of the nanostructure by varying the laser pulse spectum.

  3. Nanoscale sub-100 picosecond all-optical magnetization switching in GdFeCo microstructures.

    PubMed

    Le Guyader, L; Savoini, M; El Moussaoui, S; Buzzi, M; Tsukamoto, A; Itoh, A; Kirilyuk, A; Rasing, T; Kimel, A V; Nolting, F

    2015-01-01

    Ultrafast magnetization reversal driven by femtosecond laser pulses has been shown to be a promising way to write information. Seeking to improve the recording density has raised intriguing fundamental questions about the feasibility of combining ultrafast temporal resolution with sub-wavelength spatial resolution for magnetic recording. Here we report on the experimental demonstration of nanoscale sub-100 ps all-optical magnetization switching, providing a path to sub-wavelength magnetic recording. Using computational methods, we reveal the feasibility of nanoscale magnetic switching even for an unfocused laser pulse. This effect is achieved by structuring the sample such that the laser pulse, via both refraction and interference, focuses onto a localized region of the structure, the position of which can be controlled by the structural design. Time-resolved photo-emission electron microscopy studies reveal that nanoscale magnetic switching employing such focusing can be pushed to the sub-100 ps regime. PMID:25581133

  4. Phase-sensitive fiber-based parametric all-optical switch.

    PubMed

    Parra-Cetina, Josué; Kumpera, Aleš; Karlsson, Magnus; Andrekson, Peter A

    2015-12-28

    We experimentally demonstrate, for the first time, an all-optical switch in a phase-sensitive fiber optic parametric amplifier operated in saturation. We study the effect of phase variation of the signal and idler waves on the pump power depletion. By changing the phase of a 0.9 mW signal/idler pair wave by π/2 rad, a pump power extinction ratio of 30.4 dB is achieved. Static and dynamic characterizations are also performed and time domain results presented. PMID:26832007

  5. Nanopattern enabled terahertz all-optical switching on vanadium dioxide thin film

    NASA Astrophysics Data System (ADS)

    Choi, S. B.; Kyoung, J. S.; Kim, H. S.; Park, H. R.; Park, D. J.; Kim, Bong-Jun; Ahn, Y. H.; Rotermund, F.; Kim, Hyun-Tak; Ahn, K. J.; Kim, D. S.

    2011-02-01

    We demonstrate ultrafast all-optical control of terahertz (THz) radiation through nanoresonators, slot antennas with a hundred micron length but submicron width in thin gold layers, fabricated on vanadium dioxide (VO2) thin films. Our THz nanoresonators show almost perfect transmission at resonance. By virtue of phase transition of VO2 from insulating to metallic state, induced in subpicosecond time scale by moderate optical pump, ultrafast control of THz transmission is enabled. This is compared to bare VO2 films where no switching dynamics are observed under similar conditions.

  6. All-optical encryption based on interleaved waveband switching modulation for optical network security.

    PubMed

    Fok, Mable P; Prucnal, Paul R

    2009-05-01

    All-optical encryption for optical code-division multiple-access systems with interleaved waveband-switching modulation is experimentally demonstrated. The scheme explores dual-pump four-wave mixing in a 35 cm highly nonlinear bismuth oxide fiber to achieve XOR operation of the plaintext and the encryption key. Bit 0 and bit 1 of the encrypted data are represented by two different wavebands. Unlike on-off keying encryption methods, the encrypted data in this approach has the same intensity for both bit 0 and bit 1. Thus no plaintext or ciphertext signatures are observed.

  7. All-optical packet header and payload separation for un-slotted optical packet switched networks

    NASA Astrophysics Data System (ADS)

    Ji, Wei; Zhang, Min; Ye, Peida

    2005-11-01

    A novel all-optical header and payload separation technique that can be utilized in un-slotted optical packet switched networks is presented. The technique uses a modified TOAD for packet header extraction with differential modulation scheme and two SOAs that perform a simple XOR operation between the packet and its self-derived header to get the separated payload. The main virtue of this system is simple structure and need not any additional continuous pulses. Through numerical simulations, the operating characteristics of the scheme are illustrated. In addition, the parameters of the system are discussed and designed to optimize the operation performance.

  8. Laser-induced Bessel beams can realize fast all-optical switching in gold nanosol prepared by pulsed laser ablation

    SciTech Connect

    Joseph, Santhi Ani; Hari, Misha; Nampoori, V. P. N.; Sharma, Gaurav; Mathew, S.; Radhakrishnan, P.

    2010-03-15

    We demonstrate the possibility of realizing, all-optical switching in gold nanosol. Two overlapping laser beams are used for this purpose, due to which a low-power beam passing collinear to a high-power beam will undergo cross phase modulation and thereby distort the spatial profile. This is taken to advantage for performing logic operations. We have also measured the threshold pump power to obtain a NOT gate and the minimum response time of the device. Contrary to the general notion that the response time of thermal effects used in this application is of the order of milliseconds, we prove that short pump pulses can result in fast switching. Different combinations of beam splitters and combiners will lead to the formation of other logic functions too.

  9. 25th anniversary article: Design of polymethine dyes for all-optical switching applications: guidance from theoretical and computational studies.

    PubMed

    Gieseking, Rebecca L; Mukhopadhyay, Sukrit; Risko, Chad; Marder, Seth R; Brédas, Jean-Luc

    2014-01-01

    All-optical switching--controlling light with light--has the potential to meet the ever-increasing demand for data transmission bandwidth. The development of organic π-conjugated molecular materials with the requisite properties for all-optical switching applications has long proven to be a significant challenge. However, recent advances demonstrate that polymethine dyes have the potential to meet the necessary requirements. In this review, we explore the theoretical underpinnings that guide the design of π-conjugated materials for all-optical switching applications. We underline, from a computational chemistry standpoint, the relationships among chemical structure, electronic structure, and optical properties that make polymethines such promising materials.

  10. Integrated all-optical logic and arithmetic operations with the help of a TOAD-based interferometer device--alternative approach

    NASA Astrophysics Data System (ADS)

    Nath Roy, Jitendra; Gayen, Dilip Kumar

    2007-08-01

    Interferometric devices have drawn a great interest in all-optical signal processing for their high-speed photonic activity. The nonlinear optical loop mirror provides a major support to optical switching based all-optical logic and algebraic operations. The gate based on the terahertz optical asymmetric demultiplexer (TOAD) has added new momentum in this field. Optical tree architecture (OTA) plays a significant role in the optical interconnecting network. We have tried to exploit the advantages of both OTA- and TOAD-based switches. We have proposed a TOAD-based tree architecture, a new and alternative scheme, for integrated all-optical logic and arithmetic operations.

  11. A simple and effective theory for all-optical helicity-dependent spin switching

    NASA Astrophysics Data System (ADS)

    Zhang, Guoping; Bai, Yihua; George, Thomas F.

    All-optical helicity-dependent spin switching (AOS) represents a new frontier in magnetic recording technology, where a single ultrafast laser pulse, without any assistance from an external magnetic field, can permanently switch spin within a few hundred femtoseconds. By contrast, the existing theory does rely on an artificial magnetic field to switch spins. Here we develop a microscopic spin switch theory, free of any artificial field, and demonstrate unambiguously that both circularly and linearly polarized lights can switch spins faithfully. Our theory is based on the Hookean theory, but includes two new elements: spin-orbit coupling and exchange interaction. We predict that left (right) circularly polarized light only flips (flops) spin, a symmetry constraint that strongly favors ferrimagnetic orderings over ferromagnetic ones, with the allowable exchange interaction within 10 meV, consistent with all prior theories. The effect of the laser amplitude is highly nonlinear: If it is too weak, AOS does not occur, but if too strong, the spin cants; a compromise between them produces a narrow spin reversal window as observed experimentally. We envision that our model can be easily extended to describe spin frustrated systems and multiferroics, where the light-spin interaction Supported by the U.S. Department of Energy under Contract No. DE-FG02-06ER46304 and the National Energy Research Scientific Computing Center.

  12. All-optical Mach-Zehnder interferometer switching based on the phase-shift multiplication effect of an analog on the electromagnetically induced transparency effect

    NASA Astrophysics Data System (ADS)

    Wang, Boyun; Xiong, Liangbin; Zeng, Qingdong; Chen, Zhihong; Lv, Hao; Ding, Yaoming; Du, Jun; Yu, Huaqing

    2016-06-01

    We theoretically and numerically investigate all-optical Mach-Zehnder interferometer switching based on the phase-shift multiplication effect of an all-optical analog on the electromagnetically induced transparency effect. The free-carrier plasma dispersion effect modulation method is applied to improve the tuning rate with a response time of picoseconds. All observed schemes are analyzed rigorously through finite-difference time-domain simulations and coupled-mode formalism. Compared with no phase-shift multiplication effect, the average pump power of all-optical switching required to yield the π-phase shift difference decreases by 55.1%, and the size of the modulation region is reduced by 50.1% when the average pump power reaches 60.8 mW. This work provides a new direction for low-power consumption and miniaturization of microstructure integration light-controlled switching devices in optical communication and quantum information processing.

  13. All-optical Mach-Zehnder interferometer switching based on the phase-shift multiplication effect of an analog on the electromagnetically induced transparency effect

    NASA Astrophysics Data System (ADS)

    Wang, Boyun; Xiong, Liangbin; Zeng, Qingdong; Chen, Zhihong; Lv, Hao; Ding, Yaoming; Du, Jun; Yu, Huaqing

    2016-06-01

    We theoretically and numerically investigate all-optical Mach-Zehnder interferometer switching based on the phase-shift multiplication effect of an all-optical analog on the electromagnetically induced transparency effect. The free-carrier plasma dispersion effect modulation method is applied to improve the tuning rate with a response time of picoseconds. All observed schemes are analyzed rigorously through finite-difference time-domain simulations and coupled-mode formalism. Compared with no phase-shift multiplication effect, the average pump power of all-optical switching required to yield the π-phase shift difference decreases by 55.1%, and the size of the modulation region is reduced by 50.1% when the average pump power reaches 60.8 mW. This work provides a new direction for low-power consumption and miniaturization of microstructure integration light-controlled switching devices in optical communication and quantum information processing.

  14. Deterministic character of all-optical magnetization switching in GdFe-based ferrimagnetic alloys

    NASA Astrophysics Data System (ADS)

    Le Guyader, L.; El Moussaoui, S.; Buzzi, M.; Savoini, M.; Tsukamoto, A.; Itoh, A.; Kirilyuk, A.; Rasing, Th.; Nolting, F.; Kimel, A. V.

    2016-04-01

    Using photoemission electron microscopy with x-ray magnetic circular dichroism as a contrast mechanism, new insights into the all-optical magnetization switching (AOS) phenomenon in GdFe-based rare-earth transition-metal ferrimagnetic alloys are provided. From a sequence of static images taken after single linearly polarized laser pulse excitation, the repeatability of AOS can be quantified with a correlation coefficient. It is found that low coercivity enables thermally activated domain-wall motion, limiting in turn the repeatability of the switching. Time-resolved measurements of the magnetization dynamics reveal that while AOS occurs below and above the magnetization compensation temperature TM, it is not observed in GdFe samples where TM is absent. Finally, AOS is experimentally demonstrated against an applied magnetic field of up to 180 mT.

  15. All-Optical Generation and Switching of Few-Cycle Millimeter-Wave Pulses

    NASA Astrophysics Data System (ADS)

    Lin, Jim-Wein; Wun, Jhih-Min; Shi, Jin-Wei; Pan, Ci-Ling

    2014-10-01

    We conducted a comparative study of two schemes of photonic generation and switching of few-cycle sub-THz or millimeter wave (MMW) pulses by use of a photonic-transmitter-mixer (PTM) module with a broadband and high-power near-ballistic uni-traveling carrier photodiode (NBUTC-PD). In the first scheme, we performed all-optical ultra-fast switching (bias modulation) of the PTM injected with a 93 GHz optical local-oscillator signal. Sub-2-cycle short MMW pulses with central frequency at 93 GHz were generated. To compare, in scheme 2, we employed femtosecond optical short pulses to directly excite the PTM under a DC bias (optical modulation). The former approach is shown to be capable of providing much less signal distortion and much shorter pulse duration than the latter.

  16. Ultrafast Nyquist OTDM demultiplexing using optical Nyquist pulse sampling in an all-optical nonlinear switch.

    PubMed

    Hirooka, Toshihiko; Seya, Daiki; Harako, Koudai; Suzuki, Daiki; Nakazawa, Masataka

    2015-08-10

    We propose the ultrahigh-speed demultiplexing of Nyquist OTDM signals using an optical Nyquist pulse as both a signal and a sampling pulse in an all-optical nonlinear switch. The narrow spectral width of the Nyquist pulses means that the spectral overlap between data and control pulses is greatly reduced, and the control pulse itself can be made more tolerant to dispersion and nonlinear distortions inside the nonlinear switch. We apply the Nyquist control pulse to the 640 to 40 Gbaud demultiplexing of DPSK and DQPSK signals using a nonlinear optical loop mirror (NOLM), and demonstrate a large performance improvement compared with conventional Gaussian control pulses. We also show that the optimum spectral profile of the Nyquist control pulse depends on the walk-off property of the NOLM.

  17. Ultrasmall all-optical plasmonic switch and its application to superresolution imaging

    NASA Astrophysics Data System (ADS)

    Wu, Hsueh-Yu; Huang, Yen-Ta; Shen, Po-Ting; Lee, Hsuan; Oketani, Ryosuke; Yonemaru, Yasuo; Yamanaka, Masahito; Shoji, Satoru; Lin, Kung-Hsuan; Chang, Chih-Wei; Kawata, Satoshi; Fujita, Katsumasa; Chu, Shi-Wei

    2016-04-01

    Because of their exceptional local-field enhancement and ultrasmall mode volume, plasmonic components can integrate photonics and electronics at nanoscale, and active control of plasmons is the key. However, all-optical modulation of plasmonic response with nanometer mode volume and unity modulation depth is still lacking. Here we show that scattering from a plasmonic nanoparticle, whose volume is smaller than 0.001 μm3, can be optically switched off with less than 100 μW power. Over 80% modulation depth is observed, and shows no degradation after repetitive switching. The spectral bandwidth approaches 100 nm. The underlying mechanism is suggested to be photothermal effects, and the effective single-particle nonlinearity reaches nearly 10‑9 m2/W, which is to our knowledge the largest record of metallic materials to date. As a novel application, the non-bleaching and unlimitedly switchable scattering is used to enhance optical resolution to λ/5 (λ/9 after deconvolution), with 100-fold less intensity requirement compared to similar superresolution techniques. Our work not only opens up a new field of ultrasmall all-optical control based on scattering from a single nanoparticle, but also facilitates superresolution imaging for long-term observation.

  18. Ultrasmall all-optical plasmonic switch and its application to superresolution imaging

    PubMed Central

    Wu, Hsueh-Yu; Huang, Yen-Ta; Shen, Po-Ting; Lee, Hsuan; Oketani, Ryosuke; Yonemaru, Yasuo; Yamanaka, Masahito; Shoji, Satoru; Lin, Kung-Hsuan; Chang, Chih-Wei; Kawata, Satoshi; Fujita, Katsumasa; Chu, Shi-Wei

    2016-01-01

    Because of their exceptional local-field enhancement and ultrasmall mode volume, plasmonic components can integrate photonics and electronics at nanoscale, and active control of plasmons is the key. However, all-optical modulation of plasmonic response with nanometer mode volume and unity modulation depth is still lacking. Here we show that scattering from a plasmonic nanoparticle, whose volume is smaller than 0.001 μm3, can be optically switched off with less than 100 μW power. Over 80% modulation depth is observed, and shows no degradation after repetitive switching. The spectral bandwidth approaches 100 nm. The underlying mechanism is suggested to be photothermal effects, and the effective single-particle nonlinearity reaches nearly 10−9 m2/W, which is to our knowledge the largest record of metallic materials to date. As a novel application, the non-bleaching and unlimitedly switchable scattering is used to enhance optical resolution to λ/5 (λ/9 after deconvolution), with 100-fold less intensity requirement compared to similar superresolution techniques. Our work not only opens up a new field of ultrasmall all-optical control based on scattering from a single nanoparticle, but also facilitates superresolution imaging for long-term observation. PMID:27063920

  19. Engineered materials for all-optical helicity-dependent magnetic switching

    NASA Astrophysics Data System (ADS)

    Fullerton, Eric

    2014-03-01

    The possibilities of manipulating magnetization without applied magnetic fields have attracted growing attention over the last fifteen years. The low-power manipulation of magnetization, preferably at ultra-short time scales, has become a fundamental challenge with implications for future magnetic information memory and storage technologies. Here we explore the optical manipulation of the magnetization of engineered materials and devices using 100 fs optical pulses. We demonstrate that all optical - helicity dependent switching (AO-HDS) can be observed not only in selected rare-earth transition-metal (RE-TM) alloy films but also in a much broader variety of materials, including alloys, multilayers, heterostructures and RE-free Co-Ir-based synthetic ferrimagnets. The discovery of AO-HDS in RE-free TM-based synthetic ferrimagnets can enable breakthroughs for numerous applications since it exploits materials that are currently used in magnetic data storage, memories and logic technologies. In addition, this materials study of AO-HDS offers valuable insight into the underlying mechanisms involved. Indeed the common denominator of the diverse structures showing AO-HDS in this study is that two ferromagnetic sub-lattices exhibit magnetization compensation (and therefore angular momentum compensation) at temperatures near or above room temperature. We are highlighting that compensation plays a major role and that this compensation can be established at the atomic level as in alloys but also over a larger nanometers scale as in the multilayers or in heterostructures. We will also discuss the potential to extend AO-HDS to new classes of magnetic materials. This work was done in collaboration with S. Mangin, M. Gottwald, C-H. Lambert, D. Steil, V. Uhlíř, L. Pang, M. Hehn, S. Alebrand, M. Cinchetti, G. Malinowski, Y. Fainman, and M. Aeschlimann. Supported by the ANR-10-BLANC-1005 ``Friends,'' a grant from the Advanced Storage Technology Consortium, Partner University Fund

  20. Engineered materials for all-optical helicity-dependent magnetic switching.

    PubMed

    Mangin, S; Gottwald, M; Lambert, C-H; Steil, D; Uhlíř, V; Pang, L; Hehn, M; Alebrand, S; Cinchetti, M; Malinowski, G; Fainman, Y; Aeschlimann, M; Fullerton, E E

    2014-03-01

    The possibility of manipulating magnetic systems without applied magnetic fields have attracted growing attention over the past fifteen years. The low-power manipulation of the magnetization, preferably at ultrashort timescales, has become a fundamental challenge with implications for future magnetic information memory and storage technologies. Here we explore the optical manipulation of the magnetization in engineered magnetic materials. We demonstrate that all-optical helicity-dependent switching (AO-HDS) can be observed not only in selected rare earth-transition metal (RE-TM) alloy films but also in a much broader variety of materials, including RE-TM alloys, multilayers and heterostructures. We further show that RE-free Co-Ir-based synthetic ferrimagnetic heterostructures designed to mimic the magnetic properties of RE-TM alloys also exhibit AO-HDS. These results challenge present theories of AO-HDS and provide a pathway to engineering materials for future applications based on all-optical control of magnetic order.

  1. REMOTE CONTROLLED SWITCHING DEVICE

    DOEpatents

    Hobbs, J.C.

    1959-02-01

    An electrical switching device which can be remotely controlled and in which one or more switches may be accurately operated at predetermined times or with predetermined intervening time intervals is described. The switching device consists essentially of a deck, a post projecting from the deck at right angles thereto, cam means mounted for rotation around said posts and a switch connected to said deck and actuated by said cam means. Means is provided for rotating the cam means at a constant speed and the switching apparatus is enclosed in a sealed container with external adjusting means and electrical connection elements.

  2. Burst switching without guard interval in all-optical software-define star intra-data center network

    NASA Astrophysics Data System (ADS)

    Ji, Philip N.; Wang, Ting

    2014-02-01

    Optical switching has been introduced in intra-data center networks (DCNs) to increase capacity and to reduce power consumption. Recently we proposed a star MIMO OFDM-based all-optical DCN with burst switching and software-defined networking. Here, we introduce the control procedure for the star DCN in detail for the first time. The timing, signaling, and operation are described for each step to achieve efficient bandwidth resource utilization. Furthermore, the guidelines for the burst assembling period selection that allows burst switching without guard interval are discussed. The star all-optical DCN offers flexible and efficient control for next-generation data center application.

  3. Crosstalk analysis of ring resonator switches for all-optical routing.

    PubMed

    Ashkan Seyedi, M; Descos, Antoine; Chen, Chin-Hui; Fiorentino, Marco; Penkler, David; Vincent, François; Szelag, Bertrand; Beausoleil, Raymond G

    2016-05-30

    Optical switches based on ring resonator cavities were fabricated by a silicon photonics foundry process and analyzed for optical crosstalk at various data rates and channel spacings. These devices were compared to commercial bandpass filters and at 20Gb/s, 0.5dB power penalty is observed due to spectral filtering for bit error ratio threshold of 1 × 10-9. Concurrent modulation at 20Gb/s with a channel spacing as narrow as 40GHz shows error-free transmission with 1dB power penalty as compared to wider channel spacing for the ring-based switch. PMID:27410092

  4. Nanoscale Confinement of All-Optical Magnetic Switching in TbFeCo--Competition with Nanoscale Heterogeneity.

    PubMed

    Liu, Tian-Min; Wang, Tianhan; Reid, Alexander H; Savoini, Matteo; Wu, Xiaofei; Koene, Benny; Granitzka, Patrick; Graves, Catherine E; Higley, Daniel J; Chen, Zhao; Razinskas, Gary; Hantschmann, Markus; Scherz, Andreas; Stöhr, Joachim; Tsukamoto, Arata; Hecht, Bert; Kimel, Alexey V; Kirilyuk, Andrei; Rasing, Theo; Dürr, Hermann A

    2015-10-14

    Single femtosecond optical laser pulses, of sufficient intensity, are demonstrated to reverse magnetization in a process known as all-optical switching. Gold two-wire antennas are placed on the all-optical switching film TbFeCo. These structures are resonant with the optical field, and they create a field enhancement in the near-field which confines the area where optical switching can occur. The magnetic switching that occurs around and below the antenna is imaged using resonant X-ray holography and magnetic circular dichroism. The results not only show the feasibility of controllable switching with antenna assistance but also demonstrate the highly inhomogeneous nature of the switching process, which is attributed to the process depending on the material's heterogeneity. PMID:26312732

  5. All-optical cross-bar network architecture using TOAD based interferometric switch and designing of reconfigurable logic unit

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Tanay

    2011-12-01

    The design of all-optical 2 × 2 Terahertz Optical Asymmetric Demultiplexer (TOAD) based interferometric switch is proposed and described in this manuscript. Numerical simulation has been done to achieve the performance of the switch. Using this 2 × 2 TOAD based switch, cross-bar network architecture is designed. A reconfigurable logic unit is also proposed in this manuscript, which can perform 16-Boolean logical operations.

  6. Numerical investigation of high-contrast ultrafast all-optical switching in low-refractive-index polymeric photonic crystal nanobeam microcavities

    NASA Astrophysics Data System (ADS)

    Meng, Zi-Ming; Zhong, Xiao-Lan; Wang, Chen; Li, Zhi-Yuan

    2012-06-01

    With the development of micro- or nano-fabrication technologies, great interest has been aroused in exploiting photonic crystal nanobeam structures. In this article the design of high-quality-factor (Q) polymeric photonic crystal nanobeam microcavities suitable for realizing ultrafast all-optical switching is presented based on the three-dimensional finite-difference time-domain method. Adopting the pump-probe technique, the ultrafast dynamic response of the all-optical switching in a nanobeam microcavity with a quality factor of 1000 and modal volume of 1.22 (λ/n)3 is numerically studied and a switching time as fast as 3.6 picoseconds is obtained. Our results indicate the great promise of applying photonic crystal nanobeam microcavities to construct integrated ultrafast tunable photonic devices or circuits incorporating polymer materials with large Kerr nonlinearity and ultrafast response speed.

  7. All-optical sub-ps switching and parallel logic gates with bacteriorhodopsin (BR) protein and BR-gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Roy, Sukhdev; Yadav, Chandresh

    2014-12-01

    We propose a model for the early sub-picosecond (sub-ps) transitions in the photochromic bacteriorhodopsin (BR) protein photocycle (B570 → H → I460 → J625 → B570) and present a detailed analysis of ultrafast all-optical switching for different pump-probe combinations. BR excitation with 120 fs pump pulses at 570 or 612 nm results in the switching of cw probe beams at 460 and 580 nm exhibiting reverse saturable absorption (RSA) and saturable absorption (SA) respectively. The effect of pump intensity, pump pulse width, lifetime of I460 state, thickness and concentration on switching has been studied in detail. It is shown that low intensity (MW cm-2), high contrast (100%), sub-ps all-optical switching can be achieved with BR-gold nanoparticle solutions. The validity of the proposed model is evident from the good agreement of theoretical simulations with reported experimental results. The switching characteristics have been optimized to design ultrafast all-optical parallel NOT, OR, AND and the universal NOR and NAND logic gates. High contrast, ultrafast switching at relatively lower pump intensities, compared to other organic molecules, opens up exciting prospects for ultrafast, all-optical information processing with BR and BR nano-biophotonic hybrid materials.

  8. Photonic Switching Devices Using Light Bullets

    NASA Technical Reports Server (NTRS)

    Goorjian, Peter M. (Inventor)

    1997-01-01

    The present invention is directed toward a unique ultra-fast, all-optical switching device or switch made with readily available, relatively inexpensive, highly nonlinear photonic glasses. These photonic glasses have a sufficiently negative group velocity dispersion and high nonlinear index of refraction to support stable light bullets. The light bullets counterpropagate through, and interact within the waveguide to selectively change each others' directions of propagation into predetermined channels. In one embodiment, the switch utilizes a rectangularly planar slab waveguide, and further includes two central channels and a plurality of lateral channels for guiding the light bullets into and out of the waveguide. One advantage presented by the present all-optical switching device lies in its practical use of light bullets, thus preventing the degeneration of the pulses due to dispersion and diffraction at the front and back of the pulses. Another feature of the switching device is the relative insensitivity of the collision process to the time difference in which the counter-propagating pulses enter the waveguide. since. contrary to conventional co-propagating spatial solitons, the relative phase of the colliding pulses does not affect the interaction of these pulses. Yet another feature of the present all-optical switching device is the selection of the light pulse parameters which enables the generation of light bullets in highly nonlinear glasses.

  9. All-optical switching, bistability, and slow-light transmission in photonic crystal waveguide-resonator structures.

    PubMed

    Mingaleev, Sergei F; Miroshnichenko, Andrey E; Kivshar, Yuri S; Busch, Kurt

    2006-10-01

    We analyze the resonant linear and nonlinear transmission through a photonic crystal waveguide side-coupled to a Kerr-nonlinear photonic crystal resonator. First, we extend the standard coupled-mode theory analysis to photonic crystal structures and obtain explicit analytical expressions for the bistability thresholds and transmission coefficients which provide the basis for a detailed understanding of the possibilities associated with these structures. Next, we discuss limitations of standard coupled-mode theory and present an alternative analytical approach based on the effective discrete equations derived using a Green's function method. We find that the discrete nature of the photonic crystal waveguides allows a geometry-driven enhancement of nonlinear effects by shifting the resonator location relative to the waveguide, thus providing an additional control of resonant waveguide transmission and Fano resonances. We further demonstrate that this enhancement may result in the lowering of the bistability threshold and switching power of nonlinear devices by several orders of magnitude. Finally, we show that employing such enhancements is of paramount importance for the design of all-optical devices based on slow-light photonic crystal waveguides.

  10. Power Switching Device

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The MOS-Controlled Thyristor is a new type of power switching device for faster and more efficient control and management of power electronics. It enables power electronic switching at frequencies of 50 to 100 thousand times a second with much lower power losses than other semiconductor devices. Advantages include electric power savings and smaller space. The device is used in motor and power controllers, AC & DC motor drives and induction heating. Early development was supported by Lewis Research Center (LEW) and other agencies. General Electric''s power semiconductor operation, the initial NASA contractor, was later purchased by Harris Semiconductor.

  11. Microdisk resonator assisted all-optical switching with improved speed using a reverse-biased p-n diode

    NASA Astrophysics Data System (ADS)

    Xie, Jingya; Zhou, Linjie; Li, Xinwan; Chen, Jianping

    2015-05-01

    We present a compact and power efficient all-optical switching using a silicon microdisk resonator integrated with a p-n junction. We study the dependence of free-carrier lifetime, one of the most critical parameters to determine the switching speed, on reverse bias, optical intensity, and p-n junction position and dimension. Our experiments reveal that the carrier lifetime decreases with the increasing reverse bias, consistent with the theoretical results. The all-optical switching of a 211-1 non-return-to-zero pseudo-random binary sequence (PRBS) signal at a data rate of 10 Gbits/s is demonstrated with p-n junction reversely biased at -15 V and the pump power being 5.96 dBm.

  12. General Strategy for Broadband Coherent Perfect Absorption and Multi-wavelength All-optical Switching Based on Epsilon-Near-Zero Multilayer Films

    PubMed Central

    Kim, Tae Young; Badsha, Md. Alamgir; Yoon, Junho; Lee, Seon Young; Jun, Young Chul; Hwangbo, Chang Kwon

    2016-01-01

    We propose a general, easy-to-implement scheme for broadband coherent perfect absorption (CPA) using epsilon-near-zero (ENZ) multilayer films. Specifically, we employ indium tin oxide (ITO) as a tunable ENZ material, and theoretically investigate CPA in the near-infrared region. We first derive general CPA conditions using the scattering matrix and the admittance matching methods. Then, by combining these two methods, we extract analytic expressions for all relevant parameters for CPA. Based on this theoretical framework, we proceed to study ENZ CPA in a single layer ITO film and apply it to all-optical switching. Finally, using an ITO multilayer of different ENZ wavelengths, we implement broadband ENZ CPA structures and investigate multi-wavelength all-optical switching in the technologically important telecommunication window. In our design, the admittance matching diagram was employed to graphically extract not only the structural parameters (the film thicknesses and incident angles), but also the input beam parameters (the irradiance ratio and phase difference between two input beams). We find that the multi-wavelength all-optical switching in our broadband ENZ CPA system can be fully controlled by the phase difference between two input beams. The simple but general design principles and analyses in this work can be widely used in various thin-film devices. PMID:26965195

  13. General Strategy for Broadband Coherent Perfect Absorption and Multi-wavelength All-optical Switching Based on Epsilon-Near-Zero Multilayer Films.

    PubMed

    Kim, Tae Young; Badsha, Md Alamgir; Yoon, Junho; Lee, Seon Young; Jun, Young Chul; Hwangbo, Chang Kwon

    2016-01-01

    We propose a general, easy-to-implement scheme for broadband coherent perfect absorption (CPA) using epsilon-near-zero (ENZ) multilayer films. Specifically, we employ indium tin oxide (ITO) as a tunable ENZ material, and theoretically investigate CPA in the near-infrared region. We first derive general CPA conditions using the scattering matrix and the admittance matching methods. Then, by combining these two methods, we extract analytic expressions for all relevant parameters for CPA. Based on this theoretical framework, we proceed to study ENZ CPA in a single layer ITO film and apply it to all-optical switching. Finally, using an ITO multilayer of different ENZ wavelengths, we implement broadband ENZ CPA structures and investigate multi-wavelength all-optical switching in the technologically important telecommunication window. In our design, the admittance matching diagram was employed to graphically extract not only the structural parameters (the film thicknesses and incident angles), but also the input beam parameters (the irradiance ratio and phase difference between two input beams). We find that the multi-wavelength all-optical switching in our broadband ENZ CPA system can be fully controlled by the phase difference between two input beams. The simple but general design principles and analyses in this work can be widely used in various thin-film devices. PMID:26965195

  14. General Strategy for Broadband Coherent Perfect Absorption and Multi-wavelength All-optical Switching Based on Epsilon-Near-Zero Multilayer Films

    NASA Astrophysics Data System (ADS)

    Kim, Tae Young; Badsha, Md. Alamgir; Yoon, Junho; Lee, Seon Young; Jun, Young Chul; Hwangbo, Chang Kwon

    2016-03-01

    We propose a general, easy-to-implement scheme for broadband coherent perfect absorption (CPA) using epsilon-near-zero (ENZ) multilayer films. Specifically, we employ indium tin oxide (ITO) as a tunable ENZ material, and theoretically investigate CPA in the near-infrared region. We first derive general CPA conditions using the scattering matrix and the admittance matching methods. Then, by combining these two methods, we extract analytic expressions for all relevant parameters for CPA. Based on this theoretical framework, we proceed to study ENZ CPA in a single layer ITO film and apply it to all-optical switching. Finally, using an ITO multilayer of different ENZ wavelengths, we implement broadband ENZ CPA structures and investigate multi-wavelength all-optical switching in the technologically important telecommunication window. In our design, the admittance matching diagram was employed to graphically extract not only the structural parameters (the film thicknesses and incident angles), but also the input beam parameters (the irradiance ratio and phase difference between two input beams). We find that the multi-wavelength all-optical switching in our broadband ENZ CPA system can be fully controlled by the phase difference between two input beams. The simple but general design principles and analyses in this work can be widely used in various thin-film devices.

  15. All-Optical Label Swapping Strategies for Spectral Amplitude Code Labels in Packet-Switched Optical Networks

    NASA Astrophysics Data System (ADS)

    Habib, Christian

    There is currently much work focused on developing packet-switched optical networks to overcome the limitations of existing optical networks. Switch design for packet-switched optical networks is particularly challenging, in part due to the lack of a practical optical memory system. As a result, optical labels and all-optical label processing have attracted much attention. This thesis examines a crucial label processing component of an optical packet switch, namely the label swapper. In this thesis, three different tabletop topologies for low-cost all-optical swapping of spectral amplitude code labels for packet-switched networks are examined in a proof-of-concept phase. The first uses cross-absorption modulation in an electro-absorption modulator within a semiconductor fiber ring laser (SFRL), the second uses cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA) within an SFRL, and the third makes use of XGM in a SOA as well as injection locking in a Fabry-Perot laser diode for wavelength conversion. The benefits and limitations of each approach as well as future improvements are discussed. Building on these results, a high-performance integrated version of XGM swapper is designed, simulated, and masks are produced for fabrication using indium phosphide technology.

  16. Photonic Switching Devices Using Light Bullets

    NASA Technical Reports Server (NTRS)

    Goorjian, Peter M. (Inventor)

    1999-01-01

    A unique ultra-fast, all-optical switching device or switch is made with readily available, relatively inexpensive, highly nonlinear optical materials. which includes highly nonlinear optical glasses, semiconductor crystals and/or multiple quantum well semiconductor materials. At the specified wavelengths. these optical materials have a sufficiently negative group velocity dispersion and high nonlinear index of refraction to support stable light bullets. The light bullets counter-propagate through, and interact within the waveguide to selectively change each others' directions of propagation into predetermined channels. In one embodiment, the switch utilizes a rectangularly planar slab waveguide. and further includes two central channels and a plurality of lateral channels for guiding the light bullets into and out of the waveguide. An advantage of the present all-optical switching device lies in its practical use of light bullets, thus preventing the degeneration of the pulses due to dispersion and diffraction at the front and back of the pulses. Another advantage of the switching device is the relative insensitivity of the collision process to the time difference in which the counter-propagating pulses enter the waveguide. since. contrary to conventional co-propagating spatial solitons, the relative phase of the colliding pulses does not affect the interaction of these pulses. Yet another feature of the present all-optical switching device is the selection of the light pulse parameters which enables the generation of light bullets in nonlinear optical materials. including highly nonlinear optical glasses and semiconductor materials such as semiconductor crystals and/or multiple quantum well semiconductor materials.

  17. All-optical SR flip-flop based on SOA-MZI switches monolithically integrated on a generic InP platform

    NASA Astrophysics Data System (ADS)

    Pitris, St.; Vagionas, Ch.; Kanellos, G. T.; Kisacik, R.; Tekin, T.; Broeke, R.; Pleros, N.

    2016-03-01

    At the dawning of the exaflop era, High Performance Computers are foreseen to exploit integrated all-optical elements, to overcome the speed limitations imposed by electronic counterparts. Drawing from the well-known Memory Wall limitation, imposing a performance gap between processor and memory speeds, research has focused on developing ultra-fast latching devices and all-optical memory elements capable of delivering buffering and switching functionalities at unprecedented bit-rates. Following the master-slave configuration of electronic Flip-Flops, coupled SOA-MZI based switches have been theoretically investigated to exceed 40 Gb/s operation, provided a short coupling waveguide. However, this flip-flop architecture has been only hybridly integrated with silica-on-silicon integration technology exhibiting a total footprint of 45x12 mm2 and intra-Flip-Flop coupling waveguide of 2.5cm, limited at 5 Gb/s operation. Monolithic integration offers the possibility to fabricate multiple active and passive photonic components on a single chip at a close proximity towards, bearing promises for fast all-optical memories. Here, we present for the first time a monolithically integrated all-optical SR Flip-Flop with coupled master-slave SOA-MZI switches. The photonic chip is integrated on a 6x2 mm2 die as a part of a multi-project wafer run using library based components of a generic InP platform, fiber-pigtailed and fully packaged on a temperature controlled ceramic submount module with electrical contacts. The intra Flip-Flop coupling waveguide is 5 mm long, reducing the total footprint by two orders of magnitude. Successful flip flop functionality is evaluated at 10 Gb/s with clear open eye diagram, achieving error free operation with a power penalty of 4dB.

  18. All-optical spin switching: A new frontier in femtomagnetism — A short review and a simple theory

    NASA Astrophysics Data System (ADS)

    Zhang, G. P.; Latta, T.; Babyak, Z.; Bai, Y. H.; George, Thomas F.

    2016-08-01

    Using an ultrafast laser pulse to manipulate the spin degree of freedom has broad technological appeal. It allows one to control the spin dynamics on a femtosecond time scale. The discipline, commonly called femtomagnetism, started with the pioneering experiment by Beaurepaire and coworkers in 1996, who showed subpicosecond demagnetization occurs in magnetic Ni thin films. This finding has motivated extensive research worldwide. All-optical helicity-dependent spin switching (AOS) represents a new frontier in femtomagnetism, where a single ultrafast laser pulse can permanently switch spin without any assistance from a magnetic field. This review summarizes some of the crucial aspects of this new discipline: key experimental findings, leading mechanisms, controversial issues, and possible future directions. The emphasis is on our latest investigation. We first develop the all-optical spin switching rule that determines how the switchability depends on the light helicity. This rule allows one to understand microscopically how the spin is reversed and why the circularly polarized light appears more powerful than the linearly polarized light. Then we invoke our latest spin-orbit coupled harmonic oscillator model to simulate single spin reversal. We consider both cw excitation and pulsed laser excitation. The results are in a good agreement with the experimental result. We then extend the code to include the exchange interaction among different spin sites. We show where the "inverse Faraday field" comes from and how the laser affects the spin reversal nonlinearly. Our hope is that this review will motivate new experimental and theoretical investigations and discussions.

  19. All-optical packet header and payload separation based on two TOADs for optical packet switched networks

    NASA Astrophysics Data System (ADS)

    Ji, Wei; Zhang, Min; Ye, Peida

    2006-09-01

    We present a novel all-optical header and payload separation technique that can be utilized in Un-Slotted optical packet switched networks. The technique uses two modified TOADs, one is for packet header extraction with differential modulation scheme and the other performs a simple XOR operation between the packet and its self-derived header to get the separated payload. The main virtue of this system is simple structure and low power consumption. Through numerical simulations, the operating characteristics of the scheme are illustrated. In addition, the system parameters are discussed and designed to optimize the performance of the proposed scheme.

  20. Demonstration of all-optical MDM/WDM switching for short-reach networks.

    PubMed

    Wu, Zhongying; Li, Juhao; Ge, Dawei; Ren, Fang; Zhu, Paikun; Mo, Qi; Li, Zhengbin; Chen, Zhangyuan; He, Yongqi

    2016-09-19

    Mode division multiplexing (MDM) has been widely investigated in optical transmission systems and networks to improve network capacity. However, the MDM receiver is always expensive and complex because coherent detection and multiplex-input-and-multiplex-output (MIMO) digital signal processing (DSP) are required to demultiplex each spatial mode. In this paper, we investigate the application of MDM in short-reach scenarios such as datacenter networking. Two-dimensional MDM and wavelength division multiplexing node structure based on low modal-crosstalk few-mode fiber (FMF) and components is proposed, in which signal in each mode or wavelength can be independently switched. We experimentally demonstrate independent adding, dropping and switching functionalities with two linearly polarized modes and four wavelength channels over a total 11.8-km 2-mode low modal-crosstalk FMFs. The structure is simple without coherent detection or MIMO DSP. Only slight penalties of receiver sensitivity are observed for all switching operations. The influence of modal-crosstalk accumulation for cascaded switching nodes is also investigated. PMID:27661899

  1. Efficient all-optical switching using slow light within a hollow fiber.

    PubMed

    Bajcsy, M; Hofferberth, S; Balic, V; Peyronel, T; Hafezi, M; Zibrov, A S; Vuletic, V; Lukin, M D

    2009-05-22

    We demonstrate a fiber-optical switch that is activated at tiny energies corresponding to a few hundred optical photons per pulse. This is achieved by simultaneously confining both photons and a small laser-cooled ensemble of atoms inside the microscopic hollow core of a single-mode photonic-crystal fiber and using quantum optical techniques for generating slow light propagation and large nonlinear interaction between light beams. PMID:19519028

  2. Ultrafast, low-power, all-optical switching via birefringent phase-matched transverse mode conversion in integrated waveguides.

    PubMed

    Hellwig, Tim; Epping, Jörn P; Schnack, Martin; Boller, Klaus-J; Fallnich, Carsten

    2015-07-27

    We demonstrate the potential of birefringence-based, all-optical, ultrafast conversion between the transverse modes in integrated optical waveguides by modelling the conversion process by numerically solving the multi-mode coupled nonlinear Schroedinger equations. The observed conversion is induced by a control beam and due to the Kerr effect, resulting in a transient index grating which coherently scatters probe light from one transverse waveguide mode into another. We introduce birefringent phase matching to enable efficient all-optically induced mode conversion at different wavelengths of the control and probe beam. It is shown that tailoring the waveguide geometry can be exploited to explicitly minimize intermodal group delay as well as to maximize the nonlinear coefficient, under the constraint of a phase matching condition. The waveguide geometries investigated here, allow for mode conversion with over two orders of magnitude reduced control pulse energy compared to previous schemes and thereby promise nonlinear mode switching exceeding efficiencies of 90% at switching energies below 1 nJ. PMID:26367581

  3. All-optical Q-switching limiter for high-power gigahertz modelocked diode-pumped solid-state lasers.

    PubMed

    Klenner, Alexander; Keller, Ursula

    2015-04-01

    Passively modelocked diode-pumped solid-state lasers (DPSSLs) with pulse repetition rates in the gigahertz regime suffer from an increased tendency for Q-switching instabilities. Low saturation fluence intracavity saturable absorbers - such as the semiconductor saturable absorber mirrors (SESAMs) - can solve this problem up to a certain average output power limited by the onset of SESAM damage. Here we present a passive stabilization mechanism, an all-optical Q-switching limiter, to reduce the impact of Q-switching instabilities and increase the potential output power of SESAM modelocked lasers in the gigahertz regime. With a proper cavity design a Kerr lens induced negative saturable absorber clamps the maximum fluence on the SESAM and therefore limits the onset of Q-switching instabilities. No critical cavity alignment is required because this Q-switching limiter acts well within the cavity stability regime. Using a proper cavity design, a high-power diode-pumped Yb:CALGO solid-state laser generated sub-100 fs pulses with an average output power of 4.1 W at a pulse repetition rate of 5 GHz. With a pulse duration of 96 fs we can achieve a peak power as high as 7.5 kW directly from the SESAM modelocked laser oscillator without any further external pulse amplification and/or pulse compression. We present a quantitative analysis of this Kerr lens induced Q-switching limiter and its impact on modelocked operation. Our work provides a route to compact high-power multi-gigahertz frequency combs based on SESAM modelocked diode-pumped solid-state lasers without any additional external amplification or pulse compression. PMID:25968691

  4. All-optical switching in granular ferromagnets caused by magnetic circular dichroism

    NASA Astrophysics Data System (ADS)

    Ellis, Matthew O. A.; Fullerton, Eric E.; Chantrell, Roy W.

    2016-07-01

    Magnetic recording using circularly polarised femto-second laser pulses is an emerging technology that would allow write speeds much faster than existing field driven methods. However, the mechanism that drives the magnetisation switching in ferromagnets is unclear. Recent theories suggest that the interaction of the light with the magnetised media induces an opto-magnetic field within the media, known as the inverse Faraday effect. Here we show that an alternative mechanism, driven by thermal excitation over the anisotropy energy barrier and a difference in the energy absorption depending on polarisation, can create a net magnetisation over a series of laser pulses in an ensemble of single domain grains. Only a small difference in the absorption is required to reach magnetisation levels observed experimentally and the model does not preclude the role of the inverse Faraday effect but removes the necessity that the opto-magnetic field is 10 s of Tesla in strength.

  5. All-optical switching in granular ferromagnets caused by magnetic circular dichroism.

    PubMed

    Ellis, Matthew O A; Fullerton, Eric E; Chantrell, Roy W

    2016-01-01

    Magnetic recording using circularly polarised femto-second laser pulses is an emerging technology that would allow write speeds much faster than existing field driven methods. However, the mechanism that drives the magnetisation switching in ferromagnets is unclear. Recent theories suggest that the interaction of the light with the magnetised media induces an opto-magnetic field within the media, known as the inverse Faraday effect. Here we show that an alternative mechanism, driven by thermal excitation over the anisotropy energy barrier and a difference in the energy absorption depending on polarisation, can create a net magnetisation over a series of laser pulses in an ensemble of single domain grains. Only a small difference in the absorption is required to reach magnetisation levels observed experimentally and the model does not preclude the role of the inverse Faraday effect but removes the necessity that the opto-magnetic field is 10 s of Tesla in strength. PMID:27466066

  6. All-optical switching in granular ferromagnets caused by magnetic circular dichroism

    PubMed Central

    Ellis, Matthew O. A.; Fullerton, Eric E.; Chantrell, Roy W.

    2016-01-01

    Magnetic recording using circularly polarised femto-second laser pulses is an emerging technology that would allow write speeds much faster than existing field driven methods. However, the mechanism that drives the magnetisation switching in ferromagnets is unclear. Recent theories suggest that the interaction of the light with the magnetised media induces an opto-magnetic field within the media, known as the inverse Faraday effect. Here we show that an alternative mechanism, driven by thermal excitation over the anisotropy energy barrier and a difference in the energy absorption depending on polarisation, can create a net magnetisation over a series of laser pulses in an ensemble of single domain grains. Only a small difference in the absorption is required to reach magnetisation levels observed experimentally and the model does not preclude the role of the inverse Faraday effect but removes the necessity that the opto-magnetic field is 10 s of Tesla in strength. PMID:27466066

  7. All-optical spin switching: A new frontier in femtomagnetism — A short review and a simple theory

    NASA Astrophysics Data System (ADS)

    Zhang, G. P.; Latta, T.; Babyak, Z.; Bai, Y. H.; George, Thomas F.

    2016-08-01

    Using an ultrafast laser pulse to manipulate the spin degree of freedom has broad technological appeal. It allows one to control the spin dynamics on a femtosecond time scale. The discipline, commonly called femtomagnetism, started with the pioneering experiment by Beaurepaire and coworkers in 1996, who showed subpicosecond demagnetization occurs in magnetic Ni thin films. This finding has motivated extensive research worldwide. All-optical helicity-dependent spin switching (AO-HDS) represents a new frontier in femtomagnetism, where a single ultrafast laser pulse can permanently switch spin without any assistance from a magnetic field. This review summarizes some of the crucial aspects of this new discipline: key experimental findings, leading mechanisms, controversial issues, and possible future directions. The emphasis is on our latest investigation. We first develop the all-optical spin switching (AOS) rule that determines how the switchability depends on the light helicity. This rule allows one to understand microscopically how the spin is reversed and why the circularly polarized light appears more powerful than the linearly polarized light. Then we invoke our latest spin-orbit coupled harmonic oscillator model to simulate single spin reversal. We consider both continuous wave (cw) excitation and pulsed laser excitation. The results are in a good agreement with the experimental result (a MatLab code is available upon request from the author). We then extend the code to include the exchange interaction among different spin sites. We show where the “inverse-Faraday field” comes from and how the laser affects the spin reversal nonlinearly. Our hope is that this review will motivate new experimental and theoretical investigations and discussions.

  8. Sonic crystal acoustic switch device.

    PubMed

    Alagoz, Serkan; Alagoz, Baris Baykant

    2013-06-01

    This study reports a wave-controlled sonic crystal switch device that exhibits a destructive interference-based wave to wave reverse switching effect. By applying control waves, this acoustic device, composed of a two-dimensional square lattice sonic crystal block, reduces acoustic wave transmission from input to output. The finite difference time domain simulation and experimental results confirm the wave-to-wave reverse switching effect at the peak frequencies of the second band. The proposed sonic crystal switch prototype provides a contrast rate of 86% at 11.3 kHz frequency. This wave-to-wave switching effect is useful for controlling wave propagation for smart structure applications.

  9. Magnetic layer thickness dependence of all-optical magnetization switching in GdFeCo thin films

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Hiroki; El Moussaoui, Souliman; Terashita, Shinnosuke; Ueda, Ryohei; Tsukamoto, Arata

    2016-07-01

    To clarify the relationship between all-optical magnetization switching (AOS) and nonlocal and nonadiabatic energy dissipation process, we focus on the contribution from energy dissipation in the depth direction. Differently designed structure dependence of created magnetic domain is observed from the reversal phenomenon, AOS, or multidomains by thermomagnetic nucleation (TMN) in GdFeCo multilayer thin films. TMN depends on the shared absorbed energy throughout the continuous metallic volume. On the other hand, AOS critically depends on nonadiabatic energy dissipation process with the electron system in sub-picoseconds. Furthermore, the laser fluence dependence of AOS-created domain sizes indicates that the value of irradiated laser fluence threshold per magnetic domain volume is almost constant. However, a lower laser irradiation fluence below 1–2 mW has a larger value and thickness dependence. From these results, we suggest that AOS depends on energy dissipation from the incident surface in the depth direction for a few picoseconds.

  10. A novel all-optical label processing based on multiple optical orthogonal codes sequences for optical packet switching networks

    NASA Astrophysics Data System (ADS)

    Zhang, Chongfu; Qiu, Kun; Xu, Bo; Ling, Yun

    2008-05-01

    This paper proposes an all-optical label processing scheme that uses the multiple optical orthogonal codes sequences (MOOCS)-based optical label for optical packet switching (OPS) (MOOCS-OPS) networks. In this scheme, each MOOCS is a permutation or combination of the multiple optical orthogonal codes (MOOC) selected from the multiple-groups optical orthogonal codes (MGOOC). Following a comparison of different optical label processing (OLP) schemes, the principles of MOOCS-OPS network are given and analyzed. Firstly, theoretical analyses are used to prove that MOOCS is able to greatly enlarge the number of available optical labels when compared to the previous single optical orthogonal code (SOOC) for OPS (SOOC-OPS) network. Then, the key units of the MOOCS-based optical label packets, including optical packet generation, optical label erasing, optical label extraction and optical label rewriting etc., are given and studied. These results are used to verify that the proposed MOOCS-OPS scheme is feasible.

  11. Optical nonlinearities and ultrafast all-optical switching of m-plane GaN in the near-infrared

    SciTech Connect

    Fang, Yu; Zhou, Feng; Yang, Junyi; Yang, Yong; Xiao, Zhengguo; Wu, Xingzhi; Song, Yinglin

    2015-06-22

    We reported a systematic investigation on the three-photon absorption (3PA) spectra and wavelength dispersion of Kerr refraction of bulk m-plane GaN crystal with both polarization E⊥c and E//c by femtosecond Z-scan technique in the near-infrared region from 760 to 1030 nm. Both 3PA spectra and Kerr refraction dispersion were in good agreement with two-band models. The calculated nonlinear figure of merit and measured ultrafast nonlinear refraction dynamics via femtosecond pump-probe with phase object method revealed that m-plane GaN would be a promising candidate for ultrafast all-optical switching and autocorrelation applications at telecommunication wavelengths.

  12. All-optically reconfigurable and tunable fiber surface grating for in-fiber devices: a wideband tunable filter.

    PubMed

    Yu, Jianhui; Han, Yuqi; Huang, Hankai; Li, Haozi; Hsiao, Vincent K S; Liu, Weiping; Tang, Jieyuan; Lu, Huihui; Zhang, Jun; Luo, Yunhan; Zhong, Yongchun; Zang, Zhigang; Chen, Zhe

    2014-03-10

    A fiber surface grating (FSG) formed from a photosensitive liquid crystal hybrid (PLCH) film overlaid on a side-polished fiber (SPF) is studied and has been experimentally shown to be able to function as an all-optically reconfigurable and tunable fiber device. The device is all-optically configured to be a short period fiber surface grating (SPFSG) when a phase mask is used, and then reconfigured to be a long period FSG (LPFSG) when an amplitude mask is used. Experimental results show that both the short and long period FSGs can function as an optically tunable band-rejection filter and have different performances with different pump power and different configured period of the FSG. When configured as a SPFSG, the device can achieve a high extinction ratio (ER) of 21.5dB and a wideband tunability of 31nm are achieved. When configured as a LPFSG, the device can achieve an even higher ER of 23.4dB and a wider tunable bandwidth of 60nm. Besides these tunable performances of the device, its full width at half maximum (FWHM) can also be optically tuned. The reconfigurability and tunability of the fiber device open up possibilities for other all-optically programmable and tunable fiber devices. PMID:24663932

  13. Domain size criterion for the observation of all-optical helicity-dependent switching in magnetic thin films

    NASA Astrophysics Data System (ADS)

    El Hadri, Mohammed Salah; Hehn, Michel; Pirro, Philipp; Lambert, Charles-Henri; Malinowski, Grégory; Fullerton, Eric E.; Mangin, Stéphane

    2016-08-01

    To understand the necessary condition for the observation of all-optical helicity-dependent switching (AO-HDS) of magnetization in thin films, we investigated ferromagnetic Co/Pt and Co/Ni multilayers as well as ferrimagnetic TbCo alloys as a function of magnetic layer compositions and thicknesses. We show that both ferro- and ferrimagnets with high saturation magnetization show AO-HDS if their magnetic thickness is strongly reduced below a material-dependent threshold thickness. By taking into account the demagnetizing energy and the domain wall energy, we are able to define a criterion to predict whether AO-HDS or thermal demagnetization (TD) will be observed. This criterion for the observation of AO-HDS is that the equilibrium size of magnetic domains forming during the cooling process should be larger than the laser spot size. From these results we anticipate that more magnetic materials are expected to show AO-HDS. However, the effect of the optical pulses' helicity is hidden by the formation of small magnetic domains during the cooling process.

  14. Ferrimagnetic Tb-Fe Alloy Thin Films: Composition and Thickness Dependence of Magnetic Properties and All-Optical Switching

    NASA Astrophysics Data System (ADS)

    Hebler, Birgit; Hassdenteufel, Alexander; Reinhardt, Patrick; Karl, Helmut; Albrecht, Manfred

    2016-02-01

    Ferrimagnetic rare earth - transition metal Tb-Fe alloy thin films exhibit a variety of different magnetic properties, which depends strongly on composition and temperature. In this study, first the influence of the film thickness (5 - 85 nm) on the sample magnetic properties was investigated in a wide composition range between 15 at.% and 38 at.% of Tb. From our results, we find that the compensation point, remanent magnetization, and magnetic anisotropy of the Tb-Fe films depend not only on the composition but also on the thickness of the magnetic film up to a critical thickness of about 20-30 nm. Beyond this critical thickness, only slight changes in magnetic properties are observed. This behavior can be attributed to a growth-induced modification of the microstructure of the amorphous films, which affects the short range order. As a result, a more collinear alignment of the distributed magnetic moments of Tb along the out-of-plane direction with film thickness is obtained. This increasing contribution of the Tb sublattice magnetization to the total sample magnetization is equivalent to a sample becoming richer in Tb and can be referred to as an “effective” composition. Furthermore, the possibility of all-optical switching, where the magnetization orientation of Tb-Fe can be reversed solely by circularly polarized laser pulses, was analyzed for a broad range of compositions and film thicknesses and correlated to the underlying magnetic properties.

  15. Electrochromic optical switching device

    SciTech Connect

    Lampert, C.M.; Visco, S.J.

    1992-08-25

    An electrochromic cell is disclosed which comprises an electrochromic layer, a polymerizable organo-sulfur layer which comprises the counter electrode of the structure, and an ionically conductive electronically insulating material which comprises the separator between the electrodes. In a preferred embodiment, both the separator and the organo-sulfur electrode (in both its charged and uncharged states) are transparent either to visible light or to the entire solar spectrum. An electrochromic device is disclosed which comprises such electrodes and separator encased in glass plates on the inner surface of each of which is formed a transparent electrically conductive film in respective electrical contact with the electrodes which facilitates formation of an external electrical connection or contact to the electrodes of the device to permit electrical connection of the device to an external potential source. 3 figs.

  16. Electrochromic optical switching device

    SciTech Connect

    Lampert, Carl M.; Visco, Steven J.

    1992-01-01

    An electrochromic cell is disclosed which comprises an electrochromic layer, a polymerizable organo-sulfur layer which comprises the counter electrode of the structure, and an ionically conductive electronically insulating material which comprises the separator between the electrodes. In a preferred embodiment, both the separator and the organo-sulfur electrode (in both its charged and uncharged states) are transparent either to visible light or to the entire solar spectrum. An electrochromic device is disclosed which comprises such electrodes and separator encased in glass plates on the inner surface of each of which is formed a transparent electrically conductive film in respective electrical contact with the electrodes which facilitates formation of an external electrical connection or contact to the electrodes of the device to permit electrical connection of the device to an external potential source.

  17. All-optical repeater.

    PubMed

    Silberberg, Y

    1986-06-01

    An all-optical device containing saturable gain, saturable loss, and unsaturable loss is shown to transform weak, distorted optical pulses into uniform standard-shape pulses. The proposed device performs thresholding, amplification, and pulse shaping as required from an optical repeater. It is shown that such a device could be realized by existing semiconductor technology.

  18. Band edge tailoring of InGaAs/AlAsSb coupled double quantum wells for a monolithically integrated all-optical switch.

    PubMed

    Feng, Jijun; Akimoto, Ryoichi; Gozu, Shin-ichiro; Mozume, Teruo; Hasama, Toshifumi; Ishikawa, Hiroshi

    2013-07-01

    We demonstrate a compact all-optical Michelson interferometer (MI) gating switch with monolithic integration of two different bandgap energies. Based on the ion-induced intermixing in InGaAs/AlAsSb coupled double quantum wells, the blueshift of the band edge can be tailored. Through phosphorus ion implantation with a dose of 5 × 10(14) cm(-2) and subsequent annealing at 720 °C for 60 s, an implanted sample can acquire a high transmittance compared with the as-grown one. Meanwhile, the cross-phase modulation (XPM) efficiency of a non-implanted sample undergoing the same annealing process decreases little. An implanted part for signal propagation and a non-implanted section for XPM are thus monolithically integrated for an MI switch by an area-selective manner. Full switching of a π-rad nonlinear phase shift is achieved with pump pulse energy of 5.6 pJ at a 10-GHz repetition rate.

  19. Optically controlled waveplate at a telecom wavelength using a ladder transition in Rb atoms for all-optical switching and high speed Stokesmetric imaging.

    PubMed

    Krishnamurthy, Subramanian; Tu, Y; Wang, Y; Tseng, S; Shahriar, M S

    2014-11-17

    We demonstrate an optically controlled waveplate at ~1323 nm using the 5S(1/2)-5P(1/2)-6S(1/2) ladder transition in a Rb vapor cell. The lower leg of the transitions represents the control beam, while the upper leg represents the signal beam. We show that we can place the signal beam in any arbitrary polarization state with a suitable choice of polarization of the control beam. Specifically, we demonstrate a differential phase retardance of ~180 degrees between the two circularly polarized components of a linearly polarized signal beam. We also demonstrate that the system can act as a Quarter Wave plate. The optical activity responsible for the phase retardation process is explained in terms of selection rules involving the Zeeman sublevels. As such, the system can be used to realize a fast Stokesmetric imaging system with a speed of ~3 MHz. When implemented using a tapered nano fiber embedded in a vapor cell, this system can be used to realize an ultra-low power all-optical switch as well as a Quantum Zeno Effect based all-optical logic gate by combining it with an optically controlled polarizer, previously demonstrated by us. We present numerical simulations of the system using a comprehensive model which incorporates all the relevant Zeeman sub-levels in the system, using a novel algorithm recently developed by us for efficient computation of the evolution of an arbitrary large scale quantum system. PMID:25402129

  20. All-optical switching of localized surface plasmon resonance in single gold nanosandwich using GeSbTe film as an active medium

    SciTech Connect

    Hira, T.; Homma, T.; Uchiyama, T.; Kuwamura, K.; Kihara, Y.; Saiki, T.

    2015-01-19

    Localized surface plasmon resonance (LSPR) switching was investigated in a Au/GeSbTe/Au nanosandwich as a key active element for plasmonic integrated circuits and devices. Near-infrared single-particle spectroscopy was conducted to examine the interaction of a Au nanorod (AuNR) and Au film, between which a GeSbTe layer was incorporated as an active phase-change media. Numerical calculation revealed that hybridized modes of the AuNR and Au film exhibit a significant change of scattering intensity with the phase change. In particular, the antisymmetric (magnetic resonance) mode can be modulated effectively by the extinction coefficient of GST, as well as its refractive index. Experimental demonstration of the switching operation was performed by alternate irradiation with a picosecond pulsed laser for amorphization and a continuous wave laser for crystallization. Repeatable modulation was obtained by monitoring the scattering light around the LSPR peak at λ = 1070 nm.

  1. Switching dynamics in titanium dioxide memristive devices

    NASA Astrophysics Data System (ADS)

    Pickett, Matthew D.; Strukov, Dmitri B.; Borghetti, Julien L.; Yang, J. Joshua; Snider, Gregory S.; Stewart, Duncan R.; Williams, R. Stanley

    2009-10-01

    Memristive devices are promising components for nanoelectronics with applications in nonvolatile memory and storage, defect-tolerant circuitry, and neuromorphic computing. Bipolar resistive switches based on metal oxides such as TiO2 have been identified as memristive devices primarily based on the "pinched hysteresis loop" that is observed in their current-voltage (i-v ) characteristics. Here we show that the mathematical definition of a memristive device provides the framework for understanding the physical processes involved in bipolar switching and also yields formulas that can be used to compute and predict important electrical and dynamical properties of the device. We applied an electrical characterization and state-evolution procedure in order to capture the switching dynamics of a device and correlate the response with models for the drift diffusion of ionized dopants (vacancies) in the oxide film. The analysis revealed a notable property of nonlinear memristors: the energy required to switch a metal-oxide device decreases exponentially with increasing applied current.

  2. All-optical fast random number generator.

    PubMed

    Li, Pu; Wang, Yun-Cai; Zhang, Jian-Zhong

    2010-09-13

    We propose a scheme of all-optical random number generator (RNG), which consists of an ultra-wide bandwidth (UWB) chaotic laser, an all-optical sampler and an all-optical comparator. Free from the electric-device bandwidth, it can generate 10Gbit/s random numbers in our simulation. The high-speed bit sequences can pass standard statistical tests for randomness after all-optical exclusive-or (XOR) operation.

  3. All-optical analog comparator.

    PubMed

    Li, Pu; Yi, Xiaogang; Liu, Xianglian; Zhao, Dongliang; Zhao, Yongpeng; Wang, Yuncai

    2016-01-01

    An analog comparator is one of the core units in all-optical analog-to-digital conversion (AO-ADC) systems, which digitizes different amplitude levels into two levels of logical '1' or '0' by comparing with a defined decision threshold. Although various outstanding photonic ADC approaches have been reported, almost all of them necessitate an electrical comparator to carry out this binarization. The use of an electrical comparator is in contradiction to the aim of developing all-optical devices. In this work, we propose a new concept of an all-optical analog comparator and numerically demonstrate an implementation based on a quarter-wavelength-shifted distributed feedback laser diode (QWS DFB-LD) with multiple quantum well (MQW) structures. Our results show that the all-optical comparator is very well suited for true AO-ADCs, enabling the whole digital conversion from an analog optical signal (continuous-time signal or discrete pulse signal) to a binary representation totally in the optical domain. In particular, this all-optical analog comparator possesses a low threshold power (several mW), high extinction ratio (up to 40 dB), fast operation rate (of the order of tens of Gb/s) and a step-like transfer function.

  4. All-optical analog comparator

    NASA Astrophysics Data System (ADS)

    Li, Pu; Yi, Xiaogang; Liu, Xianglian; Zhao, Dongliang; Zhao, Yongpeng; Wang, Yuncai

    2016-08-01

    An analog comparator is one of the core units in all-optical analog-to-digital conversion (AO-ADC) systems, which digitizes different amplitude levels into two levels of logical ‘1’ or ‘0’ by comparing with a defined decision threshold. Although various outstanding photonic ADC approaches have been reported, almost all of them necessitate an electrical comparator to carry out this binarization. The use of an electrical comparator is in contradiction to the aim of developing all-optical devices. In this work, we propose a new concept of an all-optical analog comparator and numerically demonstrate an implementation based on a quarter-wavelength-shifted distributed feedback laser diode (QWS DFB-LD) with multiple quantum well (MQW) structures. Our results show that the all-optical comparator is very well suited for true AO-ADCs, enabling the whole digital conversion from an analog optical signal (continuous-time signal or discrete pulse signal) to a binary representation totally in the optical domain. In particular, this all-optical analog comparator possesses a low threshold power (several mW), high extinction ratio (up to 40 dB), fast operation rate (of the order of tens of Gb/s) and a step-like transfer function.

  5. All-optical analog comparator

    PubMed Central

    Li, Pu; Yi, Xiaogang; Liu, Xianglian; Zhao, Dongliang; Zhao, Yongpeng; Wang, Yuncai

    2016-01-01

    An analog comparator is one of the core units in all-optical analog-to-digital conversion (AO-ADC) systems, which digitizes different amplitude levels into two levels of logical ‘1’ or ‘0’ by comparing with a defined decision threshold. Although various outstanding photonic ADC approaches have been reported, almost all of them necessitate an electrical comparator to carry out this binarization. The use of an electrical comparator is in contradiction to the aim of developing all-optical devices. In this work, we propose a new concept of an all-optical analog comparator and numerically demonstrate an implementation based on a quarter-wavelength-shifted distributed feedback laser diode (QWS DFB-LD) with multiple quantum well (MQW) structures. Our results show that the all-optical comparator is very well suited for true AO-ADCs, enabling the whole digital conversion from an analog optical signal (continuous-time signal or discrete pulse signal) to a binary representation totally in the optical domain. In particular, this all-optical analog comparator possesses a low threshold power (several mW), high extinction ratio (up to 40 dB), fast operation rate (of the order of tens of Gb/s) and a step-like transfer function. PMID:27550874

  6. All-optical analog comparator.

    PubMed

    Li, Pu; Yi, Xiaogang; Liu, Xianglian; Zhao, Dongliang; Zhao, Yongpeng; Wang, Yuncai

    2016-01-01

    An analog comparator is one of the core units in all-optical analog-to-digital conversion (AO-ADC) systems, which digitizes different amplitude levels into two levels of logical '1' or '0' by comparing with a defined decision threshold. Although various outstanding photonic ADC approaches have been reported, almost all of them necessitate an electrical comparator to carry out this binarization. The use of an electrical comparator is in contradiction to the aim of developing all-optical devices. In this work, we propose a new concept of an all-optical analog comparator and numerically demonstrate an implementation based on a quarter-wavelength-shifted distributed feedback laser diode (QWS DFB-LD) with multiple quantum well (MQW) structures. Our results show that the all-optical comparator is very well suited for true AO-ADCs, enabling the whole digital conversion from an analog optical signal (continuous-time signal or discrete pulse signal) to a binary representation totally in the optical domain. In particular, this all-optical analog comparator possesses a low threshold power (several mW), high extinction ratio (up to 40 dB), fast operation rate (of the order of tens of Gb/s) and a step-like transfer function. PMID:27550874

  7. 46 CFR 169.681 - Disconnect switches and devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Disconnect switches and devices. 169.681 Section 169.681... Less Than 100 Gross Tons § 169.681 Disconnect switches and devices. (a) Externally operable switches or... supplies, means must be provided for locking the disconnect device in the “open” position. (c) For...

  8. Ultrafast all-optical switching and error-free 10 Gbit/s wavelength conversion in hybrid InP-silicon on insulator nanocavities using surface quantum wells

    SciTech Connect

    Bazin, Alexandre; Monnier, Paul; Beaudoin, Grégoire; Sagnes, Isabelle; Raj, Rama; Lenglé, Kevin; Gay, Mathilde; Bramerie, Laurent; Braive, Rémy; Raineri, Fabrice

    2014-01-06

    Ultrafast switching with low energies is demonstrated using InP photonic crystal nanocavities embedding InGaAs surface quantum wells heterogeneously integrated to a silicon on insulator waveguide circuitry. Thanks to the engineered enhancement of surface non radiative recombination of carriers, switching time is obtained to be as fast as 10 ps. These hybrid nanostructures are shown to be capable of achieving systems level performance by demonstrating error free wavelength conversion at 10 Gbit/s with 6 mW switching powers.

  9. Spark gap device for precise switching

    DOEpatents

    Boettcher, Gordon E.

    1984-01-01

    A spark gap device for precise switching of an energy storage capacitor into an exploding bridge wire load is disclosed. Niobium electrodes having a melting point of 2,415 degrees centrigrade are spaced apart by an insulating cylinder to define a spark gap. The electrodes are supported by conductive end caps which, together with the insulating cylinder, form a hermetically sealed chamber filled with an inert, ionizable gas, such as pure xenon. A quantity of solid radioactive carbon-14 within the chamber adjacent the spark gap serves as a radiation stabilizer. The sides of the electrodes and the inner wall of the insulating cylinder are spaced apart a sufficient distance to prevent unwanted breakdown initiation. A conductive sleeve may envelop the outside of the insulating member from the midpoint of the spark gap to the cap adjacent the cathode. The outer metallic surfaces of the device may be coated with a hydrogen-impermeable coating to lengthen the shelf life and operating life of the device. The device breaks down at about 1,700 volts for input voltage rates up to 570 volts/millisecond and allows peak discharge currents of up to 3,000 amperes from a 0.3 microfarad energy storage capacitor for more than 1,000 operations.

  10. Spark gap device for precise switching

    DOEpatents

    Boettcher, G.E.

    1984-10-02

    A spark gap device for precise switching of an energy storage capacitor into an exploding bridge wire load is disclosed. Niobium electrodes having a melting point of 2,415 degrees centigrade are spaced apart by an insulating cylinder to define a spark gap. The electrodes are supported by conductive end caps which, together with the insulating cylinder, form a hermetically sealed chamber filled with an inert, ionizable gas, such as pure xenon. A quantity of solid radioactive carbon-14 within the chamber adjacent the spark gap serves as a radiation stabilizer. The sides of the electrodes and the inner wall of the insulating cylinder are spaced apart a sufficient distance to prevent unwanted breakdown initiation. A conductive sleeve may envelop the outside of the insulating member from the midpoint of the spark gap to the cap adjacent the cathode. The outer metallic surfaces of the device may be coated with a hydrogen-impermeable coating to lengthen the shelf life and operating life of the device. The device breaks down at about 1,700 volts for input voltage rates up to 570 volts/millisecond and allows peak discharge currents of up to 3,000 amperes from a 0.3 microfarad energy storage capacitor for more than 1,000 operations. 3 figs.

  11. All-optical time-delay switch based on grating buildup time of two-wave mixing in a bacteriorhodopsin film.

    PubMed

    Chen, Guiying; Lu, Wenqiang; Xu, Xuxu; Tian, Jianguo; Zhang, Chunping

    2009-10-01

    We demonstrate time-delay switches using the first-order dynamic diffraction light of two-beam coupled light with wavelengths of 632.8, 650, 532, and 488 nm in a bacteriorhodopsin film. The optimal wavelengths are selected and the relationship between incident intensity and delay time is discussed. A switch delay time ranging from 3.52 to 12.5 s is presented by the 632.8 nm wavelength, while a delay time ranging from 1.24 to 10.6 s is demonstrated by the 488 nm wavelength. On the other hand, the wavelengths of 532 and 650 nm are not suitable for time-delay switches due to the large variation of first-order diffraction intensity for lower incident intensities.

  12. All-optical flip-flop and control methods thereof

    SciTech Connect

    Maywar, Drew; Agrawal, Govind P.

    2010-03-23

    Embodiments of the invention pertain to remote optical control of holding beam-type, optical flip-flop devices, as well as to the devices themselves. All-optical SET and RE-SET control signals operate on a cw holding beam in a remote manner to vary the power of the holding beam between threshold switching values to enable flip-flop operation. Cross-gain modulation and cross-polarization modulation processes can be used to change the power of the holding beam.

  13. Electrocaloric devices based on thini-film heat switches

    SciTech Connect

    Epstein, Richard I; Malloy, Kevin J

    2009-01-01

    We describe a new approach to refrigeration and electrical generation that exploits the attractive properties of thin films of electrocaloric materials. Layers of electrocaloric material coupled with thin-film heat switches can work as either refrigerators or electrical generators, depending on the phasing of the applied voltages and heat switching. With heat switches based on thin layers of liquid crystals, the efficiency of these thin-film heat engines can be at least as high as that of current thermoelectric devices. Advanced heat switches would enable thin-film heat engines to outperform conventional vaporcompression devices.

  14. Devices for wavelength switching in optical networks

    SciTech Connect

    d`Alessandro, A.; Baran, J.E.; Smith, D.A.

    1994-12-31

    Wavelength routing crossconnects are considered the core of WDM optical networks. They consist of optical switches independently rearrangeable for each wavelength channel and for any input-output configuration so that any path can be chosen almost arbitrarily by the network users. In general the implementation of the wavelength routing function requires complex switch arrays. Very simple wavelength-selection crossconnects can be realized by using acousto-optic switches (AOS), because of their unique ability of processing several optical signals simultaneously and their low driving power consumption, less than 10 mW/channel. AOS`s can be considered a particular evolution of acousto-optical tunable filters, whose integrated optic version on lithium niobate has been developed in several research institutions around the world in the past decade. This paper reviews the last accomplishments of AOS`s, whose specifications are directly tied with optical network requirements, the foremost challenge being a strong suppression of crosstalk. Dilated AOS`s can reduce interport crosstalk to below {minus}30 dB and apodization of acousto-optic interaction can reduce interchannel crosstalk to below {minus}15 dB during multiwavelength operation.

  15. Electric energy saving two position combination switching device

    SciTech Connect

    Andrews, P.

    1985-10-22

    In one form of the present preferred embodiment of the present invention it relates to a two-position feed-thru electric line cord piercing switching combination, of the rotary and even the rocker type, which saves electric energy by use of a half-wave diode rectifying means. The electric energy saving, two-position, combination switching means having only two electrical passing switching positions and thereby having no electrical ''off'' position. The switch will alternatingly provide either an electrical half-wave ''dim'' or an electrical full-wave ''on'' illumination to a single filament lamp, string of Christmas tree lamps and the like, and will even provide eight separate combinations, of one OFF abd three separate illuminations, when electrically connected ahead of a, for example, conventional LEVITON rotary 4-position lamp socket switching means which uses a conventional 3-way incandescent lamp member which is removable inserted into the lamp socket portion thereof. MICRO, CHERRY, toggle, rocker, push-button and the like, line cord non-piercing two-position switches may be used in other forms of the combination switching device or invention. The half-wave diode rectifying means is electrically connected shuntingly between and/or across substantially to two electrical contact members of the conductor wire-piercing and the wire non-piercing type of switching means. This construction results in automatic elimination of the electrical ''off'' position for generally any type 2 2-position ''off'' and ''on'' switching means.

  16. Multilevel conductance switching of memory device through photoelectric effect.

    PubMed

    Ye, Changqing; Peng, Qian; Li, Mingzhu; Luo, Jia; Tang, Zhengming; Pei, Jian; Chen, Jianming; Shuai, Zhigang; Jiang, Lei; Song, Yanlin

    2012-12-12

    A photoelectronic switch of a multilevel memory device has been achieved using a meta-conjugated donor-bridge-acceptor (DBA) molecule. Such a DBA optoelectronic molecule responds to both the optical and electrical stimuli. The device exhibits good electrical bistable switching behaviors under dark, with a large ON/OFF ratio more than 10(6). In cooperation with the UV light, photoelectronic ternary states are addressable in a bistable switching system. On the basis of the CV measurement, charge carriers transport modeling, quantum chemical calculation, and absorption spectra analysis, the mechanism of the DBA memory is suggested to be attributed to the substep charge transfer transition process. The capability of tailoring photoelectrical properties is a very promising strategy to explore the multilevel storage, and it will give a new opportunity for designing multifunctional devices.

  17. Resistive switching characteristics and mechanisms in silicon oxide memory devices

    NASA Astrophysics Data System (ADS)

    Chang, Yao-Feng; Fowler, Burt; Chen, Ying-Chen; Zhou, Fei; Wu, Xiaohan; Chen, Yen-Ting; Wang, Yanzhen; Xue, Fei; Lee, Jack C.

    2016-05-01

    Intrinsic unipolar SiOx-based resistance random access memories (ReRAM) characterization, switching mechanisms, and applications have been investigated. Device structures, material compositions, and electrical characteristics are identified that enable ReRAM cells with high ON/OFF ratio, low static power consumption, low switching power, and high readout-margin using complementary metal-oxide semiconductor transistor (CMOS)-compatible SiOx-based materials. These ideas are combined with the use of horizontal and vertical device structure designs, composition optimization, electrical control, and external factors to help understand resistive switching (RS) mechanisms. Measured temperature effects, pulse response, and carrier transport behaviors lead to compact models of RS mechanisms and energy band diagrams in order to aid the development of computer-aided design for ultralarge-v scale integration. This chapter presents a comprehensive investigation of SiOx-based RS characteristics and mechanisms for the post-CMOS device era.

  18. All optical OFDM transmission systems

    NASA Astrophysics Data System (ADS)

    Rhee, June-Koo K.; Lim, Seong-Jin; Kserawi, Malaz

    2011-12-01

    All-optical OFDM data transmission opens up a new realm of advanced optical transmission at extreme data rates, as subcarriers are multiplexed and demultiplexed by all optical discrete Fourier transforms (DFT). This paper reviews the principles of all optical OFDM transmission and its system application techniques, providing the generic ideas and the practical implementation issues to achieve 100Gbps or higher data rates with a spectral efficiency of 1 bps/Hz or better. This paper also include discussions on all-optical OFDM implementation variants such as an AWG-based OFDM multiplexer and demultiplexer, a receiver design without optical sampling, a transmitter design with frequency-locked cw lasers, an OFDM cyclic prefix designs, and a chromatic dispersion mitigation technique.

  19. Ultra compact and fast All Optical Flip Flop design in photonic crystal platform

    NASA Astrophysics Data System (ADS)

    Abbasi, Amin; Noshad, Morteza; Ranjbar, Reza; Kheradmand, Reza

    2012-11-01

    In this work we present a heterostructure All Optical Flip-Flop configuration based on all optical switching with Kerr nonlinear photonic crystal. In this square-hexagonal structure, we propose three different schemes for the cavities in order to show the trade-off between switching time and triggering power. Loss in the system is reasonably low because of the perfect band gap matching at bending points where two lattices join. The proposed RS-Flip Flop has exceptional features, which make it one of the well optimized and most practical structures to be used in the all optical integrated circuits. The novel design has a fast switching action (on the order of a few picoseconds), and low input power (on the order of 100 mW). Furthermore, high contrast of the output signals for ON and OFF states, can help the easy detection or its coupling to the other devices. The structure is fascinatingly uncomplicated, which results in ultra small dimensions which make it suitable to be placed in an all optical integrated circuit. Besides, we provide a profound analytical view on the functioning of the system, as analyzed by the finite difference time domain (FDTD) method.

  20. Device having two optical ports for switching applications

    DOEpatents

    Rosen, Ayre; Stabile, Paul J.

    1991-09-24

    A two-sided light-activatable semiconductor switch device having an optical port on each side thereof. The semiconductor device may be a p-i-n diode or of bulk intrinsic material. A two ported p-i-n diode, reverse-biased to "off" by a 1.3 kV dc power supply, conducted 192 A when activated by two 1 kW laser diode arrays, one for each optical port.

  1. Focus ion beam-induced mechanical stress switching in an ultra-fast resistive switching device

    NASA Astrophysics Data System (ADS)

    Yang, Xiang

    2016-06-01

    The Mo/Si3N4:Pt/Pt nanometallic resistive switching devices with ultra-fast write/erase speed (<50 ns) were fabricated. Other than conventional electrical switching, a mechanical stress-induced switching was demonstrated. Such mechanical stress was provided by momentum transfer of 30 keV Ga+ ions in a focus ion beam system, enabling a one-way high resistance state (HRS) to low resistance state (LRS) transition. The capability of mechanical stress switching provides evidence that electron trapping/detrapping mechanism is responsible for nanometallic resistive switching. It was further demonstrated that HRS (trapping state) is a meta-stable state, while LRS (detrapping state) is a stable state. Strong mechanical stress facilitates local bond distortion in dielectric films and thus lowers the energy barrier between HRS and LRS, eventually leading to a barrier-less state transition. A quantitative model based on stress-mediated parallel conduction paths were established to provide a more accurate description of the resistive switching devices.

  2. All-optical symmetric ternary logic gate

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Tanay

    2010-09-01

    Symmetric ternary number (radix=3) has three logical states (1¯, 0, 1). It is very much useful in carry free arithmetical operation. Beside this, the logical operation using this type of number system is also effective in high speed computation and communication in multi-valued logic. In this literature all-optical circuits for three basic symmetrical ternary logical operations (inversion, MIN and MAX) are proposed and described. Numerical simulation verifies the theoretical model. In this present scheme the different ternary logical states are represented by different polarized state of light. Terahertz optical asymmetric demultiplexer (TOAD) based interferometric switch has been used categorically in this manuscript.

  3. Integrated all-optical infrared switchable plasmonic quantum cascade laser.

    PubMed

    Kohoutek, John; Bonakdar, Alireza; Gelfand, Ryan; Dey, Dibyendu; Nia, Iman Hassani; Fathipour, Vala; Memis, Omer Gokalp; Mohseni, Hooman

    2012-05-01

    We report a type of infrared switchable plasmonic quantum cascade laser, in which far field light in the midwave infrared (MWIR, 6.1 μm) is modulated by a near field interaction of light in the telecommunications wavelength (1.55 μm). To achieve this all-optical switch, we used cross-polarized bowtie antennas and a centrally located germanium nanoslab. The bowtie antenna squeezes the short wavelength light into the gap region, where the germanium is placed. The perturbation of refractive index of the germanium due to the free carrier absorption produced by short wavelength light changes the optical response of the antenna and the entire laser intensity at 6.1 μm significantly. This device shows a viable method to modulate the far field of a laser through a near field interaction.

  4. Magneto-optical switching devices based on Si resonators

    NASA Astrophysics Data System (ADS)

    Noda, Kazuki; Okada, Kazuya; Amemiya, Yoshiteru; Yokoyama, Shin

    2016-04-01

    The magneto-optical switching devices based on Si ring and Si photonic crystal resonators have been fabricated using a Bi3Fe5O12 (BIG) film deposited by the metal organic decomposition (MOD) method. The quality of the obtained BIG film was evaluated by X-ray diffraction and the magneto-optical Kerr effect and relatively good results were obtained. The light modulations of both devices were ≦20% at a wavelength of ˜1.5 µm. The operation mechanisms of both devices are explained by the Cotton-Mouton effect where the magnetic field direction is perpendicular to the light propagation direction.

  5. All-optical reservoir computing.

    PubMed

    Duport, François; Schneider, Bendix; Smerieri, Anteo; Haelterman, Marc; Massar, Serge

    2012-09-24

    Reservoir Computing is a novel computing paradigm that uses a nonlinear recurrent dynamical system to carry out information processing. Recent electronic and optoelectronic Reservoir Computers based on an architecture with a single nonlinear node and a delay loop have shown performance on standardized tasks comparable to state-of-the-art digital implementations. Here we report an all-optical implementation of a Reservoir Computer, made of off-the-shelf components for optical telecommunications. It uses the saturation of a semiconductor optical amplifier as nonlinearity. The present work shows that, within the Reservoir Computing paradigm, all-optical computing with state-of-the-art performance is possible.

  6. All-optical reservoir computing

    NASA Astrophysics Data System (ADS)

    Duport, François; Schneider, Bendix; Smerieri, Anteo; Haelterman, Marc; Massar, Serge

    2012-09-01

    Reservoir Computing is a novel computing paradigm which uses a nonlinear recurrent dynamical system to carry out information processing. Recent electronic and optoelectronic Reservoir Computers based on an architecture with a single nonlinear node and a delay loop have shown performance on standardized tasks comparable to state-of-the-art digital implementations. Here we report an all-optical implementation of a Reservoir Computer, made of off-the-shelf components for optical telecommunications. It uses the saturation of a semiconductor optical amplifier as nonlinearity. The present work shows that, within the Reservoir Computing paradigm, all-optical computing with state-of-the-art performance is possible.

  7. Optically controlled multiple switching operations of DNA biopolymer devices

    SciTech Connect

    Hung, Chao-You; Tu, Waan-Ting; Lin, Yi-Tzu; Fruk, Ljiljana; Hung, Yu-Chueh

    2015-12-21

    We present optically tunable operations of deoxyribonucleic acid (DNA) biopolymer devices, where a single high-resistance state, write-once read-many-times memory state, write-read-erase memory state, and single low-resistance state can be achieved by controlling UV irradiation time. The device is a simple sandwich structure with a spin-coated DNA biopolymer layer sandwiched by two electrodes. Upon irradiation, the electrical properties of the device are adjusted owing to a phototriggered synthesis of silver nanoparticles in DNA biopolymer, giving rise to multiple switching scenarios. This technique, distinct from the strategy of doping of pre-formed nanoparticles, enables a post-film fabrication process for achieving optically controlled memory device operations, which provides a more versatile platform to fabricate organic memory and optoelectronic devices.

  8. Optically controlled multiple switching operations of DNA biopolymer devices

    NASA Astrophysics Data System (ADS)

    Hung, Chao-You; Tu, Waan-Ting; Lin, Yi-Tzu; Fruk, Ljiljana; Hung, Yu-Chueh

    2015-12-01

    We present optically tunable operations of deoxyribonucleic acid (DNA) biopolymer devices, where a single high-resistance state, write-once read-many-times memory state, write-read-erase memory state, and single low-resistance state can be achieved by controlling UV irradiation time. The device is a simple sandwich structure with a spin-coated DNA biopolymer layer sandwiched by two electrodes. Upon irradiation, the electrical properties of the device are adjusted owing to a phototriggered synthesis of silver nanoparticles in DNA biopolymer, giving rise to multiple switching scenarios. This technique, distinct from the strategy of doping of pre-formed nanoparticles, enables a post-film fabrication process for achieving optically controlled memory device operations, which provides a more versatile platform to fabricate organic memory and optoelectronic devices.

  9. Electrical switching in a Fe-thiacrown molecular device

    SciTech Connect

    Lan, J.; Zheng, X. H. Hao, H.; Wang, X. L.; Shi, X. Q.; Zeng, Z.

    2014-01-07

    First-principles calculations are performed to inspect the electronic and transport properties of a Fe-thiacrown molecular device, namely, a Au-Fe(9S{sub 3}){sub 2}-Au junction. It is found that the junction has a low-spin (LS) ground state and a high-spin (HS) metastable state. Further study shows that the HS state is a conducting state while the LS state is a nearly insulating one, which means that a switch between these two spin configurations results in a good electrical switching behavior and can serve as an ON/OFF state for a logic unit. Thus, it may find applications as switches or memories in molecular electronic circuits.

  10. All-optical buffering for DPSK packets

    NASA Astrophysics Data System (ADS)

    Liu, Guodong; Wu, Chongqing; Liu, Lanlan; Wang, Fu; Mao, Yaya; Sun, Zhenchao

    2013-12-01

    Advanced modulation formats, such as DPSK, DQPSK, QAM, have become the mainstream technologies in the optical network over 40Gb/s, the DPSK format is the fundamental of all advanced modulation formats. Optical buffers, as a key element for temporarily storing packets in order to synchronization or contention resolution in optical nodes, must be adapted to this new requirement. Different from other current buffers to store the NRZ or RZ format, an all-optical buffer of storing DPSK packets based on nonlinear polarization rotation in SOA is proposed and demonstrated. In this buffer, a section of PMF is used as fiber delay line to maintain the polarization states unchanged, the driver current of SOA is optimized, and no amplifier is required in the fiber loop. A packet delay resolution of 400ns is obtained and storage for tens rounds is demonstrated without significant signal degradation. Using proposed the new tunable DPSK demodulator, bit error rate has been measured after buffering for tens rounds for 10Gb/s data payload. Configurations for First-in First-out (FIFO) buffer or First-in Last-out (FILO) buffer are proposed based on this buffer. The buffer is easy control and suitable for integration. The terminal contention caused by different clients can be mitigated by managing packets delays in future all-optical network, such as optical packet switching network and WDM switching network.

  11. Rapidly reconfigurable all-optical universal logic gate

    DOEpatents

    Goddard, Lynford L.; Bond, Tiziana C.; Kallman, Jeffrey S.

    2010-09-07

    A new reconfigurable cascadable all-optical on-chip device is presented. The gate operates by combining the Vernier effect with a novel effect, the gain-index lever, to help shift the dominant lasing mode from a mode where the laser light is output at one facet to a mode where it is output at the other facet. Since the laser remains above threshold, the speed of the gate for logic operations as well as for reprogramming the function of the gate is primarily limited to the small signal optical modulation speed of the laser, which can be on the order of up to about tens of GHz. The gate can be rapidly and repeatedly reprogrammed to perform any of the basic digital logic operations by using an appropriate analog optical or electrical signal at the gate selection port. Other all-optical functionality includes wavelength conversion, signal duplication, threshold switching, analog to digital conversion, digital to analog conversion, signal routing, and environment sensing. Since each gate can perform different operations, the functionality of such a cascaded circuit grows exponentially.

  12. Electro-optical switching and memory display device

    DOEpatents

    Skotheim, T.A.; O'Grady, W.E.; Linkous, C.A.

    1983-12-29

    An electro-optical display device having a housing with wall means including one transparent wall and at least one other wall. Counter electrodes are positioned on the transparent wall and display electrodes are positioned on the other wall with both electrodes in electrically conductive relationship with an electrolyte. Circuits means are connected to the display and counter electrodes to apply different predetermined control potentials between them. The display electrodes are covered with a thin electrically conductive polymer film that is characterized according to the invention by having embedded in it pigment molecules as counter ions. The display device is operable to be switched to a plurality of different visual color states at an exceptionally rapid switching rate while each of the color states is characterized by possessing good color intensity and definition.

  13. Electro-optical switching and memory display device

    DOEpatents

    Skotheim, Terje A.; O'Grady, William E.; Linkous, Clovis A.

    1986-01-01

    An electro-optical display device having a housing with wall means including one transparent wall and at least one other wall. Counter electrodes are positioned on the transparent wall and display electrodes are positioned on the other wall with both electrodes in electrically conductive relationship with an electrolyte. Circuit means are connected to the display and counter electrodes to apply different predetermined control potentials between them. The display electrodes are covered with a thin electrically conductive polymer film that is characterized according to the invention by having embedded in it pigment molecules as counter ions. The display device is operable to be switched to a plurality of different visual color states at an exceptionally rapid switching rate while each of the color states is characterized by possessing good color intensity and definition.

  14. All-optical controlling based on nonlinear graphene plasmonic waveguides.

    PubMed

    Li, Jian; Tao, Jin; Chen, Zan Hui; Huang, Xu Guang

    2016-09-19

    We give the effective refractive index of graphene plasmonic waveguides with both linear and nonlinear effects based on the nonlinear cross-phase modulation, and address the effects of photo-induced refractive index change and absorption change. A non-resonant all-optical nonlinear graphene plasmonic switch with an ultra-compact size of 0.25 μm2 is proposed and numerically analyzed based on the dynamics of the photo-induced absorption change. The results show that the all-optical graphene plasmonic switch can realize a broad bandwidth over 5 THz, a potentially very high switching speed and an extinction ratio of 18.14 dB with the electric amplitude of the pump light of 1.5 × 107 V/m at the signal frequency of 28 THz. Our study could provide a possibility for future all-optical highly integrated optical components. PMID:27661951

  15. Materials growth and characterization of thermoelectric and resistive switching devices

    NASA Astrophysics Data System (ADS)

    Norris, Kate J.

    In the 74 years since diode rectifier based radar technology helped the allied forces win WWII, semiconductors have transformed the world we live in. From our smart phones to semiconductor-based energy conversion, semiconductors touch every aspect of our lives. With this thesis I hope to expand human knowledge of semiconductor thermoelectric devices and resistive switching devices through experimentation with materials growth and subsequent materials characterization. Metal organic chemical vapor deposition (MOCVD) was the primary method of materials growth utilized in these studies. Additionally, plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD),ion beam sputter deposition, reactive sputter deposition and electron-beam (e-beam) evaporation were also used in this research for device fabrication. Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and Electron energy loss spectroscopy (EELS) were the primary characterization methods utilized for this research. Additional device and materials characterization techniques employed include: current-voltage measurements, thermoelectric measurements, x-ray diffraction (XRD), reflection absorption infra-red spectroscopy (RAIRS), atomic force microscopy (AFM), photoluminescence (PL), and raman spectroscopy. As society has become more aware of its impact on the planet and its limited resources, there has been a push toward developing technologies to sustainably produce the energy we need. Thermoelectric devices convert heat directly into electricity. Thermoelectric devices have the potential to save huge amounts of energy that we currently waste as heat, if we can make them cost-effective. Semiconducting thin films and nanowires appear to be promising avenues of research to attain this goal. Specifically, in this work we will explore the use of ErSb thin films as well as Si and InP nanowire networks for thermoelectric applications. First we will discuss the growth of

  16. All-optical control of microfiber resonator by graphene's photothermal effect

    NASA Astrophysics Data System (ADS)

    Wang, Yadong; Gan, Xuetao; Zhao, Chenyang; Fang, Liang; Mao, Dong; Xu, Yiping; Zhang, Fanlu; Xi, Teli; Ren, Liyong; Zhao, Jianlin

    2016-04-01

    We demonstrate an efficient all-optical control of microfiber resonator assisted by graphene's photothermal effect. Wrapping graphene onto a microfiber resonator, the light-graphene interaction can be strongly enhanced via the resonantly circulating light, which enables a significant modulation of the resonance with a resonant wavelength shift rate of 71 pm/mW when pumped by a 1540 nm laser. The optically controlled resonator enables the implementation of low threshold optical bistability and switching with an extinction ratio exceeding 13 dB. The thin and compact structure promises a fast response speed of the control, with a rise (fall) time of 294.7 μs (212.2 μs) following the 10%-90% rule. The proposed device, with the advantages of compact structure, all-optical control, and low power acquirement, offers great potential in the miniaturization of active in-fiber photonic devices.

  17. Proposed new approach to design all optical AND gate using plasmonic based Mach-Zehnder interferometer for high speed communication

    NASA Astrophysics Data System (ADS)

    Kumar, Santosh; Singh, Lokendra

    2016-04-01

    The limitation of conventional electronics is mitigated by all optical integrated circuits which have potential of high speed computing and information processing. In this work, an all optical AND gate using optical Kerr effect and optical bistability of a plasmonic based Mach-Zehnder interferometer (MZI) is proposed. An MZI is capable for switching of light according to the intensities of optical input signal. The paper constitutes with mathematical formulation of device and its study is verified using finite difference time domain (FDTD) method.

  18. All-optical transistor- and diode-action and logic gates based on anisotropic nonlinear responsive liquid crystal.

    PubMed

    Wang, Cheng-Yu; Chen, Chun-Wei; Jau, Hung-Chang; Li, Cheng-Chang; Cheng, Chiao-Yu; Wang, Chun-Ta; Leng, Shi-Ee; Khoo, Iam-Choon; Lin, Tsung-Hsien

    2016-08-05

    In this paper, we show that anisotropic photosensitive nematic liquid crystals (PNLC) made by incorporating anisotropic absorbing dyes are promising candidates for constructing all-optical elements by virtue of the extraordinarily large optical nonlinearity of the nematic host. In particular, we have demonstrated several room-temperature 'prototype' PNLC-based all-optical devices such as optical diode, optical transistor and all primary logic gate operations (OR, AND, NOT) based on such optical transistor. Owing to the anisotropic absorption property and the optical activity of the twist alignment nematic cell, spatially non-reciprocal transmission response can be obtained within a sizeable optical isolation region of ~210 mW. Exploiting the same mechanisms, a tri-terminal configuration as an all-optical analogue of a bipolar junction transistor is fabricated. Its ability to be switched by an optical field enables us to realize an all-optical transistor and demonstrate cascadability, signal fan-out, logic restoration, and various logical gate operations such as OR, AND and NOT. Due to the possibility of synthesizing anisotropic dyes and wide ranging choice of liquid crystals nonlinear optical mechanisms, these all-optical operations can be optimized to have much lower thresholds and faster response speeds. The demonstrated capabilities of these devices have shown great potential in all-optical control system and photonic integrated circuits.

  19. All-optical transistor- and diode-action and logic gates based on anisotropic nonlinear responsive liquid crystal

    PubMed Central

    Wang, Cheng-Yu; Chen, Chun-Wei; Jau, Hung-Chang; Li, Cheng-Chang; Cheng, Chiao-Yu; Wang, Chun-Ta; Leng, Shi-Ee; Khoo, Iam-Choon; Lin, Tsung-Hsien

    2016-01-01

    In this paper, we show that anisotropic photosensitive nematic liquid crystals (PNLC) made by incorporating anisotropic absorbing dyes are promising candidates for constructing all-optical elements by virtue of the extraordinarily large optical nonlinearity of the nematic host. In particular, we have demonstrated several room-temperature ‘prototype’ PNLC-based all-optical devices such as optical diode, optical transistor and all primary logic gate operations (OR, AND, NOT) based on such optical transistor. Owing to the anisotropic absorption property and the optical activity of the twist alignment nematic cell, spatially non-reciprocal transmission response can be obtained within a sizeable optical isolation region of ~210 mW. Exploiting the same mechanisms, a tri-terminal configuration as an all-optical analogue of a bipolar junction transistor is fabricated. Its ability to be switched by an optical field enables us to realize an all-optical transistor and demonstrate cascadability, signal fan-out, logic restoration, and various logical gate operations such as OR, AND and NOT. Due to the possibility of synthesizing anisotropic dyes and wide ranging choice of liquid crystals nonlinear optical mechanisms, these all-optical operations can be optimized to have much lower thresholds and faster response speeds. The demonstrated capabilities of these devices have shown great potential in all-optical control system and photonic integrated circuits. PMID:27491391

  20. All-optical transistor- and diode-action and logic gates based on anisotropic nonlinear responsive liquid crystal

    NASA Astrophysics Data System (ADS)

    Wang, Cheng-Yu; Chen, Chun-Wei; Jau, Hung-Chang; Li, Cheng-Chang; Cheng, Chiao-Yu; Wang, Chun-Ta; Leng, Shi-Ee; Khoo, Iam-Choon; Lin, Tsung-Hsien

    2016-08-01

    In this paper, we show that anisotropic photosensitive nematic liquid crystals (PNLC) made by incorporating anisotropic absorbing dyes are promising candidates for constructing all-optical elements by virtue of the extraordinarily large optical nonlinearity of the nematic host. In particular, we have demonstrated several room-temperature ‘prototype’ PNLC-based all-optical devices such as optical diode, optical transistor and all primary logic gate operations (OR, AND, NOT) based on such optical transistor. Owing to the anisotropic absorption property and the optical activity of the twist alignment nematic cell, spatially non-reciprocal transmission response can be obtained within a sizeable optical isolation region of ~210 mW. Exploiting the same mechanisms, a tri-terminal configuration as an all-optical analogue of a bipolar junction transistor is fabricated. Its ability to be switched by an optical field enables us to realize an all-optical transistor and demonstrate cascadability, signal fan-out, logic restoration, and various logical gate operations such as OR, AND and NOT. Due to the possibility of synthesizing anisotropic dyes and wide ranging choice of liquid crystals nonlinear optical mechanisms, these all-optical operations can be optimized to have much lower thresholds and faster response speeds. The demonstrated capabilities of these devices have shown great potential in all-optical control system and photonic integrated circuits.

  1. All-optical transistor- and diode-action and logic gates based on anisotropic nonlinear responsive liquid crystal.

    PubMed

    Wang, Cheng-Yu; Chen, Chun-Wei; Jau, Hung-Chang; Li, Cheng-Chang; Cheng, Chiao-Yu; Wang, Chun-Ta; Leng, Shi-Ee; Khoo, Iam-Choon; Lin, Tsung-Hsien

    2016-01-01

    In this paper, we show that anisotropic photosensitive nematic liquid crystals (PNLC) made by incorporating anisotropic absorbing dyes are promising candidates for constructing all-optical elements by virtue of the extraordinarily large optical nonlinearity of the nematic host. In particular, we have demonstrated several room-temperature 'prototype' PNLC-based all-optical devices such as optical diode, optical transistor and all primary logic gate operations (OR, AND, NOT) based on such optical transistor. Owing to the anisotropic absorption property and the optical activity of the twist alignment nematic cell, spatially non-reciprocal transmission response can be obtained within a sizeable optical isolation region of ~210 mW. Exploiting the same mechanisms, a tri-terminal configuration as an all-optical analogue of a bipolar junction transistor is fabricated. Its ability to be switched by an optical field enables us to realize an all-optical transistor and demonstrate cascadability, signal fan-out, logic restoration, and various logical gate operations such as OR, AND and NOT. Due to the possibility of synthesizing anisotropic dyes and wide ranging choice of liquid crystals nonlinear optical mechanisms, these all-optical operations can be optimized to have much lower thresholds and faster response speeds. The demonstrated capabilities of these devices have shown great potential in all-optical control system and photonic integrated circuits. PMID:27491391

  2. Plasmonic enhancement of ultrafast all-optical magnetization reversal

    NASA Astrophysics Data System (ADS)

    Kochergin, Vladimir; Neely, Lauren N.; Allin, Leigh J.; Kochergin, Eugene V.; Wang, Kang L.

    2011-10-01

    Ultrafast all optical magnetization switching in GdFeCo layers on the basis of Inverse Faraday Effect (IFE) was demonstrated recently and suggested as a possible path toward next generation magnetic data storage medium with much faster writing time. However, to date, the demonstrations of ultrafast all-optical magnetization switching were performed with powerful femtosecond lasers, hardly useful for practical applications in data storage and data processing. Here we show that utilization of IFE enhancement in plasmonic nanostructures enables fast all-optical magnetization switching with smaller/cheaper laser sources with longer pulse durations. Our modeling results predict significant enhancement of IFE around all major types of plasmonic nanostructures for a circularly polarized incident light. Unlike the IFE in uniform bulk materials, nonzero value of IFE is predicted in plasmonic nanostructures even with a linearly polarized excitation. Experimentally, all-optical magnetization switching at 20 times lower laser fluence and roughly 100 times lower value of laser fluence/pulse duration ratio is demonstrated in plasmonic samples to verify the model predictions. The path to achieve higher levels of enhancement experimentally is discussed.

  3. Self-assembled nanostructured resistive switching memory devices fabricated by templated bottom-up growth

    NASA Astrophysics Data System (ADS)

    Song, Ji-Min; Lee, Jang-Sik

    2016-01-01

    Metal-oxide-based resistive switching memory device has been studied intensively due to its potential to satisfy the requirements of next-generation memory devices. Active research has been done on the materials and device structures of resistive switching memory devices that meet the requirements of high density, fast switching speed, and reliable data storage. In this study, resistive switching memory devices were fabricated with nano-template-assisted bottom up growth. The electrochemical deposition was adopted to achieve the bottom-up growth of nickel nanodot electrodes. Nickel oxide layer was formed by oxygen plasma treatment of nickel nanodots at low temperature. The structures of fabricated nanoscale memory devices were analyzed with scanning electron microscope and atomic force microscope (AFM). The electrical characteristics of the devices were directly measured using conductive AFM. This work demonstrates the fabrication of resistive switching memory devices using self-assembled nanoscale masks and nanomateirals growth from bottom-up electrochemical deposition.

  4. Self-assembled nanostructured resistive switching memory devices fabricated by templated bottom-up growth

    PubMed Central

    Song, Ji-Min; Lee, Jang-Sik

    2016-01-01

    Metal-oxide-based resistive switching memory device has been studied intensively due to its potential to satisfy the requirements of next-generation memory devices. Active research has been done on the materials and device structures of resistive switching memory devices that meet the requirements of high density, fast switching speed, and reliable data storage. In this study, resistive switching memory devices were fabricated with nano-template-assisted bottom up growth. The electrochemical deposition was adopted to achieve the bottom-up growth of nickel nanodot electrodes. Nickel oxide layer was formed by oxygen plasma treatment of nickel nanodots at low temperature. The structures of fabricated nanoscale memory devices were analyzed with scanning electron microscope and atomic force microscope (AFM). The electrical characteristics of the devices were directly measured using conductive AFM. This work demonstrates the fabrication of resistive switching memory devices using self-assembled nanoscale masks and nanomateirals growth from bottom-up electrochemical deposition. PMID:26739122

  5. Spin-transfer switching of orthogonal spin-valve devices at cryogenic temperatures

    SciTech Connect

    Ye, L. Gopman, D. B.; Rehm, L.; Backes, D.; Wolf, G.; Kent, A. D.; Ohki, T.; Kirichenko, A. F.; Vernik, I. V.; Mukhanov, O. A.

    2014-05-07

    We present the quasi-static and dynamic switching characteristics of orthogonal spin-transfer devices incorporating an out-of-plane magnetized polarizing layer and an in-plane magnetized spin valve device at cryogenic temperatures. Switching at 12 K between parallel and anti-parallel spin-valve states is investigated for slowly varied current as well as for current pulses with durations as short as 200 ps. We demonstrate 100% switching probability with current pulses 0.6 ns in duration. We also present a switching probability diagram that summarizes device switching operation under a variety of pulse durations, amplitudes, and polarities.

  6. A New All-Optical Imaging Scheme based on QWIP technology

    NASA Astrophysics Data System (ADS)

    Zeng, Debing; Chen, Gang; Martini, Rainer

    2006-03-01

    Infrared imaging applications have gained increasing interest over the recent decades due to favorable light propagation, night imaging as well as chemical sensing applications. However, the scalability of the existing techniques towards high resolution in the multi-megapixel range is one of the major challenges in today's IR imaging technologies. Here we present an alternative solution using an all-optical wavelength conversion scheme. QWIP has been successfully proven their potential in IR imaging applications. Yet the fundamental conversion process from IR light to electric current has been one of the major restrictions in such system. To overcome this problem we propose the use of an all-optical conversion scheme, which utilizes an interband resonant optical NIR beam to probe the electrical population of the QW structure. In this methodology the incident MIR radiation changes the occupation of the QWs, which in turn influences the NIR transmission. Hence the irradiated MIR images can be probed by spatially resolved measurement of the NIR transmission, as has been demonstrated by Nada et al. for all-optical switching purposes. In this talk we present an implementation scheme of the all-optical QWIP readout technique together with theoretical calculations of the sensitivity of the proposed device and its temperature dependence. First experimental results will be presented also. The Authors thankfully acknowledge financial support by US Army, Picatinny Arsenal.

  7. Design of polarization encoded all-optical 4-valued MAX logic gate and its applications

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Tanay; Nath Roy, Jitendra

    2013-07-01

    Quaternary maximum (QMAX) gate is one type of multi-valued logic gate. An all-optical scheme of polarization encoded quaternary (4-valued) MAX logic gate with the help of Terahertz Optical Asymmetric Demultiplexer (TOAD) based fiber interferometric switch is proposed and described. For the quaternary information processing in optics, the quaternary number (0, 1, 2, 3) can be represented by four discrete polarized states of light. Numerical simulation result confirming the described methods is given in this paper. Some applications of MAX gate in logical operation and memory device are also given.

  8. High power switching and other high power devices

    NASA Astrophysics Data System (ADS)

    Gundersen, Martin

    1992-09-01

    High power thyratrons and devices such as high power microwave sources have cathode-related performance limits. Research is described of a simple, robust 'super-emissive' cathode that produces greater than 10,000 A/sq cm from a macroscopic area (approx. 1 sq cm), and operates with a low pressure (approx. 0.1 torr), spatially uniform glow plasma (density greater than 1015 cu cm). The cathode also can operate as a hollow cathode, and is at the heart of the operation of the pseudospark and back-lighted thyratron. The physics of this hollow and super-emissive cathode is very rich. The hollow cathode geometry traps electrons in the hollow cathode backspace. The lifetime of these electrons enables them to ionize a spatially homogeneous high density glow, and this hollow cathode mode of operation is responsible for certain types of electron and ion beam behavior. A plasma cathode sheath that is formed during this phase leads to super-emissive behavior, which is responsible for high current emission. Super-emissive cathode thyratron-type switches (with higher peak current, voltage, di/dt) being developed for pulsed power switching of lasers, accelerators, high current and high coulomb transfer, Marx bank operation, transfer of technology to commercial applications, high current electron beams, and millimeter wave generation (1 to 100 GHz) are described.

  9. Stochastic simulations of switching error in magneto elastic and spin-Hall effect based switching of nanomagnetic devices

    NASA Astrophysics Data System (ADS)

    Al-Rashid, Md Mamun; Bandyopadhyay, Supriyo; Atulasimha, Jayasimha

    2015-03-01

    Switching of single domain multiferroic nanomagnets with electrically generated mechanical strain and with spin torque due to spin current generated via the giant spin Hall effect are two promising energy-efficient methods to switch nanomagnets in magnetic computing devices. However, switching of nanomagnets is always error-prone at room temperature owing to the effect of thermal noise. In this work, we model the strain-based and spin-Hall-effect-based switching of nanomagnetic devices using stochastic Landau-Lifshitz-Gilbert (LLG) equation and present a quantitative comparison in terms of switching time, reliability and energy dissipation. This work is supported by the US National Science Foundation under the SHF-Small Grant CCF-1216614, CAREER Grant CCF-1253370, NEB 2020 Grant ECCS-1124714 and SRC under NRI Task 2203.001.

  10. All-optical transistors and logic gates using a parity-time-symmetric Y-junction: Design and simulation

    SciTech Connect

    Ding, Shulin; Wang, Guo Ping

    2015-09-28

    Classical nonlinear or quantum all-optical transistors are dependent on the value of input signal intensity or need extra co-propagating beams. In this paper, we present a kind of all-optical transistors constructed with parity-time (PT)-symmetric Y-junctions, which perform independently on the value of signal intensity in an unsaturated gain case and can also work after introducing saturated gain. Further, we show that control signal can switch the device from amplification of peaks in time to transformation of peaks to amplified troughs. By using these PT-symmetric Y-junctions with currently available materials and technologies, we can implement interesting logic functions such as NOT and XOR (exclusive OR) gates, implying potential applications of such structures in designing optical logic gates, optical switches, and signal transformations or amplifications.

  11. Fast deterministic switching in orthogonal spin torque devices via the control of the relative spin polarizations

    NASA Astrophysics Data System (ADS)

    Park, Junbo; Ralph, D. C.; Buhrman, R. A.

    2013-12-01

    We model 100 ps pulse switching dynamics of orthogonal spin transfer (OST) devices that employ an out-of-plane polarizer and an in-plane polarizer. Simulation results indicate that increasing the spin polarization ratio, CP = PIPP/POPP, results in deterministic switching of the free layer without over-rotation (360° rotation). By using spin torque asymmetry to realize an enhanced effective PIPP, we experimentally demonstrate this behavior in OST devices in parallel to anti-parallel switching. Modeling predicts that decreasing the effective demagnetization field can substantially reduce the minimum CP required to attain deterministic switching, while retaining low critical switching current, Ip ˜ 500 μA.

  12. Development of a prototype T-shaped fast switching device for electron cyclotron current drive systems

    NASA Astrophysics Data System (ADS)

    Sekiguchi, Kenji; Nagashima, Koji; Honzu, Toshihiko; Saigusa, Mikio; Oda, Yasuhisa; Takahashi, Koji; Sakamoto, Keishi

    2016-09-01

    A T-shaped high-power switching device composed of circular corrugated waveguides with three ports and double dielectric disks made of sapphire was proposed as a fast switching device based on a new principle in electron cyclotron current drive systems. This switching device has the advantages of operating at a fixed frequency and being compact. The design of the prototype switch was obtained by numerical simulations using a finite-difference time-domain (FDTD) method. The size of these components was optimized for the frequency band of 170 GHz. Low-power tests were carried out in a cross-shaped model.

  13. All-optical information processing in photonic crystals

    NASA Astrophysics Data System (ADS)

    Yanik, Mehmet Fatih

    This thesis covers coherent and incoherent all-optical information processing using photonic bandgap nanostructures and microcavities. The first 3 chapters introduce all-optical bistable switching, transistor and memory elements with sub-micron scale dimensions. A strategy for large scale integration without optical isolators is also described. In chapters 4 and 5, dynamically modulated photonic crystal structures are introduced. It is shown that light pulses can be stopped and stored all-optically without requiring any coherent or resonant light-matter interaction. In chapter 6, it is shown that light pulses can be coherently time-reversed by using only index modulations and linear optics. In chapter 7, a supercomputer implementation of an object oriented finite difference time domain simulation is described to simulate photonic nanostructures with arbitrary material & geometric features.

  14. In-situ observation of self-regulated switching behavior in WO{sub 3-x} based resistive switching devices

    SciTech Connect

    Hong, D. S.; Wang, W. X.; Chen, Y. S. Sun, J. R.; Shen, B. G.

    2014-09-15

    The transmittance of tungsten oxides can be adjusted by oxygen vacancy (V{sub o}) concentration due to its electrochromic property. Here, we report an in-situ observation of resistive switching phenomenon in the oxygen-deficient WO{sub 3-x} planar devices. Besides directly identifying the formation/rupture of dark-colored conductive filaments in oxide layer, the stripe-like WO{sub 3-x} device demonstrated self-regulated switching behavior during the endurance testing, resulting in highly consistent switching parameters after a stabilizing process. For very high V{sub o}s mobility was demonstrated in the WO{sub 3-x} film by the pulse experiment, we suggested that the electric-field-induced homogeneous migration of V{sub o}s was the physical origin for such unique switching characteristics.

  15. All-optical logical gates based on pump-induced resonant nonlinearity in an erbium-doped fiber coupler.

    PubMed

    Li, Qiliang; Zhang, Zhen; Li, Dongqiang; Zhu, Mengyun; Tang, Xianghong; Li, Shuqin

    2014-12-01

    In this paper, we theoretically investigate all-optical logical gates based on the pump-induced resonant nonlinearity in an erbium-doped fiber coupler. The resonant nonlinearity yielded by the optical transitions between the (4)I(15/2) states and (4)I(13/2) states in Er(3+) induces the refractive index to change, which leads to switching between two output ports. First, we do a study on the switching performance, and calculate the extinction ratio (Xratio) of the device. Second, using the Xratio, we obtain the truth tables of the device. The results reveal that compared with other undoped nonlinear couplers, the erbium-doped fiber coupler can drop the switching threshold power. We also obtain different logic gates and logic operations in the cases of the same phase and different phase of two initial signals by changing the pump power.

  16. Resistive switching phenomena of HfO2 films grown by MOCVD for resistive switching memory devices

    NASA Astrophysics Data System (ADS)

    Kim, Hee-Dong; Yun, Min Ju; Kim, Sungho

    2016-08-01

    The resistive switching phenomena of HfO2 films grown by using metal organic chemical vapor deposition (MOCVD) was studied for the application of resistive random access memory (ReRAM) devices. In the fabricated Pt/HfO2/TiN memory cells, bipolar resistive switching characteristics were observed, and the set and reset states were measured to be as low as 7 μA and 4 μA, respectively, at V READ = 1 V. Regarding the resistive switching performance, stable resistive switching (RS) performance was observed under 40 repetitive dc cycles with small variations of set/reset voltages and the currents and good retention characteristics of over 105 s in both the low-resistance state (LRS) and the high-resistance state (HRS). These results show the possibility of using MOCVDgrown HfO2 films as a promising resistive switching materials for ReRAM applications.

  17. Status and Prospects of ZnO-Based Resistive Switching Memory Devices.

    PubMed

    Simanjuntak, Firman Mangasa; Panda, Debashis; Wei, Kung-Hwa; Tseng, Tseung-Yuen

    2016-12-01

    In the advancement of the semiconductor device technology, ZnO could be a prospective alternative than the other metal oxides for its versatility and huge applications in different aspects. In this review, a thorough overview on ZnO for the application of resistive switching memory (RRAM) devices has been conducted. Various efforts that have been made to investigate and modulate the switching characteristics of ZnO-based switching memory devices are discussed. The use of ZnO layer in different structure, the different types of filament formation, and the different types of switching including complementary switching are reported. By considering the huge interest of transparent devices, this review gives the concrete overview of the present status and prospects of transparent RRAM devices based on ZnO. ZnO-based RRAM can be used for flexible memory devices, which is also covered here. Another challenge in ZnO-based RRAM is that the realization of ultra-thin and low power devices. Nevertheless, ZnO not only offers decent memory properties but also has a unique potential to be used as multifunctional nonvolatile memory devices. The impact of electrode materials, metal doping, stack structures, transparency, and flexibility on resistive switching properties and switching parameters of ZnO-based resistive switching memory devices are briefly compared. This review also covers the different nanostructured-based emerging resistive switching memory devices for low power scalable devices. It may give a valuable insight on developing ZnO-based RRAM and also should encourage researchers to overcome the challenges. PMID:27541816

  18. Status and Prospects of ZnO-Based Resistive Switching Memory Devices

    NASA Astrophysics Data System (ADS)

    Simanjuntak, Firman Mangasa; Panda, Debashis; Wei, Kung-Hwa; Tseng, Tseung-Yuen

    2016-08-01

    In the advancement of the semiconductor device technology, ZnO could be a prospective alternative than the other metal oxides for its versatility and huge applications in different aspects. In this review, a thorough overview on ZnO for the application of resistive switching memory (RRAM) devices has been conducted. Various efforts that have been made to investigate and modulate the switching characteristics of ZnO-based switching memory devices are discussed. The use of ZnO layer in different structure, the different types of filament formation, and the different types of switching including complementary switching are reported. By considering the huge interest of transparent devices, this review gives the concrete overview of the present status and prospects of transparent RRAM devices based on ZnO. ZnO-based RRAM can be used for flexible memory devices, which is also covered here. Another challenge in ZnO-based RRAM is that the realization of ultra-thin and low power devices. Nevertheless, ZnO not only offers decent memory properties but also has a unique potential to be used as multifunctional nonvolatile memory devices. The impact of electrode materials, metal doping, stack structures, transparency, and flexibility on resistive switching properties and switching parameters of ZnO-based resistive switching memory devices are briefly compared. This review also covers the different nanostructured-based emerging resistive switching memory devices for low power scalable devices. It may give a valuable insight on developing ZnO-based RRAM and also should encourage researchers to overcome the challenges.

  19. All-optically simultaneous slow and fast light

    NASA Astrophysics Data System (ADS)

    Chen, Zhongjie; Luo, Bin; Liu, Yu; Guo, Hong

    2013-11-01

    Simultaneous slow and fast light can be realized all-optically by connecting a four-level closed-loop atom-light interaction scheme to Λ-type electromagnetically induced transparency system. Through manipulation of the relative phase of one of the coupling lights, probe light can be switched among dual-slow light, dual-fast light and simultaneous slow and fast light. A theoretical analysis based on dressed state picture is given.

  20. Statistical and Time Resolved Studies of Switching in Magnetic Tunnel Junction based Orthogonal Spin Transfer Devices

    NASA Astrophysics Data System (ADS)

    Liu, Huanlong; Bedau, Daniel; Backes, Dirk; Langer, Jurgen; Manandhar, Pradeep; Kent, Andrew

    2012-02-01

    We report statistical and single-shot time-resolved studies of spin transfer switching in OST-MRAM devices. These devices consist of a perpendicular polarizer integrated into a layer stack with an in-plane magnetized free and reference layer, which form the electrodes of a magnetic tunnel junction [1]. The perpendicular polarizer provides an initial torque -- designed to reduce the incubation delay in switching. The demagnetization field created during the switching can further accelerate the reversal process [2]. The devices switch reliably at 0.7 V and 500 ps duration for both voltage polarities. We record the change of the device resistance in real time during the pulse to obtain the time needed to initiate the switching τstart and the time between the initiation and the end of the switching τswitch for every single switching event. τswitch is determined to be less than a few hundreds of picoseconds, on the order of the precession time due to the demagnetization field and we find evidence for precession reversal under certain conditions. We further present results on the effects of pulse amplitude and applied field on τstart and τswitch. This work was supported by Spin Transfer Technologies. [1] H. Liu et al., APL 97, 242510 (2010). [2] A. D. Kent et al., APL 84, 3897 (2004).

  1. Photonic encryption using all optical logic.

    SciTech Connect

    Blansett, Ethan L.; Schroeppel, Richard Crabtree; Tang, Jason D.; Robertson, Perry J.; Vawter, Gregory Allen; Tarman, Thomas David; Pierson, Lyndon George

    2003-12-01

    With the build-out of large transport networks utilizing optical technologies, more and more capacity is being made available. Innovations in Dense Wave Division Multiplexing (DWDM) and the elimination of optical-electrical-optical conversions have brought on advances in communication speeds as we move into 10 Gigabit Ethernet and above. Of course, there is a need to encrypt data on these optical links as the data traverses public and private network backbones. Unfortunately, as the communications infrastructure becomes increasingly optical, advances in encryption (done electronically) have failed to keep up. This project examines the use of optical logic for implementing encryption in the photonic domain to achieve the requisite encryption rates. In order to realize photonic encryption designs, technology developed for electrical logic circuits must be translated to the photonic regime. This paper examines two classes of all optical logic (SEED, gain competition) and how each discrete logic element can be interconnected and cascaded to form an optical circuit. Because there is no known software that can model these devices at a circuit level, the functionality of the SEED and gain competition devices in an optical circuit were modeled in PSpice. PSpice allows modeling of the macro characteristics of the devices in context of a logic element as opposed to device level computational modeling. By representing light intensity as voltage, 'black box' models are generated that accurately represent the intensity response and logic levels in both technologies. By modeling the behavior at the systems level, one can incorporate systems design tools and a simulation environment to aid in the overall functional design. Each black box model of the SEED or gain competition device takes certain parameters (reflectance, intensity, input response), and models the optical ripple and time delay characteristics. These 'black box' models are interconnected and cascaded in an

  2. Threshold Switching Characteristics of Nb/NbO2/TiN Vertical Devices

    SciTech Connect

    Wang, Yuhan; Comes, Ryan B.; Wolf, Stuart A.; Lu, Jiwei

    2015-11-25

    Nb/NbO2/TiN vertical structures were synthesized in-situ and patterned to devices with different contact areas. The devices exhibited threshold resistive switching with minimal hysteresis and a small EThreshold (60~90 kV/cm). The switching behavior was unipolar, and demonstrated good repeatability. A less sharp but still sizable change in the device resistance was observed up to 150 °C. It was found that the resistive switching without Nb capping layer exhibited the hysteretic behavior and much larger EThreshold (~250 kV/cm) likely due to a 2-3 nm surface Nb2O5 layer. The stable threshold switching behavior well above room temperature shows the potential applications of this device as an electronic switch.

  3. All-optical flip-flop based on coupled SOA-PSW

    NASA Astrophysics Data System (ADS)

    Wang, Lina; Wang, Yongjun; Wu, Chen; Wang, Fu

    2016-07-01

    The semiconductor optical amplifier (SOA) has obvious advantages in all-optical signal processing, because of the simple structure, strong non-linearity, and easy integration. A variety of all-optical signal processing functions, such as all-optical wavelength conversion, all-optical logic gates and all-optical sampling, can be completed by SOA. So the SOA has been widespread concerned in the field of all-optical signal processing. Recently, the polarization rotation effect of SOA is receiving considerable interest, and many researchers have launched numerous research work utilizing this effect. In this paper, a new all-optical flip-flop structure using polarization switch (PSW) based on polarization rotation effect of SOA is presented.

  4. Ultrafast Switching in Magnetic Tunnel Junction based Orthogonal Spin Transfer Devices

    NASA Astrophysics Data System (ADS)

    Liu, Huanlong; Bedau, Daniel; Backes, Dirk; Katine, Jordan; Langer, Jürgen; Kent, Andrew; New York University, New York, NY 10003 USA Team; Hitachi-GST, San Jose, California 95135 USA Team; Singulus, 63796 Kahl am Main, Germany Team

    2011-03-01

    Orthogonal spin-transfer magnetic random access memory (OST-MRAM) uses a spin-polarizing layer magnetized perpendicularly to the free layer to achieve large spin-transfer torques and ultrafast energy efficient switching. We have fabricated and studied OST-MRAM devices that incorporate a perpendicularly magnetized polarizer and a magnetic tunnel junction, which consists of an in-plane magnetized free layer and synthetic antiferromagnetic reference layer. A switching probability of 100% is observed for 500 ps pulses, requiring an energy of 250 fJ. The fast switching process indicates there is no incubation delay of several nanoseconds as observed in conventional collinear magnetized devices. Due to the perpendicular polarizer switching is possible for both pulse polarities. There is also evidence for precessional switching in the non-monotonic dependence of the switching probability versus pulse amplitude. This work was supported by Spin Transfer Technologies.

  5. Hardware implementation of associative memory characteristics with analogue-type resistive-switching device

    NASA Astrophysics Data System (ADS)

    Moon, Kibong; Park, Sangsu; Jang, Junwoo; Lee, Daeseok; Woo, Jiyong; Cha, Euijun; Lee, Sangheon; Park, Jaesung; Song, Jeonghwan; Koo, Yunmo; Hwang, Hyunsang

    2014-12-01

    We have investigated the analogue memory characteristics of an oxide-based resistive-switching device under an electrical pulse to mimic biological spike-timing-dependent plasticity synapse characteristics. As a synaptic device, a TiN/Pr0.7Ca0.3MnO3-based resistive-switching device exhibiting excellent analogue memory characteristics was used to control the synaptic weight by applying various pulse amplitudes and cycles. Furthermore, potentiation and depression characteristics with the same spikes can be achieved by applying negative and positive pulses, respectively. By adopting complementary metal-oxide-semiconductor devices as neurons and TiN/PCMO devices as synapses, we implemented neuromorphic hardware that mimics associative memory characteristics in real time for the first time. Owing to their excellent scalability, resistive-switching devices, shows promise for future high-density neuromorphic applications.

  6. Resistive switching effect of Ag/MoS2/FTO device

    NASA Astrophysics Data System (ADS)

    Sun, Bai; Zhao, Wenxi; Liu, Yonghong; Chen, Peng

    2015-09-01

    The electric-pulse-driven resistance change of metal/oxides/metal structure, which is called resistive switching effect, is a fascinating phenomenon for the development of next generation non-volatile memory. In this work, an outstanding bipolar resistive switching behavior of Ag/MoS2/fluorine-doped tin oxide (FTO) device is demonstrated. The device can maintain superior reversible stability over 100 cycles with an OFF/ON-state resistance ratio of about 103 at room temperature.

  7. Demonstration and characterisation of a non-inverting all-optical read/write regenerative memory

    NASA Astrophysics Data System (ADS)

    Johnson, N. C.; Harrison, J. A.; Blow, K. J.

    2008-09-01

    An all-optical regenerative memory device using a single loop mirror and a semiconductor optical amplifier is experimentally demonstrated. This configuration has potential for a low power all-optical stable memory device with non-inverting characteristics where packets are stored by continuously injecting the regenerated data back into the loop.

  8. Three-terminal resistive switching memory in a transparent vertical-configuration device

    SciTech Connect

    Ungureanu, Mariana; Llopis, Roger; Casanova, Fèlix; Hueso, Luis E.

    2014-01-06

    The resistive switching phenomenon has attracted much attention recently for memory applications. It describes the reversible change in the resistance of a dielectric between two non-volatile states by the application of electrical pulses. Typical resistive switching memories are two-terminal devices formed by an oxide layer placed between two metal electrodes. Here, we report on the fabrication and operation of a three-terminal resistive switching memory that works as a reconfigurable logic component and offers an increased logic density on chip. The three-terminal memory device we present is transparent and could be further incorporated in transparent computing electronic technologies.

  9. Asymmetric resistive switching processes in W:AlOx/WOy bilayer devices

    NASA Astrophysics Data System (ADS)

    Wu, Hua-Qiang; Ming-Hao, Wu; Li, Xin-Yi; Bai, Yue; Deng, Ning; Yu, Zhi-Ping; Qian, He

    2015-05-01

    Asymmetric resistive switching processes were observed in W:AlOx/WOy bilayer RRAM devices. During pulse programming measurements, the RESET speed is in the range of hundreds of microseconds under -1.1 V bias, while the SET speed is in the range of tens of nanoseconds under 1.2 V bias. Electrical measurements with different pulse conditions and different temperatures were carried out to understand these significant differences in switching time. A redox reaction model in the W:AlOx/WOy device structure is proposed to explain this switching time difference.

  10. Graphene Based Reversible Nano-Switch/Sensor Schottky Diode (NANOSSSD) Device

    NASA Technical Reports Server (NTRS)

    Miranda, Felix A. (Inventor); Theofylaktos, Onoufrios (Inventor); Pinto, Nicholas J. (Inventor); Mueller, Carl H. (Inventor); Santos, Javier (Inventor); Meador, Michael A. (Inventor)

    2015-01-01

    A nanostructure device is provided and performs dual functions as a nano-switching/sensing device. The nanostructure device includes a doped semiconducting substrate, an insulating layer disposed on the doped semiconducting substrate, an electrode formed on the insulating layer, and at least one layer of graphene formed on the electrode. The at least one layer of graphene provides an electrical connection between the electrode and the substrate and is the electroactive element in the device.

  11. Subpicosecond photonic switching based on bacteriorhodopsin

    NASA Astrophysics Data System (ADS)

    Ormos, Pal; Fabian, Laszlo; Heiner, Zsuzsanna; Mero, Mark; Kiss, Miklos; Wolff, Elmar; Osvay, Karoly; der, Andras

    2011-03-01

    All-optical data processing is the most promising approach for further improvement in data trafficking. We present a subpicosecond photonic switch where the active role is performed by the chromoprotein bacteriorhodopsin. The changes in the refractive index that accompany the steps of the photocycle of bacteriorhodopsin are used for all optical switching in appropriate integrated optical devices. We use grating coupled planar waveguides and the coupling is modulated by the light induced refractive index changes of bacteriorhodopsin. The switching is demonstrated in ultrafast pump-probe experiments. Different transitions of the photocycle are explored for switching applications. We show that by using the bR to I transition subpicosecond switching can be readily achieved. The approach is a basis for protein-based integrated optical devices, eventually leading to a conceptual revolution in telecommunications technologies.

  12. All-optical controllable channel-drop filters in two-dimensional square-lattice photonic crystals

    NASA Astrophysics Data System (ADS)

    Fasihi, K.

    2016-05-01

    A novel all-optical controllable channel-drop filter in photonic crystals (PC) of square lattice is presented. We show that using a resonant-cavity-based add-drop filter with a wavelength-selective reflection feedback and a single-control switching module which is based on nonlinear PC microcavities, the dropped channel can be routed to the drop port or returned to the bus waveguide. Using the temporal coupled-mode theory and two-dimensional nonlinear finite-difference time-domain method, the performance of the proposed device is investigated and the simulation results show the validity of the proposed design.

  13. Dual bipolar resistive switching in the sub-forming regime of HfO2 resistive switching devices

    NASA Astrophysics Data System (ADS)

    Recher, Shani; Yalon, Eilam; Ritter, Dan; Riess, Ilan; Salzman, Joseph

    2015-09-01

    Resistive switching in HfO2 in the sub-forming regime (before an electroforming step had been fully performed) is studied by electrical measurements using a very low current compliance of 1 μA. Electroforming under low current limitation results in reduced self-heating and partial filament formation. Following the reset process in this sub-forming regime, the device fully recovers its pristine resistive state. Furthermore, a dual bipolar resistive switching (DBRS) effect is observed, which we model as two antiparallel bipolar resistive switches. We attribute this phenomenon to intermittent formation and rupture of filaments originating from opposite electrodes. Following the rupture of a filament, originating from one of the electrodes, another filament originating from the opposite electrode is formed.

  14. Application of nanomaterials in two-terminal resistive-switching memory devices

    PubMed Central

    Ouyang, Jianyong

    2010-01-01

    Nanometer materials have been attracting strong attention due to their interesting structure and properties. Many important practical applications have been demonstrated for nanometer materials based on their unique properties. This article provides a review on the fabrication, electrical characterization, and memory application of two-terminal resistive-switching devices using nanomaterials as the active components, including metal and semiconductor nanoparticles (NPs), nanotubes, nanowires, and graphenes. There are mainly two types of device architectures for the two-terminal devices with NPs. One has a triple-layer structure with a metal film sandwiched between two organic semiconductor layers, and the other has a single polymer film blended with NPs. These devices can be electrically switched between two states with significant different resistances, i.e. the ‘ON’ and ‘OFF’ states. These render the devices important application as two-terminal non-volatile memory devices. The electrical behavior of these devices can be affected by the materials in the active layer and the electrodes. Though the mechanism for the electrical switches has been in argument, it is generally believed that the resistive switches are related to charge storage on the NPs. Resistive switches were also observed on crossbars formed by nanotubes, nanowires, and graphene ribbons. The resistive switches are due to nanoelectromechanical behavior of the materials. The Coulombic interaction of transient charges on the nanomaterials affects the configurable gap of the crossbars, which results into significant change in current through the crossbars. These nanoelectromechanical devices can be used as fast-response and high-density memory devices as well. PMID:22110862

  15. Atomistic simulations of electrochemical metallization cells: mechanisms of ultra-fast resistance switching in nanoscale devices

    NASA Astrophysics Data System (ADS)

    Onofrio, Nicolas; Guzman, David; Strachan, Alejandro

    2016-07-01

    We describe a new method that enables reactive molecular dynamics (MD) simulations of electrochemical processes and apply it to study electrochemical metallization cells (ECMs). The model, called EChemDID, extends the charge equilibration method to capture the effect of external electrochemical potential on partial atomic charges and describes its equilibration over connected metallic structures, on-the-fly, during the MD simulation. We use EChemDID to simulate resistance switching in nanoscale ECMs; these devices consist of an electroactive metal separated from an inactive electrode by an insulator and can be reversibly switched to a low-resistance state by the electrochemical formation of a conducting filament between electrodes. Our structures use Cu as the active electrode and SiO2 as the dielectric and have dimensions at the foreseen limit of scalability of the technology, with a dielectric thickness of approximately 1 nm. We explore the effect of device geometry on switching timescales and find that nanowires with an electroactive shell, where ions migrate towards a smaller inactive electrode core, result in faster switching than planar devices. We observe significant device-to-device variability in switching timescales and intermittent switching for these nanoscale devices. To characterize the evolution in the electronic structure of the dielectric as dissolved metallic ions switch the device, we perform density functional theory calculations on structures obtained from an EChemDID MD simulation. These results confirm the appearance of states around the Fermi energy as the metallic filament bridges the electrodes and show that the metallic ions and not defects in the dielectric contribute to the majority of those states.

  16. A band-modulation device in advanced FDSOI technology: Sharp switching characteristics

    NASA Astrophysics Data System (ADS)

    El Dirani, Hassan; Solaro, Yohann; Fonteneau, Pascal; Legrand, Charles-Alex; Marin-Cudraz, David; Golanski, Dominique; Ferrari, Philippe; Cristoloveanu, Sorin

    2016-11-01

    A band-modulation device is demonstrated experimentally in advanced FDSOI (Fully Depleted SOI). The Z2-FET (Zero Impact Ionization and Zero Subthreshold Slope FET) is a very recent sharp switching device which achieves remarkable performance in terms of leakage current and triggering control. The device is fabricated with Ultra-Thin Body and Buried Oxide (UTBB) Silicon-On-Insulator (SOI) technology, features an extremely sharp on-switch, low leakage and an adjustable triggering voltage (VON). The Z2-FET operation relies on the modulation of electrons and holes injection barriers. In this paper, we show, for the first time, experimental data obtained with the most advanced FDSOI node.

  17. Development and fabrication of improved power transistor switches. [fabrication and manufacturing of semiconductor devices

    NASA Technical Reports Server (NTRS)

    Hower, P. L.; Chu, C. K.

    1976-01-01

    A new class of high-voltage power transistors has been achieved by adapting present interdigitated thyristor processing techniques to the fabrication of NPN Si transistors. Present devices are 2.3 cm in diameter. The electrical performance obtained is consistent with the predictions of an optimum design theory specifically developed for power switching transistors. The forward safe operating area of the experimental transistors shows a significant improvement over commercially available devices. The report describes device design, wafer processing, and various measurements which include dc characteristics, forward and reverse second breakdown limits, and switching times.

  18. Electrode with transparent series resistance for uniform switching of optical modulation devices

    DOEpatents

    Tench, D. Morgan; Cunningham, Michael A.; Kobrin, Paul H.

    2008-01-08

    Switching uniformity of an optical modulation device for controlling the propagation of electromagnetic radiation is improved by use of an electrode comprising an electrically resistive layer that is transparent to the radiation. The resistive layer is preferably an innerlayer of a wide-bandgap oxide sandwiched between layers of indium tin oxide or another transparent conductor, and may be of uniform thickness, or may be graded so as to provide further improvement in the switching uniformity. The electrode may be used with electrochromic and reversible electrochemical mirror (REM) smart window devices, as well as display devices based on various technologies.

  19. Spin-transfer magnetization switching in ordered alloy-based nanopillar devices

    NASA Astrophysics Data System (ADS)

    Mitani, S.

    2011-09-01

    This paper reviews spin-transfer magnetization switching in ordered alloy-based nanopillar devices. L10-ordered FePt was used for one of the earliest demonstrations of spin-transfer switching in perpendicularly magnetized systems. The behaviour of magnetization switching deviates from the predictions based on a macro-spin model, suggesting incoherent magnetization switching in the system with a large perpendicular magnetic anisotropy. The effect of a 90° spin injector on spin-transfer switching was also examined using L10-ordered FePt. Full-Heusler alloys are in another fascinating material class for spin-transfer switching because of their high-spin polarization of conduction electrons and possible small magnetization damping. A B2-ordered Co2FeAl0.5Si0.5-based device showed a low intrinsic critical current density of 9.3 × 106 A cm-2 for spin-transfer switching as well as a relatively large current-perpendicular-to-plane giant-magnetoresistance (CPP-GMR) up to ~9%. The specific physical properties of ordered alloys may be useful for fundamental studies and applications in spin-transfer switching.

  20. Impacts of Co doping on ZnO transparent switching memory device characteristics

    NASA Astrophysics Data System (ADS)

    Simanjuntak, Firman Mangasa; Prasad, Om Kumar; Panda, Debashis; Lin, Chun-An; Tsai, Tsung-Ling; Wei, Kung-Hwa; Tseng, Tseung-Yuen

    2016-05-01

    The resistive switching characteristics of indium tin oxide (ITO)/Zn1-xCoxO/ITO transparent resistive memory devices were investigated. An appropriate amount of cobalt dopant in ZnO resistive layer demonstrated sufficient memory window and switching stability. In contrast, pure ZnO devices demonstrated a poor memory window, and using an excessive dopant concentration led to switching instability. To achieve suitable memory performance, relying only on controlling defect concentrations is insufficient; the grain growth orientation of the resistive layer must also be considered. Stable endurance with an ON/OFF ratio of more than one order of magnitude during 5000 cycles confirmed that the Co-doped ZnO device is a suitable candidate for resistive random access memory application. Additionally, fully transparent devices with a high transmittance of up to 90% at wavelength of 550 nm have been fabricated.

  1. Nonlinear Magnetic Dynamics and The Switching Phase Diagrams in Spintronic Devices

    NASA Astrophysics Data System (ADS)

    Yan, Shu

    Spin-transfer torque induced magnetic switching, by which the spin-polarized current transfers its magnetic moment to the ferromagnetic layer and changes its magnetization, holds great promise towards faster and smaller magnetic bits in data-storage applications due to the lower power consumption and better scalability. We propose an analytic approach which can be used to calculate the switching phase diagram of a nanomagnetic system in the presence of both magnetic field and spin-transfer torque in an exact fashion. This method is applied to the study of switching conditions for the uniaxial, single domain magnetic layers in different spin-transfer devices. In a spin valve with spin polarization collinear with the easy axis, we get a modified Stoner-Wohlfarth astroid which represents many of the features that have been found in experiment. It also shows a self-crossing boundary and demonstrates a region with three stable equilibria. We demonstrate that the region of stable equilibria with energy near the maximum can be reached only through a narrow bottleneck in the field space, which sets a stringent requirement for magnetic field alignment in the experiments. Switching diagrams are then calculated for the setups with magnetic field not perfectly aligned with the easy axis. In a ferromagnet-heavy-metal bilayer device with strong spin Hall effect, the in plane current becomes spin-polarized and transfers its magnetic moment to the ferromagnetic layer by diffusion. The three-dimensional asymmetric phase diagram is calculated. In the case that the external field is confined in the vertical plane defined by the direction of the current and the easy axis, the spin-transfer torque shifts the conventional in-plane (IP) equilibria within the same plane, and also creates two out-of-plane (OOP) equilibria, one of which can be stable. The threshold switching currents for IP switching and OOP switching are discussed. We also address the magnetic switching processes. Damping

  2. Electrode-induced digital-to-analog resistive switching in TaO x -based RRAM devices.

    PubMed

    Li, Xinyi; Wu, Huaqiang; Bin Gao; Wu, Wei; Wu, Dong; Deng, Ning; Cai, Jian; Qian, He

    2016-07-29

    In RRAM devices, electrodes play a significant role during the switching process. In this paper, different top electrodes are used for TaO y /Ta2O5-x /AlO σ triple-oxide-layer devices. Top electrode-induced digital resistive switching to analog resistive switching was observed. For Pt top electrode (TE) devices, abrupt digital resistive switching behavior was observed, while Al TE devices showed gradual analog resistive switching behavior. Devices with various AlO σ thicknesses and sizes were fabricated and characterized to evaluate the reliability of the analog resistive switching. The physical mechanisms responsible for this electrode-induced resistive switching behavior were discussed. PMID:27302281

  3. Nonlinear fiber applications for ultrafast all-optical signal processing

    NASA Astrophysics Data System (ADS)

    Kravtsov, Konstantin

    In the present dissertation different aspects of all-optical signal processing, enabled by the use of nonlinear fibers, are studied. In particular, we focus on applications of a novel heavily GeO2-doped (HD) nonlinear fiber, that appears to be superior to many other types of nonlinear fibers because of its high nonlinearity and suitability for the use in nonlinear optical loop mirrors (NOLMs). Different functions, such as all-optical switching, thresholding, and wavelength conversion, are demonstrated with the HD fibers in the NOLM configuration. These basic functions are later used for realization of ultrafast time-domain demultiplexers, clock recovery, detectors of short pulses in stealth communications, and primitive elements for analog computations. Another important technology that benefits from the use of nonlinear fiber-based signal processing is optical code-division multiple access (CDMA). It is shown in both theory and experiment that all-optical thresholding is a unique way of improving existing detection methods for optical CDMA. Also, it is the way of implementation of true asynchronous optical spread-spectrum networks, which allows full realization of optical CDMA potential. Some aspects of quantum signal processing and manipulation of quantum states are also studied in this work. It is shown that propagation and collisions of Thirring solitons lead to a substantial squeezing of quantum states, which may find applications for generation of squeezed light.

  4. Superstructures of chiral nematic microspheres as all-optical switchable distributors of light

    PubMed Central

    Aβhoff, Sarah J.; Sukas, Sertan; Yamaguchi, Tadatsugu; Hommersom, Catharina A.; Le Gac, Séverine; Katsonis, Nathalie

    2015-01-01

    Light technology is based on generating, detecting and controlling the wavelength, polarization and direction of light. Emerging applications range from electronics and telecommunication to health, defence and security. In particular, data transmission and communication technologies are currently asking for increasingly complex and fast devices, and therefore there is a growing interest in materials that can be used to transmit light and also to control the distribution of light in space and time. Here, we design chiral nematic microspheres whose shape enables them to reflect light of different wavelengths and handedness in all directions. Assembled in organized hexagonal superstructures, these microspheres of well-defined sizes communicate optically with high selectivity for the colour and chirality of light. Importantly, when the microspheres are doped with photo-responsive molecular switches, their chiroptical communication can be tuned, both gradually in wavelength and reversibly in polarization. Since the kinetics of the “on” and “off” switching can be adjusted by molecular engineering of the dopants and because the photonic cross-communication is selective with respect to the chirality of the incoming light, these photo-responsive microspheres show potential for chiroptical all-optical distributors and switches, in which wavelength, chirality and direction of the reflected light can be controlled independently and reversibly. PMID:26400584

  5. Superstructures of chiral nematic microspheres as all-optical switchable distributors of light

    NASA Astrophysics Data System (ADS)

    Aβhoff, Sarah J.; Sukas, Sertan; Yamaguchi, Tadatsugu; Hommersom, Catharina A.; Le Gac, Séverine; Katsonis, Nathalie

    2015-09-01

    Light technology is based on generating, detecting and controlling the wavelength, polarization and direction of light. Emerging applications range from electronics and telecommunication to health, defence and security. In particular, data transmission and communication technologies are currently asking for increasingly complex and fast devices, and therefore there is a growing interest in materials that can be used to transmit light and also to control the distribution of light in space and time. Here, we design chiral nematic microspheres whose shape enables them to reflect light of different wavelengths and handedness in all directions. Assembled in organized hexagonal superstructures, these microspheres of well-defined sizes communicate optically with high selectivity for the colour and chirality of light. Importantly, when the microspheres are doped with photo-responsive molecular switches, their chiroptical communication can be tuned, both gradually in wavelength and reversibly in polarization. Since the kinetics of the “on” and “off” switching can be adjusted by molecular engineering of the dopants and because the photonic cross-communication is selective with respect to the chirality of the incoming light, these photo-responsive microspheres show potential for chiroptical all-optical distributors and switches, in which wavelength, chirality and direction of the reflected light can be controlled independently and reversibly.

  6. A light incident angle switchable ZnO nanorod memristor: reversible switching behavior between two non-volatile memory devices.

    PubMed

    Park, Jinjoo; Lee, Seunghyup; Lee, Junghan; Yong, Kijung

    2013-11-26

    A light incident angle selectivity of a memory device is demonstrated. As a model system, the ZnO resistive switching device has been selected. Electrical signal is reversibly switched between memristor and resistor behaviors by modulating the light incident angle on the device. Moreover, a liquid passivation layer is introduced to achieve stable and reversible exchange between the memristor and WORM behaviors.

  7. A physical model of switching dynamics in tantalum oxide memristive devices

    NASA Astrophysics Data System (ADS)

    Mickel, Patrick R.; Lohn, Andrew J.; Joon Choi, Byung; Joshua Yang, J.; Zhang, Min-Xian; Marinella, Matthew J.; James, Conrad D.; Stanley Williams, R.

    2013-06-01

    We present resistive switching model for TaOx memristors, which demonstrates that the radius of a tantalum rich conducting filament is the state variable controlling resistance. The model tracks the flux of individual oxygen ions and permits the derivation and solving of dynamical and static state equations. Model predictions for ON/OFF switching were tested experimentally with TaOx devices and shown to be in close quantitative agreement, including the experimentally observed transition from linear to non-linear conduction between RON and ROFF. This work presents a quantitative model of state variable dynamics in TaOx memristors, with direct comparison to high-speed resistive switching data.

  8. Protection relay of phase-shifting device with thyristor switch for high voltage power transmission lines

    NASA Astrophysics Data System (ADS)

    Lachugin, V. F.; Panfilov, D. I.; Akhmetov, I. M.; Astashev, M. G.; Shevelev, A. V.

    2014-12-01

    Problems of functioning of differential current protection systems of phase shifting devices (PSD) with mechanically changed coefficient of transformation of shunt transformer are analyzed. Requirements for devices of protection of PSD with thyristor switch are formulated. Based on use of nonlinear models of series-wound and shunt transformers of PSD modes of operation of major protection during PSD, switching to zero load operation and to operation under load and during short circuit operation were studied for testing PSD with failures. Use of the principle of duplicating by devices of differential current protection (with realization of functions of breaking) of failures of separate pares of PSD with thyristor switch was substantiated. To ensure protection sensitivity to the shunt transformer winding short circuit, in particular, to a short circuit that is not implemented in the current differential protection for PSD with mechanical switch, the differential current protection reacting to the amount of primary ampere-turns of high-voltage and low-voltage winding of this transformer was designed. Studies have shown that the use of differential current cutoff instead of overcurrent protection for the shunt transformer wndings allows one to provide the sensitivity during thyristor failure with the formation of a short circuit. The results of simulation mode for the PSD with switch thyristor designed to be installed as switching point of Voskhod-Tatarskaya-Barabinsk 220 kV transmission line point out the efficiency of the developed solutions that ensure reliable functioning of the PSD.

  9. Formation and all-optical control of optical patterns in semiconductor microcavities

    NASA Astrophysics Data System (ADS)

    Binder, R.; Tsang, C. Y.; Tse, Y. C.; Luk, M. H.; Kwong, N. H.; Chan, Chris K. P.; Leung, P. T.; Lewandowski, P.; Schumacher, Stefan; Lafont, O.; Baudin, E.; Tignon, J.

    2016-05-01

    Semiconductor microcavities offer a unique way to combine transient all-optical manipulation of GaAs quantum wells with the benefits of structural advantages of microcavities. In these systems, exciton-polaritons have dispersion relations with very small effective masses. This has enabled prominent effects, for example polaritonic Bose condensation, but it can also be exploited for the design of all-optical communication devices. The latter involves non-equilibrium phase transitions in the spatial arrangement of exciton-polaritons. We consider the case of optical pumping with normal incidence, yielding a spatially homogeneous distribution of exciton-polaritons in optical cavities containing the quantum wells. Exciton-exciton interactions can trigger instabilities if certain threshold behavior requirements are met. Such instabilities can lead, for example, to the spontaneous formation of hexagonal polariton lattices (corresponding to six-spot patterns in the far field), or to rolls (corresponding to two-spot far field patterns). The competition among these patterns can be controlled to a certain degree by applying control beams. In this paper, we summarize the theory of pattern formation and election in microcavities and illustrate the switching between patterns via simulation results.

  10. Real-time device-scale imaging of conducting filament dynamics in resistive switching materials

    PubMed Central

    Lee, Keundong; Tchoe, Youngbin; Yoon, Hosang; Baek, Hyeonjun; Chung, Kunook; Lee, Sangik; Yoon, Chansoo; Park, Bae Ho; Yi, Gyu-Chul

    2016-01-01

    ReRAM is a compelling candidate for next-generation non-volatile memory owing to its various advantages. However, fluctuation of operation parameters are critical weakness occurring failures in ‘reading’ and ‘writing’ operations. To enhance the stability, it is important to understand the mechanism of the devices. Although numerous studies have been conducted using AFM or TEM, the understanding of the device operation is still limited due to the destructive nature and/or limited imaging range of the previous methods. Here, we propose a new hybrid device composed of ReRAM and LED enabling us to monitor the conducting filament (CF) configuration on the device scale during resistive switching. We directly observe the change in CF configuration across the whole device area through light emission from our hybrid device. In contrast to former studies, we found that minor CFs were formed earlier than major CF contributing to the resistive switching. Moreover, we investigated the substitution of a stressed major CF with a fresh minor CF when large fluctuation of operation voltage appeared after more than 50 times of resistive switching in atmospheric condition. Our results present an advancement in the understanding of ReRAM operation mechanism, and a step toward stabilizing the fluctuations in ReRAM switching parameters. PMID:27271792

  11. Real-time device-scale imaging of conducting filament dynamics in resistive switching materials

    NASA Astrophysics Data System (ADS)

    Lee, Keundong; Tchoe, Youngbin; Yoon, Hosang; Baek, Hyeonjun; Chung, Kunook; Lee, Sangik; Yoon, Chansoo; Park, Bae Ho; Yi, Gyu-Chul

    2016-06-01

    ReRAM is a compelling candidate for next-generation non-volatile memory owing to its various advantages. However, fluctuation of operation parameters are critical weakness occurring failures in ‘reading’ and ‘writing’ operations. To enhance the stability, it is important to understand the mechanism of the devices. Although numerous studies have been conducted using AFM or TEM, the understanding of the device operation is still limited due to the destructive nature and/or limited imaging range of the previous methods. Here, we propose a new hybrid device composed of ReRAM and LED enabling us to monitor the conducting filament (CF) configuration on the device scale during resistive switching. We directly observe the change in CF configuration across the whole device area through light emission from our hybrid device. In contrast to former studies, we found that minor CFs were formed earlier than major CF contributing to the resistive switching. Moreover, we investigated the substitution of a stressed major CF with a fresh minor CF when large fluctuation of operation voltage appeared after more than 50 times of resistive switching in atmospheric condition. Our results present an advancement in the understanding of ReRAM operation mechanism, and a step toward stabilizing the fluctuations in ReRAM switching parameters.

  12. Real-time device-scale imaging of conducting filament dynamics in resistive switching materials.

    PubMed

    Lee, Keundong; Tchoe, Youngbin; Yoon, Hosang; Baek, Hyeonjun; Chung, Kunook; Lee, Sangik; Yoon, Chansoo; Park, Bae Ho; Yi, Gyu-Chul

    2016-01-01

    ReRAM is a compelling candidate for next-generation non-volatile memory owing to its various advantages. However, fluctuation of operation parameters are critical weakness occurring failures in 'reading' and 'writing' operations. To enhance the stability, it is important to understand the mechanism of the devices. Although numerous studies have been conducted using AFM or TEM, the understanding of the device operation is still limited due to the destructive nature and/or limited imaging range of the previous methods. Here, we propose a new hybrid device composed of ReRAM and LED enabling us to monitor the conducting filament (CF) configuration on the device scale during resistive switching. We directly observe the change in CF configuration across the whole device area through light emission from our hybrid device. In contrast to former studies, we found that minor CFs were formed earlier than major CF contributing to the resistive switching. Moreover, we investigated the substitution of a stressed major CF with a fresh minor CF when large fluctuation of operation voltage appeared after more than 50 times of resistive switching in atmospheric condition. Our results present an advancement in the understanding of ReRAM operation mechanism, and a step toward stabilizing the fluctuations in ReRAM switching parameters. PMID:27271792

  13. All-Optical Terahertz Optical Asymmetric Demultiplexer (toad) Based Binary Comparator:. a Proposal

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Tanay

    Comparator determines whether a number is greater than, equals to or less than another number. It plays a significant role in fast central processing unit in all-optical scheme. In all-optical scheme here 1-bit binary comparator is proposed and described by Terahertz Optical Asymmetric Demultiplexer (TOAD) based interferometric switch. Simulation result by Mathcad-7 is also given. Cascading technique of building up the n-bit binary comparator with this 1-bit comparator block is also proposed here.

  14. Stochastic switching of TiO2-based memristive devices with identical initial memory states

    PubMed Central

    2014-01-01

    In this work, we show that identical TiO2-based memristive devices that possess the same initial resistive states are only phenomenologically similar as their internal structures may vary significantly, which could render quite dissimilar switching dynamics. We experimentally demonstrated that the resistive switching of practical devices with similar initial states could occur at different programming stimuli cycles. We argue that similar memory states can be transcribed via numerous distinct active core states through the dissimilar reduced TiO2-x filamentary distributions. Our hypothesis was finally verified via simulated results of the memory state evolution, by taking into account dissimilar initial filamentary distribution. PMID:24994953

  15. All-optical logic gates based on cross phase modulation effect in a phase-shifted grating.

    PubMed

    Li, Qiliang; Song, Junfeng; Chen, Xin; Bi, Meihua; Hu, Miao; Li, Shuqin

    2016-09-01

    In this paper, we perform a theoretical study of the all-optical logic gates based on the techniques of cross phase modulation (XPM) in a phase-shifted grating. Here the pumps are used to control the switching of a weak continuous wave (cw). In order to understand the transferring process of the information from the pump light to the cw light, we first study the switching characteristic of the device. Then, by changing the combination between two pumps, in a fiber grating with zero phase shift we have realized NOT, AND, and NAND gates, and in a phase-shifted grating with the phase shift π, the other various logic operations can be realized such as NAND gates and OR gates; when selecting Δφ=3/2π, we can realize XOR gates and XNOR gates. Thus the change of the phase shift of the phase-shifted grating will yield various logic gates. PMID:27607262

  16. Ultra high voltage MOS controlled 4H-SiC power switching devices

    NASA Astrophysics Data System (ADS)

    Ryu, S.; Capell, C.; Van Brunt, E.; Jonas, C.; O'Loughlin, M.; Clayton, J.; Lam, K.; Pala, V.; Hull, B.; Lemma, Y.; Lichtenwalner, D.; Zhang, Q. J.; Richmond, J.; Butler, P.; Grider, D.; Casady, J.; Allen, S.; Palmour, J.; Hinojosa, M.; Tipton, C. W.; Scozzie, C.

    2015-08-01

    Ultra high voltage (UHV, >15 kV) 4H-silicon carbide (SiC) power devices have the potential to significantly improve the system performance, reliability, and cost of energy conversion systems by providing reduced part count, simplified circuit topology, and reduced switching losses. In this paper, we compare the two MOS based UHV 4H-SiC power switching devices; 15 kV 4H-SiC MOSFETs and 15 kV 4H-SiC n-IGBTs. The 15 kV 4H-SiC MOSFET shows a specific on-resistance of 204 mΩ cm2 at 25 °C, which increased to 570 mΩ cm2 at 150 °C. The 15 kV 4H-SiC MOSFET provides low, temperature-independent, switching losses which makes the device more attractive for applications that require higher switching frequencies. The 15 kV 4H-SiC n-IGBT shows a significantly lower forward voltage drop (VF), along with reasonable switching performance, which make it a very attractive device for high voltage applications with lower switching frequency requirements. An electrothermal analysis showed that the 15 kV 4H-SiC n-IGBT outperforms the 15 kV 4H-SiC MOSFET for applications with switching frequencies of less than 5 kHz. It was also shown that the use of a carrier storage layer (CSL) can significantly improve the conduction performance of the 15 kV 4H-SiC n-IGBTs.

  17. Pencil beam all-optical ultrasound imaging

    PubMed Central

    Alles, Erwin J.; Noimark, Sacha; Zhang, Edward; Beard, Paul C.; Desjardins, Adrien E.

    2016-01-01

    A miniature, directional fibre-optic acoustic source is presented that employs geometrical focussing to generate a nearly-collimated acoustic pencil beam. When paired with a fibre-optic acoustic detector, an all-optical ultrasound probe with an outer diameter of 2.5 mm is obtained that acquires a pulse-echo image line at each probe position without the need for image reconstruction. B-mode images can be acquired by translating the probe and concatenating the image lines, and artefacts resulting from probe positioning uncertainty are shown to be significantly lower than those observed for conventional synthetic aperture scanning of a non-directional acoustic source. The high image quality obtained for excised vascular tissue suggests that the all-optical ultrasound probe is ideally suited for in vivo, interventional applications. PMID:27699130

  18. All-optical vector atomic magnetometer.

    PubMed

    Patton, B; Zhivun, E; Hovde, D C; Budker, D

    2014-07-01

    We demonstrate an all-optical magnetometer capable of measuring the magnitude and direction of a magnetic field using nonlinear magneto-optical rotation in cesium vapor. Vector capability is added by effective modulation of the field along orthogonal axes and subsequent demodulation of the magnetic-resonance frequency. This modulation is provided by the ac Stark shift induced by circularly polarized laser beams. The sensor exhibits a demonstrated rms noise floor of ∼65  fT/√[Hz] in measurement of the field magnitude and 0.5  mrad/√[Hz] in the field direction; elimination of technical noise would improve these sensitivities to 12  fT/√[Hz] and 10  μrad/√[Hz], respectively. Applications for this all-optical vector magnetometer would include magnetically sensitive fundamental physics experiments, such as the search for a permanent electric dipole moment of the neutron. PMID:25032923

  19. All-Optical Vector Atomic Magnetometer

    NASA Astrophysics Data System (ADS)

    Patton, B.; Zhivun, E.; Hovde, D. C.; Budker, D.

    2014-07-01

    We demonstrate an all-optical magnetometer capable of measuring the magnitude and direction of a magnetic field using nonlinear magneto-optical rotation in cesium vapor. Vector capability is added by effective modulation of the field along orthogonal axes and subsequent demodulation of the magnetic-resonance frequency. This modulation is provided by the ac Stark shift induced by circularly polarized laser beams. The sensor exhibits a demonstrated rms noise floor of ˜65 fT/√Hz in measurement of the field magnitude and 0.5 mrad /√Hz in the field direction; elimination of technical noise would improve these sensitivities to 12 fT /√Hz and 10 μrad /√Hz , respectively. Applications for this all-optical vector magnetometer would include magnetically sensitive fundamental physics experiments, such as the search for a permanent electric dipole moment of the neutron.

  20. Pencil beam all-optical ultrasound imaging

    PubMed Central

    Alles, Erwin J.; Noimark, Sacha; Zhang, Edward; Beard, Paul C.; Desjardins, Adrien E.

    2016-01-01

    A miniature, directional fibre-optic acoustic source is presented that employs geometrical focussing to generate a nearly-collimated acoustic pencil beam. When paired with a fibre-optic acoustic detector, an all-optical ultrasound probe with an outer diameter of 2.5 mm is obtained that acquires a pulse-echo image line at each probe position without the need for image reconstruction. B-mode images can be acquired by translating the probe and concatenating the image lines, and artefacts resulting from probe positioning uncertainty are shown to be significantly lower than those observed for conventional synthetic aperture scanning of a non-directional acoustic source. The high image quality obtained for excised vascular tissue suggests that the all-optical ultrasound probe is ideally suited for in vivo, interventional applications.

  1. All-optical vector atomic magnetometer.

    PubMed

    Patton, B; Zhivun, E; Hovde, D C; Budker, D

    2014-07-01

    We demonstrate an all-optical magnetometer capable of measuring the magnitude and direction of a magnetic field using nonlinear magneto-optical rotation in cesium vapor. Vector capability is added by effective modulation of the field along orthogonal axes and subsequent demodulation of the magnetic-resonance frequency. This modulation is provided by the ac Stark shift induced by circularly polarized laser beams. The sensor exhibits a demonstrated rms noise floor of ∼65  fT/√[Hz] in measurement of the field magnitude and 0.5  mrad/√[Hz] in the field direction; elimination of technical noise would improve these sensitivities to 12  fT/√[Hz] and 10  μrad/√[Hz], respectively. Applications for this all-optical vector magnetometer would include magnetically sensitive fundamental physics experiments, such as the search for a permanent electric dipole moment of the neutron.

  2. All-optical control of molecular fluorescence

    SciTech Connect

    Bradshaw, David S.; Andrews, David L.

    2010-01-15

    We present a quantum electrodynamical procedure to demonstrate the all-optical control of molecular fluorescence. The effect is achieved on passage of an off-resonant laser beam through an optically activated system; the presence of a surface is not required. Following the derivation and analysis of the all-optical control mechanism, calculations are given to quantify the significant modification of spontaneous fluorescent emission with input laser irradiance. Specific results are given for molecules whose electronic spectra are dominated by transitions between three electronic levels, and suitable laser experimental methods are proposed. It is also shown that the phenomenon is sensitive to the handedness of circularly polarized throughput, producing a conferred form of optical activity.

  3. Resistive switching behavior of reduced graphene oxide memory cells for low power nonvolatile device application

    PubMed Central

    Pradhan, Sangram K.; Xiao, Bo; Mishra, Saswat; Killam, Alex; Pradhan, Aswini K.

    2016-01-01

    Graphene Oxide (GO) based low cost flexible electronics and memory cell have recently attracted more attention for the fabrication of emerging electronic devices. As a suitable candidate for resistive random access memory technology, reduced graphene oxide (RGO) can be widely used for non-volatile switching memory applications because of its large surface area, excellent scalability, retention, and endurance properties. We demonstrated that the fabricated metal/RGO/metal memory device exhibited excellent switching characteristics, with on/off ratio of two orders of magnitude and operated threshold switching voltage of less than 1 V. The studies on different cell diameter, thickness, scan voltages and period of time corroborate the reliability of the device as resistive random access memory. The microscopic origin of switching operation is governed by the establishment of conducting filaments due to the interface amorphous layer rupturing and the movement of oxygen in the GO layer. This interesting experimental finding indicates that device made up of thermally reduced GO shows more reliability for its use in next generation electronics devices. PMID:27240537

  4. Interfacial behavior of resistive switching in ITO-PVK-Al WORM memory devices

    NASA Astrophysics Data System (ADS)

    Whitcher, T. J.; Woon, K. L.; Wong, W. S.; Chanlek, N.; Nakajima, H.; Saisopa, T.; Songsiriritthigul, P.

    2016-02-01

    Understanding the mechanism of resistive switching in a memory device is fundamental in order to improve device performance. The mechanism of current switching in a basic organic write-once read-many (WORM) memory device is investigated by determining the energy level alignments of indium tin oxide (ITO), poly(9-vinylcarbazole) (PVK) and aluminum (Al) using x-ray and ultraviolet photoelectron spectroscopy, current-voltage characterization and Auger depth profiling. The current switching mechanism was determined to be controlled by the interface between the ITO and the PVK. The electric field applied across the device causes the ITO from the uneven surface of the anode to form metallic filaments through the PVK, causing a shorting effect within the device leading to increased conduction. This was found to be independent of the PVK thickness, although the switch-on voltage was non-linearly dependent on the thickness. The formation of these filaments also caused the destruction of the interfacial dipole at the PVK-Al interface.

  5. Resistive switching behavior of reduced graphene oxide memory cells for low power nonvolatile device application

    NASA Astrophysics Data System (ADS)

    Pradhan, Sangram K.; Xiao, Bo; Mishra, Saswat; Killam, Alex; Pradhan, Aswini K.

    2016-05-01

    Graphene Oxide (GO) based low cost flexible electronics and memory cell have recently attracted more attention for the fabrication of emerging electronic devices. As a suitable candidate for resistive random access memory technology, reduced graphene oxide (RGO) can be widely used for non-volatile switching memory applications because of its large surface area, excellent scalability, retention, and endurance properties. We demonstrated that the fabricated metal/RGO/metal memory device exhibited excellent switching characteristics, with on/off ratio of two orders of magnitude and operated threshold switching voltage of less than 1 V. The studies on different cell diameter, thickness, scan voltages and period of time corroborate the reliability of the device as resistive random access memory. The microscopic origin of switching operation is governed by the establishment of conducting filaments due to the interface amorphous layer rupturing and the movement of oxygen in the GO layer. This interesting experimental finding indicates that device made up of thermally reduced GO shows more reliability for its use in next generation electronics devices.

  6. Resistive switching behavior of reduced graphene oxide memory cells for low power nonvolatile device application.

    PubMed

    Pradhan, Sangram K; Xiao, Bo; Mishra, Saswat; Killam, Alex; Pradhan, Aswini K

    2016-01-01

    Graphene Oxide (GO) based low cost flexible electronics and memory cell have recently attracted more attention for the fabrication of emerging electronic devices. As a suitable candidate for resistive random access memory technology, reduced graphene oxide (RGO) can be widely used for non-volatile switching memory applications because of its large surface area, excellent scalability, retention, and endurance properties. We demonstrated that the fabricated metal/RGO/metal memory device exhibited excellent switching characteristics, with on/off ratio of two orders of magnitude and operated threshold switching voltage of less than 1 V. The studies on different cell diameter, thickness, scan voltages and period of time corroborate the reliability of the device as resistive random access memory. The microscopic origin of switching operation is governed by the establishment of conducting filaments due to the interface amorphous layer rupturing and the movement of oxygen in the GO layer. This interesting experimental finding indicates that device made up of thermally reduced GO shows more reliability for its use in next generation electronics devices. PMID:27240537

  7. Plasmonic All-Optical Tunable Wavelength Shifter

    SciTech Connect

    Flugel, B.; Macararenhas, A.; Snoke, D. W.; Pfeiffer, L. N.; West, K.

    2007-12-01

    At present, wavelength-division-multiplexed fibre lines routinely operate at 10 Gbit s{sup -1} per channel. The transition from static-path networks to true all-optical networks encompassing many nodes, in which channels are added/dropped and efficiently reassigned, will require improved tools for all-optical wavelength shifting. Specifically, one must be able to shift the carrier wavelength (frequency) of an optical data signal over tens of nanometres (a THz range) without the bottleneck of electrical conversion. Popular approaches to this problem make use of the nonlinear interaction between two wavelengths within a semiconductor optical amplifier whereas more novel methods invoke terahertz-frequency electro-optic modulation and polaritons. Here we outline the principles and demonstrate the use of optically excited plasmons as a tunable frequency source that can be mixed with a laser frequency through Raman scattering. The scheme is all-optical and enables dynamical control of the output carrier wavelength simply by varying the power of a control laser.

  8. All-optical arithmetic unit with the help of terahertz-optical-asymmetric-demultiplexer-based tree architecture

    NASA Astrophysics Data System (ADS)

    Gayen, Dilip Kumar; Nath Roy, Jitendra

    2008-03-01

    An all-optical arithmetic unit with the help of terahertz-optical-asymmetric-demultiplexer (TOAD)-based tree architecture is proposed. We describe the all-optical arithmetic unit by using a set of all-optical multiplexer, all-optical full-adder, and optical switch. The all-optical arithmetic unit can be used to perform a fast central processor unit using optical hardware components. We have tried to exploit the advantages of both optical tree architecture and TOAD-based switch to design an integrated all-optical circuit that can perform binary addition, addition with carry, subtract with borrow, subtract (2's complement), double, increment, decrement, and transfer operations.

  9. Solid-state memcapacitive device based on memristive switch

    NASA Astrophysics Data System (ADS)

    Flak, J.; Lehtonen, E.; Laiho, M.; Rantala, A.; Prunnila, M.; Haatainen, T.

    2014-10-01

    This article describes the implementation of a solid-state memcapacitor based on combination of a memristor and traditional metal-insulator-metal capacitor. A device with an area of 5 μ M× 5 μ M has been fabricated and tested. The structure has been simulated and analyzed using circuit equivalents with parameters obtained from measurements. The memristor is represented by a sinh (\\cdot )-type model. The performance of the memcapacitor is discussed, and some methods to improve it are proposed.

  10. Model of current-limited negative differential resistance in oxide-based resistance-switching devices

    NASA Astrophysics Data System (ADS)

    Chen, Frederick T.

    2015-01-01

    Resistance-switching devices such as resistive random access memories (RRAMs) exhibit the ability to rapidly reduce resistance upon exceeding a threshold voltage, as part of the SET operation. For oxide-based RRAMs, the progressive generation of defects during SET requires strict regulation of the current, e.g., by a transistor, in order to avoid irreversible breakdown. In doing so, the current-limiting device itself takes some voltage burden. The observed negative differential resistance for both the initial (forming) and regular SET operations can be analytically explained with a basic circuit model for the current-limited switching element, linking the voltage transfer to the current-limiting device with the degree of current rise. Consequently, it is found that RRAM operation current is a vital consideration for the reliability of the current-limiting device.

  11. Bipolar resistive switching characteristics in tantalum nitride-based resistive random access memory devices

    SciTech Connect

    Kim, Myung Ju; Jeon, Dong Su; Park, Ju Hyun; Kim, Tae Geun

    2015-05-18

    This paper reports the bipolar resistive switching characteristics of TaN{sub x}-based resistive random access memory (ReRAM). The conduction mechanism is explained by formation and rupture of conductive filaments caused by migration of nitrogen ions and vacancies; this mechanism is in good agreement with either Ohmic conduction or the Poole-Frenkel emission model. The devices exhibit that the reset voltage varies from −0.82 V to −0.62 V, whereas the set voltage ranges from 1.01 V to 1.30 V for 120 DC sweep cycles. In terms of reliability, the devices exhibit good retention (>10{sup 5 }s) and pulse-switching endurance (>10{sup 6} cycles) properties. These results indicate that TaN{sub x}-based ReRAM devices have a potential for future nonvolatile memory devices.

  12. First-principles studies on switching properties of azobenzene based molecular device

    NASA Astrophysics Data System (ADS)

    Dhivya, G.; Nagarajan, V.; Chandiramouli, R.

    2016-09-01

    The switching behavior of cis and trans-azobenzene molecular device is studied using DFT method in combination with non-equilibrium Green's function. The peak maximum is found to be more in the density of states spectrum for trans-azobenzene device rather than cis-azobenzene device due to direct link of two phenyl group by Ndbnd N bonds. The current voltage characteristics clearly show the closed configuration of cis-azobenzene and open configuration of trans-azobenzene, which is attributed through the HOMO and LUMO level of cis and trans isomers. The observations of the present work give an insight on switching behavior of azobenzene based molecular device in the atomistic level.

  13. Cyclic electric field stress on bipolar resistive switching devices

    NASA Astrophysics Data System (ADS)

    Schulman, A.; Acha, C.

    2013-12-01

    We have studied the effects of accumulating cyclic electrical pulses of increasing amplitude on the non-volatile resistance state of interfaces made by sputtering a metal (Au, Pt) on top of the surface of a cuprate superconductor YBa2Cu3O7-δ. We have analyzed the influence of the number of applied pulses N on the relative amplitude of the remnant resistance change between the high (RH) and the low (RL) state [(α=(RH-RL)/RL] at different temperatures (T). We show that the critical voltage (Vc) needed to produce a resistive switching (RS, i.e., α >0) decreases with increasing N or T. We also find a power law relation between the voltage of the pulses and the number of pulses Nα0 required to produce a RS of α =α0. This relation remains very similar to the Basquin equation used to describe the stress-fatigue lifetime curves in mechanical tests. This points out to the similarity between the physics of the RS, associated with the diffusion of oxygen vacancies induced by electrical pulses, and the propagation of defects in materials subjected to repeated mechanical stress.

  14. Determinants of Method Switching among Social Franchise Clients Who Discontinued the Use of Intrauterine Contraceptive Device

    PubMed Central

    Hameed, Waqas; Azmat, Syed Khurram; Ali, Moazzam; Hussain, Wajahat; Mustafa, Ghulam; Ishaque, Muhammad; Ali, Safdar; Ahmed, Aftab; Temmerman, Marleen

    2015-01-01

    Introduction. Women who do not switch to alternate methods after contraceptive discontinuation, for reasons other than the desire to get pregnant or not needing it, are at obvious risk for unplanned pregnancies or unwanted births. This paper examines the factors that influence women to switch from Intrauterine Contraceptive Device (IUCD) to other methods instead of terminating contraceptive usage altogether. Methods. The data used for this study comes from a larger cross-sectional survey conducted in nine (9) randomly selected districts of Sindh and Punjab provinces of Pakistan, during January 2011. Using Stata 11.2, we analyzed data on 333 women, who reported the removal of IUCDs due to reasons other than the desire to get pregnant. Results. We found that 39.9% of the women do not switch to another method of contraception within one month after IUCD discontinuation. Use of contraception before IUCD insertion increases the odds for method switching by 2.26 times after removal. Similarly, postremoval follow-up by community health worker doubles (OR = 2.0) the chances of method switching. Compared with women who received free IUCD service (via voucher scheme), the method switching is 2.01 times higher among women who had paid for IUCD insertion. Conclusion. To increase the likelihood of method switching among IUCD discontinuers this study emphasizes the need for postremoval client counseling, follow-up by healthcare provider, improved choices to a wider range of contraceptives for poor clients, and user satisfaction. PMID:26576454

  15. Determinants of Method Switching among Social Franchise Clients Who Discontinued the Use of Intrauterine Contraceptive Device.

    PubMed

    Hameed, Waqas; Azmat, Syed Khurram; Ali, Moazzam; Hussain, Wajahat; Mustafa, Ghulam; Ishaque, Muhammad; Ali, Safdar; Ahmed, Aftab; Temmerman, Marleen

    2015-01-01

    Introduction. Women who do not switch to alternate methods after contraceptive discontinuation, for reasons other than the desire to get pregnant or not needing it, are at obvious risk for unplanned pregnancies or unwanted births. This paper examines the factors that influence women to switch from Intrauterine Contraceptive Device (IUCD) to other methods instead of terminating contraceptive usage altogether. Methods. The data used for this study comes from a larger cross-sectional survey conducted in nine (9) randomly selected districts of Sindh and Punjab provinces of Pakistan, during January 2011. Using Stata 11.2, we analyzed data on 333 women, who reported the removal of IUCDs due to reasons other than the desire to get pregnant. Results. We found that 39.9% of the women do not switch to another method of contraception within one month after IUCD discontinuation. Use of contraception before IUCD insertion increases the odds for method switching by 2.26 times after removal. Similarly, postremoval follow-up by community health worker doubles (OR = 2.0) the chances of method switching. Compared with women who received free IUCD service (via voucher scheme), the method switching is 2.01 times higher among women who had paid for IUCD insertion. Conclusion. To increase the likelihood of method switching among IUCD discontinuers this study emphasizes the need for postremoval client counseling, follow-up by healthcare provider, improved choices to a wider range of contraceptives for poor clients, and user satisfaction.

  16. Memory characteristics of flexible resistive switching devices with triangular-shaped silicon nanowire bottom electrodes

    NASA Astrophysics Data System (ADS)

    Park, Sukhyung; Cho, Kyoungah; Kim, Sangsig

    2015-05-01

    In this paper, we demonstrate the bipolar resistive switching characteristics of flexible resistive random access memory (ReRAM) devices, whose bottom electrodes are made of silicon nanowires (Si NWs) with a triangular structure, which offer preferential sites for the filaments. The temperature dependence of the low resistance state (LRS) of the resistive Al2O3/ZnO bilayers of ReRAM devices reveals that Ag filaments originating from the top Ag electrodes are responsible for bipolar resistive switching. With respect to the endurance characteristics of the LRS, resistance fluctuation is negligible because of the filaments generated at the specific sites of the vertices of the Si NW bottom electrodes. In addition, the resistive switching characteristics are maintained even after 1000 bending cycles.

  17. Development of Curie point switching for thin film, random access, memory device

    NASA Technical Reports Server (NTRS)

    Lewicki, G. W.; Tchernev, D. I.

    1967-01-01

    Managanese bismuthide films are used in the development of a random access memory device of high packing density and nondestructive readout capability. Memory entry is by Curie point switching using a laser beam. Readout is accomplished by microoptical or micromagnetic scanning.

  18. Analysis on optical bistability parameters in photonic switching devices

    NASA Astrophysics Data System (ADS)

    Sarafraz, Hossein; Sayeh, Mohammad R.

    2016-06-01

    An investigation has been done on the parameters of a hysteretic bistable optical Schmitt trigger device. From a design point of view, it is important to know the regions where this bistability occurs and is fully functional with respect to its subsystem parameters. Otherwise experimentally reaching such behavior will be very time-consuming and frustrating, especially with multiple devices employed in a single photonic circuit. A photonic Schmitt trigger consisting of two feedbacked inverting amplifiers, each characterized by -m (slope), A (y-intercept), and B (constant base) parameters is considered. This system is investigated dynamically with a varying input to find its stable and unstable states both mathematically and with simulation. In addition to a complete mathematical analysis of the system, we also describe how m, A, and B can be properly chosen in order to satisfy certain system conditions that result in bistability. More restrictions are also imposed to these absolute conditions by the system conditions as will be discussed. Finally, all results are verified in a more realistic photonic simulation.

  19. All optical binary delta-sigma modulator

    NASA Astrophysics Data System (ADS)

    Sayeh, Mohammad R.; Siahmakoun, Azad

    2005-09-01

    This paper describes a novel A/D converter called "Binary Delta-Sigma Modulator" (BDSM) which operates only with nonnegative signal with positive feedback and binary threshold. This important modification to the conventional delta-sigma modulator makes the high-speed (>100GHz) all-optical implementation possible. It has also the capability to modify its own sampling frequency as well as its input dynamic range. This adaptive feature helps designers to optimize the system performance under highly noisy environment and also manage the power consumption of the A/D converters.

  20. All-optical nanomechanical heat engine.

    PubMed

    Dechant, Andreas; Kiesel, Nikolai; Lutz, Eric

    2015-05-01

    We propose and theoretically investigate a nanomechanical heat engine. We show how a levitated nanoparticle in an optical trap inside a cavity can be used to realize a Stirling cycle in the underdamped regime. The all-optical approach enables fast and flexible control of all thermodynamical parameters and the efficient optimization of the performance of the engine. We develop a systematic optimization procedure to determine optimal driving protocols. Further, we perform numerical simulations with realistic parameters and evaluate the maximum power and the corresponding efficiency. PMID:26001001

  1. All-optical nanomechanical heat engine.

    PubMed

    Dechant, Andreas; Kiesel, Nikolai; Lutz, Eric

    2015-05-01

    We propose and theoretically investigate a nanomechanical heat engine. We show how a levitated nanoparticle in an optical trap inside a cavity can be used to realize a Stirling cycle in the underdamped regime. The all-optical approach enables fast and flexible control of all thermodynamical parameters and the efficient optimization of the performance of the engine. We develop a systematic optimization procedure to determine optimal driving protocols. Further, we perform numerical simulations with realistic parameters and evaluate the maximum power and the corresponding efficiency.

  2. All-Optical Nanomechanical Heat Engine

    NASA Astrophysics Data System (ADS)

    Dechant, Andreas; Kiesel, Nikolai; Lutz, Eric

    2015-05-01

    We propose and theoretically investigate a nanomechanical heat engine. We show how a levitated nanoparticle in an optical trap inside a cavity can be used to realize a Stirling cycle in the underdamped regime. The all-optical approach enables fast and flexible control of all thermodynamical parameters and the efficient optimization of the performance of the engine. We develop a systematic optimization procedure to determine optimal driving protocols. Further, we perform numerical simulations with realistic parameters and evaluate the maximum power and the corresponding efficiency.

  3. Comparison of all optical forwarding packet architectures

    NASA Astrophysics Data System (ADS)

    Farhat, Rim; Farhat, Amel; Menif, Mourad

    2016-04-01

    In this paper two all optical packet forwarding architectures based on non linear effect in semiconductor optical amplifier in Mach-Zehnder configuration SOA-MZI are studied. The first architecture consist in combing flip flop functionality with the AND logic functionality in the same unit. Error free operation at 40 Gbps for two cascaded nodes is achieved. In the second architecture two separated units namely the flip flop and the AND logic gate are used. 100 Gbps bit rate is reached. At 40 Gbps error free operation is achieved for three cascaded nodes.

  4. 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.

  5. Realization of an all optical exciton-polariton router

    SciTech Connect

    Marsault, Félix; Nguyen, Hai Son; Tanese, Dimitrii; Lemaître, Aristide; Galopin, Elisabeth; Sagnes, Isabelle; Amo, Alberto

    2015-11-16

    We report on the experimental realization of an all optical router for exciton-polaritons. This device is based on the design proposed by Flayac and Savenko [Appl. Phys. Lett. 103, 201105 (2013)], in which a zero-dimensional island is connected through tunnel barriers to two periodically modulated wires of different periods. Selective transmission of polaritons injected in the island, into either of the two wires, is achieved by tuning the energy of the island state across the band structure of the modulated wires. We demonstrate routing of ps polariton pulses using an optical control beam which controls the energy of the island quantum states, thanks to polariton-exciton interactions.

  6. In-fiber all-optical fractional differentiator.

    PubMed

    Cuadrado-Laborde, C; Andrés, M V

    2009-03-15

    We demonstrate that an asymmetrical pi phase-shifted fiber Bragg grating operated in reflection can provide the required spectral response for implementing an all-optical fractional differentiator. There are different (but equivalent) ways to design it, e.g., by using different gratings lengths and keeping the same index modulation depth at both sides of the pi phase shift, or vice versa. Analytical expressions were found relating the fractional differentiator order with the grating parameters. The device shows a good accuracy calculating the fractional time derivatives of the complex field of an arbitrary input optical waveform. The introduced concept is supported by numerical simulations.

  7. All-optical implementation of ASCII by use of nonlinear material for optical encoding of necessary symbols

    NASA Astrophysics Data System (ADS)

    Dhar, Shantanu K.; Mukhopadhyay, Sourangshu

    2005-06-01

    We propose a simple all-optical technique for digital encoding of ASCII. The method accommodates a digital encoding system by using the optical tree architecture and a nonlinear-material-based optical switching operation.

  8. Hanging foot switch for bipolar forceps: a device for surgeons operating in the standing position: technical note.

    PubMed

    Shimizu, Satoru; Kondo, Koji; Yamazaki, Tomoya; Koizumi, Hiroyuki; Miyazaki, Tomoko; Osawa, Shigeyuki; Sagiuchi, Takao; Nakayama, Kenji; Yamamoto, Isao; Fujii, Kiyotaka

    2013-01-01

    For surgeons operating in the standing position, the manipulation of foot switches involves shifting of the weight to the pivoting leg and the possible loss of contact between the switch and the foot. We solved this problem by changing the position of the switch that operates bipolar forceps. Our novel device is made of aluminum plates. The base plate features a foot strap and a height-adjustable overhang over the switch-operating foot. A commercially-available disc type foot switch is attached to the underside of the overhang in upside-down position, so the switch is operable with the toe. To turn on the switch, the toe is flexed dorsally to push the switch pedal, so the action is limited to the part distal to the metatarsophalangeal joints. Our switch was used in more than 100 consecutive microsurgeries performed by surgeons operating in the standing position. The switch manipulation required no shifting of the weight and was easier and quicker than manipulation of conventionally-placed switches. The surgeons were able to change the foot position freely with the modified switch, thereby avoiding loss of contact with the switch. The modified switch placement reduced physical fatigue in the lower extremities, annoyance related to the manipulation of conventionally-placed switches, and increased the comfort of surgeons operating in the standing position. PMID:23358172

  9. A transparent electrochromic metal-insulator switching device with three-terminal transistor geometry.

    PubMed

    Katase, Takayoshi; Onozato, Takaki; Hirono, Misako; Mizuno, Taku; Ohta, Hiromichi

    2016-01-01

    Proton and hydroxyl ion play an essential role for tuning functionality of oxides because their electronic state can be controlled by modifying oxygen off-stoichiometry and/or protonation. Tungsten trioxide (WO3), a well-known electrochromic (EC) material for smart window, is a wide bandgap insulator, whereas it becomes a metallic conductor HxWO3 by protonation. Although one can utilize electrochromism together with metal-insulator (MI) switching for one device, such EC-MI switching cannot be utilized in current EC devices because of their two-terminal structure with parallel-plate configuration. Here we demonstrate a transparent EC-MI switchable device with three-terminal TFT-type structure using amorphous (a-) WO3 channel layer, which was fabricated on glass substrate at room temperature. We used water-infiltrated nano-porous glass, CAN (calcium aluminate with nano-pores), as a liquid-leakage-free solid gate insulator. At virgin state, the device was fully transparent in the visible-light region. For positive gate voltage, the active channel became dark blue, and electrical resistivity of the a-WO3 layer drastically decreased with protonation. For negative gate voltage, deprotonation occurred and the active channel returned to transparent insulator. Good cycleability of the present transparent EC-MI switching device would have potential for the development of advanced smart windows.

  10. A transparent electrochromic metal-insulator switching device with three-terminal transistor geometry.

    PubMed

    Katase, Takayoshi; Onozato, Takaki; Hirono, Misako; Mizuno, Taku; Ohta, Hiromichi

    2016-01-01

    Proton and hydroxyl ion play an essential role for tuning functionality of oxides because their electronic state can be controlled by modifying oxygen off-stoichiometry and/or protonation. Tungsten trioxide (WO3), a well-known electrochromic (EC) material for smart window, is a wide bandgap insulator, whereas it becomes a metallic conductor HxWO3 by protonation. Although one can utilize electrochromism together with metal-insulator (MI) switching for one device, such EC-MI switching cannot be utilized in current EC devices because of their two-terminal structure with parallel-plate configuration. Here we demonstrate a transparent EC-MI switchable device with three-terminal TFT-type structure using amorphous (a-) WO3 channel layer, which was fabricated on glass substrate at room temperature. We used water-infiltrated nano-porous glass, CAN (calcium aluminate with nano-pores), as a liquid-leakage-free solid gate insulator. At virgin state, the device was fully transparent in the visible-light region. For positive gate voltage, the active channel became dark blue, and electrical resistivity of the a-WO3 layer drastically decreased with protonation. For negative gate voltage, deprotonation occurred and the active channel returned to transparent insulator. Good cycleability of the present transparent EC-MI switching device would have potential for the development of advanced smart windows. PMID:27174791

  11. A transparent electrochromic metal-insulator switching device with three-terminal transistor geometry

    PubMed Central

    Katase, Takayoshi; Onozato, Takaki; Hirono, Misako; Mizuno, Taku; Ohta, Hiromichi

    2016-01-01

    Proton and hydroxyl ion play an essential role for tuning functionality of oxides because their electronic state can be controlled by modifying oxygen off-stoichiometry and/or protonation. Tungsten trioxide (WO3), a well-known electrochromic (EC) material for smart window, is a wide bandgap insulator, whereas it becomes a metallic conductor HxWO3 by protonation. Although one can utilize electrochromism together with metal-insulator (MI) switching for one device, such EC-MI switching cannot be utilized in current EC devices because of their two-terminal structure with parallel-plate configuration. Here we demonstrate a transparent EC-MI switchable device with three-terminal TFT-type structure using amorphous (a-) WO3 channel layer, which was fabricated on glass substrate at room temperature. We used water-infiltrated nano-porous glass, CAN (calcium aluminate with nano-pores), as a liquid-leakage-free solid gate insulator. At virgin state, the device was fully transparent in the visible-light region. For positive gate voltage, the active channel became dark blue, and electrical resistivity of the a-WO3 layer drastically decreased with protonation. For negative gate voltage, deprotonation occurred and the active channel returned to transparent insulator. Good cycleability of the present transparent EC-MI switching device would have potential for the development of advanced smart windows. PMID:27174791

  12. A transparent electrochromic metal-insulator switching device with three-terminal transistor geometry

    NASA Astrophysics Data System (ADS)

    Katase, Takayoshi; Onozato, Takaki; Hirono, Misako; Mizuno, Taku; Ohta, Hiromichi

    2016-05-01

    Proton and hydroxyl ion play an essential role for tuning functionality of oxides because their electronic state can be controlled by modifying oxygen off-stoichiometry and/or protonation. Tungsten trioxide (WO3), a well-known electrochromic (EC) material for smart window, is a wide bandgap insulator, whereas it becomes a metallic conductor HxWO3 by protonation. Although one can utilize electrochromism together with metal-insulator (MI) switching for one device, such EC-MI switching cannot be utilized in current EC devices because of their two-terminal structure with parallel-plate configuration. Here we demonstrate a transparent EC-MI switchable device with three-terminal TFT-type structure using amorphous (a-) WO3 channel layer, which was fabricated on glass substrate at room temperature. We used water-infiltrated nano-porous glass, CAN (calcium aluminate with nano-pores), as a liquid-leakage-free solid gate insulator. At virgin state, the device was fully transparent in the visible-light region. For positive gate voltage, the active channel became dark blue, and electrical resistivity of the a-WO3 layer drastically decreased with protonation. For negative gate voltage, deprotonation occurred and the active channel returned to transparent insulator. Good cycleability of the present transparent EC-MI switching device would have potential for the development of advanced smart windows.

  13. Stability and its mechanism in Ag/CoOx/Ag interface-type resistive switching device

    PubMed Central

    Fu, Jianbo; Hua, Muxin; Ding, Shilei; Chen, Xuegang; Wu, Rui; Liu, Shunquan; Han, Jingzhi; Wang, Changsheng; Du, Honglin; Yang, Yingchang; Yang, Jinbo

    2016-01-01

    Stability is an important issue for the application of resistive switching (RS) devices. In this work, the endurance and retention properties of Ag/CoOx/Ag interface-type RS device were investigated. This device exhibits rectifying I–V curve, multilevel storage states and retention decay behavior, which are all related to the Schottky barrier at the interface. The device can switch for thousands of cycles without endurance failure and shows narrow resistance distributions with relatively low fluctuation. However, both the high and low resistance states spontaneously decay to an intermediate resistance state during the retention test. This retention decay phenomenon is due to the short lifetime τ (τ = 0.5 s) of the metastable pinning effect caused by the interface states. The data analysis indicated that the pinning effect is dependent on the depth and density of the interface state energy levels, which determine the retention stability and the switching ratio, respectively. This suggests that an appropriate interface structure can improve the stability of the interface-type RS device PMID:27759116

  14. CROWNs: all-optical WDM multiring topologies

    NASA Astrophysics Data System (ADS)

    Chlamtac, Imrich; Fumagalli, Andrea F.

    1993-10-01

    Ring networks present an attractive solution for optical, high speed local and metropolitan area networks due to the simplicity of network interfaces and access control. Two problems need to be overcome to obtain an all optical network. One, the limitation on power budget resulting from optical losses that occur when data passes through intermediate nodes. The other, a reduced network throughput related to the linearity of the ring topology. Recent progress in WDM techniques has opened the possibility of overcoming this problem by an optical multi- channel solution. WDM taps the large fiber bandwidth by using different portions of the optical spectrum to realize (omega) different channels on the same fiber. However, in extant electronic node based architectures, even though high bandwidth optical transmission can be used to propagate packets between the nodes, the electronic elaboration of data at each node creates a performance bottleneck for the whole communication system. This leads to network throughput that is a mere fraction of the optical bandwidth potential. This work presents an approach to obtaining a concurrently accessed multi-ring all-optical WDM network (CROWN) with a node architecture in which packets pass through the node without being converted into the electronic domain. Using a single high speed transmitter and receiver, CROWN allows the data to be maintained in optical format while resolving receiver contentions.

  15. All-optical OFDM network coding scheme for all-optical virtual private communication in PON

    NASA Astrophysics Data System (ADS)

    Li, Lijun; Gu, Rentao; Ji, Yuefeng; Bai, Lin; Huang, Zhitong

    2014-03-01

    A novel optical orthogonal frequency division multiplexing (OFDM) network coding scheme is proposed over passive optical network (PON) system. The proposed scheme for all-optical virtual private network (VPN) does not only improve transmission efficiency, but also realize full-duplex communication mode in a single fiber. Compared with the traditional all-optical VPN architectures, the all-optical OFDM network coding scheme can support higher speed, more flexible bandwidth allocation, and higher spectrum efficiency. In order to reduce the difficulty of alignment for encoding operation between inter-communication traffic, the width of OFDM subcarrier pulse is stretched in our proposed scheme. The feasibility of all-optical OFDM network coding scheme for VPN is verified, and the relevant simulation results show that the full-duplex inter-communication traffic stream can be transmitted successfully. Furthermore, the tolerance of misalignment existing in inter-ONUs traffic is investigated and analyzed for all-optical encoding operation, and the difficulty of pulse alignment is proved to be lower.

  16. Spatially resolved TiOx phases in switched RRAM devices using soft X-ray spectromicroscopy

    NASA Astrophysics Data System (ADS)

    Carta, D.; Hitchcock, A. P.; Guttmann, P.; Regoutz, A.; Khiat, A.; Serb, A.; Gupta, I.; Prodromakis, T.

    2016-02-01

    Reduction in metal-oxide thin films has been suggested as the key mechanism responsible for forming conductive phases within solid-state memory devices, enabling their resistive switching capacity. The quantitative spatial identification of such conductive regions is a daunting task, particularly for metal-oxides capable of exhibiting multiple phases as in the case of TiOx. Here, we spatially resolve and chemically characterize distinct TiOx phases in localized regions of a TiOx–based memristive device by combining full-field transmission X-ray microscopy with soft X-ray spectroscopic analysis that is performed on lamella samples. We particularly show that electrically pre-switched devices in low-resistive states comprise reduced disordered phases with O/Ti ratios around 1.37 that aggregate in a ~100 nm highly localized region electrically conducting the top and bottom electrodes of the devices. We have also identified crystalline rutile and orthorhombic-like TiO2 phases in the region adjacent to the main reduced area, suggesting that the temperature increases locally up to 1000 K, validating the role of Joule heating in resistive switching. Contrary to previous studies, our approach enables to simultaneously investigate morphological and chemical changes in a quantitative manner without incurring difficulties imposed by interpretation of electron diffraction patterns acquired via conventional electron microscopy techniques.

  17. Spatially resolved TiOx phases in switched RRAM devices using soft X-ray spectromicroscopy.

    PubMed

    Carta, D; Hitchcock, A P; Guttmann, P; Regoutz, A; Khiat, A; Serb, A; Gupta, I; Prodromakis, T

    2016-01-01

    Reduction in metal-oxide thin films has been suggested as the key mechanism responsible for forming conductive phases within solid-state memory devices, enabling their resistive switching capacity. The quantitative spatial identification of such conductive regions is a daunting task, particularly for metal-oxides capable of exhibiting multiple phases as in the case of TiOx. Here, we spatially resolve and chemically characterize distinct TiOx phases in localized regions of a TiOx-based memristive device by combining full-field transmission X-ray microscopy with soft X-ray spectroscopic analysis that is performed on lamella samples. We particularly show that electrically pre-switched devices in low-resistive states comprise reduced disordered phases with O/Ti ratios around 1.37 that aggregate in a ~100 nm highly localized region electrically conducting the top and bottom electrodes of the devices. We have also identified crystalline rutile and orthorhombic-like TiO2 phases in the region adjacent to the main reduced area, suggesting that the temperature increases locally up to 1000 K, validating the role of Joule heating in resistive switching. Contrary to previous studies, our approach enables to simultaneously investigate morphological and chemical changes in a quantitative manner without incurring difficulties imposed by interpretation of electron diffraction patterns acquired via conventional electron microscopy techniques. PMID:26891776

  18. Spatially resolved TiOx phases in switched RRAM devices using soft X-ray spectromicroscopy

    PubMed Central

    Carta, D.; Hitchcock, A. P.; Guttmann, P.; Regoutz, A.; Khiat, A.; Serb, A.; Gupta, I.; Prodromakis, T.

    2016-01-01

    Reduction in metal-oxide thin films has been suggested as the key mechanism responsible for forming conductive phases within solid-state memory devices, enabling their resistive switching capacity. The quantitative spatial identification of such conductive regions is a daunting task, particularly for metal-oxides capable of exhibiting multiple phases as in the case of TiOx. Here, we spatially resolve and chemically characterize distinct TiOx phases in localized regions of a TiOx–based memristive device by combining full-field transmission X-ray microscopy with soft X-ray spectroscopic analysis that is performed on lamella samples. We particularly show that electrically pre-switched devices in low-resistive states comprise reduced disordered phases with O/Ti ratios around 1.37 that aggregate in a ~100 nm highly localized region electrically conducting the top and bottom electrodes of the devices. We have also identified crystalline rutile and orthorhombic-like TiO2 phases in the region adjacent to the main reduced area, suggesting that the temperature increases locally up to 1000 K, validating the role of Joule heating in resistive switching. Contrary to previous studies, our approach enables to simultaneously investigate morphological and chemical changes in a quantitative manner without incurring difficulties imposed by interpretation of electron diffraction patterns acquired via conventional electron microscopy techniques. PMID:26891776

  19. Large Conductance Switching in a Single-Molecule Device through Room Temperature Spin-Dependent Transport.

    PubMed

    Aragonès, Albert C; Aravena, Daniel; Cerdá, Jorge I; Acís-Castillo, Zulema; Li, Haipeng; Real, José Antonio; Sanz, Fausto; Hihath, Josh; Ruiz, Eliseo; Díez-Pérez, Ismael

    2016-01-13

    Controlling the spin of electrons in nanoscale electronic devices is one of the most promising topics aiming at developing devices with rapid and high density information storage capabilities. The interface magnetism or spinterface resulting from the interaction between a magnetic molecule and a metal surface, or vice versa, has become a key ingredient in creating nanoscale molecular devices with novel functionalities. Here, we present a single-molecule wire that displays large (>10000%) conductance switching by controlling the spin-dependent transport under ambient conditions (room temperature in a liquid cell). The molecular wire is built by trapping individual spin crossover Fe(II) complexes between one Au electrode and one ferromagnetic Ni electrode in an organic liquid medium. Large changes in the single-molecule conductance (>100-fold) are measured when the electrons flow from the Au electrode to either an α-up or a β-down spin-polarized Ni electrode. Our calculations show that the current flowing through such an interface appears to be strongly spin-polarized, thus resulting in the observed switching of the single-molecule wire conductance. The observation of such a high spin-dependent conductance switching in a single-molecule wire opens up a new door for the design and control of spin-polarized transport in nanoscale molecular devices at room temperature. PMID:26675052

  20. All-optical vector atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Zhivun, Elena; Patton, Brian; Hovde, Chris; Budker, Dmitry

    2014-05-01

    Alkali-vapor magnetometers are among the most precise magnetic sensors today, reaching sensitivities on the scale of fT/√{Hz}. In general, alkali-vapor magnetometers operating in finite fields can only measure the scalar magnitude of the field (not its direction or projection). In this work we demonstrate an all-optical vector cesium magnetometer with 0 . 2pT /√{Hz} sensitivity to the field magnitude and 4mrad /√{Hz} angular precision in the field direction. Although this can be accomplished by applying orthogonal magnetic fields to the sensor and measuring the change in Larmor frequency, in our sensor we employ the vector light shift induced by orthogonal laser beams to achieve the same effect. We will present results from such a sensor operating in a 10 mG magnetic field and discuss its applications to fundamental physics experiments and remote magnetometry.

  1. Ultrafast switching in magnetic tunnel junction based orthogonal spin transfer devices

    NASA Astrophysics Data System (ADS)

    Liu, H.; Bedau, D.; Backes, D.; Katine, J. A.; Langer, J.; Kent, A. D.

    2010-12-01

    Orthogonal spin-transfer magnetic random access memory (OST-MRAM) uses a spin-polarizing layer magnetized perpendicularly to a free layer to achieve large spin-transfer torques and ultrafast energy efficient switching. We have fabricated and studied OST-MRAM devices that incorporate a perpendicularly magnetized spin-polarizing layer and a magnetic tunnel junction, which consists of an in-plane magnetized free layer and synthetic antiferromagnetic reference layer. Reliable switching is observed at room temperature with 0.7 V amplitude pulses of 500 ps duration. The switching is bipolar, occurring for positive and negative polarity pulses, consistent with a precessional reversal mechanism, and requires an energy of less than 450 fJ.

  2. Switch programming of reflectivity control devices for the coupled dynamics of a solar sail

    NASA Astrophysics Data System (ADS)

    Hu, Tianjian; Gong, Shengping; Mu, Junshan; Li, Junfeng; Wang, Tianshu; Qian, Weiping

    2016-03-01

    As demonstrated in the Interplanetary Kite-craft Accelerated by Radiation Of the Sun (IKAROS), reflectivity control devices (RCDs) are switched on or off independently with each other, which has nevertheless been ignored by many previous researches. This paper emphasizes the discrete property of RCDs, and aims to obtain an appropriate switch law of RCDs for a rigid spinning solar sail. First, the coupled attitude-orbit dynamics is derived from the basic solar force and torque model into an underdetermined linear system with a binary set constraint. Subsequently, the coupled dynamics is reformulated into a constrained quadratic programming and a basic gradient projection method is designed to search for the optimal solution. Finally, a circular sail flying in the Venus rendezvous mission demonstrates the model and method numerically, which illustrates approximately 103 km terminal position error and 0.5 m/s terminal velocity error as 80 independent RCDs are switched on or off appropriately.

  3. Fast Deterministic Bipolar Switching in Orthogonal Spin Torque Devices via the Control of the Relative Spin Polarizations

    NASA Astrophysics Data System (ADS)

    Park, Junbo; Ralph, Daniel C.; Buhrman, Robert A.

    2014-03-01

    We model 100 ps pulse switching dynamics of orthogonal spin transfer (OST) devices that employ an out-of-plane polarizer (OPP) and an in-plane polarizer (IPP). Simulation results indicate that increasing the spin polarization ratio, CP =PIPP /POPP , results in deterministic switching of the free layer without over-rotation (360 degree rotation). By using spin torque asymmetry to realize an enhanced effective PIPP, we experimentally demonstrate this behavior in OST devices. Modeling predicts that decreasing the effective demagnetization field can substantially reduce the minimum CP required to attain deterministic bipolar switching, while retaining low critical switching current, Ip = 500 μA.

  4. A complementary switching mechanism for organic memory devices to regulate the conductance of binary states

    NASA Astrophysics Data System (ADS)

    Vyas, Giriraj; Dagar, Parveen; Sahu, Satyajit

    2016-06-01

    We have fabricated an organic non-volatile memory device wherein the ON/OFF current ratio has been controlled by varying the concentration of a small organic molecule, 2,3-Dichloro-5,6-dicyano-p-benzoquinone (DDQ), in an insulating matrix of a polymer Poly(4-vinylphenol) (PVP). A maximum ON-OFF ratio of 106 is obtained when the concentration of DDQ is half or 10 wt. % of PVP. In this process, the switching direction for the devices has also been altered, indicating the disparity in conduction mechanism. Conduction due to metal filament formation through the active material and the voltage dependent conformational change of the organic molecule seem to be the motivation behind the gradual change in the switching direction.

  5. Polarity-dependent effect of humidity on the resistive switching characteristics of nonpolar devices

    NASA Astrophysics Data System (ADS)

    Yin, Qiaonan; Wei, Chunyang; Wei, Qi; Chen, Yan; Xia, Yidong; Xu, Bo; Yin, Jiang; Liu, Zhiguo

    2016-10-01

    The roles of moisture in resistive switching (RS) devices are closely related to the RS mechanism. In principle, the nonpolar RS promises symmetric behaviors independent of the polarities of operating voltages. However, the effect of humidity on the RS characteristics of Pt/TiO2- x /Pt nonpolar cells is confirmed to be polarity-dependent. The positive electroforming threshold voltage decreases when humidity increases, whereas the negative one is unaffected. This asymmetric phenomenon can be attributed to the polarity-associated rule of current varying with humidity before electroforming. The voltage distribution in the device and then the electroforming threshold voltage are modified.

  6. All-Optical Interrogation of Neural Circuits

    PubMed Central

    2015-01-01

    There have been two recent revolutionary advances in neuroscience: First, genetically encoded activity sensors have brought the goal of optical detection of single action potentials in vivo within reach. Second, optogenetic actuators now allow the activity of neurons to be controlled with millisecond precision. These revolutions have now been combined, together with advanced microscopies, to allow “all-optical” readout and manipulation of activity in neural circuits with single-spike and single-neuron precision. This is a transformational advance that will open new frontiers in neuroscience research. Harnessing the power of light in the all-optical approach requires coexpression of genetically encoded activity sensors and optogenetic probes in the same neurons, as well as the ability to simultaneously target and record the light from the selected neurons. It has recently become possible to combine sensors and optical strategies that are sufficiently sensitive and cross talk free to enable single-action-potential sensitivity and precision for both readout and manipulation in the intact brain. The combination of simultaneous readout and manipulation from the same genetically defined cells will enable a wide range of new experiments as well as inspire new technologies for interacting with the brain. The advances described in this review herald a future where the traditional tools used for generations by physiologists to study and interact with the brain—stimulation and recording electrodes—can largely be replaced by light. We outline potential future developments in this field and discuss how the all-optical strategy can be applied to solve fundamental problems in neuroscience. SIGNIFICANCE STATEMENT This review describes the nexus of dramatic recent developments in optogenetic probes, genetically encoded activity sensors, and novel microscopies, which together allow the activity of neural circuits to be recorded and manipulated entirely using light. The

  7. Conductance Fluctuation and Superconducting-to-Normal State Switching Measurements of Superconducting Graphene Devices

    NASA Astrophysics Data System (ADS)

    Lambert, Joseph; Carabello, Steven; Ramos, Roberto

    2013-03-01

    We report on gate voltage dependent conductance fluctuations (CF) in superconducting graphene devices and compare measurements in the superconducting versus normal state at temperatures down to 20 mK. The CF arise from the averaged interference of charge carrier wave functions caused by scattering in the graphene. An enhancement in the magnitude of the average CF is expected when in the superconducting state due to Andreev reflections. We fabricate devices by contacting graphene with two parallel superconducting leads that are spaced a few hundred nanometers apart. The leads are a Pd/Al or Ti/Al bilayer with the thin Pd or Ti layer providing high transparency contact to graphene. Additionally, we report on our ongoing superconducting-to-normal state switching measurements in graphene Josephson junctions. The distribution of the stochastic switching current gives insight into the dynamics of the junction such as the phase particle escape mechanisms and dissipation processes. The use of graphene as the weak link allows novel control of the critical current, and thus the dynamics of the junction. By gathering switching data, we can study the modified Josephson washboard potential in these devices (J. G. Lambert, et al., IEEE Trans. in Appl. Supercond. 21, 734 (2011)). We gratefully acknowledge Prof. Fred Wellstood, University of Maryland, for access to fabrication facilities.

  8. Numerical simulation of a novel all-optical flip-flop based on a chirped nonlinear distributed feedback semiconductor laser structure using GPGPU computing

    NASA Astrophysics Data System (ADS)

    Zoweil, H.

    2015-05-01

    A novel all-optical flip-flop based on a chirped nonlinear distributed feedback laser structure is proposed. The flip-flop does not require a holding beam. The optical gain is provided by a current injection into an active layer. The nonlinear wave-guiding layer consists of a chirped phase shifted grating accompanied with a negative nonlinear refractive index coefficient that increases in magnitude along the wave-guide. In the 'OFF' state, the chirped grating does not provide the required optical feedback to start lasing. An optical pulse switches the device 'ON' by reducing the chirp due to the negative nonlinear refractive index coefficient. The reduced chirp grating provides enough feedback to sustain a laser mode. The device is switched 'OFF' by cross gain modulation. GPGPU computing allows for long simulation time of multiple SET-RESET operations. The 'ON/OFF' transitions delays are in nanoseconds time scale.

  9. The GALAXIE all-optical FEL project

    SciTech Connect

    Rosenzweig, J. B.; Arab, E.; Andonian, G.; Cahill, A.; Fitzmorris, K.; Fukusawa, A.; Hoang, P.; Jovanovic, I.; Marcus, G.; Marinelli, A.; Murokh, A.; Musumeci, P.; Naranjo, B.; O'Shea, B.; O'Shea, F.; Ovodenko, A.; Pogorelsky, I.; Putterman, S.; Roberts, K.; Shumail, M.; and others

    2012-12-21

    We describe a comprehensive project, funded under the DARPA AXiS program, to develop an all-optical table-top X-ray FEL based on dielectric acceleration and electromagnetic undulators, yielding a compact source of coherent X-rays for medical and related applications. The compactness of this source demands that high field (>GV/m) acceleration and undulation-inducing fields be employed, thus giving rise to the project's acronym: GV/m AcceLerator And X-ray Integrated Experiment (GALAXIE). There are numerous physics and technical hurdles to surmount in this ambitious scenario, and the integrated solutions include: a biharmonic photonic TW structure, 200 micron wavelength electromagnetic undulators, 5 {mu}m laser development, ultra-high brightness magnetized/asymmetric emittance electron beam generation, and SASE FEL operation. We describe the overall design philosophy of the project, the innovative approaches to addressing the challenges presented by the design, and the significant progress towards realization of these approaches in the nine months since project initialization.

  10. Description of all-optical network test bed and applications

    NASA Astrophysics Data System (ADS)

    Marquis, Douglas; Castagnozzi, Daniel M.; Hemenway, B. R.; Parikh, Salil A.; Stevens, Mark L.; Swanson, Eric A.; Thomas, Robert E.; Ozveren, C.; Kaminow, Ivan P.

    1995-12-01

    We describe an all-optical network testbed deployed in the Boston metropolitan area, and some of the experimental applications running over the network. The network was developed by a consortium of AT&T Bell Laboratories, Digital Equipment Corporation, and Massachusetts Institute of Technology under a grant from ARPA. The network is an optical WDM system organized as a hierarchy consisting of local, metropolitan, and wide area nodes that support optical broadcast and routing modes. Frequencies are shared and reused to enhance network scalability. Electronic access is provided through optical terminals that support multiple services having data rates between 10 Mbps/user and 10 Gbps/user. Novel components used to implement the network include fast-tuning 1.5 micrometers distributed Bragg reflector lasers, passive wavelength routers, and broadband optical frequency converters. An overlay control network implemented at 1.3 micrometers allows reliable out-of-band control and standardized network management of all network nodes. We have created interfaces between the AON and commercially available electronic circuit-switched and packet-switched networks. We will report on network applications that can dynamically allocate optical bandwidth between electronic packet-switches based on the offered load presented by users, without requiring interfaces between users and the AON control system. We will also describe video and telemedicine applications running over the network. We have demonstrated an audio/video codec that is directly interfaced to the optical network, and is capable of transmitting high-rate digitized video signals for broadcast or videoconferencing applications. We have also demonstrated a state-of-the-art radiological workstation that uses the AON to transport 2000 X 2000 X 16 bit images from a remote image server.

  11. Anomalous reduction of the switching voltage of Bi-doped Ge{sub 0.5}Se{sub 0.5} ovonic threshold switching devices

    SciTech Connect

    Seo, Juhee; Ahn, Hyung-Woo; Shin, Sang-yeol; Cheong, Byung-ki; Lee, Suyoun

    2014-04-14

    Switching devices based on Ovonic Threshold Switching (OTS) have been considered as a solution to overcoming limitations of Si-based electronic devices, but the reduction of switching voltage is a major challenge. Here, we investigated the effect of Bi-doping in Ge{sub 0.5}Se{sub 0.5} thin films on their thermal, optical, electrical properties, as well as on the characteristics of OTS devices. As Bi increased, it was found that both of the optical energy gap (E{sub g}{sup opt}) and the depth of trap states decreased resulting in a drastic reduction of the threshold voltage (V{sub th}) by over 50%. In addition, E{sub g}{sup opt} was found to be about three times of the conduction activation energy for each composition. These results are explained in terms of the Mott delocalization effect by doping Bi.

  12. All-optical steering of the interactions between multiple spatial solitons in isotropic polymers

    NASA Astrophysics Data System (ADS)

    Yan, Li-fen; Zhang, Dong; Jin, Qing-li; Wang, Hong-cheng; Zhang, Yao-ju

    2010-11-01

    All-optical steering of the nonlinear interactions between multiple spatial solitons can be performed in an isotropic photoisomerization polymer, by propagating an external control beam in perpendicular direction. Fusing, giving birth to another new soliton, and transferring energy can take place in the interactions of signal beams, which can be achieved by changing the incident position of the control beam, the initial relative phase and the power ratio between the signal beams and the control beam. These phenomena are physically explained, and they have significantly potential applications in optical signal readdressing, logic gating, and all-optical switching, etc.

  13. Optical Square-Wave Clock Generation Based on an All-Optical Flip-Flop

    SciTech Connect

    Kaplan, A.M.; Agrawal, G.P.; Maywar, D.N.

    2010-03-10

    We demonstrate optical square-wave clock generation based on an all-optical flip-flop. The bistable output power from a resonant-type semiconductor optical amplifier (SOA) is switched ON and OFF by modulating its input with its output via cross-gain modulation in a traveling-wave SOA. All active components are driven by dc currents, and the wavelength and clock frequency are selectable. A clock frequency of 3.5 MHz is demonstrated, limited by the time of flight between bulk optical components. Optical square-wave clock signals are promising for applications in photonic integrated circuits and all-optical signal processing.

  14. All-optical reservoir computer based on saturation of absorption.

    PubMed

    Dejonckheere, Antoine; Duport, François; Smerieri, Anteo; Fang, Li; Oudar, Jean-Louis; Haelterman, Marc; Massar, Serge

    2014-05-01

    Reservoir computing is a new bio-inspired computation paradigm. It exploits a dynamical system driven by a time-dependent input to carry out computation. For efficient information processing, only a few parameters of the reservoir needs to be tuned, which makes it a promising framework for hardware implementation. Recently, electronic, opto-electronic and all-optical experimental reservoir computers were reported. In those implementations, the nonlinear response of the reservoir is provided by active devices such as optoelectronic modulators or optical amplifiers. By contrast, we propose here the first reservoir computer based on a fully passive nonlinearity, namely the saturable absorption of a semiconductor mirror. Our experimental setup constitutes an important step towards the development of ultrafast low-consumption analog computers. PMID:24921786

  15. All-optical reservoir computer based on saturation of absorption.

    PubMed

    Dejonckheere, Antoine; Duport, François; Smerieri, Anteo; Fang, Li; Oudar, Jean-Louis; Haelterman, Marc; Massar, Serge

    2014-05-01

    Reservoir computing is a new bio-inspired computation paradigm. It exploits a dynamical system driven by a time-dependent input to carry out computation. For efficient information processing, only a few parameters of the reservoir needs to be tuned, which makes it a promising framework for hardware implementation. Recently, electronic, opto-electronic and all-optical experimental reservoir computers were reported. In those implementations, the nonlinear response of the reservoir is provided by active devices such as optoelectronic modulators or optical amplifiers. By contrast, we propose here the first reservoir computer based on a fully passive nonlinearity, namely the saturable absorption of a semiconductor mirror. Our experimental setup constitutes an important step towards the development of ultrafast low-consumption analog computers.

  16. Electrochromically switched, gas-reservoir metal hydride devices with application to energy-efficient windows

    SciTech Connect

    Anders, Andre; Slack, Jonathan L.; Richardson, Thomas J.

    2008-05-05

    Proof-of-principle gas-reservoir MnNiMg electrochromic mirror devices have been investigated. In contrast to conventional electrochromic approaches, hydrogen is stored (at low concentration) in the gas volume between glass panes of the insulated glass units (IGUs). The elimination of a solid state ion storage layer simplifies the layer stack, enhances overall transmission, and reduces cost. The cyclic switching properties were demonstrated and system durability improved with the incorporation a thin Zr barrier layer between the MnNiMg layer and the Pd catalyst. Addition of 9 percent silver to the palladium catalyst further improved system durability. About 100 full cycles have been demonstrated before devices slow considerably. Degradation of device performance appears to be related to Pd catalyst mobility, rather than delamination or metal layer oxidation issues originally presumed likely to present significant challenges.

  17. Automatic switching and guidance system to facilitate unassisted uroflowmetry using commercial electronic devices.

    PubMed

    Terai, Akito; Ueda, Nobufumi; Utsunomiya, Noriaki; Kohei, Naoki; Aoyama, Teruyoshi; Inoue, Koji

    2006-08-01

    To enable male patients to undergo uroflowmetry in a private condition without medical supervision, we devised an automatic switching and patient guidance system for the spinning disk uroflowmeter Urodyn 1000, using two commercial electronic devices (an infrared motion sensor tap and a memorizable vacuum fluorescent display). Instead of running the uroflowmeter continuously, which shortens the life of the spinning disk due to mechanical wear, an infrared motion sensor turns on the devices each time a patient enters the room. The patient urinates according to the timely instructions on the visible display and voided urine directly flows into a urinal. The devices are automatically turned off 5 min after the patient leaves the room. With the use of our system, men already acquainted with uroflowmetry could perform self-administered uroflowmetry any time in private. The system was considered useful for improving the quality of patient service.

  18. Towards developing a compact model for magnetization switching in straintronics magnetic random access memory devices

    NASA Astrophysics Data System (ADS)

    Barangi, Mahmood; Erementchouk, Mikhail; Mazumder, Pinaki

    2016-08-01

    Strain-mediated magnetization switching in a magnetic tunneling junction (MTJ) by exploiting a combination of piezoelectricity and magnetostriction has been proposed as an energy efficient alternative to spin transfer torque (STT) and field induced magnetization switching methods in MTJ-based magnetic random access memories (MRAM). Theoretical studies have shown the inherent advantages of strain-assisted switching, and the dynamic response of the magnetization has been modeled using the Landau-Lifshitz-Gilbert (LLG) equation. However, an attempt to use LLG for simulating dynamics of individual elements in large-scale simulations of multi-megabyte straintronics MRAM leads to extremely time-consuming calculations. Hence, a compact analytical solution, predicting the flipping delay of the magnetization vector in the nanomagnet under stress, combined with a liberal approximation of the LLG dynamics in the straintronics MTJ, can lead to a simplified model of the device suited for fast large-scale simulations of multi-megabyte straintronics MRAMs. In this work, a tensor-based approach is developed to study the dynamic behavior of the stressed nanomagnet. First, using the developed method, the effect of stress on the switching behavior of the magnetization is investigated to realize the margins between the underdamped and overdamped regimes. The latter helps the designer realize the oscillatory behavior of the magnetization when settling along the minor axis, and the dependency of oscillations on the stress level and the damping factor. Next, a theoretical model to predict the flipping delay of the magnetization vector is developed and tested against LLG-based numerical simulations to confirm the accuracy of findings. Lastly, the obtained delay is incorporated into the approximate solutions of the LLG dynamics, in order to create a compact model to liberally and quickly simulate the magnetization dynamics of the MTJ under stress. Using the developed delay equation, the

  19. Negative Capacitance in Organic/Ferroelectric Capacitor to Implement Steep Switching MOS Devices.

    PubMed

    Jo, Jaesung; Choi, Woo Young; Park, Jung-Dong; Shim, Jae Won; Yu, Hyun-Yong; Shin, Changhwan

    2015-07-01

    Because of the "Boltzmann tyranny" (i.e., the nonscalability of thermal voltage), a certain minimum gate voltage in metal-oxide-semiconductor (MOS) devices is required for a 10-fold increase in drain-to-source current. The subthreshold slope (SS) in MOS devices is, at best, 60 mV/decade at 300 K. Negative capacitance in organic/ferroelectric materials is proposed in order to address this physical limitation in MOS technology. Here, we experimentally demonstrate the steep switching behavior of a MOS device-that is, SS ∼ 18 mV/decade (much less than 60 mV/decade) at 300 K-by taking advantage of negative capacitance in a MOS gate stack. This negative capacitance, originating from the dynamics of the stored energy in a phase transition of a ferroelectric material, can achieve the step-up conversion of internal voltage (i.e., internal voltage amplification in a MOS device). With the aid of a series-connected negative capacitor as an assistive device, the surface potential in the MOS device becomes higher than the applied gate voltage, so that a SS of 18 mV/decade at 300 K is reliably observed.

  20. Negative Capacitance in Organic/Ferroelectric Capacitor to Implement Steep Switching MOS Devices.

    PubMed

    Jo, Jaesung; Choi, Woo Young; Park, Jung-Dong; Shim, Jae Won; Yu, Hyun-Yong; Shin, Changhwan

    2015-07-01

    Because of the "Boltzmann tyranny" (i.e., the nonscalability of thermal voltage), a certain minimum gate voltage in metal-oxide-semiconductor (MOS) devices is required for a 10-fold increase in drain-to-source current. The subthreshold slope (SS) in MOS devices is, at best, 60 mV/decade at 300 K. Negative capacitance in organic/ferroelectric materials is proposed in order to address this physical limitation in MOS technology. Here, we experimentally demonstrate the steep switching behavior of a MOS device-that is, SS ∼ 18 mV/decade (much less than 60 mV/decade) at 300 K-by taking advantage of negative capacitance in a MOS gate stack. This negative capacitance, originating from the dynamics of the stored energy in a phase transition of a ferroelectric material, can achieve the step-up conversion of internal voltage (i.e., internal voltage amplification in a MOS device). With the aid of a series-connected negative capacitor as an assistive device, the surface potential in the MOS device becomes higher than the applied gate voltage, so that a SS of 18 mV/decade at 300 K is reliably observed. PMID:26103511

  1. Electronic devices containing switchably conductive silicon oxides as a switching element and methods for production and use thereof

    DOEpatents

    Tour, James M.; Yao, Jun; Natelson, Douglas; Zhong, Lin; He, Tao

    2015-09-08

    In various embodiments, electronic devices containing switchably conductive silicon oxide as a switching element are described herein. The electronic devices are two-terminal devices containing a first electrical contact and a second electrical contact in which at least one of the first electrical contact or the second electrical contact is deposed on a substrate to define a gap region therebetween. A switching layer containing a switchably conductive silicon oxide resides in the gap region between the first electrical contact and the second electrical contact. The electronic devices exhibit hysteretic current versus voltage properties, enabling their use in switching and memory applications. Methods for configuring, operating and constructing the electronic devices are also presented herein.

  2. Electronic devices containing switchably conductive silicon oxides as a switching element and methods for production and use thereof

    DOEpatents

    Tour, James M; Yao, Jun; Natelson, Douglas; Zhong, Lin; He, Tao

    2013-11-26

    In various embodiments, electronic devices containing switchably conductive silicon oxide as a switching element are described herein. The electronic devices are two-terminal devices containing a first electrical contact and a second electrical contact in which at least one of the first electrical contact or the second electrical contact is deposed on a substrate to define a gap region therebetween. A switching layer containing a switchably conductive silicon oxide resides in the the gap region between the first electical contact and the second electrical contact. The electronic devices exhibit hysteretic current versus voltage properties, enabling their use in switching and memory applications. Methods for configuring, operating and constructing the electronic devices are also presented herein.

  3. Analog memory and spike-timing-dependent plasticity characteristics of a nanoscale titanium oxide bilayer resistive switching device.

    PubMed

    Seo, Kyungah; Kim, Insung; Jung, Seungjae; Jo, Minseok; Park, Sangsu; Park, Jubong; Shin, Jungho; Biju, Kuyyadi P; Kong, Jaemin; Lee, Kwanghee; Lee, Byounghun; Hwang, Hyunsang

    2011-06-24

    We demonstrated analog memory, synaptic plasticity, and a spike-timing-dependent plasticity (STDP) function with a nanoscale titanium oxide bilayer resistive switching device with a simple fabrication process and good yield uniformity. We confirmed the multilevel conductance and analog memory characteristics as well as the uniformity and separated states for the accuracy of conductance change. Finally, STDP and a biological triple model were analyzed to demonstrate the potential of titanium oxide bilayer resistive switching device as synapses in neuromorphic devices. By developing a simple resistive switching device that can emulate a synaptic function, the unique characteristics of synapses in the brain, e.g. combined memory and computing in one synapse and adaptation to the outside environment, were successfully demonstrated in a solid state device. PMID:21572200

  4. Transient Resistive Switching Devices Made from Egg Albumen Dielectrics and Dissolvable Electrodes.

    PubMed

    He, Xingli; Zhang, Jian; Wang, Wenbo; Xuan, Weipeng; Wang, Xiaozhi; Zhang, Qilong; Smith, Charles G; Luo, Jikui

    2016-05-01

    Egg albumen as the dielectric, and dissolvable Mg and W as the top and bottom electrodes are used to fabricate water-soluble memristors. 4 × 4 cross-bar configuration memristor devices show a bipolar resistive switching behavior with a high to low resistance ratio in the range of 1 × 10(2) to 1 × 10(4), higher than most other biomaterial-based memristors, and a retention time over 10(4) s without any sign of deterioration, demonstrating its high stability and reliability. Metal filaments accompanied by hopping conduction are believed to be responsible for the switching behavior of the memory devices. The Mg and W electrodes, and albumen film all can be dissolved in water within 72 h, showing their transient characteristics. This work demonstrates a new way to fabricate biocompatible and dissolvable electronic devices by using cheap, abundant, and 100% natural materials for the forthcoming bioelectronics era as well as for environmental sensors when the Internet of things takes off.

  5. Transient Resistive Switching Devices Made from Egg Albumen Dielectrics and Dissolvable Electrodes.

    PubMed

    He, Xingli; Zhang, Jian; Wang, Wenbo; Xuan, Weipeng; Wang, Xiaozhi; Zhang, Qilong; Smith, Charles G; Luo, Jikui

    2016-05-01

    Egg albumen as the dielectric, and dissolvable Mg and W as the top and bottom electrodes are used to fabricate water-soluble memristors. 4 × 4 cross-bar configuration memristor devices show a bipolar resistive switching behavior with a high to low resistance ratio in the range of 1 × 10(2) to 1 × 10(4), higher than most other biomaterial-based memristors, and a retention time over 10(4) s without any sign of deterioration, demonstrating its high stability and reliability. Metal filaments accompanied by hopping conduction are believed to be responsible for the switching behavior of the memory devices. The Mg and W electrodes, and albumen film all can be dissolved in water within 72 h, showing their transient characteristics. This work demonstrates a new way to fabricate biocompatible and dissolvable electronic devices by using cheap, abundant, and 100% natural materials for the forthcoming bioelectronics era as well as for environmental sensors when the Internet of things takes off. PMID:27052437

  6. Flexible all-optical frequency allocation of OFDM subcarriers.

    PubMed

    Lowery, Arthur James; Schröder, Jochen; Du, Liang B

    2014-01-13

    We investigate the underlying mechanism that allows OFDM subcarriers in an all-optical OFDM system to be assigned to any optical frequency using an optical filter, even if that frequency is not generated by the comb-line source feeding the filters. We confirm our analysis using simulations, and present experimental results from a 252-subcarrier system that uses a mode-locked laser (MLL) as the comb source and a wavelength selective switch. The experimental results show that there is no correlation between the programmed frequency offset between a subcarrier and nearest comb line, and the received signal quality. Thus, subcarriers could be inserted into unused portions of an optical transmission system's spectrum without restriction on their particular center frequencies. Any percentage of cyclic prefix can be added to the OFDM symbol simply by reprogramming the optical filter to give wider subcarrier frequency spacing than the comb line spacing, which is useful for tailoring the CP to the dispersion of various optical transmission paths, to maximize the spectral efficiency. Finally, the MLL's center frequency need not be locked to a system reference. PMID:24515064

  7. Bipolar resistive switching in room temperature grown disordered vanadium oxide thin-film devices

    NASA Astrophysics Data System (ADS)

    Wong, Franklin J.; Sriram, Tirunelveli S.; Smith, Brian R.; Ramanathan, Shriram

    2013-09-01

    We demonstrate bipolar switching with high OFF/ON resistance ratios (>104) in Pt/vanadium oxide/Cu structures deposited entirely at room temperature. The SET (RESET) process occurs when negative (positive) bias is applied to the top Cu electrode. The vanadium oxide (VOx) films are amorphous and close to the vanadium pentoxide stoichiometry. We also investigated Cu/VOx/W structures, reversing the position of the Cu electrode, and found the same polarity dependence with respect to the top and bottom electrodes, which suggests that the bipolar nature is linked to the VOx layer itself. Bipolar switching can be observed at 100 °C, indicating that it not due to a temperature-induced metal-insulator transition of a vanadium dioxide second phase. We discuss how ionic drift can lead to the bipolar electrical behavior of our junctions, similar to those observed in devices based on several other defective oxides. Such low-temperature processed oxide switches could be of relevance to back-end or package integration processing schemes.

  8. 49 CFR 213.235 - Inspection of switches, track crossings, and lift rail assemblies or other transition devices on...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... rail assemblies or other transition devices on moveable bridges. 213.235 Section 213.235 Transportation... assemblies or other transition devices on moveable bridges. (a) Except as provided in paragraph (c) of this section, each switch, turnout, track crossing, and moveable bridge lift rail assembly or other...

  9. 49 CFR 213.235 - Inspection of switches, track crossings, and lift rail assemblies or other transition devices on...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... rail assemblies or other transition devices on moveable bridges. 213.235 Section 213.235 Transportation... assemblies or other transition devices on moveable bridges. (a) Except as provided in paragraph (c) of this section, each switch, turnout, track crossing, and moveable bridge lift rail assembly or other...

  10. 49 CFR 213.235 - Inspection of switches, track crossings, and lift rail assemblies or other transition devices on...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... rail assemblies or other transition devices on moveable bridges. 213.235 Section 213.235 Transportation... assemblies or other transition devices on moveable bridges. (a) Except as provided in paragraph (c) of this section, each switch, turnout, track crossing, and moveable bridge lift rail assembly or other...

  11. 49 CFR 213.235 - Inspection of switches, track crossings, and lift rail assemblies or other transition devices on...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... rail assemblies or other transition devices on moveable bridges. 213.235 Section 213.235 Transportation... assemblies or other transition devices on moveable bridges. (a) Except as provided in paragraph (c) of this section, each switch, turnout, track crossing, and moveable bridge lift rail assembly or other...

  12. 49 CFR 213.235 - Inspection of switches, track crossings, and lift rail assemblies or other transition devices on...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... rail assemblies or other transition devices on moveable bridges. 213.235 Section 213.235 Transportation... assemblies or other transition devices on moveable bridges. (a) Except as provided in paragraph (c) of this section, each switch, turnout, track crossing, and moveable bridge lift rail assembly or other...

  13. Realization of transient memory-loss with NiO-based resistive switching device

    NASA Astrophysics Data System (ADS)

    Hu, S. G.; Liu, Y.; Chen, T. P.; Liu, Z.; Yu, Q.; Deng, L. J.; Yin, Y.; Hosaka, Sumio

    2012-11-01

    A resistive switching device based on a nickel-rich nickel oxide thin film, which exhibits inherent learning and memory-loss abilities, is reported in this work. The conductance of the device gradually increases and finally saturates with the number of voltage pulses (or voltage sweepings), which is analogous to the behavior of the short-term and long-term memory in the human brain. Furthermore, the number of the voltage pulses (or sweeping cycles) required to achieve a given conductance state increases with the interval between two consecutive voltage pulses (or sweeping cycles), which is attributed to the heat diffusion in the material of the conductive filaments formed in the nickel oxide thin film. The phenomenon resembles the behavior of the human brain, i.e., forgetting starts immediately after an impression, a larger interval of the impressions leads to more memory loss, thus the memorization needs more impressions to enhance.

  14. Ultralow-power switching via defect engineering in germanium telluride phase-change memory devices

    PubMed Central

    Nukala, Pavan; Lin, Chia-Chun; Composto, Russell; Agarwal, Ritesh

    2016-01-01

    Crystal–amorphous transformation achieved via the melt-quench pathway in phase-change memory involves fundamentally inefficient energy conversion events; and this translates to large switching current densities, responsible for chemical segregation and device degradation. Alternatively, introducing defects in the crystalline phase can engineer carrier localization effects enhancing carrier–lattice coupling; and this can efficiently extract work required to introduce bond distortions necessary for amorphization from input electrical energy. Here, by pre-inducing extended defects and thus carrier localization effects in crystalline GeTe via high-energy ion irradiation, we show tremendous improvement in amorphization current densities (0.13–0.6 MA cm−2) compared with the melt-quench strategy (∼50 MA cm−2). We show scaling behaviour and good reversibility on these devices, and explore several intermediate resistance states that are accessible during both amorphization and recrystallization pathways. Existence of multiple resistance states, along with ultralow-power switching and scaling capabilities, makes this approach promising in context of low-power memory and neuromorphic computation. PMID:26805748

  15. Ultralow-power switching via defect engineering in germanium telluride phase-change memory devices

    NASA Astrophysics Data System (ADS)

    Nukala, Pavan; Lin, Chia-Chun; Composto, Russell; Agarwal, Ritesh

    2016-01-01

    Crystal-amorphous transformation achieved via the melt-quench pathway in phase-change memory involves fundamentally inefficient energy conversion events; and this translates to large switching current densities, responsible for chemical segregation and device degradation. Alternatively, introducing defects in the crystalline phase can engineer carrier localization effects enhancing carrier-lattice coupling; and this can efficiently extract work required to introduce bond distortions necessary for amorphization from input electrical energy. Here, by pre-inducing extended defects and thus carrier localization effects in crystalline GeTe via high-energy ion irradiation, we show tremendous improvement in amorphization current densities (0.13-0.6 MA cm-2) compared with the melt-quench strategy (~50 MA cm-2). We show scaling behaviour and good reversibility on these devices, and explore several intermediate resistance states that are accessible during both amorphization and recrystallization pathways. Existence of multiple resistance states, along with ultralow-power switching and scaling capabilities, makes this approach promising in context of low-power memory and neuromorphic computation.

  16. In Vitro Validation of a Sector-Switching HIFU Device for Accelerated Treatment

    SciTech Connect

    Petrusca, Lorena; Salomir, Rares; Chapelon, Jean-Yves; Brasset, Lucie; Cotton, Francois

    2009-04-14

    A sector-switching method that increases the HIFU sequence duty-cycle and reduces the equivalent treatment time was tested in vitro. The MR-compatible HIFU device used consisted of 2 symmetric sectors arranged on a truncated spherical cap (focus = 45 mm, long diameter = 57.5 mm, short diameter = 35 mm). A MR-compatible, 2D positioning system provided 0.5 mm accuracy. Two sonication sequences were considered, each with the same pattern for the focal point trajectory and with identical on-state power. First, both sectors radiated simultaneously, with a power duty cycle of 60%. Second, the sectors radiated separately with balanced temporally-interleaved sonication and a power duty cycle of 87.5%. Numerical simulations were performed to predict the shape of the lesion for a given set of sequence parameters, according to a theoretical model. Fast MR thermometry (voxel size: 0.85x0.85x4.25 mm3; temporal resolution: 2 sec) was performed in two orthogonal planes (sagittal and transverse) while the 2D sonication pattern was contained in the coronal plane. Fresh samples of degassed porcine liver were used, and the macroscopic lesions were measured after HIFU. The 14400 s equivalent thermal dose isolevel was compared respectively for the two sonication sequences, both with numerical simulations and experimental MR data. No susceptibility or RF artifacts could be detected on MR data. The lesion's size ratio between reference versus the sector-switched sequence was 1.12 from simulations and 1.25 ({+-}3.2%) from MRI derived TD. Switching the device sectors reduced the treatment time by 20% while the shape and size of the lesions were maintained. In vivo studies are required for pre-clinical validation.

  17. All-optical time-delay relay based on a bacteriorhodopsin film.

    PubMed

    Chen, Guiying; Yuan, Yizhe; Zhang, Chunping; Yang, Guan; Tian, Jian Guo; Xu, Tang; Song, Q W

    2006-05-15

    Using the property of dynamic complementary suppression modulated transmission of bacteriorhodopsin film, we propose and demonstrate an all-optical time-delay relay in an incoherent light system. The relay can last for a certain amount of time after the switch function of turn off (or turn on) is activated. Furthermore, the delay time can be adjusted by changing the lifetime of the M state and the intensities of blue and yellow beams.

  18. Voltage-impulse-induced non-volatile ferroelastic switching of ferromagnetic resonance for reconfigurable magnetoelectric microwave devices.

    PubMed

    Liu, Ming; Howe, Brandon M; Grazulis, Lawrence; Mahalingam, Krishnamurthy; Nan, Tianxiang; Sun, Nian X; Brown, Gail J

    2013-09-20

    A critical challenge in realizing magnetoelectrics based on reconfigurable microwave devices, which is the ability to switch between distinct ferromagnetic resonances (FMR) in a stable, reversible and energy efficient manner, has been addressed. In particular, a voltage-impulse-induced two-step ferroelastic switching pathway can be used to in situ manipulate the magnetic anisotropy and enable non-volatile FMR tuning in FeCoB/PMN-PT (011) multiferroic heterostructures. PMID:23857709

  19. Photonic encryption : modeling and functional analysis of all optical logic.

    SciTech Connect

    Tang, Jason D.; Schroeppel, Richard Crabtree; Robertson, Perry J.

    2004-10-01

    With the build-out of large transport networks utilizing optical technologies, more and more capacity is being made available. Innovations in Dense Wave Division Multiplexing (DWDM) and the elimination of optical-electrical-optical conversions have brought on advances in communication speeds as we move into 10 Gigabit Ethernet and above. Of course, there is a need to encrypt data on these optical links as the data traverses public and private network backbones. Unfortunately, as the communications infrastructure becomes increasingly optical, advances in encryption (done electronically) have failed to keep up. This project examines the use of optical logic for implementing encryption in the photonic domain to achieve the requisite encryption rates. This paper documents the innovations and advances of work first detailed in 'Photonic Encryption using All Optical Logic,' [1]. A discussion of underlying concepts can be found in SAND2003-4474. In order to realize photonic encryption designs, technology developed for electrical logic circuits must be translated to the photonic regime. This paper examines S-SEED devices and how discrete logic elements can be interconnected and cascaded to form an optical circuit. Because there is no known software that can model these devices at a circuit level, the functionality of S-SEED devices in an optical circuit was modeled in PSpice. PSpice allows modeling of the macro characteristics of the devices in context of a logic element as opposed to device level computational modeling. By representing light intensity as voltage, 'black box' models are generated that accurately represent the intensity response and logic levels in both technologies. By modeling the behavior at the systems level, one can incorporate systems design tools and a simulation environment to aid in the overall functional design. Each black box model takes certain parameters (reflectance, intensity, input response), and models the optical ripple and time delay

  20. Investigation of fullerenes for high speed low latency, photonic switching

    SciTech Connect

    Lee, H. W. H; Shelton, R.N.

    1997-02-13

    The components in high-speed, all-optical photonic systems must satisfy two essential requirements: (1) high switching speeds in the range of Tbit/s, and (2) low latency, where the latency is the amount of time that the optical signal remains in the device. An important problem precluding the practical implementation of high-speed, all- optical switching is the lack of a material with appropriate nonlinear optical properties needed to effect the switching. Numerous material systems have been studied in the past, but none have met all the necessary requirements. Development of such a material and its incorporation into photonic devices would advance the field tremendously. This Lab-wide LDRD project resolved this critical problem.

  1. Evidence of Filamentary Switching in Oxide-based Memory Devices via Weak Programming and Retention Failure Analysis.

    PubMed

    Younis, Adnan; Chu, Dewei; Li, Sean

    2015-01-01

    Further progress in high-performance microelectronic devices relies on the development of novel materials and device architectures. However, the components and designs that are currently in use have reached their physical limits. Intensive research efforts, ranging from device fabrication to performance evaluation, are required to surmount these limitations. In this paper, we demonstrate that the superior bipolar resistive switching characteristics of a CeO2:Gd-based memory device can be manipulated by means of UV radiation, serving as a new degree of freedom. Furthermore, the metal oxide-based (CeO2:Gd) memory device was found to possess electrical and neuromorphic multifunctionalities. To investigate the underlying switching mechanism of the device, its plasticity behaviour was studied by imposing weak programming conditions. In addition, a short-term to long-term memory transition analogous to the forgetting process in the human brain, which is regarded as a key biological synaptic function for information processing and data storage, was realized. Based on a careful examination of the device's retention behaviour at elevated temperatures, the filamentary nature of switching in such devices can be understood from a new perspective. PMID:26324073

  2. Integrated elastomeric components for autonomous regulation of sequential and oscillatory flow switching in microfluidic devices

    NASA Astrophysics Data System (ADS)

    Mosadegh, Bobak; Kuo, Chuan-Hsien; Tung, Yi-Chung; Torisawa, Yu-Suke; Bersano-Begey, Tommaso; Tavana, Hossein; Takayama, Shuichi

    2010-06-01

    A critical need for enhancing the usability and capabilities of microfluidic technologies is the development of standardized, scalable and versatile control systems. Electronically controlled valves and pumps typically used for dynamic flow regulation, although useful, can limit convenience, scalability and robustness. This shortcoming has motivated the development of device-embedded non-electrical flow-control systems. Existing approaches to regulate operation timing on-chip, however, still require external signals such as timed generation of fluid flow, bubbles, liquid plugs or droplets or an alteration of chemical compositions or temperature. Here, we describe a strategy to provide device-embedded flow switching and clocking functions. Physical gaps and cavities interconnected by holes are fabricated into a three-layer elastomer structure to form networks of fluidic gates that can spontaneously generate cascading and oscillatory flow output using only a constant flow of Newtonian fluids as the device input. The resulting microfluidic substrate architecture is simple, scalable and should be applicable to various materials. This flow-powered fluidic gating scheme brings the autonomous signal processing ability of microelectronic circuits to microfluidics where there is the added diversity in current information of having distinct chemical or particulate species and richness in current operation of having chemical reactions and physical interactions.

  3. Investigation of resistive switching behavior of Ag/SnOx/ITO device

    NASA Astrophysics Data System (ADS)

    Chen, Da; Huang, Shi-Hua

    2015-04-01

    SnOx thin film was deposited by reactive magnetron sputtering and the resistance switching behavior of Ag/SnOx/ITO was investigated. The endurance testing indicates that HRS resistance decreases with an increase in the number of cycles. After annealing, the memory performance is enhanced, and the ratio of the device resistance of HRS and LRS increases greatly. The abnormal transformation sequence from HRS to LRS was observed for the annealed device and can be explained by electron trapping and detrapping based on the analysis of x-ray diffraction and the Raman spectrum. The temperature-dependent I-V measurement indicates that the thermal activation process is responsible for the temperature range of 300 to 200 K however, the carrier transport can be ascribed to the nearest-neighbor hopping conduction mechanism for the temperature range of 200 to 100 K. The general conduction mechanism of Ag/SnOx/ITO device can be elucidated by the trap-controlled space charge limited conduction model, and the conductive schematic in the SET and RESET processes has been given.

  4. Resistive Switching in Al/Al2O3/TiO2/Al/PES Flexible Device for Nonvolatile Memory Application.

    PubMed

    Lin, Chun-Chieh; Lee, Wang-Ying; Lee, Han-Tang

    2016-05-01

    Resistive switching memory devices with superior properties are possibly used in next-generation nonvolatile memory to replace the flash memory. In addition, flexible electronics has also attracted much attention because of its light-weight and flexibility. Therefore, an Al/Al2O3/TiO2/Al/PES flexible resistive switching memory is employed in this study. The resistive switching characteristics and stability of the flexible device are improved by inserting the Al2O3 film. The resistive switching of the flexible device can be repeated over hundreds of times after the bending test. A possible resistive switching model of the flexible device is also proposed. In addition, the non-volatility of the flexible device is demonstrated. Based on our research results, the proposed Al2O3/TiO2-based resistive switching memory is possibly used in next-generation flexible electronics and nonvolatile memory applications. PMID:27483828

  5. A study of high repetition rate pulse generation and all-optical add/drop multiplexing

    NASA Astrophysics Data System (ADS)

    Chen, Hongmin

    Ultra high-speed optical time-division-multiplexed (OTDM) transmission technologies are essential for the construction of ultra high-speed all-optical networks needed in the information era. In this Ph. D thesis dissertation, essential mechanisms associated with ultra high speed OTDM transmission systems, such as, high speed ultra short pulse generation, all optical demultiplexing and all optical add/drop multiplexing, have been studied. Both experimental demonstrations and numerical simulations have been performed. In order to realize high-speed optical TDM systems, high repetition rate, ultra short pulses are needed. A rational harmonic mode-locked ring fiber laser has been used to produce ultrashort pulses, the pulse jitter will be eliminated using a Phase-Locked-Loop (PLL), and the self-pulsation has been suppressed using a semiconductor optical amplifier (SOA). Sub pico-second pulses are very important for all optical sampling in the ultrahigh-speed OTDM transmission system. In this thesis, a two stage compression scheme utilizing the nonlinearity and dispersion of the optical fibers has been constructed and used to compress the gain switched DFB laser pulses. Also a nonlinear optical loop mirror has been constructed to suppress the wings associated with nonlinear compression. Pedestal free, transform-limited pulses with pulse widths in range of 0.2 to 0.4 ps have been generated. LiNbO3 modulators play a very important role in fiber optical communication systems. In this thesis, LiNbO3 modulators have been used to perform high repetition rate pulse generation, all optical demultiplexing and all optical add/drop for the TDM transmission system.

  6. Tunable all-optical plasmonic rectifier in nanoscale metal-insulator-metal waveguides.

    PubMed

    Xu, Yi; Wang, Xiaomeng; Deng, Haidong; Guo, Kangxian

    2014-10-15

    We propose a tunable all-optical plasmonic rectifier based on the nonlinear Fano resonance in a metal-insulator-metal plasmonic waveguide and cavities coupling system. We develop a theoretical model based on the temporal coupled-mode theory to study the device physics of the nanoscale rectifier. We further demonstrate via the finite difference time domain numerical experiment that our idea can be realized in a plasmonic system with an ultracompact size of ~120×800  nm². The tunable plasmonic rectifier could facilitate the all-optical signal processing in nanoscale.

  7. Iii-V Compound Multiple Quantum Well Based Modulator and Switching Devices.

    NASA Astrophysics Data System (ADS)

    Hong, Songcheol

    A general formalism to study the absorption and photocurrent in multiple quantum well is provided with detailed consideration of quantum confined Stark shift, exciton binding energy, line broadening, tunneling, polarization, and strain effects. Results on variation of exciton size, binding energies and transition energies as a function electric field and well size have been presented. Inhomogeneous line broadening of exciton lines due to interface roughness, alloy disorder and well to well size fluctuation is calculated. The potential of material tailoring by introducing strain for specific optical response is discussed. Theoretical and experimental results on excitonic and band-to-band absorption spectra in strained multi-quantum well structures are shown. I also report on polarization dependent optical absorption for excitonic and interband transitions in lattice matched and strained multiquantum well structures in presence of transverse electric field. Photocurrent in a p-i(MQW)-n diode with monochromatic light is examined with respect to different temperatures and intensities. The negative resistance of I-V characteristic of the p-i-n diode is based on the quantum confined Stark effect of the heavy hole excitonic transition in a multiquantum well. This exciton based photocurrent characteristic allows efficient switching. A general purpose low power optical logic device using the controller-modulator concept bas been proposed and realized. The controller is a heterojunction phototransistor with multiquantum wells in the base-collector depletion region. This allows an amplified photocurrent controlled voltage feedback with low light intensity levels. Detailed analysis of the sensitivity of this device in various modes of operation is studied. Studies are also presented on the cascadability of the device as well as its integrating -thresholding properties. A multiquantum well heterojunction bipolar transistor (MHBT), which has N^+ -p^+-i(MQW)-N structure has been

  8. Optical switches and switching methods

    SciTech Connect

    Doty, Michael

    2008-03-04

    A device and method for collecting subject responses, particularly during magnetic imaging experiments and testing using a method such as functional MRI. The device comprises a non-metallic input device which is coupled via fiber optic cables to a computer or other data collection device. One or more optical switches transmit the subject's responses. The input device keeps the subject's fingers comfortably aligned with the switches by partially immobilizing the forearm, wrist, and/or hand of the subject. Also a robust nonmetallic switch, particularly for use with the input device and methods for optical switching.

  9. Evidence of Filamentary Switching in Oxide-based Memory Devices via Weak Programming and Retention Failure Analysis

    PubMed Central

    Younis, Adnan; Chu, Dewei; Li, Sean

    2015-01-01

    Further progress in high-performance microelectronic devices relies on the development of novel materials and device architectures. However, the components and designs that are currently in use have reached their physical limits. Intensive research efforts, ranging from device fabrication to performance evaluation, are required to surmount these limitations. In this paper, we demonstrate that the superior bipolar resistive switching characteristics of a CeO2:Gd-based memory device can be manipulated by means of UV radiation, serving as a new degree of freedom. Furthermore, the metal oxide-based (CeO2:Gd) memory device was found to possess electrical and neuromorphic multifunctionalities. To investigate the underlying switching mechanism of the device, its plasticity behaviour was studied by imposing weak programming conditions. In addition, a short-term to long-term memory transition analogous to the forgetting process in the human brain, which is regarded as a key biological synaptic function for information processing and data storage, was realized. Based on a careful examination of the device’s retention behaviour at elevated temperatures, the filamentary nature of switching in such devices can be understood from a new perspective. PMID:26324073

  10. Evidence of Filamentary Switching in Oxide-based Memory Devices via Weak Programming and Retention Failure Analysis

    NASA Astrophysics Data System (ADS)

    Younis, Adnan; Chu, Dewei; Li, Sean

    2015-09-01

    Further progress in high-performance microelectronic devices relies on the development of novel materials and device architectures. However, the components and designs that are currently in use have reached their physical limits. Intensive research efforts, ranging from device fabrication to performance evaluation, are required to surmount these limitations. In this paper, we demonstrate that the superior bipolar resistive switching characteristics of a CeO2:Gd-based memory device can be manipulated by means of UV radiation, serving as a new degree of freedom. Furthermore, the metal oxide-based (CeO2:Gd) memory device was found to possess electrical and neuromorphic multifunctionalities. To investigate the underlying switching mechanism of the device, its plasticity behaviour was studied by imposing weak programming conditions. In addition, a short-term to long-term memory transition analogous to the forgetting process in the human brain, which is regarded as a key biological synaptic function for information processing and data storage, was realized. Based on a careful examination of the device’s retention behaviour at elevated temperatures, the filamentary nature of switching in such devices can be understood from a new perspective.

  11. Illumination Effect on Bipolar Switching Properties of Gd:SiO2 RRAM Devices Using Transparent Indium Tin Oxide Electrode.

    PubMed

    Chen, Kai-Huang; Chang, Kuan-Chang; Chang, Ting-Chang; Tsai, Tsung-Ming; Liang, Shu-Ping; Young, Tai-Fa; Syu, Yong-En; Sze, Simon M

    2016-12-01

    To discuss the optoelectronic effect on resistive random access memory (RRAM) devices, the bipolar switching properties and electron-hole pair generation behavior in the transparent indium tin oxide (ITO) electrode of Gd:SiO2 thin films under the ultraviolet (λ = 400 nm) and red-light (λ = 770 nm) illumination for high resistance state (HRS)/low resistance state (LRS) was observed and investigated. In dark environment, the Gd:SiO2 RRAM devices exhibited the ohmic conduction mechanism for LRS, exhibited the Schottky emission conduction and Poole-Frankel conduction mechanism for HRS. For light illumination effect, the operation current of the Gd:SiO2 RRAM devices for HRS/LRS was slightly increased. Finally, the electron-hole pair transport mechanism, switching conduction diagram, and energy band of the RRAM devices will be clearly demonstrated and explained. PMID:27117634

  12. Self-learning ability realized with a resistive switching device based on a Ni-rich nickel oxide thin film

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Chen, T. P.; Liu, Z.; Yu, Y. F.; Yu, Q.; Li, P.; Fung, S.

    2011-12-01

    The resistive switching device based on a Ni-rich nickel oxide thin film exhibits an inherent learning ability of a neural network. The device has the short-term-memory and long-term-memory functions analogous to those of the human brain, depending on the history of its experience of voltage pulsing or sweeping. Neuroplasticity could be realized with the device, as the device can be switched from a high-resistance state to a low-resistance state due to the formation of stable filaments by a series of electrical pulses, resembling the changes such as the growth of new connections and the creation of new neurons in the brain in response to experience.

  13. Illumination Effect on Bipolar Switching Properties of Gd:SiO2 RRAM Devices Using Transparent Indium Tin Oxide Electrode

    NASA Astrophysics Data System (ADS)

    Chen, Kai-Huang; Chang, Kuan-Chang; Chang, Ting-Chang; Tsai, Tsung-Ming; Liang, Shu-Ping; Young, Tai-Fa; Syu, Yong-En; Sze, Simon M.

    2016-04-01

    To discuss the optoelectronic effect on resistive random access memory (RRAM) devices, the bipolar switching properties and electron-hole pair generation behavior in the transparent indium tin oxide (ITO) electrode of Gd:SiO2 thin films under the ultraviolet ( λ = 400 nm) and red-light ( λ = 770 nm) illumination for high resistance state (HRS)/low resistance state (LRS) was observed and investigated. In dark environment, the Gd:SiO2 RRAM devices exhibited the ohmic conduction mechanism for LRS, exhibited the Schottky emission conduction and Poole-Frankel conduction mechanism for HRS. For light illumination effect, the operation current of the Gd:SiO2 RRAM devices for HRS/LRS was slightly increased. Finally, the electron-hole pair transport mechanism, switching conduction diagram, and energy band of the RRAM devices will be clearly demonstrated and explained.

  14. Polarization encoded all-optical quaternary R-S flip-flop using binary latch

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Tanay; Roy, Jitendra Nath; Chakraborty, Ajoy Kumar

    2009-04-01

    The developments of different multi-valued logic (MVL) systems have received considerable interests in recent years all over the world. In electronics, efforts have already been made to incorporate multi-valued system in logic and arithmetic data processing. But, very little efforts have been given in realization of MVL with optics. In this paper we present novel designs of certain all-optical circuits that can be used for realizing multi-valued logic functions. Polarization encoded all-optical quaternary (4-valued) R-S flip-flop is proposed and described. Two key circuits (all-optical encoder/decoder and a binary latch) are designed first. They are used to realize quaternary flip-flop in all-optical domain. Here the different quaternary logical states are represented by different polarized state of light. Terahertz Optical Asymmetric Demultiplexer (TOAD) based interferometric switch can take an important role. Computer simulation result confirming described methods and conclusion are given in this paper.

  15. Ionic current rectification, breakdown, and switching in heterogeneous oxide nanofluidic devices.

    PubMed

    Cheng, Li-Jing; Guo, L Jay

    2009-03-24

    We investigate several ion transport behaviors in sub-20 nm nanofluidic channels consisting of heterogeneous oxide materials. By utilizing distinct isoelectric points of SiO2 and Al2O3 surfaces and photolithography to define the charge distribution, nanofluidic channels containing positively and negatively charged surfaces are created to form an abrupt junction. This method provides much more robust surface charges than previous approaches by surface chemical treatment. The fabricated nanofluidic diodes exhibit high rectification of ion current and achieve record-high rectification factors (ratio of forward current to reverse current) of over 300. The current-voltage property of the device follows the theoretical model quantitatively, except that at low ion concentrations the forward current degrades and the reverse current is greater than theoretical prediction, which can be attributed to access resistance and breakdown of water molecules. The breakdown effect characterized by a negative conductance followed by a rapid increase of current is observed in a double junction diode. The occurrence of the breakdown is found to be enhanced by the abruptness of the junction between the heterogeneous nanochannels. Finally, we demonstrate ionic switching in a three-terminal nanofluidic triode in which the ionic flow can be electrically regulated between different channel branches. The study provides insight into the ion transport behavior in nanofluidic devices containing heterogeneous surfaces. PMID:19220010

  16. Skewness and Kurtosis of the Switching Current Distribution in Superconductor-Graphene-Superconductor Junctions and Superconductor-Nanowire-Superconductor Devices

    NASA Astrophysics Data System (ADS)

    Murphy, Andrew; Aref, Thomas; Coskun, Ulas; Weinberg, Phillip; Levchenko, Alex; Vakaryuk, Victor; Bezryadin, Alexey

    2013-03-01

    We study statistical properties of the switching current in superconductor-graphene-superconductor proximity junctions and superconductor-nanowire-superconductor devices. The fluctuations of the switching current are related to Little's phase slips, generated by thermal and quantum fluctuations of the superconducting order parameter. The study focuses on higher moments of the statistical probability distributions of the switching current. Namely we study the skewness, which defines the asymmetry of the distribution, and kurtosis, which is a measure of the ``peakedness.'' The skewness is defined as sk= m3 /m23 / 2 where m2 is the second moment of the distribution, called the variance, and m3 is the third moment. Kurtosis is defined as kur= m4 /m22 , where m4 is the fourth moment of the distribution. It is known that for Gaussian distributions sk=0 and kur=3. On our devices we find, in most cases, sk ~ -1 and kur ~ 5. These results are in agreement with numerical simulations as well as an analytic model. Finally we present preliminary experimental results for a two-nanowire device. We have found that the standard deviation, skewness and kurtosis of the switching current distributions in these devices vary periodically with magnetic field.

  17. Dynamics of an all-optical atomic spin gyroscope.

    PubMed

    Fang, Jiancheng; Wan, Shuangai; Yuan, Heng

    2013-10-20

    We present the transfer function of an all-optical atomic spin gyroscope through a series of differential equations and validate the transfer function by experimental test. A transfer function is the basis for further control system design. We build the differential equations based on a complete set of Bloch equations describing the all-optical atomic spin gyroscope, and obtain the transfer function through application of the Laplace transformation to these differential equations. Moreover, we experimentally validate the transfer function in an all-optical Cs-Xe129 atomic spin gyroscope through a series of step responses. This transfer function is convenient for analysis of the form of control system required. Furthermore, it is available for the design of the control system specifically to improve the performance of all-optical atomic spin gyroscopes.

  18. All-optical modulation in gallium arsenide integrated optical waveguides

    SciTech Connect

    McWright, G.; Ross, B.; Guthreau, W.; Lafaw, D.; Lowry, M.; Tindall, W.

    1988-01-27

    We have investigated all-optical modulators in gallium arsenide integrated optical waveguides; these modulators use electron-hole pair generation to alter the propagation characteristics of a guided light beam. 6 refs., 6 figs.

  19. Design of all-optical read-only memory.

    PubMed

    Jung, Young Jin; Park, Namkyoo; Jhon, Young Min; Lee, Seok

    2009-11-01

    A semiconductor optical amplifier-based all-optical read-only memory (ROM) is successfully demonstrated through simulations using a one-level simplification method optimized for optical logic circuits. Design details are presented, and advantages are discussed in comparison with an all-optical ROM-employing decoder. We demonstrate that eight characters can be stored at each address in the American Standard Code for Information Interchange. PMID:19881640

  20. All-optical signal processing using dynamic Brillouin gratings

    PubMed Central

    Santagiustina, Marco; Chin, Sanghoon; Primerov, Nicolay; Ursini, Leonora; Thévenaz, Luc

    2013-01-01

    The manipulation of dynamic Brillouin gratings in optical fibers is demonstrated to be an extremely flexible technique to achieve, with a single experimental setup, several all-optical signal processing functions. In particular, all-optical time differentiation, time integration and true time reversal are theoretically predicted, and then numerically and experimentally demonstrated. The technique can be exploited to process both photonic and ultra-wide band microwave signals, so enabling many applications in photonics and in radio science. PMID:23549159

  1. Resistive switching in the Au/Zr/ZrO2-Y2O3/TiN/Ti memristive devices deposited by magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Gorshkov, O. N.; Mikhaylov, A. N.; Kasatkin, A. P.; Tikhov, S. V.; Filatov, D. O.; Pavlov, D. A.; Belov, A. I.; Koryazhkina, M. N.; Bobrov, A. I.; Malekhonova, N. V.; Gryaznov, E. G.; Antonov, I. N.; Shenina, M. E.

    2016-08-01

    Bipolar resistive switching phenomenon in the Au/Zr/ZrO2-Y2O3/TiN/Ti memristive devices deposited by magnetron sputtering has been studied. The structure of devices and electrical measurements data for the temperature range from 77 to 490 K are analyzed. The stable switching is demonstrated at room temperature, but the decrease in the resistive switching performance at elevated temperatures is observed.

  2. All-optical code routing in interconnected optical CDMA and WDM ring networks.

    PubMed

    Deng, Yanhua; Fok, Mable P; Prucnal, Paul R; Wang, Ting

    2010-11-01

    We propose an all-optical hybrid network composed of optical code division multiple access (CDMA) rings interconnecting through a reconfigurable wavelength division multiplexing (WDM) metro area ring. This network retains the advantages of both the optical CDMA and WDM techniques, including asynchronous access and differentiated quality of service, while removing the hard limit on the number of subscribers and increasing network flexibility. The all-optical network is enabled by using nonlinear optical loop mirrors in an add/drop router (ADR) that performs code conversion, dropping, and switching asynchronously. We experimentally demonstrate the functionalities of the ADR in the proposed scheme asynchronously and obtain error-free performance. The bit-error rate measurements show acceptable power penalties for different code routes.

  3. Optical packet header identification utilizing an all-optical feedback chaotic reservoir computing

    NASA Astrophysics Data System (ADS)

    Qin, Jie; Zhao, Qingchun; Xu, Dongjiao; Yin, Hongxi; Chang, Ying; Huang, Degen

    2016-06-01

    In this paper, an all-optical reservoir computing (RC) setup is proposed for identifying the types of optical packet headers in optical packet switching (OPS) network. The numerical simulation identification results of 3 bits and 32 bits optical headers with the bit rate of 10 Gbps are as low as 0.625% and 2.25%, respectively. The identification errors with the variation of the feedback strength and feedback delay are presented separately. Hence, the optimal feedback parameters are obtained. The all-optical feedback RC setup is robust to the white Gaussian noise. The recognition error is acceptable when the signal-to-noise ratio (SNR) is greater than 15 dB.

  4. 20Gbit/s all-optical logic OR in terahertz optical asymmetric demultiplexer (TOAD)

    NASA Astrophysics Data System (ADS)

    Yan, Yumei; Wu, Jian; Lin, Jintong

    2005-01-01

    A scheme for all-optical logic OR based on transparent teraherz optical asymmetric demultiplexer (transparent-TOAD) is proposed in this paper. In the transparent-TOAD, the SOA is biased at transparency and the gain recovery time determined by the intraband effect has the value of only a few picoseconds. Numerical analysis shows that the switching window of the transparent-TOAD is only about 0.54ps and the potential for ultrahigh speed all-optical logic processing is shown. Numerical demonstration is performed for 4-bit and 16-bit logic OR at 20Gbit/s. The results coincide with the OR truth table, showing high extinction ratio and no pattern dependency. Detailed analysis is carried out on the performance of the logic OR scheme.

  5. Comparison between Pt/TiO2/Pt and Pt/TaO X /TaO Y /Pt based bipolar resistive switching devices

    NASA Astrophysics Data System (ADS)

    Ho, Patrick W. C.; Odai Hatem, Firas; Almurib, Haider Abbas F.; Nandha Kumar, T.

    2016-06-01

    Nonvolatile memories have emerged in recent years and have become a leading candidate towards replacing dynamic and static random-access memory devices. In this article, the performances of TiO2 and TaO2 nonvolatile memristive devices were compared and the factors that make TaO2 memristive devices better than TiO2 memristive devices were studied. TaO2 memristive devices have shown better endurance performances (108 times more switching cycles) and faster switching speed (5 times) than TiO2 memristive devices. Electroforming of TaO2 memristive devices requires ∼4.5 times less energy than TiO2 memristive devices of a similar size. The retention period of TaO2 memristive devices is expected to exceed 10 years with sufficient experimental evidence. In addition to comparing device performances, this article also explains the differences in physical device structure, switching mechanism, and resistance switching performances of TiO2 and TaO2 memristive devices. This article summarizes the reasons that give TaO2 memristive devices the advantage over TiO2 memristive devices, in terms of electroformation, switching speed, and endurance.

  6. Fiber Lasers and all Optical Logic Gates for Header Processing in High-Bit Optical Networks

    NASA Astrophysics Data System (ADS)

    Barnett, Brandon Craig

    As information technologies push network capacities toward higher bit rates, fiber-optic communication networks will eventually be capable of transmitting data at a rate at which electronic switches cannot respond. A solution to this problem is to replace the electronics at the front and back ends of the transmission system where data enters and exists in optical format with all-optical header processors. In this thesis, I will describe how the header processor has been divided into all-optical switching modules, which will act as the basic building block for the header processing unit. Each module arises from the integration of an erbium -doped fiber laser and an all-optical logic gate. The erbium-doped fiber laser (EDFL) acts as a local power supply for the module. It restores the pulse shape, pulse amplitude, and timing of an incoming optical bit stream. The development of a short-pulse EDFL and a high-power EDFL for this application is described. The high-power EDFL employs a unique cavity design that eliminates multiple pulses when pumped with high powers. Data processing is performed within the module by all-optical logic gates, which switch due to the nonlinear interaction of one pulse of light with another in optical fiber. Therefore, these gates can work at the bit rate of the transmission system and avoid the bottlenecks inherent in electronic processors. The design and demonstration of a low-latency soliton-dragging gate and a low-birefringent nonlinear optical loop mirror (low-bi NOLM) logic gate are described. The two logic gates are optimized for energy contrast, switching energy, timing sensitivity, and cascadability. Logic functionality is also demonstrated. The thesis culminates in an experiment that integrates the laser and logic gate work by driving two cascaded low -bi NOLM's with an EDFL. It is shown that this experiment utilizes all the components necessary to read the header of a high-bit-rate data packet, bringing closure to the switching

  7. All-Optical Ultrasound Transducers for High Resolution Imaging

    NASA Astrophysics Data System (ADS)

    Sheaff, Clay Smith

    High frequency ultrasound (HFUS) has increasingly been used within the past few decades to provide high resolution (< 200 mum) imaging in medical applications such as endoluminal imaging, intravascular imaging, ophthalmology, and dermatology. The optical detection and generation of HFUS using thin films offers numerous advantages over traditional piezoelectric technology. Circumvention of an electronic interface with the device head is one of the most significant given the RF noise, crosstalk, and reduced capacitance that encumbers small-scale electronic transducers. Thin film Fabry-Perot interferometers - also known as etalons - are well suited for HFUS receivers on account of their high sensitivity, wide bandwidth, and ease of fabrication. In addition, thin films can be used to generate HFUS when irradiated with optical pulses - a method referred to as Thermoelastic Ultrasound Generation (TUG). By integrating a polyimide (PI) film for TUG into an etalon receiver, we have created for the first time an all-optical ultrasound transducer that is both thermally stable and capable of forming fully sampled 2-D imaging arrays of arbitrary configuration. Here we report (1) the design and fabrication of PI-etalon transducers; (2) an evaluation of their optical and acoustic performance parameters; (3) the ability to conduct high-resolution imaging with synthetic 2-D arrays of PI-etalon elements; and (4) work towards a fiber optic PI-etalon for in vivo use. Successful development of a fiber optic imager would provide a unique field-of-view thereby exposing an abundance of prospects for minimally-invasive analysis, diagnosis, and treatment of disease.

  8. Fabrication and resistive switching characteristics of high compact Ga-doped ZnO nanorod thin film devices

    NASA Astrophysics Data System (ADS)

    Yao, I.-Chuan; Lee, Dai-Ying; Tseng, Tseung-Yuen; Lin, Pang

    2012-04-01

    This study investigates the resistive switching behavior of Ga-doped ZnO (GZO) nanorod thin films with various Ga/Zn molar ratios. Vertically well-aligned and uniform GZO nanorod thin films were successfully grown on Au/Ti/SiO2/p-Si substrates using an aqueous solution method. X-ray diffraction (XRD) results indicate that GZO nanorods have [0001] highly preferred orientation. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations show the formation of highly ordered and dense nanorod thin films. These compact GZO nanorod thin films can be used to make resistive switching memory devices. Such memory devices can be reversibly switched between ON and OFF states, with a stable resistance ratio of ten times, narrow dispersion of ON and OFF voltages, and good endurance performance of over 100 cycles. The resistive switching mechanism in these devices is related to the formation and rupture of conducting filaments consisting of oxygen vacancies, occurring at interfaces between GZO nanorods (grain boundaries). Results show that the resulting compact GZO nanorod thin films have a high potential for resistive memory applications.

  9. Threshold switching behavior of Ag-Si based selector device and hydrogen doping effect on its characteristics

    SciTech Connect

    Yoo, Jongmyung; Woo, Jiyong; Song, Jeonghwan; Hwang, Hyunsang

    2015-12-15

    The effect of hydrogen treatment on the threshold switching property in a Ag/amorphous Si based programmable metallization cells was investigated for selector device applications. Using the Ag filament formed during motion of Ag ions, a steep-slope (5 mV/dec.) for threshold switching with higher selectivity (∼10{sup 5}) could be achieved. Because of the faster diffusivity of Ag atoms, which are inside solid-electrolytes, the resulting Ag filament could easily be dissolved under low current regime, where the Ag filament possesses weak stability. We found that the dissolution process could be further enhanced by hydrogen treatment that facilitated the movement of the Ag atoms.

  10. Design of an All-Optical Network Based on LCoS Technologies

    NASA Astrophysics Data System (ADS)

    Cheng, Yuh-Jiuh; Shiau, Yhi

    2016-06-01

    In this paper, an all-optical network composed of the ROADMs (reconfigurable optical add-drop multiplexer), L2/L3 optical packet switches, and the fiber optical cross-connection for fiber scheduling and measurement based on LCoS (liquid crystal on silicon) technologies is proposed. The L2/L3 optical packet switches are designed with optical output buffers. Only the header of optical packets is converted to electronic signals to control the wavelength of input ports and the packet payloads can be transparently destined to their output ports. An optical output buffer is designed to queue the packets when more than one incoming packet should reach to the same destination output port. For preserving service-packet sequencing and fairness of routing sequence, a priority scheme and a round-robin algorithm are adopted at the optical output buffer. The wavelength of input ports is designed for routing incoming packets using LCoS technologies. Finally, the proposed OFS (optical flow switch) with input buffers can quickly transfer the big data to the output ports and the main purpose of the OFS is to reduce the number of wavelength reflections. The all-optical content delivery network is comprised of the OFSs for a large amount of audio and video data transmissions in the future.

  11. Two-wavelength switching with a 1310nm-QDot DFB laser

    NASA Astrophysics Data System (ADS)

    Hurtado, A.; Nami, M.; Henning, I. D.; Adams, M. J.; Lester, L. F.

    2013-03-01

    We report a first experimental observation of two-wavelength switching (2WS) and bistability with a 1310nm-Quantum Dot (QDot) Distributed Feedback (DFB) laser subject to external optical injection and operated in reflection. We experimentally demonstrate the switching of the emission wavelength of the QDot laser when an external optical signal is injected into one of the subsidiary longitudinally modes located in the longer wavelength side of the device's lasing mode. Clockwise nonlinear switching and bistability are attained in all cases for both the emitting and the injected mode of the QDot laser as the injection strength is increased. Moreover, very high on-off contrast ratio is measured in the switching (and bistability) transition of the emission mode of the device. We have also analysed the switching properties of the 1310-QDot DFB laser as a function of the applied bias current and the initial wavelength detuning between the wavelengths of the external signal and that of the device's injected mode. In general, wider bistable loops, higher on-off contrast ratio between output states and higher input power requirements for switching are observed as the applied bias and initial detuning are increased. This diversity of switching behaviors obtained with a 1310 QDot DFB laser under external optical injection, added to the theoretically superior properties of nanostructure lasers, offers exciting prospects for novel uses of these devices in all-optical logic and all-optical switching/routing applications in present and future optical telecommunication networks.

  12. Multilevel programming in Cu/NiO y /NiO x /Pt unipolar resistive switching devices

    NASA Astrophysics Data System (ADS)

    Sarkar, P. K.; Bhattacharjee, S.; Barman, A.; Kanjilal, A.; Roy, A.

    2016-10-01

    The application of a NiO y /NiO x bilayer in resistive switching (RS) devices with x > y was studied for its ability to achieve reliable multilevel cell (MLC) characteristics. A sharp change in resistance brought about by sweeping the voltage, along with an improved on/off ratio (>103) and endurance (104) were achieved in the bilayer structure as compared to the single NiO x layer devices. Moreover, it was found that nonvolatile and stable resistance levels, especially the multiple low-resistance states of Cu/NiO y /NiO x /Pt memory devices, could be controlled by varying the compliance current. All the multilevel resistance states of the Cu/NiO y /NiO x /Pt bilayer devices were stable for up to 500 consecutive dc switching cycles, as compared to the Cu/NiO x /Pt single layer devices. The temperature-dependent variation of the high and low resistance states of both the bilayer and single layer devices was further investigated to elucidate the charge conduction mechanism. Finally, based on a detailed analysis of the experimental results, comparisons of the possible models for RS in bilayer and single layer memory devices have also been discussed.

  13. Multilevel programming in Cu/NiO y /NiO x /Pt unipolar resistive switching devices.

    PubMed

    Sarkar, P K; Bhattacharjee, S; Barman, A; Kanjilal, A; Roy, A

    2016-10-28

    The application of a NiO y /NiO x bilayer in resistive switching (RS) devices with x > y was studied for its ability to achieve reliable multilevel cell (MLC) characteristics. A sharp change in resistance brought about by sweeping the voltage, along with an improved on/off ratio (>10(3)) and endurance (10(4)) were achieved in the bilayer structure as compared to the single NiO x layer devices. Moreover, it was found that nonvolatile and stable resistance levels, especially the multiple low-resistance states of Cu/NiO y /NiO x /Pt memory devices, could be controlled by varying the compliance current. All the multilevel resistance states of the Cu/NiO y /NiO x /Pt bilayer devices were stable for up to 500 consecutive dc switching cycles, as compared to the Cu/NiO x /Pt single layer devices. The temperature-dependent variation of the high and low resistance states of both the bilayer and single layer devices was further investigated to elucidate the charge conduction mechanism. Finally, based on a detailed analysis of the experimental results, comparisons of the possible models for RS in bilayer and single layer memory devices have also been discussed.

  14. Multilevel programming in Cu/NiO y /NiO x /Pt unipolar resistive switching devices.

    PubMed

    Sarkar, P K; Bhattacharjee, S; Barman, A; Kanjilal, A; Roy, A

    2016-10-28

    The application of a NiO y /NiO x bilayer in resistive switching (RS) devices with x > y was studied for its ability to achieve reliable multilevel cell (MLC) characteristics. A sharp change in resistance brought about by sweeping the voltage, along with an improved on/off ratio (>10(3)) and endurance (10(4)) were achieved in the bilayer structure as compared to the single NiO x layer devices. Moreover, it was found that nonvolatile and stable resistance levels, especially the multiple low-resistance states of Cu/NiO y /NiO x /Pt memory devices, could be controlled by varying the compliance current. All the multilevel resistance states of the Cu/NiO y /NiO x /Pt bilayer devices were stable for up to 500 consecutive dc switching cycles, as compared to the Cu/NiO x /Pt single layer devices. The temperature-dependent variation of the high and low resistance states of both the bilayer and single layer devices was further investigated to elucidate the charge conduction mechanism. Finally, based on a detailed analysis of the experimental results, comparisons of the possible models for RS in bilayer and single layer memory devices have also been discussed. PMID:27651380

  15. KOMEKAMI Switch: A Wearable Input Device Based on the Concept of Affordance

    NASA Astrophysics Data System (ADS)

    Taniguchi, Kazuhiro; Nishikawa, Atsushi; Miyazaki, Fumio

    A wearable computing system plays a leading role in the ubiquitous computing era, in which computers are used at any place and at any time. Now the mobile multimedia communication technology based devices, such as mobile phone, handy-type PC, etc., have come to be used in such a broad range of areas, the features of wearable hands-free computing system, which people can constantly use in their daily life or workplace while doing some other job, are highly valued more than ever. However, the wearable computing system has not yet spread so widely owing to various factors. Among such factors is the delay in the development of human machine interface, which is applicable to the wearable computing system. We developed a blink based human-machine interface for the wearable computing system, called KOMEKAMI Switch. This interface makes it easy to manipulate machine with intentional movements of temple. User can constantly use machine with no interference, as well as with hands free. It is compact and lightweight, permitting ease of manufacturing at a low cost. It does not react to daily actions like conversation, diet, etc., other than movements intended to control the machine.

  16. All-optical NOR and NAND gates based on photonic crystal ring resonator

    NASA Astrophysics Data System (ADS)

    Bao, Junjie; Xiao, Jun; Fan, Lin; Li, Xiaoxu; Hai, Yunfei; Zhang, Tong; Yang, Chunbo

    2014-10-01

    We report a new configuration of all-optical logic gates based on two-dimensional (2D) square lattice photonic crystals (PCs) composed of silicon (Si) rods in Silica (SiO2). The proposed device is composed of cross-shaped waveguide and two photonic crystal ring resonators (PCRRs) without nonlinear materials and optical amplifiers. The gate has been simulated and analyzed by finite difference time domain (FDTD) and plane wave expansion (PWE) methods. The simulation results show that the proposed all-optical logic gates could really function as NOR and NAND logic gates. This new device can potentially be used in large-scale optical integration and on-chip photonic logic integrated circuits.

  17. Chip-integrated all-optical 4-bit Gray code generation based on silicon microring resonators.

    PubMed

    Liu, Li; Dong, Jianji; Zhang, Xinliang

    2015-08-10

    We propose and experimentally demonstrate a 4-port passive encoder for 4-bit Gray code on pure silicon platform. The operation principle for this device is the thermo-optic (TO) effect in silicon microring resonator (MRR) whose transmission spectrum could be shifted by injecting strong light power. Therefore, the output powers of both the through-port and drop-port of the MRR could be controllable and switchable. Two threshold powers are defined to decide the port output code of bit "0" or "1". By combining two independent resonant wavelengths of two MRRs and adjusting their powers in a certain order, all-optical 4-bit Gray code generation has been successfully demonstrated. The proposed integrated device is competent in on-chip all-optical communication and optical interconnection systems with significant advantages, such as simple operation, compact size, economical fabrication process and great scalability.

  18. Verification of redox-processes as switching and retention failure mechanisms in Nb:SrTiO3/metal devices.

    PubMed

    Baeumer, C; Raab, N; Menke, T; Schmitz, C; Rosezin, R; Müller, P; Andrä, M; Feyer, V; Bruchhaus, R; Gunkel, F; Schneider, C M; Waser, R; Dittmann, R

    2016-08-01

    Nanoscale redox reactions in transition metal oxides are believed to be the physical foundation of memristive devices, which present a highly scalable, low-power alternative for future non-volatile memory devices. The interface between noble metal top electrodes and Nb-doped SrTiO3 single crystals may serve as a prominent but not yet well-understood example of such memristive devices. In this report, we will present experimental evidence that nanoscale redox reactions and the associated valence change mechanism are indeed responsible for the resistance change in noble metal/Nb-doped SrTiO3 junctions with dimensions ranging from the micrometer scale down to the nanometer regime. Direct verification of the valence change mechanism is given by spectromicroscopic characterization of switching filaments. Furthermore, it is found that the resistance change over time is driven by the reoxidation of a previously oxygen-deficient region. The retention times of the low resistance states, accordingly, can be dramatically improved under vacuum conditions as well as through the insertion of a thin Al2O3 layer which prevents this reoxidation. These insights finally confirm the resistive switching mechanism at these interfaces and are therefore of significant importance for the study and application of memristive devices based on Nb-doped SrTiO3 as well as systems with similar switching mechanisms. PMID:27089047

  19. All-Optical NAND Gate Based on Nonlinear Photonic Crystal Ring Resonators

    NASA Astrophysics Data System (ADS)

    Serajmohammadi, Somaye

    2016-06-01

    In this paper we proposed a new design for all-optical NAND gate. By combining nonlinear Kerr effect with photonic crystal ring resonators first we designed a structure, whose optical behavior can be controlled via input power intensity. The switching power threshold obtained for this structure equal to 1 kW/μm2. For designing the proposed optical logic gate we employed two resonant rings with the same structures, both rings at the logic gates were designed such that their resonant wavelength be at λ=1,550 nm. Every proposed logic gate has one bias and two logic input ports.

  20. Ultrafast all-optical NOR gate based on semiconductor optical amplifier and fiber delay interferometer.

    PubMed

    Xu, Jing; Zhang, Xinliang; Liu, Deming; Huang, Dexiu

    2006-10-30

    An ultrafast all-optical logic NOR gate based on a semiconductor optical amplifier (SOA) and a fiber delay interferometer (FDI) is presented. For high-speed input return-to-zero (RZ) signal, nonreturn-to-zero (NRZ) switching windows which satisfy Boolean NOR operation can be formed by properly choosing the delay time and the phase shift of FDI. 40Gb/s NOR operation has been demonstrated successfully with low control optical power. The factors that degrade the NOR operation have been discussed.

  1. Ultrafast all-optical NOR gate based on semiconductor optical amplifier and fiber delay interferometer

    NASA Astrophysics Data System (ADS)

    Xu, Jing; Zhang, Xinliang; Liu, Deming; Huang, Dexiu

    2006-10-01

    An ultrafast all-optical logic NOR gate based on a semiconductor optical amplifier (SOA) and a fiber delay interferometer (FDI) is presented. For high-speed input return-to-zero (RZ) signal, nonreturn-to-zero (NRZ) switching windows which satisfy Boolean NOR operation can be formed by properly choosing the delay time and the phase shift of FDI. 40Gb/s NOR operation has been demonstrated successfully with low control optical power. The factors that degrade the NOR operation have been discussed.

  2. Spectrally-efficient all-optical OFDM by WSS and AWG.

    PubMed

    Hoxha, J; Morosi, J; Shimizu, S; Martelli, P; Boffi, P; Wada, N; Cincotti, G

    2015-05-01

    We report on the transmission experiment of seven 12.5-GHz spaced all optical-orthogonal frequency division multiplexed (AO-OFDM) subcarriers over a 35-km fiber link, using differential quadrature phase shift keying (DQPSK) modulation and direct detection. The system does not require chromatic dispersion compensation, optical time gating at the receiver (RX) or cyclic prefix (CP), achieving the maximum spectral efficiency. We use a wavelength selective switch (WSS) at the transmitter (TX) to allow subcarrier assignment flexibility and optimal filter shaping; an arrayed waveguide grating (AWG) AO-OFDM demultiplexer is used at the RX, to reduce the system cost and complexity. PMID:25969193

  3. A light-modified ferroelectric resistive switching behavior in Ag/BaMoO{sub 4}/FTO device at ambient temperature

    SciTech Connect

    Zhao, W.X.; Sun, B.; Liu, Y.H.; Wei, L.J.; Li, H.W.; Chen, P.

    2014-12-15

    BaMoO{sub 4} powder was prepared by a facile hydrothermal synthesis. And the BaMoO{sub 4}/FTO device was fabricated by a spin-coated method, in which the thickness of BaMoO{sub 4} layer is about 20 µm. The bipolar resistive switching effect has been observed in Ag/BaMoO{sub 4}/FTO device. Moreover, the resistive switching effect of the device is greatly improved by white light irradiation. The resistive switching behavior is explained by the polarization reversal that changes the charge distribution and modulates the Schottky barriers. - Graphical abstract: We fabricate a resistive switching device based on Ag/BaMoO{sub 4}/FTO, the device shows superior white-light controlled bipolar resistive switching memristive characteristics. - Highlights: • The BaMoO{sub 4} nanosquares powder was prepared by a hydrothermal synthesis. • The resistive switching of the Ag/BaMoO{sub 4}/FTO device was observed for the first time. • It is shown that the resistive switching is greatly improved under the white light irradiation. • The mechanism of resistive switching is attributed to the ferroelectric polarization reversal.

  4. All-optical depth coloring based on directional gating.

    PubMed

    Lim, Sungjin; Kim, Mugeon; Hahn, Joonku

    2016-09-19

    In non-contacting depth extraction there are several issues, such as the accuracy and the measurement speed. In the issue of the measurement speed, the computation cost for image processing is significant. We present an all-optical depth extraction method by coloring objects according to their depth. Our system is operated fully optically and both encoding and decoding processes are optically performed. Therefore, all-optical depth coloring has a distinct advantage to extract the depth information in real time without any computation cost. We invent a directional gating method to extract the points from the object which are positioned at the same distance. Based on this method, the objects look painted by different colors according to the distance when the objects are observed through our system. In this paper, we demonstrate the all-optical depth coloring system and verify the feasibility of our method. PMID:27661875

  5. Simple novel all-optical half-adder

    NASA Astrophysics Data System (ADS)

    Chen, Zhixin

    2010-04-01

    On the basis of Sagnac interferometric structure, a simple novel ultrafast scheme of all-optical half-adder is proposed. The structure comprises two of the same balanced terahertz optical asymmetric demultiplexers (TOADs). One TOAD is utilized to achieve an all-optical XOR gate, which is logic SUM. The other is utilized to obtain an all-optical AND gate, which is logic CARRY. Logical SUM and CARRY are simultaneously realized at 80 Gbit/s. Through numerical analysis, the operating characteristics of the scheme are illustrated at 80 Gbit/s. Furthermore, the carrier recovery time of the semiconductor optical amplifier is no longer a crucial parameter to restrict the operation speed of this scheme.

  6. Femtojoule-Scale All-Optical Latching and Modulation via Cavity Nonlinear Optics

    NASA Astrophysics Data System (ADS)

    Kwon, Yeong-Dae; Armen, Michael A.; Mabuchi, Hideo

    2013-11-01

    We experimentally characterize Hopf bifurcation phenomena at femtojoule energy scales in a multiatom cavity quantum electrodynamical (cavity QED) system and demonstrate how such behaviors can be exploited in the design of all-optical memory and modulation devices. The data are analyzed by using a semiclassical model that explicitly treats heterogeneous coupling of atoms to the cavity mode. Our results highlight the interest of cavity QED systems for ultralow power photonic signal processing as well as for fundamental studies of mesoscopic nonlinear dynamics.

  7. All-Optical Logic Gates in Organic Materials

    NASA Technical Reports Server (NTRS)

    Adbeldayem, H. A.; Frazier, D. O.; Witherow, W.; Paley, M. S.; Penn, B.; Banks, E.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    A picosecond switch made of polydiacetylene thin film coated on the interior of a 50-micron diameter hollow fiber and a nanosecond switch made of a micron thick film of phthalocyanine on glass were developed.

  8. Cascaded transformerless DC-DC voltage amplifier with optically isolated switching devices

    NASA Technical Reports Server (NTRS)

    Sridharan, Govind (Inventor)

    1993-01-01

    A very high voltage amplifier is provided in which plural cascaded banks of capacitors are switched by optically isolated control switches so as to be charged in parallel from the preceding stage or capacitor bank and to discharge in series to the succeeding stage or capacitor bank in alternating control cycles. The optically isolated control switches are controlled by a logic controller whose power supply is virtually immune to interference from the very high voltage output of the amplifier by the optical isolation provided by the switches, so that a very high voltage amplification ratio may be attained using many capacitor banks in cascade.

  9. All-optical pseudorandom bit sequences generator based on TOADs

    NASA Astrophysics Data System (ADS)

    Sun, Zhenchao; Wang, Zhi; Wu, Chongqing; Wang, Fu; Li, Qiang

    2016-03-01

    A scheme for all-optical pseudorandom bit sequences (PRBS) generator is demonstrated with optical logic gate 'XNOR' and all-optical wavelength converter based on cascaded Tera-Hertz Optical Asymmetric Demultiplexer (TOADs). Its feasibility is verified by generation of return-to-zero on-off keying (RZ-OOK) 263-1 PRBS at the speed of 1 Gb/s with 10% duty radio. The high randomness of ultra-long cycle PRBS is validated by successfully passing the standard benchmark test.

  10. Analysis of all-optically tunable functionalities in subwavelength periodic structures by the Fourier modal method

    NASA Astrophysics Data System (ADS)

    Bej, Subhajit; Tervo, Jani; Francés, Jorge; Svirko, Yuri P.; Turunen, Jari

    2016-05-01

    We propose the nonlinear Fourier Modal Method (FMM) [J. Opt. Soc. Am. B 31, 2371 (2014)] as a convenient and versatile numerical tool for the design and analysis of grating based next generation all-optical devices. Here, we include several numerical examples where the FMM is used to simulate all-optically tunable functionalities in sub-wavelength periodic structures. At first, we numerically investigate a 1-D periodic nonlinear binary grating with amorphous TiO2. We plot the diffraction efficiency in the transmitted orders against the structure depth for normally incident plane wave. Change in diffraction efficiencies for different incident field amplitudes are evident from the plots. We verify the accuracy of our implementation by comparing our results with the results obtained with the nonlinear Split Field-Finite Difference Time Domain (SF-FDTD) method. Next we repeat the same experiment with vertically standing amorphous Titanium dioxide (TiO2) nanowire arrays grown on top of quartz which are periodic in two mutually perpendicular directions and examine the efficiencies in the direct transmitted light for different incident field amplitudes. Our third example includes analysis of a form birefringent linear grating with Kerr medium. With FMM we demonstrate that the birefringence of such a structure can be tuned by all-optical means. As a final example, we design a narrow band Guided Mode Resonance Filter (GMRF). Numerical experiments based on the nonlinear FMM reveal that the spectral tunability of such a filter can be obtained by all-optical means.

  11. Processing of Diamond for Integrated Optic Devices Using Q-Switched Nd:YAG Laser at Different Wavelengths

    NASA Astrophysics Data System (ADS)

    Sudheer, S. K.; Pillai, V. P. Mahadevan; Nayar, V. U.

    In the present investigation, a Q-switched Nd:YAG laser is used to study the various aspects of diamond processing for fabricating integrated optic and UV optoelectronic devices. Diamond is a better choice of substrate compared to silicon and gallium arsenide for the fabrication of waveguides to perform operations such as modulation, switching, multiplexing, and filtering, particularly in the ultraviolet spectrum. The experimental setup of the present investigation consists of two Q-Switched Nd:YAG lasers capable of operating at wavelengths of 1064 nm and 532 nm. The diamond cutting is performed using these two wavelengths by making the "V"-shaped groove with various opening angle. The variation of material loss of diamond during cutting is noted for the two wavelengths. The cut surface morphology and elemental and structural analysis of graphite formed during processing in both cases are compared using scanning electron microscopy (SEM) and laser Raman spectroscopy. Both the Q-Switched Nd:YAG laser systems (at 1064 nm and 532 nm) show very good performance in terms of peak-to-peak output stability, minimal spot diameter, smaller divergence angle, higher peak power in Q-switched mode, and good fundamental TEM00 mode quality for processing natural diamond stones. Less material loss and minimal micro cracks are achieved with wavelength 532 nm whereas a better diamond cut surface is achieved with processing at 1064 nm with minimum roughness.

  12. Large and robust resistive switching in co-sputtered Pt-(NiO-Al2O3)-Pt devices

    NASA Astrophysics Data System (ADS)

    Rebello, A.; Adeyeye, A. O.

    2016-02-01

    We have systematically investigated the resistive switching and electroresistance behavior in Pt-[NiO-Al2O3]-Pt (PNAP) capacitor-like structures. The PNAP devices show a large ON-OFF ratio (˜107), which is strongly dependent on the rate of the voltage sweep. Interestingly, the devices exhibit a robust electroresistance behavior in the high resistance OFF state and show an intriguing change of sign of rectification with increasing end voltage. Our direct measurement of the surface temperature of the sample during resistive switching indicates that RESET process is assisted by Joule heating effects. The results are explained on the basis of plausible interplay between Schottky barrier modification due to the trapped charge carriers at the metal-oxide interface and percolation effects of conducting nanofilaments.

  13. High optical and switching performance electrochromic devices based on a zinc oxide nanowire with poly(methyl methacrylate) gel electrolytes

    SciTech Connect

    Chun, Young Tea; Chu, Daping; Neeves, Matthew; Placido, Frank; Smithwick, Quinn

    2014-11-10

    High performance electrochromic devices have been fabricated and demonstrated utilizing a solid polymer electrolyte and zinc oxide (ZnO) nanowire (NW) array counter electrode. The poly(methyl methacrylate) based polymer electrolyte was spin coated upon hydrothermally grown ZnO NW array counter electrodes, while electron beam evaporated NiO{sub x} thin films formed the working electrodes. Excellent optical contrast and switching speeds were observed in the fabricated devices with active areas of 2 cm{sup 2}, exhibiting an optical contrast of 73.11% at the wavelength of 470 nm, combined with a fast switching time of 0.2 s and 0.4 s for bleaching and coloration, respectively.

  14. Resistive switching characteristics of Al/Si3N4/p-Si MIS-based resistive switching memory devices

    NASA Astrophysics Data System (ADS)

    Kim, Hee-Dong; Yun, Min Ju; Kim, Sungho

    2016-08-01

    In this study, we proposed and demonstrated a self-rectifying property of a silicon nitride (Si3N4)-based resistive random access memory (RRAM) device by employing p-type silicon ( p-Si) as the bottom electrode. The RRAM devices consisting of Al/Si3N4/ p-Si are fabricated by using a low-pressure chemical-vapor deposition and exhibited an intrinsic diode property with non-linear current-voltage ( I-V) behavior. In addition, compared to the conventional metal/insulator/metal (MIM) structure of Al/Si3N4/Ti RRAM cells, the operating current over the entire bias region for the proposed metal/insulator/semiconductor (MIS) cells is dramatically lower because the introduced p-Si bottom electrode efficiently suppresses the current in both the low- and the high resistance states. Then, the results mean that when p-Si is employed as a bottom electrode, the Si3N4-based RRAM cells can be applied to selector-free RRAM cells.

  15. Ultralow-light-level all-optical transistor in rubidium vapor

    SciTech Connect

    Jing, Jietai Zhou, Zhifan; Liu, Cunjin; Qin, Zhongzhong; Fang, Yami; Zhou, Jun; Zhang, Weiping

    2014-04-14

    An all-optical transistor (AOT) is a device in which one light beam can efficiently manipulate another. It is the foundational component of an all-optical communication network. An AOT that can operate at ultralow light levels is especially attractive for its potential application in the quantum information field. Here, we demonstrate an AOT driven by a weak light beam with an energy density of 2.5 × 10{sup −5} photons/(λ{sup 2}/2π) (corresponding to 6  yJ/(λ{sup 2}/2π) and about 800 total photons) using the double-Λ four-wave mixing process in hot rubidium vapor. This makes it a promising candidate for ultralow-light-level optical communication and quantum information science.

  16. Verification of redox-processes as switching and retention failure mechanisms in Nb:SrTiO3/metal devices

    NASA Astrophysics Data System (ADS)

    Baeumer, C.; Raab, N.; Menke, T.; Schmitz, C.; Rosezin, R.; Müller, P.; Andrä, M.; Feyer, V.; Bruchhaus, R.; Gunkel, F.; Schneider, C. M.; Waser, R.; Dittmann, R.

    2016-07-01

    Nanoscale redox reactions in transition metal oxides are believed to be the physical foundation of memristive devices, which present a highly scalable, low-power alternative for future non-volatile memory devices. The interface between noble metal top electrodes and Nb-doped SrTiO3 single crystals may serve as a prominent but not yet well-understood example of such memristive devices. In this report, we will present experimental evidence that nanoscale redox reactions and the associated valence change mechanism are indeed responsible for the resistance change in noble metal/Nb-doped SrTiO3 junctions with dimensions ranging from the micrometer scale down to the nanometer regime. Direct verification of the valence change mechanism is given by spectromicroscopic characterization of switching filaments. Furthermore, it is found that the resistance change over time is driven by the reoxidation of a previously oxygen-deficient region. The retention times of the low resistance states, accordingly, can be dramatically improved under vacuum conditions as well as through the insertion of a thin Al2O3 layer which prevents this reoxidation. These insights finally confirm the resistive switching mechanism at these interfaces and are therefore of significant importance for the study and application of memristive devices based on Nb-doped SrTiO3 as well as systems with similar switching mechanisms.Nanoscale redox reactions in transition metal oxides are believed to be the physical foundation of memristive devices, which present a highly scalable, low-power alternative for future non-volatile memory devices. The interface between noble metal top electrodes and Nb-doped SrTiO3 single crystals may serve as a prominent but not yet well-understood example of such memristive devices. In this report, we will present experimental evidence that nanoscale redox reactions and the associated valence change mechanism are indeed responsible for the resistance change in noble metal/Nb-doped Sr

  17. Investigation on the RESET switching mechanism of bipolar Cu/HfO2/Pt RRAM devices with a statistical methodology

    NASA Astrophysics Data System (ADS)

    Yang, Xiaoyi; Long, Shibing; Zhang, Kangwei; Liu, Xiaoyu; Wang, Guoming; Lian, Xiaojuan; Liu, Qi; Lv, Hangbing; Wang, Ming; Xie, Hongwei; Sun, Haitao; Sun, Pengxiao; Suñé, Jordi; Liu, Ming

    2013-06-01

    The RESET switching of bipolar Cu/HfO2/Pt resistance random access memory (RRAM) is investigated. With a statistical methodology, we systematically analyze the RESET voltage (VRESET) and RESET current (IRESET). VRESET shows a U-shape distribution as a function of RON according to the scatter plot of the raw experimental data. After data correction by a series resistance (RS), VRESET is nearly constant, while IRESET decreases linearly with RCF. These behaviours are consistent with the thermal dissolution model of RESET. Moreover, the IRESET and VRESET distributions are strongly affected by the RON distribution. Using a ‘resistance screening’ method, the IRESET and VRESET distributions are found to be compatible with the Weibull distribution model. The Weibull slopes of the VRESET and IRESET distributions are independent of RCF, indicating that the RESET point corresponds to the initial phase of conductive filament (CF) dissolution, according to our cell-based model for the unipolar RESET of RRAM devices. The scale factor of the VRESET distributions is roughly constant, while that of the IRESET distributions scale with 1/RCF. Accordingly, the RESET switching of the HfO2-based solid electrolyte memory is compatible with the thermal dissolution mechanism, improving our understanding on the physics of resistive switching of RRAM devices.

  18. Bufferless Ultra-High Speed All-Optical Packet Routing

    NASA Astrophysics Data System (ADS)

    Muttagi, Shrihari; Prince, Shanthi

    2011-10-01

    All-Optical network is still in adolescence to cope up with steep rise in data traffic at the backbone network. Routing of packets in optical network depends on the processing speed of the All-Optical routers, thus there is a need to enhance optical processing to curb the delay in packet forwarding unit. In the proposed scheme, the header processing takes place on fly, therefore processing delay is at its lower limit. The objective is to propose a framework which establishes high data rate transmission with least latency in data routing from source to destination. The Routing table and optical header pulses are converted into Pulse Position (PP) format, thus reducing the complexity and in turn the processing delay. Optical pulse matching is exercised which results in multi-output transmission. This results in ultra-high speed packet forwarding unit. In addition, this proposed scheme includes dispersion compensation unit, which makes the data reliable.

  19. Inhalation errors due to device switch in patients with chronic obstructive pulmonary disease and asthma: critical health and economic issues

    PubMed Central

    Roggeri, Alessandro; Micheletto, Claudio; Roggeri, Daniela Paola

    2016-01-01

    Background Different inhalation devices are characterized by different techniques of use. The untrained switching of device in chronic obstructive pulmonary disease (COPD) and asthma patients may be associated with inadequate inhalation technique and, consequently, could lead to a reduction in adherence to treatment and limit control of the disease. The aim of this analysis was to estimate the potential economic impact related to errors in inhalation in patients switching device without adequate training. Methods An Italian real-practice study conducted in patients affected by COPD and asthma has shown an increase in health care resource consumption associated with misuse of inhalers. Particularly, significantly higher rates of hospitalizations, emergency room visits (ER), and pharmacological treatments (steroids and antimicrobials) were observed. In this analysis, those differences in resource consumption were monetized considering the Italian National Health Service (INHS) perspective. Results Comparing a hypothetical cohort of 100 COPD patients with at least a critical error in inhalation vs 100 COPD patients without errors in inhalation, a yearly excess of 11.5 hospitalizations, 13 ER visits, 19.5 antimicrobial courses, and 47 corticosteroid courses for the first population were revealed. In the same way, considering 100 asthma patients with at least a critical error in inhalation vs 100 asthma patients without errors in inhalation, the first population is associated with a yearly excess of 19 hospitalizations, 26.5 ER visits, 4.5 antimicrobial courses, and 21.5 corticosteroid courses. These differences in resource consumption could be associated with an increase in health care expenditure for INHS, due to inhalation errors, of €23,444/yr in COPD and €44,104/yr in asthma for the considered cohorts of 100 patients. Conclusion This evaluation highlights that misuse of inhaler devices, due to inadequate training or nonconsented switch of inhaled medications

  20. All-optical ultrafast XOR/XNOR logic gates, binary counter, and double-bit comparator with silicon microring resonators.

    PubMed

    Sethi, Purnima; Roy, Sukhdev

    2014-10-01

    We present designs of all-optical ultrafast YES/NOT, XOR/XNOR logic gates, binary counter, and double-bit comparator based on all-optical switching by two-photon absorption induced free-carrier injection in silicon 2 × 2 add-drop microring resonators. The proposed circuits have been theoretically analyzed using time-domain coupled-mode theory based on reported experimental values to realize low power (∼ 28 mW) ultrafast (∼ 22 ps) operation with high modulation (80%) and bit rate (45 Gb/s). The designs are complementary metal-oxide semiconductor compatible and provide advantages of high Q-factor, tunability, compactness, cascadibility, scalability, reconfigurability, simplicity, and minimal number of switches and inputs for realization of the desired logic. Although a two-bit counter has been shown, the scheme can easily be extended to N-bit counter through cascading.

  1. Evaluation of laser diode based optical switches for optical processors

    NASA Astrophysics Data System (ADS)

    Swanson, Paul D.; Parker, Michael A.; Libby, Stuart I.

    1993-07-01

    Three optical switching elements have been designed, fabricated, and tested for use in an integrated, optical signal processor. The first, an optical NOR logic gate, uses gain quenching as a means of allowing one (or more) light beam(s) to control the output light. This technique, along with the use of a two pad bistable output laser, is used in demonstrating the feasibility of the second device, an all optical RS flip flop. The third device consists of a broad area orthogonal model switching laser, whose corollary outputs correspond to the sign of the voltage difference between its two high impedance electrical inputs. This device also has possible memory applications if bistable mode switching within the broad area laser can be achieved.

  2. Stereoscopic three-dimensional display based on polarization-switching device with low cross talk and high contrast ratio.

    PubMed

    Shin, Hun Ki; Lee, Joong Ha; Jin, Hye-Jung; Yoon, Tae-Hoon; Kim, Jae Chang

    2010-07-01

    We present a polarization-switching device with dual-frequency liquid crystal material for a stereoscopic three-dimensional (3D) display. This device shows good properties, such as low 3D cross talk and high brightness, due to a fast dynamic response time. Without optical compensation, however, this device has an asymmetric contrast ratio on the left- and right-hand sides of 3D glasses, because the viewing principles on both sides are different from each other. To solve this problem, we design an optical structure with two half-wave plate films using the Jones matrix method. As the results of simulation and experiment show, excellent dark states and high brightness are realized over the entire range of visible wavelengths on both sides.

  3. Stereoscopic three-dimensional display based on polarization-switching device with low cross talk and high contrast ratio.

    PubMed

    Shin, Hun Ki; Lee, Joong Ha; Jin, Hye-Jung; Yoon, Tae-Hoon; Kim, Jae Chang

    2010-07-01

    We present a polarization-switching device with dual-frequency liquid crystal material for a stereoscopic three-dimensional (3D) display. This device shows good properties, such as low 3D cross talk and high brightness, due to a fast dynamic response time. Without optical compensation, however, this device has an asymmetric contrast ratio on the left- and right-hand sides of 3D glasses, because the viewing principles on both sides are different from each other. To solve this problem, we design an optical structure with two half-wave plate films using the Jones matrix method. As the results of simulation and experiment show, excellent dark states and high brightness are realized over the entire range of visible wavelengths on both sides. PMID:20596202

  4. Electron transfer at the contact between Al electrode and gold nanoparticles of polymer: Nanoparticle resistive switching devices studied by alternating current impedance spectroscopy

    SciTech Connect

    Ouyang, Jianyong

    2013-12-02

    Electron transfer at the contact between an Al electrode and Au nanoparticles of polymer:nanoparticle devices is studied by ac impedance spectroscopy. The devices have a polystyrene layer embedded with Au nanoparticles capped with conjugated 2-naphthalenethiol sandwiched between Al and MoO{sub 3}/Al electrodes, and they exhibit electrode-sensitive resistive switches. The devices in the pristine or high resistance state have high capacitance. The capacitance decreases after the devices switch to a low resistance state by a voltage scan. The change in the capacitance is attributed to the voltage-induced change on the electronic structure of the contact between the Al electrode and Au nanoparticles.

  5. An 8 channel, 20 V output CMOS switching driver with 3.3 V power supply using triple-well biasing techniques for integrated MEMS device control

    NASA Astrophysics Data System (ADS)

    Takayasu, Motohiro; Shirane, Atsushi; Lee, Sangyeop; Yamane, Daisuke; Ito, Hiroyuki; Mi, Xiaoyu; Inoue, Hiroaki; Nakazawa, Fumihiko; Ueda, Satoshi; Ishihara, Noboru; Masu, Kazuya

    2014-01-01

    An 8 channel output switching driver has been implemented for integrated micro-electro-mechanical systems (MEMS) device control using the 0.18 µm CMOS process technology. The driver can output 20 V switching signals for 1 nF capacitive loads with a 3.3 V power supply. The switching time is less than 100 µs. To obtain a high output voltage that exceeds the transistors’ and capacitors’ breakdown voltages, a new charge pump and a discharge circuit, using optimal transistor-well-biasing techniques for triple-well-structured n-MOS transistors, were investigated, and the circuit parameters were also optimized to obtain high-speed switching.

  6. Design and analysis of an all-optical Demultiplexer based on photonic crystals

    NASA Astrophysics Data System (ADS)

    Goodarzi, K.; Mir, A.

    2015-01-01

    An all-optical 1of 2 De-multiplexer (D-mux) based on silicon rods in the air, created by two dimensional square lattice photonic crystals (PCs), is proposed and demonstrated. The device operation is because of line and point defects and phase difference between input beams that created by point defects. The device has a selection line, S, an input data port, A, and three output data ports, Q0, Q1 and Q2. Photonic band gap (PBG) calculation is done by plane wave expansion (PWE) method and electrical field distribution (EFD) in the device by finite difference time domain (FDTD) method. Power levels lower than "0.25P0" is considered as "0" logic value and higher than "0.4P0" as "1" logic value. When S = 0, the data of port A, is directed to Q0 and when S = 1, is directed to Q1. Moreover, one of the output ports, Q1 or Q2, can be used as an AND logic gate. The device is applicable for all-optical processors and integrated circuit.

  7. Improvement of Bipolar Switching Properties of Gd:SiOx RRAM Devices on Indium Tin Oxide Electrode by Low-Temperature Supercritical CO2 Treatment

    NASA Astrophysics Data System (ADS)

    Chen, Kai-Huang; Chang, Kuan-Chang; Chang, Ting-Chang; Tsai, Tsung-Ming; Liang, Shu-Ping; Young, Tai-Fa; Syu, Yong-En; Sze, Simon M.

    2016-02-01

    Bipolar switching resistance behaviors of the Gd:SiO2 resistive random access memory (RRAM) devices on indium tin oxide electrode by the low-temperature supercritical CO2-treated technology were investigated. For physical and electrical measurement results obtained, the improvement on oxygen qualities, properties of indium tin oxide electrode, and operation current of the Gd:SiO2 RRAM devices were also observed. In addition, the initial metallic filament-forming model analyses and conduction transferred mechanism in switching resistance properties of the RRAM devices were verified and explained. Finally, the electrical reliability and retention properties of the Gd:SiO2 RRAM devices for low-resistance state (LRS)/high-resistance state (HRS) in different switching cycles were also measured for applications in nonvolatile random memory devices.

  8. Improvement of Bipolar Switching Properties of Gd:SiOx RRAM Devices on Indium Tin Oxide Electrode by Low-Temperature Supercritical CO2 Treatment.

    PubMed

    Chen, Kai-Huang; Chang, Kuan-Chang; Chang, Ting-Chang; Tsai, Tsung-Ming; Liang, Shu-Ping; Young, Tai-Fa; Syu, Yong-En; Sze, Simon M

    2016-12-01

    Bipolar switching resistance behaviors of the Gd:SiO2 resistive random access memory (RRAM) devices on indium tin oxide electrode by the low-temperature supercritical CO2-treated technology were investigated. For physical and electrical measurement results obtained, the improvement on oxygen qualities, properties of indium tin oxide electrode, and operation current of the Gd:SiO2 RRAM devices were also observed. In addition, the initial metallic filament-forming model analyses and conduction transferred mechanism in switching resistance properties of the RRAM devices were verified and explained. Finally, the electrical reliability and retention properties of the Gd:SiO2 RRAM devices for low-resistance state (LRS)/high-resistance state (HRS) in different switching cycles were also measured for applications in nonvolatile random memory devices.

  9. A feedback silicon-on-insulator steep switching device with gate-controlled carrier injection

    NASA Astrophysics Data System (ADS)

    Wan, J.; Cristoloveanu, S.; Le Royer, C.; Zaslavsky, A.

    2012-10-01

    We experimentally demonstrate a field-effect transistor with a single front gate built on fully-depleted silicon-on-insulator substrate that possesses extremely steep switching slope (≪1 mV/decade) and gate-controllable hysteresis. The mechanism for the sharp switching, confirmed by simulations, involves the positive feedback between the gate-modulated charge injection barriers and the electron and hole components of the source-drain current. The transistor is named Z2-FET as it features zero impact ionization (unlike thyristors) and zero subthreshold swing.

  10. Self-rectifying resistive-switching characteristics with ultralow operating currents in SiOxNy/AlN bilayer devices

    NASA Astrophysics Data System (ADS)

    Kwon, Jeong Yong; Park, Ju Hyun; Kim, Tae Geun

    2015-06-01

    We propose a SiOxNy/AlN bilayer resistive switching random access memory scheme to eliminate crosstalk in a crossbar array structure. We demonstrated forming-free self-rectifying behaviors at an ultralow operating current (below 200 nA) by optimizing the current compliance and operating voltage. The set and reset voltages were reduced using a thin AlN layer, and the voltages' on/off ratio and rectifying ratio were as high as 80 and 102, respectively. In addition, the device showed an endurance of 103 dc cycles and a retention time over 105 s.

  11. A sharp-switching device with free surface and buried gates based on band modulation and feedback mechanisms

    NASA Astrophysics Data System (ADS)

    Solaro, Y.; Fonteneau, P.; Legrand, C. A.; Fenouillet-Beranger, C.; Ferrari, P.; Cristoloveanu, S.

    2016-02-01

    We propose and demonstrate experimentally a band-modulation device with extremely sharp switching capability. The Z3-FET (Zero gate, Zero swing and Zero impact ionization) has no top gate, is processed with FDSOI CMOS technology, and makes use of two adjacent buried ground planes acting as back gates. The buried gates emulate respectively N+ and P+ regions in the undoped body, forming a virtual thyristor-like NPNP structure with feedback operation. Vertical output IA-VA and transfer IA-VG characteristics over more than 8 decades of current are measured with relatively low gate and drain bias (<3 V).

  12. All-optical processes in double quantum dot structure.

    PubMed

    Rehman, Ektefaa; Al-Khursan, Amin H

    2016-09-10

    The ladder-plus-Y double quantum dot structure was modeled for all-optical processing by combining the density matrix theory with the pulse width description of the applied pulse. The momentum matrix elements are calculated including the wetting layer. The ladder-plus-Y structure exhibits pattern-free output with high bit rate (50 Tbps), which is critical in optical communication applications. It is shown that very high ground-state occupation with periodic shape for state occupations is critical in obtaining a pattern-free eye diagram.

  13. Protection method of all-optical mesh networks

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Zhang, Min; Liu, Junwei; Gu, Wanyi

    2001-10-01

    A protection scheme that chooses protection routes in advance in All-Optical Mesh network is proposed in this paper. Two rules, minimum relativity among routes and minimum the number of hops, are given and analyzed in detail. In order to perform protection quickly and correctly, the compromise between two principles must be considered when choosing protection routes. The protection method that appointing ring networks in mesh networks is proposed too. In addition, some key technologies such as avoiding oscillation, line protection and misconnect squelched are also proposed in this paper.

  14. Ultrafast all-optical technologies for bidirectional optical wireless communications.

    PubMed

    Jin, Xian; Hristovski, Blago A; Collier, Christopher M; Geoffroy-Gagnon, Simon; Born, Brandon; Holzman, Jonathan F

    2015-04-01

    In this Letter, a spherical retro-modulator architecture is introduced for operation as a bidirectional transceiver in passive optical wireless communication links. The architecture uses spherical retroreflection to enable retroreflection with broad directionality (2π steradians), and it uses all-optical beam interaction to enable modulation on ultrafast timescales (120 fs duration). The spherical retro-modulator is investigated from a theoretical standpoint and is fabricated for testing with three glasses, N-BK7, N-LASF9, and S-LAH79. It is found that the S-LAH79 structure provides the optimal refraction and nonlinearity for the desired retroreflection and modulation capabilities.

  15. All-optical processes in double quantum dot structure.

    PubMed

    Rehman, Ektefaa; Al-Khursan, Amin H

    2016-09-10

    The ladder-plus-Y double quantum dot structure was modeled for all-optical processing by combining the density matrix theory with the pulse width description of the applied pulse. The momentum matrix elements are calculated including the wetting layer. The ladder-plus-Y structure exhibits pattern-free output with high bit rate (50 Tbps), which is critical in optical communication applications. It is shown that very high ground-state occupation with periodic shape for state occupations is critical in obtaining a pattern-free eye diagram. PMID:27661371

  16. All-optical processing in coherent nonlinear spectroscopy

    SciTech Connect

    Oron, Dan; Dudovich, Nirit; Silberberg, Yaron

    2004-08-01

    In spectroscopy, the fingerprint of a substance is usually comprised of a sequence of spectral lines with characteristic frequencies and strengths. Identification of substances often involves postprocessing, where the measured spectrum is compared with tabulated fingerprint spectra. Here we suggest a scheme for nonlinear spectroscopy, where, through coherent control of the nonlinear process, the information from the entire spectrum can be practically collected into a single coherent entity. We apply this for all-optical analysis of coherent Raman spectra and demonstrate enhanced detection and effective background suppression using coherent processing.

  17. All-Optical Flip-Flop Operation of VCSOA

    SciTech Connect

    Kaplan, A.M.; Agrawal, G.P.; Maywar, D.N.

    2009-01-22

    An all-optical flip-flop, the memory of which is based on dispersive bistability in a single vertical cavity semiconductor optical amplifier, is demonstrated experimentally. Flip-flop control is achieved using two mechanisms: cross-phase modulation to set the flip-flop and cross-gain modulation of the holding beam within a remote SOA to reset it. Optical control signals are sub-milliwatt in power and derived from a single 5 ns, 1539 nm initial pulse. Flip-flop operation at 1542 nm is polarisation insensitive to control signals and achieved with an on-off contrast greater than 3 dB.

  18. Nonlinear silicon-on-insulator waveguides for all-optical signal processing

    NASA Astrophysics Data System (ADS)

    Koos, C.; Jacome, L.; Poulton, C.; Leuthold, J.; Freude, W.

    2007-05-01

    Values up to γ=7×106/(Wkm) for the nonlinear parameter are feasible if silicon-on-insulator based strip and slot waveguides are properly designed. This is more than three orders of magnitude larger than for state-of-the-art highly nonlinear fibers, and it enables ultrafast all-optical signal processing with nonresonant compact devices. At λ=1.55μm we provide universal design curves for strip and slot waveguides which are covered with different linear and nonlinear materials, and we calculate the resulting maximum γ.

  19. Anomalous nonlinear absorption in epsilon-near-zero materials: optical limiting and all-optical control.

    PubMed

    Vincenti, M A; de Ceglia, D; Scalora, Michael

    2016-08-01

    We investigate nonlinear absorption in films of epsilon-near-zero materials. The combination of large local electric fields at the fundamental frequency and material losses at the harmonic frequencies induce unusual intensity-dependent phenomena. We predict that the second-order nonlinearity of a low-damping, epsilon-near-zero slab produces an optical limiting effect that mimics a two-photon absorption process. Anomalous absorption profiles that depend on low permittivity values at the pump frequency are also predicted for third-order nonlinearities. These findings suggest new opportunities for all-optical light control and novel ways to design reconfigurable and tunable nonlinear devices.

  20. All-optical mitigation of amplitude and phase-shift drift noise in semiconductor optical amplifiers

    NASA Astrophysics Data System (ADS)

    Rocha, Peterson; Gallep, Cristiano M.; Conforti, Evandro

    2015-10-01

    An all-optical scheme aimed at minimizing distortions induced by semiconductor optical amplifiers (SOAs) over modulated optical carriers is presented. The scheme employs an additional SOA properly biased to act as a saturated absorber, and thus counteract the distortions induced by the first amplifying device. The scheme here is demonstrated in silico, for 40 and 100 Gb/s (10 and 25 Gbaud, 16 QAM), with reasonable total gain (>20 dB) for symbol error rate below the forward error correction limit.

  1. Photonic crystal-based all-optical on-chip sensor.

    PubMed

    Liu, Y; Salemink, H W M

    2012-08-27

    In this paper we demonstrate a sensor based on a two-dimensional photonic crystal cavity structure. Design, theoretical simulations, fabrication and experiments are shown to illustrate the working principle of this device. Sensitivity of our sensor is determined by observing the shift of resonant wavelength of the photonic crystal cavity as a function of the refractive index variation of the analyte. By experimentally infiltrating solutions of water and ethanol through an elastomeric micro-fluidic channel, we have confirmed that our all-optical sensor achieves a sensitivity of 460 nm/RIU. PMID:23037043

  2. All-optical multiplexing schemes for multiple access networks based on wavelet packet filter banks

    NASA Astrophysics Data System (ADS)

    Cincotti, Gabriella; Svaluto Moreolo, Michela; Neri, Alessandro

    2004-08-01

    All optical architectures for Wavelet Packet Division Multiplexing (WPDM) are presented, that can be used in multiple access networks to increase the number of simultaneous users. Wavelet waveform coding spreads data signals both in time and frequency domains, with a large capacity improvement with respect to standard Optical-Code Division Multiple Access (O-CDMA) systems. In addition, the orthogonal property of the wavelet atoms ensures low InterSymbol Interference (ISI) and Multiple Access Interference (MAI) noises. To exploit the large bandwidth capacity of optical fibres, the Optical-Electrical-Optical (O-E-O) conversion is completely avoided, and we designed an all optical system that realizes the WPDM fully in the optical domain. A single Planar Lightwave Circuit (PLC) device multiplies/demultiplies N different users and a diffractive or an integrated optical device performs the waveform coding/decoding. The Wavelet Packet (WP) encoder/decoder is realized as a tree of lattice-form delay-line filters, and can be integrated on a single device along with the optical waveform modulator, resulting in a compact planar optical system. In addition, we show that different choices of WP encoders/decoders are possible to further enhance the system performances.

  3. All-optical dynamical Casimir effect in a three-dimensional terahertz photonic band gap

    NASA Astrophysics Data System (ADS)

    Hagenmüller, David

    2016-06-01

    We identify an architecture for the observation of all-optical dynamical Casimir effect in realistic experimental conditions. We suggest that by integrating quantum wells in a three-dimensional (3D) photonic band-gap material made out of large-scale (˜200 -μ m ) germanium logs, it is possible to achieve ultrastrong light-matter coupling at terahertz frequencies for the cyclotron transition of a two-dimensional electron gas interacting with long-lived optical modes, in which vacuum Rabi splitting is comparable to the Landau level spacing. When a short, intense electromagnetic transient of duration ˜250 fs and carrying a peak magnetic field ˜5 T is applied to the structure, the cyclotron transition can be suddenly tuned on resonance with a desired photon mode, switching on the light-matter interaction and leading to a Casimir radiation emitted parallel to the quantum well plane. The radiation spectrum consists of sharp peaks with frequencies coinciding with engineered optical modes within the 3D photonic band gap, and its characteristics are extremely robust to the nonradiative damping which can be large in our system. Furthermore, the absence of continuum with associated low-energy excitations for both electromagnetic and electronic quantum states can prevent the rapid absorption of the photon flux which is likely to occur in other proposals for all-optical dynamical Casimir effect.

  4. New alternative approach to all-optical flip-flop with nonlinear material

    NASA Astrophysics Data System (ADS)

    Giri, Dibyendu; Das, Partha Pratima

    2010-07-01

    Due to its inherent parallelism and tremendous operational speed, optical signal is the most suitable for data processing and digital communication in various fields. Conventional electronic and opto-electronic systems are unable to fulfill this arena, because of their low speed and time delay. In the case of pure electronic flip-flop, when a switch is turned ON, there is notable propagation delay on the order of nanoseconds. For an opto-electronic flip-flop although the propagation delay time is much less than that of an electronic flip-flop (about 10 to 100 times less), there are many disadvantages. Some of these disadvantages are delay of response time due to the use of spatial light modulators, an O/E converter that does not operate at all frequencies or wavelengths, and the unavailability of such materials. An optical input encoding methodology is proposed for the performance of all-optical flip-flop operations possible for two inputs. These operations were conducted in all-optical mode and are parallel in nature. All the operations are treated with proper exploitation of some nonlinear materials.

  5. Multiport InP monolithically integrated all-optical wavelength router.

    PubMed

    Zheng, Xiu; Raz, Oded; Calabretta, Nicola; Zhao, Dan; Lu, Rongguo; Liu, Yong

    2016-08-15

    An indium phosphide-based monolithically integrated wavelength router is demonstrated in this Letter. The wavelength router has four input ports and four output ports, which integrate four wavelength converters and a 4×4 arrayed-waveguide grating router. Each wavelength converter is achieved based on cross-gain modulation and cross-phase modulation effects in a semiconductor optical amplifier. Error-free wavelength switching for a non-return-to-zero 231-1 ps eudorandom binary sequence at 40 Gb/s data rate is performed. Both 1×4 and 3×1 all-optical routing functions of this chip are demonstrated for the first time with power penalties as low as 3.2 dB. PMID:27519116

  6. Effects of drying temperature and ethanol concentration on bipolar switching characteristics of natural Aloe vera-based memory devices.

    PubMed

    Lim, Zhe Xi; Cheong, Kuan Yew

    2015-10-28

    Extracted, formulated, and processed natural Aloe vera has been used as an active layer for memory applications. The functional memory device is realized by a bottom-up structure of ITO/Aloe vera/Al in which the Aloe vera is spin-coated after mixing with different concentrations of ethanol (0-80 wt%) and subsequently dried at different temperatures (50-120 °C). From the current density-voltage measurements, the device can exhibit a reproducible bipolar switching characteristic with pure Aloe vera dried at 50 °C. It is proposed that charges are transported across the Aloe vera layer via space-charge-limited conduction (SCLC), and clusters of interstitial space formed by the functional groups of acemannans and de-esterified pectins in the dried Aloe vera contribute to the memory effect. The formation of charge traps in the Aloe vera layer is dependent on the drying temperature. The drying temperature of a memory-switching Aloe vera layer can be extended to 120 °C with the addition of appropriate amounts of ethanol. The concept of using natural Aloe vera as an active material for memory applications has been demonstrated, and the read memory window, ON/OFF ratio, and retention time are approximately 5.0 V, 10(3), and >10(4) s, respectively. PMID:26400096

  7. Effects of drying temperature and ethanol concentration on bipolar switching characteristics of natural Aloe vera-based memory devices.

    PubMed

    Lim, Zhe Xi; Cheong, Kuan Yew

    2015-10-28

    Extracted, formulated, and processed natural Aloe vera has been used as an active layer for memory applications. The functional memory device is realized by a bottom-up structure of ITO/Aloe vera/Al in which the Aloe vera is spin-coated after mixing with different concentrations of ethanol (0-80 wt%) and subsequently dried at different temperatures (50-120 °C). From the current density-voltage measurements, the device can exhibit a reproducible bipolar switching characteristic with pure Aloe vera dried at 50 °C. It is proposed that charges are transported across the Aloe vera layer via space-charge-limited conduction (SCLC), and clusters of interstitial space formed by the functional groups of acemannans and de-esterified pectins in the dried Aloe vera contribute to the memory effect. The formation of charge traps in the Aloe vera layer is dependent on the drying temperature. The drying temperature of a memory-switching Aloe vera layer can be extended to 120 °C with the addition of appropriate amounts of ethanol. The concept of using natural Aloe vera as an active material for memory applications has been demonstrated, and the read memory window, ON/OFF ratio, and retention time are approximately 5.0 V, 10(3), and >10(4) s, respectively.

  8. Polarized UV cured reactive mesogens for fast switching and low voltage driving liquid crystal device.

    PubMed

    Chung, Hyung-Koo; Lee, Won-Kyu; Park, Hong-Gyu; Lee, Hak Moo; Jeong, Hae-Chang; Cho, Min-Cha; Seo, Dae-Shik

    2014-09-01

    Uniaxial alignment of liquid crystals (LCs) is prerequisite for a vast number of LC applications. To accomplish stable and uniform LC orientation, an alignment process to orient the LCs is required. Herein, we demonstrate a simple strategy for fabricating novel LC alignment layers that ensures well aligned LC, superior switching without any capacitance hysteresis, low transmittance loss, and high thermal stability with sufficient anchoring action. Thin films of reactive mesogens (RMs) were transferred onto conventional homeotropic polyimides from a UV-cured RM stamp via contact printing. LC displays using defect free RM/PI polymeric stacks exhibited superior electro-optic (EO) properties to those containing rubbed PI layers. This approach allows for the fabrication of various-mode LC displays such as twisted nematic (TN), in-plane switching (IPS), and optically compensated bend (OCB) mode LCDs by changing the combinations of RMs, base PIs and LCs. PMID:25321534

  9. Optical backplane interconnect switch for data processors and computers

    NASA Technical Reports Server (NTRS)

    Hendricks, Herbert D.; Benz, Harry F.; Hammer, Jacob M.

    1989-01-01

    An optoelectronic integrated device design is reported which can be used to implement an all-optical backplane interconnect switch. The switch is sized to accommodate an array of processors and memories suitable for direct replacement into the basic avionic multiprocessor backplane. The optical backplane interconnect switch is also suitable for direct replacement of the PI bus traffic switch and at the same time, suitable for supporting pipelining of the processor and memory. The 32 bidirectional switchable interconnects are configured with broadcast capability for controls, reconfiguration, and messages. The approach described here can handle a serial interconnection of data processors or a line-to-link interconnection of data processors. An optical fiber demonstration of this approach is presented.

  10. The rules of the resistive switching operation parameters based on Ta/Ta2O5 RRAM device

    NASA Astrophysics Data System (ADS)

    Li, Haitao; Richter, Curt; Kirillov, Oleg; Yuan, Hui; Zhu, Hao; Ioannou, Dimitris; Li, Qiliang; Dept. ECE, George Mason University Team; Semiconductor and Dimensional Metrology Division, NIST Team

    2013-03-01

    The resistive switching (RS) of the TaOx based RRAM has been widely studied due to its excellent endurance and thermal stability. The RS mechanism is generally understood as the formation and dissolution of nanometer-size conductive filament (CF) formed in set and reset process, respectively. However the exact process of dielectric break down remains unknown. In this work we studied the RS of the Ta/Ta2O5 based RRAM devices from the dependences of operation parameters Vset, ICC, Vreset, and Ireset on device resistance. From statistical analysis of variation in the threshold parameters, we found that the set process is mainly determined by the voltage stress on the device, instead of current. The first forming process is different from the following set process. The forming voltage exponentially depends on the pristine resistance. The forming process gives a smallest low resistance (RLRS) for each device. As a result change in compliance current (ICC) has no obvious effects on this low resistance state. Supported by Virginia Microelectronics Consortium Research Funding

  11. All-optical generation of surface plasmons in graphene

    NASA Astrophysics Data System (ADS)

    Constant, T. J.; Hornett, S. M.; Chang, D. E.; Hendry, E.

    2016-02-01

    Surface plasmons in graphene offer a compelling route to many useful photonic technologies. As a plasmonic material, graphene offers several intriguing properties, such as excellent electro-optic tunability, crystalline stability, large optical nonlinearities and extremely high electromagnetic field concentration. As such, recent demonstrations of surface plasmon excitation in graphene using near-field scattering of infrared light have received intense interest. Here we present an all-optical plasmon coupling scheme which takes advantage of the intrinsic nonlinear optical response of graphene. Free-space, visible light pulses are used to generate surface plasmons in a planar graphene sheet using difference frequency wave mixing to match both the wavevector and energy of the surface wave. By carefully controlling the phase matching conditions, we show that one can excite surface plasmons with a defined wavevector and direction across a large frequency range, with an estimated photon efficiency in our experiments approaching 10-5.

  12. All-Optical Implementation of the Ant Colony Optimization Algorithm.

    PubMed

    Hu, Wenchao; Wu, Kan; Shum, Perry Ping; Zheludev, Nikolay I; Soci, Cesare

    2016-01-01

    We report all-optical implementation of the optimization algorithm for the famous "ant colony" problem. Ant colonies progressively optimize pathway to food discovered by one of the ants through identifying the discovered route with volatile chemicals (pheromones) secreted on the way back from the food deposit. Mathematically this is an important example of graph optimization problem with dynamically changing parameters. Using an optical network with nonlinear waveguides to represent the graph and a feedback loop, we experimentally show that photons traveling through the network behave like ants that dynamically modify the environment to find the shortest pathway to any chosen point in the graph. This proof-of-principle demonstration illustrates how transient nonlinearity in the optical system can be exploited to tackle complex optimization problems directly, on the hardware level, which may be used for self-routing of optical signals in transparent communication networks and energy flow in photonic systems. PMID:27222098

  13. Graphene based All-Optical Spatial Terahertz Modulator

    PubMed Central

    Wen, Qi-Ye; Tian, Wei; Mao, Qi; Chen, Zhi; Liu, Wei-Wei; Yang, Qing-Hui; Sanderson, Matthew; Zhang, Huai-Wu

    2014-01-01

    We demonstrate an all-optical terahertz modulator based on single-layer graphene on germanium (GOG), which can be driven by a 1.55 μm CW laser with a low-level photodoping power. Both the static and dynamic THz transmission modulation experiments were carried out. A spectrally wide-band modulation of the THz transmission is obtained in a frequency range from 0.25 to 1 THz, and a modulation depth of 94% can be achieved if proper pump power is applied. The modulation speed of the modulator was measured to be ~200 KHz using a 340 GHz carrier. A theoretical model is proposed for the modulator and the calculation results indicate that the enhanced THz modulation is mainly due to the third order nonlinear effect in the optical conductivity of the graphene monolayer. PMID:25491194

  14. All-optical optoacoustic microscope based on wideband pulse interferometry.

    PubMed

    Wissmeyer, Georg; Soliman, Dominik; Shnaiderman, Rami; Rosenthal, Amir; Ntziachristos, Vasilis

    2016-05-01

    Optical and optoacoustic (photoacoustic) microscopy have been recently joined in hybrid implementations that resolve extended tissue contrast compared to each modality alone. Nevertheless, the application of the hybrid technique is limited by the requirement to combine an optical objective with ultrasound detection collecting signal from the same micro-volume. We present an all-optical optoacoustic microscope based on a pi-phase-shifted fiber Bragg grating (π-FBG) with coherence-restored pulsed interferometry (CRPI) used as the interrogation method. The sensor offers an ultra-small footprint and achieved higher sensitivity over piezoelectric transducers of similar size. We characterize the spectral bandwidth of the ultrasound detector and interrogate the imaging performance on phantoms and tissues. We show the first optoacoustic images of biological specimen recorded with π-FBG sensors. We discuss the potential uses of π-FBG sensors based on CRPI. PMID:27128047

  15. All-Optical Implementation of the Ant Colony Optimization Algorithm

    PubMed Central

    Hu, Wenchao; Wu, Kan; Shum, Perry Ping; Zheludev, Nikolay I.; Soci, Cesare

    2016-01-01

    We report all-optical implementation of the optimization algorithm for the famous “ant colony” problem. Ant colonies progressively optimize pathway to food discovered by one of the ants through identifying the discovered route with volatile chemicals (pheromones) secreted on the way back from the food deposit. Mathematically this is an important example of graph optimization problem with dynamically changing parameters. Using an optical network with nonlinear waveguides to represent the graph and a feedback loop, we experimentally show that photons traveling through the network behave like ants that dynamically modify the environment to find the shortest pathway to any chosen point in the graph. This proof-of-principle demonstration illustrates how transient nonlinearity in the optical system can be exploited to tackle complex optimization problems directly, on the hardware level, which may be used for self-routing of optical signals in transparent communication networks and energy flow in photonic systems. PMID:27222098

  16. All-Optical Implementation of the Ant Colony Optimization Algorithm

    NASA Astrophysics Data System (ADS)

    Hu, Wenchao; Wu, Kan; Shum, Perry Ping; Zheludev, Nikolay I.; Soci, Cesare

    2016-05-01

    We report all-optical implementation of the optimization algorithm for the famous “ant colony” problem. Ant colonies progressively optimize pathway to food discovered by one of the ants through identifying the discovered route with volatile chemicals (pheromones) secreted on the way back from the food deposit. Mathematically this is an important example of graph optimization problem with dynamically changing parameters. Using an optical network with nonlinear waveguides to represent the graph and a feedback loop, we experimentally show that photons traveling through the network behave like ants that dynamically modify the environment to find the shortest pathway to any chosen point in the graph. This proof-of-principle demonstration illustrates how transient nonlinearity in the optical system can be exploited to tackle complex optimization problems directly, on the hardware level, which may be used for self-routing of optical signals in transparent communication networks and energy flow in photonic systems.

  17. Switching Characteristics of Silica Nanoparticle-Doped Dual-Mode Liquid Crystal Device

    NASA Astrophysics Data System (ADS)

    Huang, Chi-Yen; Lai, Chien-Cheng; Huang, Yi-Jen; Chen, Jian-Hong

    2010-02-01

    We investigate the switching characteristics of a silica nanoparticle-doped dual-mode liquid crystal (LC) display. In the multistable mode, aggregated silica networks impede the relaxation of LCs and increase the response time of the cell. A low-frequency AC pulse voltage rotates LCs and breaks aggregated silica networks. The breaking of silica networks accelerates the relaxation of LCs and hence decreases the response time of the cell. The low-frequency AC pulse voltage gives the cell a fast response time of ˜23 ms, which is ˜4% of our previous result.

  18. SEMICONDUCTOR DEVICES: A novel high voltage start up circuit for an integrated switched mode power supply

    NASA Astrophysics Data System (ADS)

    Hao, Hu; Xingbi, Chen

    2010-09-01

    A novel high voltage start up circuit for providing an initial bias voltage to an integrated switched mode power supply (SMPS) is presented. An enhanced mode VDMOS transistor, the gate of which is biased by a floating p-island, is used to provide start up current and sustain high voltage. An NMOS transistor having a high source to ground breakdown voltage is included to extend the bias voltage range to the SMPS. Simulation results indicate that the high voltage start up circuit can start and restart as designed. The proposed structure is believed to be more energy saving and cost-effective compared with other solutions.

  19. All-optical switching using second-order nonlinearities in KTP

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Hagan, David J.; Sheik-Bahae, Mansoor; DeSalvo, Richard J.; Stegeman, George I.; Van Stryland, Eric W.; Assanto, Gaetano

    1994-07-01

    Photoelectron spectroscopy of coordinatively unsaturated organometallic anions can provide a means to probe the ground and low lying excited states of the corresponding neutral radicals. We report results for the early 3D transition metal monocarbonyls VCO and CrCO, and for the late metal complexes FeCO, CoCO and NiCO. Each spectrum displays a transition to the ground state of the neutral complex, and to an excited state whose spin multiplicity differs by two from that of the ground state. For a given complex, these states share nominally the same electron configuration but differ in the spin coupling of the metal 4s electron. There is a reversal in the state ordering as one proceeds across the transition series, from a high spin ground state for VCO (6(Sigma) +) and CrCO (7(Sigma) +) to a low spin ground state for FeCO (3(Sigma) -), CoCO (2(Delta) ) and NiCO (+1)(Sigma) )+). The measured state splittings and vibrational frequencies provide insight into the factors that determine the ordering and bonding properties of these states. Recent results for the linear H-M-CO isomers of Fe and Co are also reported.

  20. Optical Circuit Switched Protocol

    NASA Technical Reports Server (NTRS)

    Monacos, Steve P. (Inventor)

    2000-01-01

    The present invention is a system and method embodied in an optical circuit switched protocol for the transmission of data through a network. The optical circuit switched protocol is an all-optical circuit switched network and includes novel optical switching nodes for transmitting optical data packets within a network. Each optical switching node comprises a detector for receiving the header, header detection logic for translating the header into routing information and eliminating the header, and a controller for receiving the routing information and configuring an all optical path within the node. The all optical path located within the node is solely an optical path without having electronic storage of the data and without having optical delay of the data. Since electronic storage of the header is not necessary and the initial header is eliminated by the first detector of the first switching node. multiple identical headers are sent throughout the network so that subsequent switching nodes can receive and read the header for setting up an optical data path.

  1. Studies in optical parallel processing. [All optical and electro-optic approaches

    NASA Technical Reports Server (NTRS)

    Lee, S. H.

    1978-01-01

    Threshold and A/D devices for converting a gray scale image into a binary one were investigated for all-optical and opto-electronic approaches to parallel processing. Integrated optical logic circuits (IOC) and optical parallel logic devices (OPA) were studied as an approach to processing optical binary signals. In the IOC logic scheme, a single row of an optical image is coupled into the IOC substrate at a time through an array of optical fibers. Parallel processing is carried out out, on each image element of these rows, in the IOC substrate and the resulting output exits via a second array of optical fibers. The OPAL system for parallel processing which uses a Fabry-Perot interferometer for image thresholding and analog-to-digital conversion, achieves a higher degree of parallel processing than is possible with IOC.

  2. Geometric conductive filament confinement by nanotips for resistive switching of HfO2-RRAM devices with high performance

    PubMed Central

    Niu, Gang; Calka, Pauline; Auf der Maur, Matthias; Santoni, Francesco; Guha, Subhajit; Fraschke, Mirko; Hamoumou, Philippe; Gautier, Brice; Perez, Eduardo; Walczyk, Christian; Wenger, Christian; Di Carlo, Aldo; Alff, Lambert; Schroeder, Thomas

    2016-01-01

    Filament-type HfO2-based RRAM has been considered as one of the most promising candidates for future non-volatile memories. Further improvement of the stability, particularly at the “OFF” state, of such devices is mainly hindered by resistance variation induced by the uncontrolled oxygen vacancies distribution and filament growth in HfO2 films. We report highly stable endurance of TiN/Ti/HfO2/Si-tip RRAM devices using a CMOS compatible nanotip method. Simulations indicate that the nanotip bottom electrode provides a local confinement for the electrical field and ionic current density; thus a nano-confinement for the oxygen vacancy distribution and nano-filament location is created by this approach. Conductive atomic force microscopy measurements confirm that the filaments form only on the nanotip region. Resistance switching by using pulses shows highly stable endurance for both ON and OFF modes, thanks to the geometric confinement of the conductive path and filament only above the nanotip. This nano-engineering approach opens a new pathway to realize forming-free RRAM devices with improved stability and reliability. PMID:27181525

  3. Structural Phase Transition Effect on Resistive Switching Behavior of MoS2 -Polyvinylpyrrolidone Nanocomposites Films for Flexible Memory Devices.

    PubMed

    Zhang, Peng; Gao, Cunxu; Xu, Benhua; Qi, Lin; Jiang, Changjun; Gao, Meizhen; Xue, Desheng

    2016-04-01

    The 2H phase and 1T phase coexisting in the same molybdenum disulfide (MoS2 ) nanosheets can influence the electronic properties of the materials. The 1T phase of MoS2 is introduced into the 2H-MoS2 nanosheets by two-step hydrothermal synthetic methods. Two types of nonvolatile memory effects, namely write-once read-many times memory and rewritable memory effect, are observed in the flexible memory devices with the configuration of Al/1T@2H-MoS2 -polyvinylpyrrolidone (PVP)/indium tin oxide (ITO)/polyethylene terephthalate (PET) and Al/2H-MoS2 -PVP/ITO/PET, respectively. It is observed that structural phase transition in MoS2 nanosheets plays an important role on the resistive switching behaviors of the MoS2 -based device. It is hoped that our results can offer a general route for the preparation of various promising nanocomposites based on 2D nanosheets of layered transition metal dichalcogenides for fabricating the high performance and flexible nonvolatile memory devices through regulating the phase structure in the 2D nanosheets.

  4. Fundamentals and technology for monolithically integrated RF MEMS switches with ultra-nanocrystaline diamond dielectric/CMOS devices.

    SciTech Connect

    Auciello, O.; Sumant, A.; Goldsmith, C.; O'Brien, S.; Sampath, S.; Gudeman, C; Wang, W.; Hwang, J.; Swonger, J.; Carlisle, J.; Balachandran, S.; MEMtronics Corp.; Innovative Micro Technology; Lehigh Univ.; Peregrine Semiconductor; Advanced Diamond Technologies

    2010-01-01

    Most current capacitive RF-MEMS switch technology is based on conventional dielectric materials such as SiO{sub 2} and Si{sub 3}N{sub 4}. However, they suffer not only from charging problems but also stiction problems leading to premature failure of an RF-MEMS switch. Ultrananocrystalline diamond (UNCD{sup (R)}) (2-5 nm grains) and nanocrystalline diamond (NCD) (10-100 nm grains) films exhibit one of the highest Young's modulus ({approx} 980-1100 GPa) and demonstrated MEMS resonators with the highest quality factor (Q {ge} 10,000 in air for NCD) today, they also exhibit the lowest force of adhesion among MEMS/NEMS materials ({approx}10 mJ/m{sup 2}-close to van der Waals attractive force for UNCD) demonstrated today. Finally, UNCD exhibits dielectric properties (fast discharge) superior to those of Si and SiO{sub 2}, as shown in this paper. Thus, UNCD and NCD films provide promising platform materials beyond Si for a new generation of important classes of high-performance MEMS/NEMS devices.

  5. Flexoelectric effect in an in-plane switching (IPS) liquid crystal cell for low-power consumption display devices

    PubMed Central

    Kim, Min Su; Bos, Philip J.; Kim, Dong-Woo; Yang, Deng-Ke; Lee, Joong Hee; Lee, Seung Hee

    2016-01-01

    Technology of displaying static images in portable displays, advertising panels and price tags pursues significant reduction in power consumption and in product cost. Driving at a low-frequency electric field in fringe-field switching (FFS) mode can be one of the efficient ways to save powers of the recent portable devices, but a serious drop of image-quality, so-called image-flickering, has been found in terms of the coupling of elastic deformation to not only quadratic dielectric effect but linear flexoelectric effect. Despite of the urgent requirement of solving the issue, understanding of such a phenomenon is yet vague. Here, we thoroughly analyze and firstly report the flexoelectric effect in in-plane switching (IPS) liquid crystal cell. The effect takes place on the area above electrodes due to splay and bend deformations of nematic liquid crystal along oblique electric fields, so that the obvious spatial shift of the optical transmittance is experimentally observed and is clearly demonstrated based on the relation between direction of flexoelectric polarization and electric field polarity. In addition, we report that the IPS mode has inherent characteristics to solve the image-flickering issue in the low-power consumption display in terms of the physical property of liquid crystal material and the electrode structure. PMID:27731372

  6. Flexoelectric effect in an in-plane switching (IPS) liquid crystal cell for low-power consumption display devices

    NASA Astrophysics Data System (ADS)

    Kim, Min Su; Bos, Philip J.; Kim, Dong-Woo; Yang, Deng-Ke; Lee, Joong Hee; Lee, Seung Hee

    2016-10-01

    Technology of displaying static images in portable displays, advertising panels and price tags pursues significant reduction in power consumption and in product cost. Driving at a low-frequency electric field in fringe-field switching (FFS) mode can be one of the efficient ways to save powers of the recent portable devices, but a serious drop of image-quality, so-called image-flickering, has been found in terms of the coupling of elastic deformation to not only quadratic dielectric effect but linear flexoelectric effect. Despite of the urgent requirement of solving the issue, understanding of such a phenomenon is yet vague. Here, we thoroughly analyze and firstly report the flexoelectric effect in in-plane switching (IPS) liquid crystal cell. The effect takes place on the area above electrodes due to splay and bend deformations of nematic liquid crystal along oblique electric fields, so that the obvious spatial shift of the optical transmittance is experimentally observed and is clearly demonstrated based on the relation between direction of flexoelectric polarization and electric field polarity. In addition, we report that the IPS mode has inherent characteristics to solve the image-flickering issue in the low-power consumption display in terms of the physical property of liquid crystal material and the electrode structure.

  7. Percolation network in resistive switching devices with the structure of silver/amorphous silicon/p-type silicon

    SciTech Connect

    Liu, Yanhong; Gao, Ping; Bi, Kaifeng; Peng, Wei; Jiang, Xuening; Xu, Hongxia

    2014-01-27

    Conducting pathway of percolation network was identified in resistive switching devices (RSDs) with the structure of silver/amorphous silicon/p-type silicon (Ag/a-Si/p-Si) based on its gradual RESET-process and the stochastic complex impedance spectroscopy characteristics (CIS). The formation of the percolation network is attributed to amounts of nanocrystalline Si particles as well as defect sites embedded in a-Si layer, in which the defect sites supply positions for Ag ions to nucleate and grow. The similar percolation network has been only observed in Ag-Ge-Se based RSD before. This report provides a better understanding for electric properties of RSD based on the percolation network.

  8. Multiple Negative Differential Resistance Device by Using the Ambipolar Behavior of Tunneling Field Effect Transistor with Fast Switching Characteristics.

    PubMed

    Jeong, Jae Won; Jang, E-San; Shin, Sunhae; Kim, Kyung Rok

    2016-05-01

    We propose a novel double-peak negative differential resistance (NDR) characteristic at the conventional single-peak MOS-NDR circuit by employing ambipolar behavior of TFET. The fluctuated voltage transfer curve (VTC) from ambipolar inverter is analyzed with simple model and successfully demonstrated with TFET, as a practical example, on the device simulation. We also verified that the fluctuated VTC generates additional peak and valleys on NDR characteristics by using circuit simulations. Moreover, by adjusting the threshold voltage of conventional MOSFET, ultra-high 1st and 2nd peak-to-valley current ratio (PVCR) over 10(7) is obtained with fully suppressed valley currents. The proposed double-peak NDR circuit expected to apply on faster switching and low power multi-functional applications. PMID:27483818

  9. All-optical wavelength conversion for mode division multiplexed superchannels.

    PubMed

    Gong, Jiaxin; Xu, Jing; Luo, Ming; Li, Xiang; Qiu, Ying; Yang, Qi; Zhang, Xinliang; Yu, Shaohua

    2016-04-18

    We report in this work the first all-optical wavelength conversion (AOWC) of a mode division multiplexed (MDM) superchannel consisting of 2N modes by dividing the superchannel into N single-mode (SM) tributaries, wavelength converting N SM signals using well developed SM-AOWC techniques, and finally combining the N SM tributaries back to an MDM superchannel at the converted wavelength, inspired by the idea of using SM filtering techniques to filter multimode signals in astronomy. The conversions between multimode and SM are realized by 3D laser-writing photonic lanterns and SM-AOWCs are realized based on polarization insensitive four wave mixing (FWM) configuration in N semiconductor optical amplifiers (SOAs). As a proof of concept demonstration, the conversion of a 6-mode MDM superchannel with each mode modulated with orthogonal frequency division multiplexed (OFDM) quadrature phase-shift keying (QPSK)/16 quadrature amplitude modulation (QAM) signals is demonstrated in this work, indicating that the scheme is transparent to data format, polarization and compatible with multi-carrier signals. Data integrity of the converted superchannel has been verified by using coherent detection and digital signal processing (DSP). Bit error rates (BERs) below the forward error correction (FEC) hard limit (3.8 × 10-3) have been obtained for QPSK modulation at a net bitrate of 104.2 Gbit/s and BERs below the soft decision FEC threshold (1.98 × 10-2) have been achieved for 16-QAM format, giving a total aggregate bit rate of 185.8 Gbit/s when taking 20% coding overhead into account. Add and drop functionalities that usually come along with wavelength conversion in flexible network nodes have also been demonstrated. The working conditions of the SOAs, especially the pump and signal power levels, are critical for the quality of the converted signal and have been thoroughly discussed. The impact of imbalanced FWM conversion efficiency among different SM

  10. Switch contact device for interrupting high current, high voltage, AC and DC circuits

    DOEpatents

    Via, Lester C.; Witherspoon, F. Douglas; Ryan, John M.

    2005-01-04

    A high voltage switch contact structure capable of interrupting high voltage, high current AC and DC circuits. The contact structure confines the arc created when contacts open to the thin area between two insulating surfaces in intimate contact. This forces the arc into the shape of a thin sheet which loses heat energy far more rapidly than an arc column having a circular cross-section. These high heat losses require a dramatic increase in the voltage required to maintain the arc, thus extinguishing it when the required voltage exceeds the available voltage. The arc extinguishing process with this invention is not dependent on the occurrence of a current zero crossing and, consequently, is capable of rapidly interrupting both AC and DC circuits. The contact structure achieves its high performance without the use of sulfur hexafluoride.

  11. Spontaneous symmetry breaking in cosmos: the hybrid symmetron as a dark energy switching device

    SciTech Connect

    Bamba, K.; Nojiri, S.; Gannouji, R.; Kamijo, M.; Sami, M. E-mail: gannouji@rs.kagu.tus.ac.jp E-mail: nojiri@phys.nagoya-u.ac.jp

    2013-07-01

    We consider symmetron model in a generalized background with a hope to make it compatible with dark energy. We observe a ''no go'' theorem at least in case of a conformal coupling. Being convinced of symmetron incapability to be dark energy, we try to retain its role for spontaneous symmetry breaking and assign the role of dark energy either to standard quintessence or F(R) theory which are switched on by symmetron field in the symmetry broken phase. The scenario reduces to standard Einstein gravity in the high density region. After the phase transition generated by symmetron field, either the F(R) gravity or the standard quintessence are induced in the low density region. we demonstrate that local gravity constraints and other requirements are satisfied although the model could generate the late-time acceleration of Universe.

  12. All-optical regulation of gene expression in targeted cells

    NASA Astrophysics Data System (ADS)

    Wang, Yisen; He, Hao; Li, Shiyang; Liu, Dayong; Lan, Bei; Hu, Minglie; Cao, Youjia; Wang, Chingyue

    2014-06-01

    Controllable gene expression is always a challenge and of great significance to biomedical research and clinical applications. Recently, various approaches based on extra-engineered light-sensitive proteins have been developed to provide optogenetic actuators for gene expression. Complicated biomedical techniques including exogenous genes engineering, transfection, and material delivery are needed. Here we present an all-optical method to regulate gene expression in targeted cells. Intrinsic or exogenous genes can be activated by a Ca2+-sensitive transcription factor nuclear factor of activated T cells (NFAT) driven by a short flash of femtosecond-laser irradiation. When applied to mesenchymal stem cells, expression of a differentiation regulator Osterix can be activated by this method to potentially induce differentiation of them. A laser-induced ``Ca2+-comb'' (LiCCo) by multi-time laser exposure is further developed to enhance gene expression efficiency. This noninvasive method hence provides an encouraging advance of gene expression regulation, with promising potential of applying in cell biology and stem-cell science.

  13. All-optical broadband ultrasonography of single cells

    PubMed Central

    Dehoux, T.; Ghanem, M. Abi; Zouani, O. F.; Rampnoux, J.-M.; Guillet, Y.; Dilhaire, S.; Durrieu, M.-C.; Audoin, B.

    2015-01-01

    Cell mechanics play a key role in several fundamental biological processes, such as migration, proliferation, differentiation and tissue morphogenesis. In addition, many diseased conditions of the cell are correlated with altered cell mechanics, as in the case of cancer progression. For this there is much interest in methods that can map mechanical properties with a sub-cell resolution. Here, we demonstrate an inverted pulsed opto-acoustic microscope (iPOM) that operates in the 10 to 100 GHz range. These frequencies allow mapping quantitatively cell structures as thin as 10 nm and resolving the fibrillar details of cells. Using this non-invasive all-optical system, we produce high-resolution images based on mechanical properties as the contrast mechanisms, and we can observe the stiffness and adhesion of single migrating stem cells. The technique should allow transferring the diagnostic and imaging abilities of ultrasonic imaging to the single-cell scale, thus opening new avenues for cell biology and biomaterial sciences. PMID:25731090

  14. On the impact of fiber-delay-lines (FDL) in an all-optical network (AON) bottleneck without wavelength conversion

    NASA Astrophysics Data System (ADS)

    Argibay-Losada, Pablo Jesus; Sahin, Gokhan

    2014-08-01

    Random access memories (RAM) are fundamental in conventional electronic switches and routers to manage short-term congestion and to decrease data loss probabilities. Switches in all-optical networks (AONs), however, do not have access to optical RAM, and therefore are prone to much higher loss levels than their electronic counterparts. Fiber-delay-lines (FDLs), able to delay an optical data packet a fixed amount of time, have been proposed in the literature as a means to alleviate those high loss levels. However, they are extremely bulky to manage, so their usage introduces a trade-off between practicality and performance in the design and operation of the AON. In this paper we study the influence that FDLs have in the performance of flows crossing an all-optical switch that acts as their bottleneck. We show how extremely low numbers of FDLs (e.g., 1 or 2) can help in reducing losses by several orders of magnitude in several illustrative scenarios with high aggregation levels. Our results therefore suggest that FDLs can be a practical means of dealing with congestion in AONs in the absence of optical RAM buffers or of suitable data interchange protocols specifically designed for AONs.

  15. Ultrafast switching of an electrochromic device based on layered double hydroxide/Prussian blue multilayered films

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoxi; Zhou, Awu; Dou, Yibo; Pan, Ting; Shao, Mingfei; Han, Jingbin; Wei, Min

    2015-10-01

    Electrochromic materials are the most important and essential components in an electrochromic device. Herein, we fabricated high-performance electrochromic films based on exfoliated layered double hydroxide (LDH) nanosheets and Prussian blue (PB) nanoparticles via the layer-by-layer assembly technique. X-ray diffraction and UV-vis absorption spectroscopy indicate a periodic layered structure with uniform and regular growth of (LDH/PB)n ultrathin films (UTFs). The resulting (LDH/PB)n UTF electrodes exhibit electrochromic behavior arising from the reversible K+ ion migration into/out of the PB lattice, which induces a change in the optical properties of the UTFs. Furthermore, an electrochromic device (ECD) based on the (LDH/PB)n-ITO/0.1 M KCl electrolyte/ITO sandwich structure displays superior response properties (0.91/1.21 s for coloration/bleaching), a comparable coloration efficiency (68 cm2 C-1) and satisfactory optical contrast (45% at 700 nm), in comparison with other inorganic material-based ECDs reported previously. Therefore, this work presents a facile and cost-effective strategy to immobilize electrochemically active nanoparticles in a 2D inorganic matrix for potential application in displays, smart windows and optoelectronic devices.Electrochromic materials are the most important and essential components in an electrochromic device. Herein, we fabricated high-performance electrochromic films based on exfoliated layered double hydroxide (LDH) nanosheets and Prussian blue (PB) nanoparticles via the layer-by-layer assembly technique. X-ray diffraction and UV-vis absorption spectroscopy indicate a periodic layered structure with uniform and regular growth of (LDH/PB)n ultrathin films (UTFs). The resulting (LDH/PB)n UTF electrodes exhibit electrochromic behavior arising from the reversible K+ ion migration into/out of the PB lattice, which induces a change in the optical properties of the UTFs. Furthermore, an electrochromic device (ECD) based on the (LDH

  16. Origin of multi-level switching and telegraphic noise in organic nanocomposite memory devices

    PubMed Central

    Song, Younggul; Jeong, Hyunhak; Chung, Seungjun; Ahn, Geun Ho; Kim, Tae-Young; Jang, Jingon; Yoo, Daekyoung; Jeong, Heejun; Javey, Ali; Lee, Takhee

    2016-01-01

    The origin of negative differential resistance (NDR) and its derivative intermediate resistive states (IRSs) of nanocomposite memory systems have not been clearly analyzed for the past decade. To address this issue, we investigate the current fluctuations of organic nanocomposite memory devices with NDR and the IRSs under various temperature conditions. The 1/f noise scaling behaviors at various temperature conditions in the IRSs and telegraphic noise in NDR indicate the localized current pathways in the organic nanocomposite layers for each IRS. The clearly observed telegraphic noise with a long characteristic time in NDR at low temperature indicates that the localized current pathways for the IRSs are attributed to trapping/de-trapping at the deep trap levels in NDR. This study will be useful for the development and tuning of multi-bit storable organic nanocomposite memory device systems. PMID:27659298

  17. Polarity switching of charge transport and thermoelectricity in self-assembled monolayer devices.

    PubMed

    Egger, David A; Rissner, Ferdinand; Zojer, Egbert; Heimel, Georg

    2012-08-22

    Self-assembled monolayer devices can exhibit drastically different charge-transport characteristics and thermoelectric properties despite being composed of isomeric molecules with essentially identical frontier-orbital energies. This is rationalized by the cooperative electrostatic action of local intramolecular dipoles in otherwise nonpolar species, thus revealing new challenges but also new opportunities for the targeted design of functional building blocks in future nanoelectronics. PMID:22807087

  18. Role of interfacial layer on complementary resistive switching in the TiN/HfO{sub x}/TiN resistive memory device

    SciTech Connect

    Zhang, H. Z.; Ang, D. S. Gu, C. J.; Yew, K. S.; Wang, X. P.; Lo, G. Q.

    2014-12-01

    The role of the bottom interfacial layer (IL) in enabling stable complementary resistive switching (CRS) in the TiN/HfO{sub x}/IL/TiN resistive memory device is revealed. Stable CRS is obtained for the TiN/HfO{sub x}/IL/TiN device, where a bottom IL comprising Hf and Ti sub-oxides resulted from the oxidation of TiN during the initial stages of atomic-layer deposition of HfO{sub x} layer. In the TiN/HfO{sub x}/Pt device, where formation of the bottom IL is suppressed by the inert Pt metal, no CRS is observed. Oxygen-ion exchange between IL and the conductive path in HfO{sub x} layer is proposed to have caused the complementary bipolar switching behavior observed in the TiN/HfO{sub x}/IL/TiN device.

  19. Ultrafast switching of an electrochromic device based on layered double hydroxide/Prussian blue multilayered films.

    PubMed

    Liu, Xiaoxi; Zhou, Awu; Dou, Yibo; Pan, Ting; Shao, Mingfei; Han, Jingbin; Wei, Min

    2015-10-28

    Electrochromic materials are the most important and essential components in an electrochromic device. Herein, we fabricated high-performance electrochromic films based on exfoliated layered double hydroxide (LDH) nanosheets and Prussian blue (PB) nanoparticles via the layer-by-layer assembly technique. X-ray diffraction and UV-vis absorption spectroscopy indicate a periodic layered structure with uniform and regular growth of (LDH/PB)n ultrathin films (UTFs). The resulting (LDH/PB)n UTF electrodes exhibit electrochromic behavior arising from the reversible K(+) ion migration into/out of the PB lattice, which induces a change in the optical properties of the UTFs. Furthermore, an electrochromic device (ECD) based on the (LDH/PB)n-ITO/0.1 M KCl electrolyte/ITO sandwich structure displays superior response properties (0.91/1.21 s for coloration/bleaching), a comparable coloration efficiency (68 cm(2) C(-1)) and satisfactory optical contrast (45% at 700 nm), in comparison with other inorganic material-based ECDs reported previously. Therefore, this work presents a facile and cost-effective strategy to immobilize electrochemically active nanoparticles in a 2D inorganic matrix for potential application in displays, smart windows and optoelectronic devices. PMID:26420230

  20. High Speed All Optical Nyquist Signal Generation and Full-band Coherent Detection

    PubMed Central

    Zhang, Junwen; Yu, Jianjun; Fang, Yuan; Chi, Nan

    2014-01-01

    Spectrum efficient data transmission is of key interest for high capacity optical communication systems considering the limited available bandwidth. Transmission of the high speed signal with higher-order modulation formats within the Nyquist bandwidth using coherent detection brings attractive performance advantages. However, high speed Nyquist signal generation with high order modulation formats is challenging. Electrical Nyquist pulse generation is restricted by the limited sampling rate and processor capacities of digital-to-analog convertor devices, while the optical Nyquist signals can provide a much higher symbol rate using time domain multiplexing method. However, most optical Nyquist signals are based on direct detection with simple modulation formats. Here we report the first experimental demonstration of high speed all optical Nyquist signal generation based on Sinc-shaped pulse generation and time-division multiplexing with high level modulation format and full-band coherent detection. Our experiments demonstrate a highly flexible and compatible all optical high speed Nyquist signal generation and detection scheme for future fiber communication systems. PMID:25142269

  1. High speed all optical Nyquist signal generation and full-band coherent detection.

    PubMed

    Zhang, Junwen; Yu, Jianjun; Fang, Yuan; Chi, Nan

    2014-08-21

    Spectrum efficient data transmission is of key interest for high capacity optical communication systems considering the limited available bandwidth. Transmission of the high speed signal with higher-order modulation formats within the Nyquist bandwidth using coherent detection brings attractive performance advantages. However, high speed Nyquist signal generation with high order modulation formats is challenging. Electrical Nyquist pulse generation is restricted by the limited sampling rate and processor capacities of digital-to-analog convertor devices, while the optical Nyquist signals can provide a much higher symbol rate using time domain multiplexing method. However, most optical Nyquist signals are based on direct detection with simple modulation formats. Here we report the first experimental demonstration of high speed all optical Nyquist signal generation based on Sinc-shaped pulse generation and time-division multiplexing with high level modulation format and full-band coherent detection. Our experiments demonstrate a highly flexible and compatible all optical high speed Nyquist signal generation and detection scheme for future fiber communication systems.

  2. All-optical coherent population trapping with defect spin ensembles in silicon carbide.

    PubMed

    Zwier, Olger V; O'Shea, Danny; Onur, Alexander R; van der Wal, Caspar H

    2015-01-01

    Divacancy defects in silicon carbide have long-lived electronic spin states and sharp optical transitions. Because of the various polytypes of SiC, hundreds of unique divacancies exist, many with spin properties comparable to the nitrogen-vacancy center in diamond. If ensembles of such spins can be all-optically manipulated, they make compelling candidate systems for quantum-enhanced memory, communication, and sensing applications. We report here direct all-optical addressing of basal plane-oriented divacancy spins in 4H-SiC. By means of magneto-spectroscopy, we fully identify the spin triplet structure of both the ground and the excited state, and use this for tuning of transition dipole moments between particular spin levels. We also identify a role for relaxation via intersystem crossing. Building on these results, we demonstrate coherent population trapping -a key effect for quantum state transfer between spins and photons- for divacancy sub-ensembles along particular crystal axes. These results, combined with the flexibility of SiC polytypes and device processing, put SiC at the forefront of quantum information science in the solid state.

  3. ZnO/Al:ZnO Transparent Resistive Switching Devices Grown by Atomic Layer Deposition for Memristor Applications.

    PubMed

    Mundle, Rajeh; Carvajal, Christian; Pradhan, Aswini K

    2016-05-17

    ZnO has intrinsic semiconductor conductivity because of an unintentional doping mechanism resulting from the growth process that is mainly attributable to oxygen vacancies (VO) positioned in the bandgap. ZnO has multiple electronic states that depend on the number of vacancies and the charge state of each vacancy. In addition to the individual electron states, the vacancies have different vibrational states. We developed a high-temperature precursor vapor mask technique using Al2O3 to pattern the atomic layer deposition of ZnO and Al:ZnO layers on ZnO-based substrates. This technique was used to create a memristor device based on Al:ZnO thin films having metallic and semiconducting and insulating transport properties ZnO. We demonstrated that adding combination of Al2O3 and TiO2 barrier layers improved the resistive switching behavior. The change in the resistance between the high- and low-resistivity states of the memristor with a combination of Al2O3 and TiO2 was approximately 157%. The devices were exposed to laser light from three different laser diodes. The 450 nm laser diode noticeably affected the combined Al2O3 and TiO2 barrier, creating a high-resistivity state with a 2.9% shift under illumination. The high-resistivity state shift under laser illumination indicates defect shifts and the thermodynamic transition of ZnO defects. PMID:27124366

  4. [Measuring device for rapid determination of tube peak voltage and the switch-on time of roentgen equipment].

    PubMed

    Bronder, T; Eickelkamp, U; Jakschik, J

    1982-11-01

    A prototype of a measuring device is described, which reads the tube peak voltage and the switch-on time of x-ray units by means of two radiation detectors with different energy dependences due to detector materials (Caesium Iodine and Silicon). With a storage oscilloscope the curves of the tube voltage and the relative absorbed dose rate of intensifying screens can be displayed. The measuring range of the tube peak voltage is 60 kV to 150 kV. It is possible to measure exposure times of radiography equipment above 2 ms wit sufficiently low uncertainty. The tube peak voltage has been read with a relative uncertainty below 5% for almost all dose rates, which arise in practical application of medical x-ray units, and its calibration is made by means of x-ray apparatus with tube voltage reading, which has been compared to a Ge(Li) spectrometer. The stability of tube voltage reading of the measuring device is only effected by radiation damage of the detectors after a long time of utilization. The small diameter of the probe permits the accommodation of other probes, ionization chambers, phantoms, etc. in the radiation field at the same time. PMID:6217132

  5. ZnO/Al:ZnO Transparent Resistive Switching Devices Grown by Atomic Layer Deposition for Memristor Applications.

    PubMed

    Mundle, Rajeh; Carvajal, Christian; Pradhan, Aswini K

    2016-05-17

    ZnO has intrinsic semiconductor conductivity because of an unintentional doping mechanism resulting from the growth process that is mainly attributable to oxygen vacancies (VO) positioned in the bandgap. ZnO has multiple electronic states that depend on the number of vacancies and the charge state of each vacancy. In addition to the individual electron states, the vacancies have different vibrational states. We developed a high-temperature precursor vapor mask technique using Al2O3 to pattern the atomic layer deposition of ZnO and Al:ZnO layers on ZnO-based substrates. This technique was used to create a memristor device based on Al:ZnO thin films having metallic and semiconducting and insulating transport properties ZnO. We demonstrated that adding combination of Al2O3 and TiO2 barrier layers improved the resistive switching behavior. The change in the resistance between the high- and low-resistivity states of the memristor with a combination of Al2O3 and TiO2 was approximately 157%. The devices were exposed to laser light from three different laser diodes. The 450 nm laser diode noticeably affected the combined Al2O3 and TiO2 barrier, creating a high-resistivity state with a 2.9% shift under illumination. The high-resistivity state shift under laser illumination indicates defect shifts and the thermodynamic transition of ZnO defects.

  6. Tangled nonlinear driven chain reactions of all optical singularities

    NASA Astrophysics Data System (ADS)

    Vasil'ev, V. I.; Soskin, M. S.

    2012-03-01

    Dynamics of polarization optical singularities chain reactions in generic elliptically polarized speckle fields created in photorefractive crystal LiNbO3 was investigated in details Induced speckle field develops in the tens of minutes scale due to photorefractive 'optical damage effect' induced by incident beam of He-Ne laser. It was shown that polarization singularities develop through topological chain reactions of developing speckle fields driven by photorefractive nonlinearities induced by incident laser beam. All optical singularities (C points, optical vortices, optical diabolos,) are defined by instantaneous topological structure of the output wavefront and are tangled by singular optics lows. Therefore, they have develop in tangled way by six topological chain reactions driven by nonlinear processes in used nonlinear medium (photorefractive LiNbO3:Fe in our case): C-points and optical diabolos for right (left) polarized components domains with orthogonally left (right) polarized optical vortices underlying them. All elements of chain reactions consist from loop and chain links when nucleated singularities annihilated directly or with alien singularities in 1:9 ratio. The topological reason of statistics was established by low probability of far enough separation of born singularities pair from existing neighbor singularities during loop trajectories. Topology of developing speckle field was measured and analyzed by dynamic stokes polarimetry with few seconds' resolution. The hierarchy of singularities govern scenario of tangled chain reactions was defined. The useful space-time data about peculiarities of optical damage evolution were obtained from existence and parameters of 'islands of stability' in developing speckle fields.

  7. Phase-coherent all-optical frequency division by three

    SciTech Connect

    Lee, Dong-Hoon; Klein, Marvin E.; Meyn, Jan-Peter; Wallenstein, Richard; Gross, Petra; Boller, Klaus-Jochen

    2003-01-01

    The properties of all-optical phase-coherent frequency division by 3, based on a self-phase-locked continuous-wave (cw) optical parametric oscillator (OPO), are investigated theoretically and experimentally. The frequency to be divided is provided by a diode laser master-oscillator power-amplifier system operated at a wavelength of 812 nm and used as the pump source of the OPO. Optical self-phase-locking of the OPO signal and idler waves is achieved by mutual injection locking of the signal wave and the intracavity frequency-doubled idler wave. The OPO process and the second-harmonic generation of the idler wave are simultaneously phase matched through quasi-phase-matching using two periodically poled sections of different period manufactured within the same LiNbO{sub 3} crystal. An optical self-phase-locking range of up to 1 MHz is experimentally observed. The phase coherence of frequency division by three is measured via the phase stability of an interference pattern formed by the input and output waves of the OPO. The fractional frequency instability of the divider is measured to be smaller than 7.6x10{sup -14} for a measurement time of 10 s (resolution limited). The self-phase-locking characteristics of the cw OPO are theoretically investigated by analytically solving the coupled field equations in the steady-state regime. For the experimental parameters of the OPO, the calculations predict a locking range of 1.3 MHz and a fractional frequency instability of 1.6x10{sup -15}, in good agreement with the experimental results.

  8. Using light and heat to controllably switch and reset disorder configuration in nanoscale devices

    NASA Astrophysics Data System (ADS)

    See, A. M.; Hamilton, A. R.; Micolich, A. P.; Aagesen, M.; Lindelof, P. E.

    2015-02-01

    Quantum dots exhibit reproducible conductance fluctuations at low temperatures due to electron quantum interference. These fluctuations are not solely determined by dot geometry; they are also highly sensitive to the underlying disorder potential. Here we exploit this sensitivity to better understand the role that background impurities play in the electronic properties of undoped AlGaAs/GaAs heterostructures, and nanoscale devices based thereon. In particular, we report the remarkable ability to first alter the disorder potential in an undoped AlGaAs/GaAs heterostructure by optical illumination and then reset it back to its initial configuration by room temperature thermal cycling in the dark. We attribute this behavior to a mixture of C background impurities acting as shallow acceptors and deep trapping by Si background donor impurities, i.e., DX centers. This "alter and reset" capability is not possible in modulation-doped heterostructures and offers a route to new studies of how background impurities influence transport in nanoscale semiconductor devices.

  9. Practical concept of an all-optical hot carrier solar cell

    NASA Astrophysics Data System (ADS)

    König, Dirk; Yao, Yao

    2015-08-01

    The all-optical hot carrier solar cell (aoHCSC) is an intriguing device concept which circumvents HC thermalization by feeding HCs into local radiative recombination centers. These have transition energies above the HC absorber (HCA) bandgap and are located within the HCA to match the HC ballistic mean free path, suppressing HC cooling as major loss mechanism. HC energy extraction proceeds by photon emission. We propose a technologically feasible concept of the aoHC energy converter (aoHCEC) which feeds into a conventional solar cell with its bandgap matching the emitted photons. Using real materials, the concept builds upon waveguides within a HCA which consist of highly polar direct bandgap material to promote radiative carrier recombination.

  10. All-optical phase modulation in a cavity-polariton Mach–Zehnder interferometer

    PubMed Central

    Sturm, C.; Tanese, D.; Nguyen, H.S.; Flayac, H.; Galopin, E.; Lemaître, A.; Sagnes, I.; Solnyshkov, D.; Amo, A.; Malpuech, G.; Bloch, J.

    2014-01-01

    Quantum fluids based on light is a highly developing research field, since they provide a nonlinear platform for developing optical functionalities and quantum simulators. An important issue in this context is the ability to coherently control the properties of the fluid. Here we propose an all-optical approach for controlling the phase of a flow of cavity-polaritons, making use of their strong interactions with localized excitons. Here we illustrate the potential of this method by implementing a compact exciton–polariton interferometer, which output intensity and polarization can be optically controlled. This interferometer is cascadable with already reported polariton devices and is promising for future polaritonic quantum optic experiments. Complex phase patterns could be also engineered using this optical method, providing a key tool to build photonic artificial gauge fields. PMID:24513781

  11. Coherent all-optical control of ultracold atoms arrays in permanent magnetic traps.

    PubMed

    Abdelrahman, Ahmed; Mukai, Tetsuya; Häffner, Hartmut; Byrnes, Tim

    2014-02-10

    We propose a hybrid architecture for quantum information processing based on magnetically trapped ultracold atoms coupled via optical fields. The ultracold atoms, which can be either Bose-Einstein condensates or ensembles, are trapped in permanent magnetic traps and are placed in microcavities, connected by silica based waveguides on an atom chip structure. At each trapping center, the ultracold atoms form spin coherent states, serving as a quantum memory. An all-optical scheme is used to initialize, measure and perform a universal set of quantum gates on the single and two spin-coherent states where entanglement can be generated addressably between spatially separated trapped ultracold atoms. This allows for universal quantum operations on the spin coherent state quantum memories. We give detailed derivations of the composite cavity system mediated by a silica waveguide as well as the control scheme. Estimates for the necessary experimental conditions for a working hybrid device are given. PMID:24663640

  12. All-optical hash code generation and verification for low latency communications.

    PubMed

    Paquot, Yvan; Schröder, Jochen; Pelusi, Mark D; Eggleton, Benjamin J

    2013-10-01

    We introduce an all-optical, format transparent hash code generator and a hash comparator for data packets verification with low latency at high baudrate. The device is reconfigurable and able to generate hash codes based on arbitrary functions and perform the comparison directly in the optical domain. Hash codes are calculated with custom interferometric circuits implemented with a Fourier domain optical processor. A novel nonlinear scheme featuring multiple four-wave mixing processes in a single waveguide is implemented for simultaneous phase and amplitude comparison of the hash codes before and after transmission. We demonstrate the technique with single polarisation BPSK and QPSK signals up to a data rate of 80 Gb/s.

  13. Sub-nanosecond threshold-switching dynamics and set process of In3SbTe2 phase-change memory devices

    NASA Astrophysics Data System (ADS)

    Pandey, Shivendra Kumar; Manivannan, Anbarasu

    2016-06-01

    Phase-change materials show promising features for high-speed, non-volatile, random access memory, however achieving a fast electrical switching is a key challenge. We report here, the dependence of electrical switching dynamics including transient parameters such as delay time, switching time, etc., on the applied voltage and the set process of In3SbTe2 phase-change memory devices at the picosecond (ps) timescale. These devices are found to exhibit threshold-switching at a critical voltage called threshold-voltage, VT of 1.9 ± 0.1 V, having a delay time of 25 ns. Further, the delay time decreases exponentially to a remarkably smaller value, as short as 300 ± 50 ps upon increasing the applied voltage up to 1.1VT. Furthermore, we demonstrate a rapid phase-change behavior from amorphous (˜10 MΩ) to poly-crystalline (˜10 kΩ) phase using time-resolved measurements revealing an ultrafast set process, which is primarily initiated by the threshold-switching process within 550 ps for an applied voltage pulse with a pulse-width of 1.5 ns and an amplitude of 2.3 V.

  14. S-Seed Switching, Noise, and Applications

    NASA Astrophysics Data System (ADS)

    Loh, Lup Meng

    The switching and noise characteristics of the Symmetric Self Electrooptic Effect Device (S-SEED) are studied in detail. The resulting analysis provides concise, closed form expressions for the S-SEED switching condition, the switching voltage of the device, and its switching time, all for a noiseless S-SEED model. A noise analysis, using a carrier state diagram, produced Bit Error Rate (BER) curves for the S-SEED that can be used in the design of a photonic switching system. This thesis also deals with application issues, demonstrating the versatility of the S-SEED as an optical logic device with memory. Two applications of the S-SEED are presented. A system to realize an All Optical Analog-to-Digital Converter (OADC) and an All Optical Digital-to-Analog Converter (ODAC) are conceived. The switching analysis presented here first models the noiseless S-SEED responsivity characteristics with a linear slope approximation. Such a model allows the derivation of a first order linear differential equation using a purely capacitive electric circuit model of an S-SEED. Similarly, an S-SEED model with series resistors results in a second order linear differential equation for the device. The resulting closed form solutions relate the noiseless S-SEED switching voltage and switching time to the operating parameters of the device. A discrete carrier approach is used to emulate S-SEED operation with shot noise. S-SEED state diagrams in conjunction with a Poisson probability density function (pdf), as well as an estimated Gaussian pdf, are used to determine both the probability of error P_ {E}, and the probability of abnormal operation P_{ABN}. The results provide a range of input parameter values for acceptable S-SEED performance when noise is included in the device model. Applications of S-SEEDs are presented that require logic and memory for their implementation. Experimental designs are detailed where S-SEEDs are the building blocks for an OADC and an ODAC. The inherent S

  15. Five-stage free-space optical switching network with field-effect transistor self-electro-optic-effect-device smart-pixel arrays.

    PubMed

    McCormick, F B; Cloonan, T J; Lentine, A L; Sasian, J M; Morrison, R L; Beckman, M G; Walker, S L; Wojcik, M J; Hinterlong, S J; Crisci, R J; Novotny, R A; Hinton, H S

    1994-03-10

    The design, construction, and operational testing of a five-stage, fully interconnected 32 × 16 switching fabric by the use of smart-pixel (2, 1, 1) switching nodes are described. The arrays of switching nodes use monolithically integrated GaAs field-effect transistors, multiple-quantum-well p-i-n detectors, and self-electro-optic-device modulators. Each switching node incorporates 25 field-effect transistors and 17 p-i-n diodes to realize two differential optical receivers, the 2 × 1 node switching logic, a single-bit node control memory, and one differential optical transmitter. The five stages of node arrays are interconnected to form a two-dimensional banyan network by the use of Fourier-plane computer-generated holograms. System input and output are made by two-dimensional fiber-bundle matrices, and the system optical hardware design incorporates frequency-stabilized lasers, pupil-division beam combination, and a hybrid micro-macro lens for fiber-bundle imaging. Optomechanical packaging of the system ut lizes modular kinematic component positioning and active thermal control to enable simple rapid assembly. Two preliminary operational experiments are completed. In the first experiment, five stages are operated at 50 Mbits/s with 15 active inputs and outputs. The second experiment attempts to operate two stages of second-generation node arrays at 155 Mbits/s, with eight of the 15 active nodes functioning correctly along the straight switch-routing paths. PMID:20862186

  16. All-optical automatic pollen identification: Towards an operational system

    NASA Astrophysics Data System (ADS)

    Crouzy, Benoît; Stella, Michelle; Konzelmann, Thomas; Calpini, Bertrand; Clot, Bernard

    2016-09-01

    We present results from the development and validation campaign of an optical pollen monitoring method based on time-resolved scattering and fluorescence. Focus is first set on supervised learning algorithms for pollen-taxa identification and on the determination of aerosol properties (particle size and shape). The identification capability provides a basis for a pre-operational automatic pollen season monitoring performed in parallel to manual reference measurements (Hirst-type volumetric samplers). Airborne concentrations obtained from the automatic system are compatible with those from the manual method regarding total pollen and the automatic device provides real-time data reliably (one week interruption over five months). In addition, although the calibration dataset still needs to be completed, we are able to follow the grass pollen season. The high sampling from the automatic device allows to go beyond the commonly-presented daily values and we obtain statistically significant hourly concentrations. Finally, we discuss remaining challenges for obtaining an operational automatic monitoring system and how the generic validation environment developed for the present campaign could be used for further tests of automatic pollen monitoring devices.

  17. Optically-switched multiwavelength networks

    NASA Astrophysics Data System (ADS)

    Jeong, Gibong

    1997-05-01

    of a semiconductor optical amplifier. Finally, we analyze the performance degradation caused by optical crosstalk, considering the effects of the modulating signals such as clock synchronism and transmitted spectrum, and the effects of source coherence and wavelength differences between the light sources. These analyses and techniques show promise of extending the utility of photonic switching, which may provide the means for all-optical networks in the future.

  18. Analysis of all-optical light modulation in proteorhodopsin protein molecules

    NASA Astrophysics Data System (ADS)

    Roy, Sukhdev; Sharma, Parag

    2008-03-01

    We present a detailed steady-state and time-dependent theoretical analysis of all-optical light modulation in the recently discovered, wild-type proteorhodopsin (WTpR) protein molecules based on excited-state absorption. Amplitude modulation of cw probe laser beam transmissions at 520, 405, 555 and 560 nm, corresponding to the peak absorption of pR, pRM, pRK and pRN intermediate states of pR photocycle, respectively, by cw and pulsed modulating pump laser beam at 520 nm have been analyzed. The effect of various spectral and kinetic parameters on modulation characteristics has been studied. There is an optimum value of concentration for a given pump intensity value for which maximum modulation of the probe beam can be achieved. The switching characteristics of probe beam at 405 and 520 nm exhibit dip and peak, respectively, which can be removed by decreasing the absorption of pRM state at 520 nm. The modulation in WTpR is at lower pump powers with smaller contrast in comparison to WT bacteriorhodopsin (bR) and WT pharaonis phoborhodopsin (ppR). The modulation characteristics exhibit unique features compared to bR and ppR.

  19. Green Distributed Quality of Transmission Aware Routing and Wavelength Assignment in All-Optical Networks

    NASA Astrophysics Data System (ADS)

    Kakekhani, Amir; Rahbar, Akbar Ghaffarpour

    2013-06-01

    The Routing and Wavelength Assignment (RWA) algorithms that consider quality of transmission (QoT) in light-path setup spend more time than their conventional counterparts due to exhaustive search and QoT estimation. This paper proposes distributed Quality of Transmission Aware Routing and Wavelength Assignment (QARWA) algorithm to handle dynamic light-path provisioning in wavelength routed all-optical networks taking energy consumption of optical switch nodes into account. Specifically, the QARWA considers bit-error rate (BER), setup delay, and energy consumption constraints at the same time, and establishes light-paths with small BER, low setup latency, and reduced energy consumption. We present and evaluate an enhanced wavelength-assignment solution in the QARWA to handle the wavelength continuity constraint. In QARWA, a source node determines the connection path by means of the shortest path algorithm and a destination node selects a wavelength based on the BER limitation and decreasing order of setup latency. Relating energy consumption to processing time, we show that QARWA can decrease the total energy consumption by reducing the processing time at each node. Under QARWA, when a node finishes the processing of the last control packet, it makes transition to either sleep state or idle state. Hence, QARWA can provide the best performance since it can reduce processing time in control units, light-path setup latency, and energy consumption of nodes.

  20. The effect of oxygen vacancies on the electrical properties of TiO2-x Re-RAM switching devices

    NASA Astrophysics Data System (ADS)

    Benkraouda, Maamar

    2014-03-01

    The main goal of this work is to contribute toward an accurate determination of the electronic properties of Resistance random access memory (Re-RAM) using the density functional theory, which is the current state of the art method that employs high accuracy, it can treat a few hundred atoms on medium sized PC. All the fundamental properties are studied as a function of the mole fraction. The density of states arising from vacancy distribution, the electron transport and formation energy are analyzed. Using controllable mole fraction, various intermediate resistance states are induced. Oxygen vacancy has a considerable effect on the electrical properties of most transition metal oxides such as TiOx Re-RAM devices. The presence of oxygen vacancies is linked to the on-state conduction and resistance switching mechanism. Hydrogen is a ubiquitous impurity in most semiconductors, insertion of hydrogen atoms will remove some of defect states which were induced by oxygen vacancies; this will obviously have an effect on the conductive path, because hydrogen in the vacancy site results in the rupture of conductive channel by localizing electrons, the conductivity may decrease in this case.

  1. Recent Advances in Photonic Devices for Optical Computing and the Role of Nonlinear Optics-Part II

    NASA Technical Reports Server (NTRS)

    Abdeldayem, Hossin; Frazier, Donald O.; Witherow, William K.; Banks, Curtis E.; Paley, Mark S.

    2007-01-01

    The twentieth century has been the era of semiconductor materials and electronic technology while this millennium is expected to be the age of photonic materials and all-optical technology. Optical technology has led to countless optical devices that have become indispensable in our daily lives in storage area networks, parallel processing, optical switches, all-optical data networks, holographic storage devices, and biometric devices at airports. This chapters intends to bring some awareness to the state-of-the-art of optical technologies, which have potential for optical computing and demonstrate the role of nonlinear optics in many of these components. Our intent, in this Chapter, is to present an overview of the current status of optical computing, and a brief evaluation of the recent advances and performance of the following key components necessary to build an optical computing system: all-optical logic gates, adders, optical processors, optical storage, holographic storage, optical interconnects, spatial light modulators and optical materials.

  2. All-optical slow-light on a photonic chip.

    PubMed

    Okawachi, Yoshitomo; Foster, Mark; Sharping, Jay; Gaeta, Alexander; Xu, Qianfan; Lipson, Michal

    2006-03-20

    We demonstrate optically tunable delays in a silicon-on-insulator planar waveguide based on slow light induced by stimulated Raman scattering (SRS). Inside an 8-mm-long nanoscale waveguide, we produce a group-index change of 0.15 and generate controllable delays as large as 4 ps for signal pulses as short as 3 ps. The scheme can be implemented at bandwidths exceeding 100 GHz for wavelengths spanning the entire low-loss fiber-optics communications window and thus represents an important step in the development of chip-scale photonics devices that process light with light.

  3. Fabrication of graphene-nanoflake/poly(4-vinylphenol) polymer nanocomposite thin film by electrohydrodynamic atomization and its application as flexible resistive switching device

    NASA Astrophysics Data System (ADS)

    Choi, Kyung Hyun; Ali, Junaid; Na, Kyoung-Hoan

    2015-10-01

    This paper describes synthesis of graphene/poly(4-vinylphenol) (PVP) nanocomposite and deposition of thin film by electrohydrodynamic atomization (EHDA) for fabrication flexible resistive switching device. EHDA technique proved its viability for thin film deposition after surface morphology analyses by field emission scanning electron microscope (FESEM) and non-destructive 3D Nano-profilometry, as the deposited films were, devoid of abnormalities. The commercially available graphene micro-flakes were exfoliated and broken down to ultra-small (20 nm-200 nm) nano-flakes by ultra-sonication in presence of N-methyl-pyrrolidone (NMP). These graphene nanoflakes with PVP nanocomposite, were successfully deposited as thin films (thickness ~140±7 nm, Ra=2.59 nm) on indium-tin-oxide (ITO) coated polyethylene terephthalate (PET) substrate. Transmittance data revealed that thin films are up to ~87% transparent in visible and NIR region. Resistive switching behaviour of graphene/PVP nanocomposite thin film was studied by using the nanocomposite as active layer in Ag/active layer/ITO sandwich structure. The resistive switching devices thus fabricated, showed characteristic OFF to ON (high resistance to low resistance) transition at low voltages, when operated between ±3 V, characterized at 10 nA compliance currents. The devices fabricated by this approach exhibited a stable room temperature, low power current-voltage hysteresis and well over 1 h retentivity, and ROFF/RON≈35:1. The device showed stable flexibility up to a minimum bending diameter of 1.8 cm.

  4. Unipolar resistive switching with forming-free and self-rectifying effects in Cu/HfO2/n-Si devices

    NASA Astrophysics Data System (ADS)

    Wang, M. J.; Gao, S.; Zeng, F.; Song, C.; Pan, F.

    2016-02-01

    One of the most effective methods integrating self-rectifying RRAM is alleviating sneak current in crossbar architecture. In this work, to investigate RRAMs with excellent properties of self-rectifying effect, simple Cu/HfO2/n-Si tri-layer devices are fabricated and investigated through I - V characteristic measurement. The experimental results demonstrate that the device exhibits forming-free behavior and a remarkable rectifying effect in low resistance state (LRS) with rectification ratio of 104 at ±1 V, as well as considerable OFF/ON ratio (resistive switching window) of 104 at 1 V. The formation and annihilation of localized Cu conductive filament plays a key role in the resistive switching between low resistance state (LRS) and high resistance state (HRS). In addition, intrinsic rectifying effect in LRS attributes to the Schottky contact between Cu filament and n-Si electrode. Furthermore, satisfactory switching uniformity of cycles and devices is observed. As indicated by the results, Cu/HfO2/n-Si devices have a high potential for high-density storage practical application due to its excellent properties.

  5. Complete all-optical processing polarization-based binary logic gates and optical processors.

    PubMed

    Zaghloul, Y A; Zaghloul, A R M

    2006-10-16

    We present a complete all-optical-processing polarization-based binary-logic system, by which any logic gate or processor can be implemented. Following the new polarization-based logic presented in [Opt. Express 14, 7253 (2006)], we develop a new parallel processing technique that allows for the creation of all-optical-processing gates that produce a unique output either logic 1 or 0 only once in a truth table, and those that do not. This representation allows for the implementation of simple unforced OR, AND, XOR, XNOR, inverter, and more importantly NAND and NOR gates that can be used independently to represent any Boolean expression or function. In addition, the concept of a generalized gate is presented which opens the door for reconfigurable optical processors and programmable optical logic gates. Furthermore, the new design is completely compatible with the old one presented in [Opt. Express 14, 7253 (2006)], and with current semiconductor based devices. The gates can be cascaded, where the information is always on the laser beam. The polarization of the beam, and not its intensity, carries the information. The new methodology allows for the creation of multiple-input-multiple-output processors that implement, by itself, any Boolean function, such as specialized or non-specialized microprocessors. Three all-optical architectures are presented: orthoparallel optical logic architecture for all known and unknown binary gates, singlebranch architecture for only XOR and XNOR gates, and the railroad (RR) architecture for polarization optical processors (POP). All the control inputs are applied simultaneously leading to a single time lag which leads to a very-fast and glitch-immune POP. A simple and easy-to-follow step-by-step algorithm is provided for the POP, and design reduction methodologies are briefly discussed. The algorithm lends itself systematically to software programming and computer-assisted design. As examples, designs of all binary gates, multiple

  6. Study of the switching rate of gas-discharge devices based on the open discharge with counter-propagating electron beams

    SciTech Connect

    Bokhan, P. A.; Gugin, P. P.; Lavrukhin, M. A.; Zakrevsky, Dm. E.

    2015-06-15

    The switching rate of gas-discharge devices “kivotrons” based on the open discharge with counter-propagating electron beams has been experimentally studied. Structures with 2-cm{sup 2} overall cathode area were examined. The switching time was found to show a monotonic decrease with increasing the working-gas helium pressure and with increasing the voltage across the discharge gap at breakdown. The minimum switching time was found to be ∼240 ps at 17 kV voltage, and the maximum rate of electric-current rise limited by the discharge-circuit inductance was 3 × 10{sup 12 }A/s.

  7. Percolation mechanism through trapping/de-trapping process at defect states for resistive switching devices with structure of Ag/SixC1-x/p-Si

    NASA Astrophysics Data System (ADS)

    Liu, Yanhong; Gao, Ping; Jiang, Xuening; Li, La; Zhang, Jialiang; Peng, Wei

    2014-08-01

    Pure SixC1-x (x > 0.5) and B-containing SixC1-x (x > 0.5) based resistive switching devices (RSD) with the structure of Ag/SixC1-x/p-Si were fabricated and their switching characteristics and mechanism were investigated systematically. Percolation mechanism through trapping/ de-trapping at defect states was suggested for the switching process. Through the introduction of B atoms into SixC1-x, the density of defect states was reduced, then, the SET and RESET voltages were also decreased. Based on the percolation theory, the dependence of SET/RESET voltage on the density of defect states was analyzed. These results supply a deep understanding for the SiC-based RSD, which have a potential application in extreme ambient conditions.

  8. Voltage-controlled low-energy switching of nanomagnets through Ruderman-Kittel-Kasuya-Yosida interactions for magnetoelectric device applications

    NASA Astrophysics Data System (ADS)

    Ghosh, Bahniman; Dey, Rik; Register, Leonard F.; Banerjee, Sanjay K.

    2016-07-01

    In this article, we consider through simulation low-energy switching of nanomagnets via electrostatically gated inter-magnet Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions on the surface of three-dimensional topological insulators, for possible memory and nonvolatile logic applications. We model the possibility and dynamics of RKKY-based switching of one nanomagnet by coupling to one or more nanomagnets of set orientation. Potential applications to both memory and nonvolatile logic are illustrated. Sub-attojoule switching energies, far below conventional spin transfer torque (STT)-based memories and even below CMOS logic appear possible. Switching times on the order of a few nanoseconds, comparable to times for STT switching, are estimated for ferromagnetic nanomagnets, but the approach also appears compatible with the use of antiferromagnets which may allow for faster switching.

  9. Bipolar resistive switching properties of Ti-CuO/(hexafluoro-hexa-peri-hexabenzocoronene)-Cu hybrid interface device: Influence of electronic nature of organic layer

    NASA Astrophysics Data System (ADS)

    Singh, Bharti; Mehta, B. R.; Varandani, Deepak; Govind; Narita, A.; Feng, X.; Müllen, K.

    2013-05-01

    This study reports the change in the structural and junction properties of Ti-CuO-Cu structure on incorporation of a 2-dimensional (2D) organic layer comprising of n-type hexafluoro-hexa-peri-hexabenzocoronene (6F-HBC). A bipolar resistive switching is observed in the device having interface between sputter deposited copper oxide (CuO) and vacuum sublimated 6F-HBC hybrid interface. The CuO/6F-HBC hybrid interface exhibits rectifying I-V characteristics in complete contrast to the ohmic and rectifying characteristics of junctions based on individual 6F-HBC and CuO layers. Large change in resistive switching property from unipolar resistive switching in CuO/HBC to bipolar resistive switching in CuO/6F-HBC interface was observed. At the CuO/6F-HBC interface, C1s peak corresponding to fluorinated carbon is shifted by 0.68 eV towards higher binding energy (BE) side and O1s peak due to non-lattice oxygen is shifted by 0.6 eV towards lower BE, confirming the interaction of O2- ion in CuO with fluorinated carbon atoms in 6F-HBC at the hybrid interface. Correlation between conductive atomic force microscopy images and atomic force microscopy topography images, I-V characteristics in conducting, non-conducting, and pristine regions along with x-ray photoelectron spectroscopy results establishes the important role of hybrid interface to determining the resistive switching properties. This study demonstrates that the resistive switching and interface properties of a hybrid device based on inorganic and organic 2D materials can be modified by changing the electronic properties of organic layer by attaching suitable functional groups.

  10. Bipolar resistive switching properties of Ti-CuO/(hexafluoro-hexa-peri-hexabenzocoronene)-Cu hybrid interface device: Influence of electronic nature of organic layer

    SciTech Connect

    Singh, Bharti; Mehta, B. R.; Varandani, Deepak; Govind; Narita, A.; Feng, X.; Muellen, K.

    2013-05-28

    This study reports the change in the structural and junction properties of Ti-CuO-Cu structure on incorporation of a 2-dimensional (2D) organic layer comprising of n-type hexafluoro-hexa-peri-hexabenzocoronene (6F-HBC). A bipolar resistive switching is observed in the device having interface between sputter deposited copper oxide (CuO) and vacuum sublimated 6F-HBC hybrid interface. The CuO/6F-HBC hybrid interface exhibits rectifying I-V characteristics in complete contrast to the ohmic and rectifying characteristics of junctions based on individual 6F-HBC and CuO layers. Large change in resistive switching property from unipolar resistive switching in CuO/HBC to bipolar resistive switching in CuO/6F-HBC interface was observed. At the CuO/6F-HBC interface, C1s peak corresponding to fluorinated carbon is shifted by 0.68 eV towards higher binding energy (BE) side and O1s peak due to non-lattice oxygen is shifted by 0.6 eV towards lower BE, confirming the interaction of O{sup 2-} ion in CuO with fluorinated carbon atoms in 6F-HBC at the hybrid interface. Correlation between conductive atomic force microscopy images and atomic force microscopy topography images, I-V characteristics in conducting, non-conducting, and pristine regions along with x-ray photoelectron spectroscopy results establishes the important role of hybrid interface to determining the resistive switching properties. This study demonstrates that the resistive switching and interface properties of a hybrid device based on inorganic and organic 2D materials can be modified by changing the electronic properties of organic layer by attaching suitable functional groups.

  11. Electromechanical switch

    NASA Astrophysics Data System (ADS)

    Antonuzzi, Anthony P.; Carignan, Donald J.

    1986-06-01

    A hardened electromechanical switch is disclosed. When appropriate electrical contacts and pick-offs are aligned, four switches close. The possible number of switch combinations selectable are 4095 based upon a base eight counting system. The switch has a counter section and a memory section. The counter section uses an odometer like device based upon octal. Each counter wheel of the counter section has an electrical pick-off that interacts with the memory section. In the memory section, a plurality of octal numbers, four, are entered into and locked thereon such that each counter set disk, four, therein has one octal number thereon. Electrical contacts are placed on the counter set disks of the memory section and these touch the pick-offs of the counter wheels which will simultaneously close on the four contacts of the counter set disk in only one of the 4095 combinations noted above.

  12. Switching Transistor

    NASA Astrophysics Data System (ADS)

    1981-01-01

    Westinghouse Electric Corporation's D60T transistors are used primarily as switching devices for controlling high power in electrical circuits. It enables reduction in the number and size of circuit components and promotes more efficient use of energy. Wide range of application from a popcorn popper to a radio frequency generator for solar cell production.

  13. Femtosecond all-optical parallel logic gates based on tunable saturable to reverse saturable absorption in graphene-oxide thin films

    SciTech Connect

    Roy, Sukhdev Yadav, Chandresh

    2013-12-09

    A detailed theoretical analysis of ultrafast transition from saturable absorption (SA) to reverse saturable absorption (RSA) has been presented in graphene-oxide thin films with femtosecond laser pulses at 800 nm. Increase in pulse intensity leads to switching from SA to RSA with increased contrast due to two-photon absorption induced excited-state absorption. Theoretical results are in good agreement with reported experimental results. Interestingly, it is also shown that increase in concentration results in RSA to SA transition. The switching has been optimized to design parallel all-optical femtosecond NOT, AND, OR, XOR, and the universal NAND and NOR logic gates.

  14. Multi-Angle Switched HIFU: A New Ultrasound Device for Controlled Non-Invasive Induction of Small Spherical Ablation Zones—Simulation and Ex-Vivo Results

    NASA Astrophysics Data System (ADS)

    Novák, Petr; Jamshidi-Parsian, Azemat; Benson, Donny G.; Webber, Jessica S.; Moros, Eduardo G.; Shafirstein, Gal; Griffin, Robert J.

    2009-04-01

    Current HIFU devices produce elongated elliptical lesions (cigar shaped) in a single energy deposition. This prohibits the effective use of HIFU in small animal research as well as in clinical treatment where small volumes of tissue surrounded by critical structures need to be destroyed. We developed an ultrasound ablation device that non-invasively creates spheroidal lesions of an arbitrary diameter of up to 1 cm in a depth of up to 5 cm. The device consists of two focused ultrasound transducers aimed to the ablation target volume from two directions at a 90 degree angle. The operation of the transducers is switched back and forth so that only one transducer is energized at a time. A transient analysis of this ablation approach was performed using coupled simulations of acoustical pressure distributions, resulting temperature distributions, and thermal dose deposited to soft tissue. A prototype of the device was developed and tested in-vitro in a phantom and later in ex-vivo experiments in pig liver. The experimental results agreed with the numerical simulations and confirmed the ability of the multi-angle switched HIFU (MASH) device to create small spheroidal lesions in soft tissue within 2 minutes without significantly affecting the surrounding tissues.

  15. Interfacial Electrode-Driven Enhancement of the Switching Parameters of a Copper Oxide-Based Resistive Random-Access Memory Device

    NASA Astrophysics Data System (ADS)

    Sangani, L. D. Varma; Kumar, Ch. Ravi; Krishna, M. Ghanashyam

    2016-01-01

    The characteristics of an Au/Cu x O/Au bipolar resistive random-access memory device are reported. It is demonstrated that switching parameters of this device structure can be enhanced by introducing an interfacial Al layer between the Au top electrode and the Cu x O-based dielectric layer. The set and reset voltages are, respectively, between -2.5 V to -6.0 V and +1.2 V to +3.0 V for the Al-based device. In contrast, the range of values are -0.5 V to -2.5 V and +0.5 V to +1.5 V for the set and reset voltages in the absence of Al. The Al-based device has a higher low resistance state value of 5-6 KΩ as compared to the 0.3-0.5 KΩ for the Au-based device, which leads to a 12 times lower power dissipation factor and lower reset current of 370 μA. Endurance studies carried out over 50 switching cycles show less than 2% variation in both the low resistance and high resistance values. The conduction is ohmic at low values of bias and non-ohmic at higher bias voltage which shows that the enhanced behaviour is a result of the formation of an insulating aluminum oxide layer at the Al-Cu x O interface.

  16. Impact of device size and thickness of Al2O 3 film on the Cu pillar and resistive switching characteristics for 3D cross-point memory application.

    PubMed

    Panja, Rajeswar; Roy, Sourav; Jana, Debanjan; Maikap, Siddheswar

    2014-12-01

    Impact of the device size and thickness of Al2O3 film on the Cu pillars and resistive switching memory characteristics of the Al/Cu/Al2O3/TiN structures have been investigated for the first time. The memory device size and thickness of Al2O3 of 18 nm are observed by transmission electron microscope image. The 20-nm-thick Al2O3 films have been used for the Cu pillar formation (i.e., stronger Cu filaments) in the Al/Cu/Al2O3/TiN structures, which can be used for three-dimensional (3D) cross-point architecture as reported previously Nanoscale Res. Lett.9:366, 2014. Fifty randomly picked devices with sizes ranging from 8 × 8 to 0.4 × 0.4 μm(2) have been measured. The 8-μm devices show 100% yield of Cu pillars, whereas only 74% successful is observed for the 0.4-μm devices, because smaller size devices have higher Joule heating effect and larger size devices show long read endurance of 10(5) cycles at a high read voltage of -1.5 V. On the other hand, the resistive switching memory characteristics of the 0.4-μm devices with a 2-nm-thick Al2O3 film show superior as compared to those of both the larger device sizes and thicker (10 nm) Al2O3 film, owing to higher Cu diffusion rate for the larger size and thicker Al2O3 film. In consequence, higher device-to-device uniformity of 88% and lower average RESET current of approximately 328 μA are observed for the 0.4-μm devices with a 2-nm-thick Al2O3 film. Data retention capability of our memory device of >48 h makes it a promising one for future nanoscale nonvolatile application. This conductive bridging resistive random access memory (CBRAM) device is forming free at a current compliance (CC) of 30 μA (even at a lowest CC of 0.1 μA) and operation voltage of ±3 V at a high resistance ratio of >10(4). PMID:26088986

  17. The Switching Dynamics and Optimisation of Optical Bistability in Indium Antimonide.

    NASA Astrophysics Data System (ADS)

    Iltaif, Abdul-Hussain Khudhair

    Available from UMI in association with The British Library. This thesis is concerned with the experimental study and analysis of optical bistability in fully optimised InSb systems. The related phenomena of coherent modulation, switching dynamics, noise effects, high finesse etalons and the development of optoelectronic devices are also included. The gain bandwidth product of an InSb transphasor has been studied experimentally using two beams from a low power cw CO laser. The switching dynamics are analysed in terms of effective time constants which change dramatically near the switch points. Results are presented which show that by overdriving the system, switch times of ~250 ns may be obtained with the CO laser system and <10 ns using pulsed sources. The influence of noise levels, on both the switching dynamics and the system stability close to switching are discussed. Switching out of noise and optical bimodality have been observed through a statistical sequence of ~ 10 ^3 discrete switching operations. An optimisation procedure using a high reflectivity (~80%) InSb etalon (~ 50 μm thick) is described. For this etalon with a 50 μm spot diameter beam, the minimum switching power is ~ 550 muW and switching times are 150 ns, leading to a switching energy for this device ~80 pJ. The practical development of the concept of the direct injection of carriers from an electrode system to InSb material to achieve an optically bistable optoelectronic (OBOE) device which can make complete and interactive communication between an all-optical element and conventional electronic circuitry and computing systems are also discussed.

  18. All-optical clock recovery, photonic balancing, and saturated asymmetric filtering for fiber optic communication systems

    NASA Astrophysics Data System (ADS)

    Parsons, Earl Ryan

    In this dissertation I investigated a multi-channel and multi-bit rate all-optical clock recovery device. This device, a birefringent Fabry-Perot resonator, had previously been demonstrated to simultaneously recover the clock signal from 10 wavelength channels operating at 10 Gb/s and one channel at 40 Gb/s. Similar to clock signals recovered from a conventional Fabry-Perot resonator, the clock signal from the birefringent resonator suffers from a bit pattern effect. I investigated this bit pattern effect for birefringent resonators numerically and experimentally and found that the bit pattern effect is less prominent than for clock signals from a conventional Fabry-Perot resonator. I also demonstrated photonic balancing which is an all-optical alternative to electrical balanced detection for phase shift keyed signals. An RZ-DPSK data signal was demodulated using a delay interferometer. The two logically opposite outputs from the delay interferometer then counter-propagated in a saturated SOA. This process created a differential signal which used all the signal power present in two consecutive symbols. I showed that this scheme could provide an optical alternative to electrical balanced detection by reducing the required OSNR by 3 dB. I also show how this method can provide amplitude regeneration to a signal after modulation format conversion. In this case an RZ-DPSK signal was converted to an amplitude modulation signal by the delay interferometer. The resulting amplitude modulated signal is degraded by both the amplitude noise and the phase noise of the original signal. The two logically opposite outputs from the delay interferometer again counter-propagated in a saturated SOA. Through limiting amplification and noise modulation this scheme provided amplitude regeneration and improved the Q-factor of the demodulated signal by 3.5 dB. Finally I investigated how SPM provided by the SOA can provide a method to reduce the in-band noise of a communication signal. The

  19. Ultralow-power and ultrafast all-optical tunable plasmon-induced transparency in metamaterials at optical communication range.

    PubMed

    Zhu, Yu; Hu, Xiaoyong; Fu, Yulan; Yang, Hong; Gong, Qihuang

    2013-01-01

    Actively all-optical tunable plasmon-induced transparency in metamaterials paves the way for achieving ultrahigh-speed quantum information processing chips. Unfortunately, up to now, very small experimental progress has been made for all-optical tunable plasmon-induced transparency in metamaterials in the visible and near-infrared range because of small third-order optical nonlinearity of conventional materials. The achieved operating pump intensity was as high as several GW/cm(2) order. Here, we report an ultralow-power and ultrafast all-optical tunable plasmon-induced transparency in metamaterials coated on polycrystalline indium-tin oxide layer at the optical communication range. Compared with previous reports, the threshold pump intensity is reduced by four orders of magnitude, while an ultrafast response time of picoseconds order is maintained. This work not only offers a way to constructing photonic materials with large nonlinearity and ultrafast response, but also opens up the possibility for realizing quantum solid chips and ultrafast integrated photonic devices based on metamaterials.

  20. Ultralow-power and ultrafast all-optical tunable plasmon-induced transparency in metamaterials at optical communication range

    PubMed Central

    Zhu, Yu; Hu, Xiaoyong; Fu, Yulan; Yang, Hong; Gong, Qihuang

    2013-01-01

    Actively all-optical tunable plasmon-induced transparency in metamaterials paves the way for achieving ultrahigh-speed quantum information processing chips. Unfortunately, up to now, very small experimental progress has been made for all-optical tunable plasmon-induced transparency in metamaterials in the visible and near-infrared range because of small third-order optical nonlinearity of conventional materials. The achieved operating pump intensity was as high as several GW/cm2 order. Here, we report an ultralow-power and ultrafast all-optical tunable plasmon-induced transparency in metamaterials coated on polycrystalline indium-tin oxide layer at the optical communication range. Compared with previous reports, the threshold pump intensity is reduced by four orders of magnitude, while an ultrafast response time of picoseconds order is maintained. This work not only offers a way to constructing photonic materials with large nonlinearity and ultrafast response, but also opens up the possibility for realizing quantum solid chips and ultrafast integrated photonic devices based on metamaterials. PMID:23903825

  1. All-optical polarization control and noise cleaning based on a nonlinear lossless polarizer

    NASA Astrophysics Data System (ADS)

    Barozzi, Matteo; Vannucci, Armando; Picchi, Giorgio

    2015-01-01

    We propose an all-optical fiber-based device able to accomplish both polarization control and OSNR enhancement of an amplitude modulated optical signal, affected by unpolarized additive white Gaussian noise, at the same time. The proposed noise cleaning device is made of a nonlinear lossless polarizer (NLP), that performs polarization control, followed by an ideal polarizing filter that removes the orthogonally polarized half of additive noise. The NLP transforms every input signal polarization into a unique, well defined output polarization (without any loss of signal energy) and its task is to impose a signal polarization aligned with the transparent eigenstate of the polarizing filter. In order to effectively control the polarization of the modulated signal, we show that two different NLP configurations (with counter- or co-propagating pump laser) are needed, as a function of the signal polarization coherence time. The NLP is designed so that polarization attraction is effective only on the "noiseless" (i.e., information-bearing) component of the signal and not on noise, that remains unpolarized at the NLP output. Hence, the proposed device is able to discriminate signal power (that is preserved) from in-band noise power (that is partly suppressed). Since signal repolarization is detrimental if applied to polarization-multiplexed formats, the noise cleaner application is limited here to "legacy" links, with 10 Gb/s OOK modulation, still representing the most common format in deployed networks. By employing the appropriate NLP configurations, we obtain an OSNR gain close to 3dB. Furthermore, we show how the achievable OSNR gain can be estimated theoretically.

  2. All-optical signal processing at 10 GHz using a photonic crystal molecule

    SciTech Connect

    Combrié, Sylvain; Lehoucq, Gaëlle; Junay, Alexandra; De Rossi, Alfredo; Malaguti, Stefania; Bellanca, Gaetano; Trillo, Stefano; Ménager, Loic; Peter Reithmaier, Johann

    2013-11-04

    We report on 10 GHz operation of an all-optical gate based on an Indium Phosphide Photonic Crystal Molecule. Wavelength conversion and all-optical mixing of microwave signals are demonstrated using the 2 mW output of a mode locked diode laser. The spectral separation of the optical pump and signal is crucial in suppressing optical cross-talk.

  3. On the mechanism of the picosecond switching phenomenon in devices based on the open discharge with counter-propagating electron beams

    NASA Astrophysics Data System (ADS)

    Bokhan, P. A.; Gugin, P. P.; Lavrukhin, M. A.; Zakrevsky, Dm E.

    2016-06-01

    The subnanosecond breakdown stage in the kivotron, a switching device with counter-propagating electron beams based on the open discharge in helium, was experimentally studied. It was shown that the fast discharge stage arises when the discharge self-sustaining regime is ensured by the photoelectron emission from of the cathodes due to the resonant radiation, emitted by fast helium atoms that have large Doppler shifts with respect to the line center; as a result, the emitted radiation reaches the cathodes without imprisonment by the helium gas. Since the cross-section for the excitation of a helium atom with another (fast) helium atom increases rapidly with the energy of the fast atom, the duration of the breakdown stage strongly depends on the working voltage. The transient characteristic is modulated by microwave oscillations of ~4.4 GHz frequency generated during the discharge of kivotron self-capacitance through its self-induction. An increase in working pressure leads to suppression of oscillations. A switching time of 80 ps was achieved in a discharge circuit loaded to a resistance R L  ⩾  50 Ω. On decreasing the value of R L down to 10 Ω, the switching time increases to about 100 ps at 1.5 kA current. A minimum switching time that can be achieved via kivotron design optimization is estimated to be about 35 ps.

  4. Optical switch

    DOEpatents

    Reedy, Robert P.

    1987-01-01

    An optical switching device (10) is provided whereby light from a first glass fiber (16) or a second glass fiber (14) may be selectively transmitted into a third glass fiber (18). Each glass fiber is provided with a focusing and collimating lens system (26, 28, 30). In one mode of operation, light from the first glass fiber (16) is reflected by a planar mirror (36) into the third glass fiber (18). In another mode of operation, light from the second glass fiber (14) passes directly into the third glass fiber (18). The planar mirror (36) is attached to a rotatable table (32) which is rotated to provide the optical switching.

  5. Polyimide-etalon all-optical ultrasound transducer for high frequency applications

    NASA Astrophysics Data System (ADS)

    Sheaff, Clay; Ashkenazi, Shai

    2014-03-01

    We have enhanced our design for an all-optical high frequency ultrasound transducer consisting of a UV-absorbing polyimide film integrated into an etalon receiver operating in the NIR range. A dielectric stack having high NIR reflectivity and high UV transmittance was chosen as the first mirror for increased sensitivity and the allowance of polyimide as the etalon medium. A 13 ns, 0.7 μJ optical pulse at 355 nm and a continuous-wave NIR laser were focused onto the structure with a spot diameter of 120 and 35 μm, respectively. In receive mode the etalon had a noise-equivalent pressure of 4.1 kPa over a bandwidth of 5 - 50 MHz (0.61 Pa/√Hz ). The device generated a pressure of 270 kPa at a depth of 200 μm, and the -3 dB bandwidth of the emission extended from 27 to 60 MHz. In transmit/receive mode, the pulse-echo had a center frequency of 35 MHz with a -6 dB bandwidth of 49 MHz (140 %). Lastly, wire targets were imaged by scanning the UV spot to create a synthetic aperture of transmitters centered upon a single receiver.

  6. An all-optical Compton source for single-exposure x-ray imaging

    NASA Astrophysics Data System (ADS)

    Döpp, A.; Guillaume, E.; Thaury, C.; Gautier, J.; Andriyash, I.; Lifschitz, A.; Malka, V.; Rousse, A.; Phuoc, K. Ta

    2016-03-01

    All-optical Compton sources are innovative, compact devices to produce high energy femtosecond x-rays. Here we present results on a single-pulse scheme that uses a plasma mirror to reflect the drive beam of a laser plasma accelerator and to make it collide with the highly-relativistic electrons in its wake. The accelerator is operated in the self-injection regime, producing quasi-monoenergetic electron beams of around 150 MeV peak energy. Scattering with the intense femtosecond laser pulse leads to the emission of a collimated high energy photon beam. Using continuum-attenuation filters we measure significant signal content beyond 100 keV and with simulations we estimate a peak photon energy of around 500 keV. The source divergence is about 13 mrad and the pointing stability is 7 mrad. We demonstrate that the photon yield from the source is sufficiently high to illuminate a centimeter-size sample placed 90 centimeters behind the source, thus obtaining radiographs in a single shot.

  7. All-optical digital 4 × 2 encoder based on 2D photonic crystal ring resonators

    NASA Astrophysics Data System (ADS)

    Moniem, Tamer A.

    2016-04-01

    The photonic crystals draw significant attention to build all-optical logic devices and are considered one of the solutions for the opto-electronic bottleneck via speed and size. The paper presents a novel optical 4 × 2 encoder based on 2D square lattice photonic crystals of silicon rods. The main realization of optical encoder is based on the photonic crystal ring resonator NOR gates. The proposed structure has four logic input ports, two output ports, and two bias input port. The photonic crystal structure has a square lattice of silicon rods with a refractive index of 3.39 in air. The structure has lattice constant 'a' equal to 630 nm and bandgap range from 0.32 to 044. The total size of the proposed 4 × 2 encoder is equal to 35 μm × 35 μm. The simulation results using the dimensional finite difference time domain and Plane Wave Expansion methods confirm the operation and the feasibility of the proposed optical encoder for ultrafast optical digital circuits.

  8. A novel all-optical label processing for OPS networks based on multiple OOC sequences from multiple-groups OOC

    NASA Astrophysics Data System (ADS)

    Qiu, Kun; Zhang, Chongfu; Ling, Yun; Wang, Yibo

    2007-11-01

    This paper proposes an all-optical label processing scheme using multiple optical orthogonal codes sequences (MOOCS) for optical packet switching (OPS) (MOOCS-OPS) networks, for the first time to the best of our knowledge. In this scheme, the multiple optical orthogonal codes (MOOC) from multiple-groups optical orthogonal codes (MGOOC) are permuted and combined to obtain the MOOCS for the optical labels, which are used to effectively enlarge the capacity of available optical codes for optical labels. The optical label processing (OLP) schemes are reviewed and analyzed, the principles of MOOCS-based optical labels for OPS networks are given, and analyzed, then the MOOCS-OPS topology and the key realization units of the MOOCS-based optical label packets are studied in detail, respectively. The performances of this novel all-optical label processing technology are analyzed, the corresponding simulation is performed. These analysis and results show that the proposed scheme can overcome the lack of available optical orthogonal codes (OOC)-based optical labels due to the limited number of single OOC for optical label with the short code length, and indicate that the MOOCS-OPS scheme is feasible.

  9. Fast, high-fidelity, all-optical and dynamically-controlled polarization gate using room-temperature atomic vapor

    SciTech Connect

    Li, Runbing; Zhu, Chengjie; Deng, L.; Hagley, E. W.

    2014-10-20

    We demonstrate a fast, all-optical polarization gate in a room-temperature atomic medium. Using a Polarization-Selective-Kerr-Phase-Shift (PSKPS) technique, we selectively write a π phase shift to one circularly-polarized component of a linearly-polarized input signal field. The output signal field maintains its original strength but acquires a 90° linear polarization rotation, demonstrating fast, high-fidelity, dynamically-controlled polarization gate operation. The intensity of the polarization-switching field used in this PKSPK-based polarization gate operation is only 2 mW/cm{sup 2}, which would be equivalent to 0.5 nW of light power (λ = 800 nm) confined in a typical commercial photonic hollow-core fiber. This development opens a realm of possibilities for potential future extremely low light level telecommunication and information processing systems.

  10. A new design procedure for all-optical photonic crystal logic gates and functions based on threshold logic

    NASA Astrophysics Data System (ADS)

    Sharifi, Hojjat; Hamidi, Seyyedeh Mehri; Navi, Keivan

    2016-07-01

    In this paper, a general method is proposed to design all-optical photonic crystal logic gates and functions based on threshold logic concept that have regular pattern in inputs. In our proposed structure, a photonic crystal junction is cascaded by a threshold power level detector. Additionally, a novel mechanism is introduced to shift the threshold power level for designing different logic gates and functions. The finite difference time domain and plane wave expansion methods are used to evaluate the proposed structures. The proposed gates and functions occupy an area less than 150 μm2 and also, the maximum power required for the switching mechanism is 15 μW. The inputs and output in the mentioned gates and functions are homogeneous and they can operate with a bit rate of about 500 Gbits/s.

  11. Multi-step resistive switching behavior of Li-doped ZnO resistance random access memory device controlled by compliance current

    NASA Astrophysics Data System (ADS)

    Lin, Chun-Cheng; Tang, Jian-Fu; Su, Hsiu-Hsien; Hong, Cheng-Shong; Huang, Chih-Yu; Chu, Sheng-Yuan

    2016-06-01

    The multi-step resistive switching (RS) behavior of a unipolar Pt/Li0.06Zn0.94O/Pt resistive random access memory (RRAM) device is investigated. It is found that the RRAM device exhibits normal, 2-, 3-, and 4-step RESET behaviors under different compliance currents. The transport mechanism within the device is investigated by means of current-voltage curves, in-situ transmission electron microscopy, and electrochemical impedance spectroscopy. It is shown that the ion transport mechanism is dominated by Ohmic behavior under low electric fields and the Poole-Frenkel emission effect (normal RS behavior) or Li+ ion diffusion (2-, 3-, and 4-step RESET behaviors) under high electric fields.

  12. Nanoscale memristive radiofrequency switches

    NASA Astrophysics Data System (ADS)

    Pi, Shuang; Ghadiri-Sadrabadi, Mohammad; Bardin, Joseph C.; Xia, Qiangfei

    2015-06-01

    Radiofrequency switches are critical components in wireless communication systems and consumer electronics. Emerging devices include switches based on microelectromechanical systems and phase-change materials. However, these devices suffer from disadvantages such as large physical dimensions and high actuation voltages. Here we propose and demonstrate a nanoscale radiofrequency switch based on a memristive device. The device can be programmed with a voltage as low as 0.4 V and has an ON/OFF conductance ratio up to 1012 with long state retention. We measure the radiofrequency performance of the switch up to 110 GHz and demonstrate low insertion loss (0.3 dB at 40 GHz), high isolation (30 dB at 40 GHz), an average cutoff frequency of 35 THz and competitive linearity and power-handling capability. Our results suggest that, in addition to their application in memory and computing, memristive devices are also a leading contender for radiofrequency switch applications.

  13. Resistive switching characteristics of Cu/ZnO0.4S0.6/Al devices constructed on plastic substrates.

    PubMed

    Han, Yong; Cho, Kyoungah; Kim, Sangsig

    2012-07-01

    In this study, Cu/ZnO0.4S0.6Al devices are fabricated on plastic substrates using the sputtering method at room temperature. The ratio of O/S in the zinc oxysulfide thin film is confirmed to be 0.4/0.6 from the Auger depth profiling. The Cu/ZnO0.4S0.6/Al devices show unipolar resistive switching behaviors and the ratio of the measured resistance in the low-resistance state (LRS) to that in the high-resistance state (HRS) is above 10(4). The conduction mechanism of the LRS is governed by Ohm's law. On the other hand, in the HRS, the conduction mechanism at low voltages is controlled by Ohm's law, but that at high voltages results from the Poole-Frenkel emission mechanism. The Ohmic and Poole-Frenkel conduction mechanisms observed in the LRS and HRS support the filament model of unipolar resistive switching. The memory characteristics of the Cu/ZnO0.4S0.6/Al devices are retained for 10(4) sec without any change.

  14. Nanoscale on-chip all-optical logic parity checker in integrated plasmonic circuits in optical communication range.

    PubMed

    Wang, Feifan; Gong, Zibo; Hu, Xiaoyong; Yang, Xiaoyu; Yang, Hong; Gong, Qihuang

    2016-01-01

    The nanoscale chip-integrated all-optical logic parity checker is an essential core component for optical computing systems and ultrahigh-speed ultrawide-band information processing chips. Unfortunately, little experimental progress has been made in development of these devices to date because of material bottleneck limitations and a lack of effective realization mechanisms. Here, we report a simple and efficient strategy for direct realization of nanoscale chip-integrated all-optical logic parity checkers in integrated plasmonic circuits in the optical communication range. The proposed parity checker consists of two-level cascaded exclusive-OR (XOR) logic gates that are realized based on the linear interference of surface plasmon polaritons propagating in the plasmonic waveguides. The parity of the number of logic 1s in the incident four-bit logic signals is determined, and the output signal is given the logic state 0 for even parity (and 1 for odd parity). Compared with previous reports, the overall device feature size is reduced by more than two orders of magnitude, while ultralow energy consumption is maintained. This work raises the possibility of realization of large-scale integrated information processing chips based on integrated plasmonic circuits, and also provides a way to overcome the intrinsic limitations of serious surface plasmon polariton losses for on-chip integration applications.

  15. Nanoscale on-chip all-optical logic parity checker in integrated plasmonic circuits in optical communication range.

    PubMed

    Wang, Feifan; Gong, Zibo; Hu, Xiaoyong; Yang, Xiaoyu; Yang, Hong; Gong, Qihuang

    2016-01-01

    The nanoscale chip-integrated all-optical logic parity checker is an essential core component for optical computing systems and ultrahigh-speed ultrawide-band information processing chips. Unfortunately, little experimental progress has been made in development of these devices to date because of material bottleneck limitations and a lack of effective realization mechanisms. Here, we report a simple and efficient strategy for direct realization of nanoscale chip-integrated all-optical logic parity checkers in integrated plasmonic circuits in the optical communication range. The proposed parity checker consists of two-level cascaded exclusive-OR (XOR) logic gates that are realized based on the linear interference of surface plasmon polaritons propagating in the plasmonic waveguides. The parity of the number of logic 1s in the incident four-bit logic signals is determined, and the output signal is given the logic state 0 for even parity (and 1 for odd parity). Compared with previous reports, the overall device feature size is reduced by more than two orders of magnitude, while ultralow energy consumption is maintained. This work raises the possibility of realization of large-scale integrated information processing chips based on integrated plasmonic circuits, and also provides a way to overcome the intrinsic limitations of serious surface plasmon polariton losses for on-chip integration applications. PMID:27073154

  16. Nanoscale on-chip all-optical logic parity checker in integrated plasmonic circuits in optical communication range

    PubMed Central

    Wang, Feifan; Gong, Zibo; Hu, Xiaoyong; Yang, Xiaoyu; Yang, Hong; Gong, Qihuang

    2016-01-01

    The nanoscale chip-integrated all-optical logic parity checker is an essential core component for optical computing systems and ultrahigh-speed ultrawide-band information processing chips. Unfortunately, little experimental progress has been made in development of these devices to date because of material bottleneck limitations and a lack of effective realization mechanisms. Here, we report a simple and efficient strategy for direct realization of nanoscale chip-integrated all-optical logic parity checkers in integrated plasmonic circuits in the optical communication range. The proposed parity checker consists of two-level cascaded exclusive-OR (XOR) logic gates that are realized based on the linear interference of surface plasmon polaritons propagating in the plasmonic waveguides. The parity of the number of logic 1s in the incident four-bit logic signals is determined, and the output signal is given the logic state 0 for even parity (and 1 for odd parity). Compared with previous reports, the overall device feature size is reduced by more than two orders of magnitude, while ultralow energy consumption is maintained. This work raises the possibility of realization of large-scale integrated information processing chips based on integrated plasmonic circuits, and also provides a way to overcome the intrinsic limitations of serious surface plasmon polariton losses for on-chip integration applications. PMID:27073154

  17. The super junction bipolar transistor: a new silicon power device concept for ultra low loss switching applications at medium to high voltages

    NASA Astrophysics Data System (ADS)

    Bauer, Friedhelm D.

    2004-05-01

    A new silicon power device concept based on the super junction (SJ) principle for power electronics in a broad spectrum of consumer, industrial and other energy conversion applications is presented in this paper. This new concept can help to sustain the trend towards ultra low loss switching--the past, present and future dominant driving force in the development of silicon high power switches. The super junction bipolar transistor (SJBT) shares many similarities with the super junction MOSFET. It has a similar MOS control structure integrated on the cathode side on top of a base region, which is organized into a columnar structure of alternating p- and n-doped pillars. The anode consists of a p-doped emitter--the SJBT is thus a bipolar super junction power device with carrier modulation taking place in only some portion of the base. The super junction structure makes up for fundamentally different device characteristics compared to an IGBT: carrier modulation in the SJBT is made possible by elimination of the reverse bias between p- and n-doped pillars when large quantities of majority carriers are injected from the p-emitter into the p-type pillar. With the electrostatic potential being grounded at the cathode, de-biasing of the pillars as well as carrier modulation will vanish towards the cathode. The unique characteristic of the SJBT on-state is an electron-hole plasma originating at the anode, which will segregate and give place to unipolar current flow in both pillars (de-mixing of the plasma) in the base region close to the cathode. Compared to an IGBT, the SJBT offers the same or lower conduction losses at a very small fraction (25%) of the cost in terms of switching losses.

  18. Fabrication of a novel RF switch device with high performance using In0.4Ga0.6As MOSFET technology

    NASA Astrophysics Data System (ADS)

    Jiahui, Zhou; Hudong, Chang; Xufang, Zhang; Jingzhi, Yang; Guiming, Liu; Haiou, Li; Honggang, Liu

    2016-02-01

    A novel radio frequency (RF) switch device has been successfully fabricated using InGaAs metal-oxide-semiconductor field-effect transistor (MOSFET) technology. The device showed drain saturation currents of 250 mA/mm, a maximum transconductance of 370 mS/mm, a turn-on resistance of 0.72 mω·mm2 and a drain current on-off (Ion/Ioff) ratio of 1 × 106. The maximum handling power of on-state of 533 mW/mm and off-state of 3667 mW/mm is obtained. The proposed In0.4Ga0.6 As MOSFET RF switch showed an insertion loss of less than 1.8 dB and an isolation of better than 20 dB in the frequency range from 0.1 to 7.5 GHz. The lowest insertion loss and the highest isolation can reach 0.27 dB and more than 68 dB respectively. This study demonstrates that the InGaAs MOSFET technology has a great potential for RF switch application. Project supported by the National Natural Science Foundation of China (Nos. 61274077, 61474031), the Guangxi Natural Science Foundation (No. 2013GXNSFGA019003), the Guangxi Department of Education Project (No. 201202ZD041), the Guilin City Technology Bureau (Nos. 20120104-8, 20130107-4), the China Postdoctoral Science Foundation Funded Project (Nos. 2012M521127, 2013T60566), the National Basic Research Program of China (Nos. 2011CBA00605, 2010CB327501), the Innovation Project of GUET Graduate Education (Nos. GDYCSZ201448, GDYCSZ201449), the State key Laboratory of Electronic Thin Films and Integrated Devices, UESTC (No. KFJJ201205), and the Guilin City Science and Technology Development Project (Nos. 20130107-4, 20120104-8).

  19. A reconfigurable all-optical VPN based on XGM effect of SOA in WDM PON

    NASA Astrophysics Data System (ADS)

    Hu, Xiaofeng; Zhang, Liang; Cao, Pan; Wang, Tao; Su, Yikai

    2010-12-01

    We propose and experimentally demonstrate a reconfigurable all-optical VPN scheme enabling intercommunications among different ONUs in a WDM PON. Reconfiguration is realized by dynamically setting wavelength conversion of optical VPN signal using a SOA in the OLT.

  20. Magnetic induction tomography using an all-optical ⁸⁷Rb atomic magnetometer.

    PubMed

    Wickenbrock, Arne; Jurgilas, Sarunas; Dow, Albert; Marmugi, Luca; Renzoni, Ferruccio

    2014-11-15

    We demonstrate magnetic induction tomography (MIT) with an all-optical atomic magnetometer. Our instrument creates a conductivity map of conductive objects. Both the shape and size of the imaged samples compare very well with the actual shape and size. Given the potential of all-optical atomic magnetometers for miniaturization and extreme sensitivity, the proof-of-principle presented in this Letter opens up promising avenues in the development of instrumentation for MIT.

  1. Optical networking by DLP-based switched blazed grating

    NASA Astrophysics Data System (ADS)

    Lin, Hoang Yan; Chung, Shuang-Chao

    2005-02-01

    All-optical modules are devices which process and transport optical signals without transforming to electronic signals. They get more attention as the optical communication network becomes more and more complicated. Among them, OADM (optical add drop module) is one of the most important devices in the optical DWDM (dense wavelength division multiplex) network. It plays the role of a node in network to upload/download signals or to route signals for optical performance monitoring. Applied broadly in projection display systems, DLP (Digital Light Processing) from Texas Instruments turns out to be a versatile device for optical signal processing. The working principle of DLP is based on so called switched-blazed-grating. Part of its micro-mirror array can be formed as a dynamic blazed grating with a period of 14 μm by tilting the micro-mirrors at an angle of +/-12 degrees. It is expected to function as either a switch or an attenuator by directing total or part of the incident light between the 2nd and -2nd diffraction orders. In this paper, we investigate the optical characteristics of a switched-blazed-grating, its application as a re-configurable OADM, and the performance of such a device. Ray tracing and optical analysis of the OADM are made by using package software ASAP from Breault Research Organization. In conclusion, as a mature and reliable MEMS device, DLP-based switched-blazed-grating provides a very versatile platform for digital optical signal processing and can be used as a dynamic optical-networking device with good performance.

  2. Experimental verification of an all-optical dual-hop 10  Gbit/s free-space optics link under turbulence regimes.

    PubMed

    Libich, Jiri; Komanec, Matej; Zvanovec, Stanislav; Pesek, Petr; Popoola, Wasiu O; Ghassemlooy, Zabih

    2015-02-01

    This Letter presents original measurement results from an all-optical 10 Gbit/s free-space optics (FSO) relay link involving two FSO links and an all-optical switch. Considering the fact that reported analyses of relay links are dominated by analytical findings, the experimental results represent a vital resource for evaluating the performance of relay FSO links in the presence of atmospheric turbulence. Bit-error-rate (BER) performance of the relay system is tested for single and dual-hop links under several turbulence regimes. Furthermore, results from this measurement are used to ascertain real parameters of the outdoor links and to improve the accuracy of simulation results. Results show that using a dual-hop FSO link against a single FSO link could result in up to four orders of magnitude improvement in BER in the presence of atmospheric turbulence.

  3. A synaptic device built in one diode-one resistor (1D-1R) architecture with intrinsic SiOx-based resistive switching memory

    NASA Astrophysics Data System (ADS)

    Chang, Yao-Feng; Fowler, Burt; Chen, Ying-Chen; Zhou, Fei; Pan, Chih-Hung; Chang, Kuan-Chang; Tsai, Tsung-Ming; Chang, Ting-Chang; Sze, Simon M.; Lee, Jack C.

    2016-04-01

    We realize a device with biological synaptic behaviors by integrating silicon oxide (SiOx) resistive switching memory with Si diodes to further minimize total synaptic power consumption due to sneak-path currents and demonstrate the capability for spike-induced synaptic behaviors, representing critical milestones for the use of SiO2-based materials in future neuromorphic computing applications. Biological synaptic behaviors such as long-term potentiation, long-term depression, and spike-timing dependent plasticity are demonstrated systemically with comprehensive investigation of spike waveform analyses and represent a potential application for SiOx-based resistive switching materials. The resistive switching SET transition is modeled as hydrogen (proton) release from the (SiH)2 defect to generate the hydrogenbridge defect, and the RESET transition is modeled as an electrochemical reaction (proton capture) that re-forms (SiH)2. The experimental results suggest a simple, robust approach to realize programmable neuromorphic chips compatible with largescale complementary metal-oxide semiconductor manufacturing technology.

  4. Broadband optically controlled switching effect in a microfluid-filled photonic bandgap fiber

    NASA Astrophysics Data System (ADS)

    Guo, Junqi; Liu, Yan-ge; Wang, Zhi; Luo, Mingming; Huang, Wei; Han, Tingting; Liu, Xiaoqi

    2016-05-01

    Broadband optically controlled switching in a microfluid-filled photonic bandgap fiber (MF-PBGF) was observed and investigated. The MF-PBGF was formed by infusing a temperature-sensitive high-index fluid into all of the cladding holes of a microstructured optical fiber (MOF). The fiber was then side pumped with a 532 nm continuous wave laser. An extinction ratio of greater than 20 dB at most of the bandgap wavelengths (more than 200 nm) was obtained with a switching power of ∼147 mW. Theoretical and experimental investigations revealed that the effect originated from changes in the temperature gradient induced by heat absorption of the fiber coating with laser illumination. These investigations offer a new and simple approach to achieve wideband and flexible all-optical fiber switching devices without using any photosensitive materials.

  5. Role of ITO electrode in the resistive switching behavior of TiN/HfO2/ITO memory devices at different annealing temperatures

    NASA Astrophysics Data System (ADS)

    Ye, Cong; Deng, Teng-fei; Wu, Jiaji; Zhan, Chao; Wang, Hao; Zhang, Jun

    2015-05-01

    TiN/HfO2/ITO memory devices were fabricated and annealed at 200, 300, and 400 °C. At room temperature (RT), 200 °C, and 300 °C, the devices show the self-compliance phenomenon and a low SET voltage of 0.2 V, while at 400 °C the SET voltage increases to 1.1 V and the low resistance state (LRS) current increases to 8 mA. We deduced that the impact of annealing temperature on the resistive switching behavior is mainly attributed to the indium tin oxide (ITO) electrode. Some Sn4+ ions in the ITO electrode drift towards the HfO2 layer owing to the electrical force, then an interfacial layer is formed and acts as an internal resistor. At 400 °C, the remarkable increase of LRS current is attributed to the decreases in both the ITO electrode resistance and the interface resistance.

  6. Reproducible bipolar resistive switching in entire nitride AlN/n-GaN metal-insulator-semiconductor device and its mechanism

    SciTech Connect

    Chen, Yiren; Song, Hang E-mail: lidb@ciomp.ac.cn; Jiang, Hong; Li, Zhiming; Zhang, Zhiwei; Sun, Xiaojuan; Li, Dabing E-mail: lidb@ciomp.ac.cn; Miao, Guoqing

    2014-11-10

    Reproducible bipolar resistive switching characteristics are demonstrated in entire nitride AlN/n-GaN metal-insulator-semiconductor devices. The mechanism involved confirms to trap-controlled space charge limited current theory and can be attributed to the nitrogen vacancies of AlN serving as electron traps that form/rupture electron transport channel by trapping/detrapping electrons. This study will lead to the development of in-situ growth of group-III nitrides by metal-organic chemical vapor deposition as a candidate for next-generation nonvolatile memory device. Moreover, it will be benefit to structure monolithic integrated one-transistor-one-resistor memory with nitride high electron mobility transistors.

  7. Impact of composition and crystallization behavior of atomic layer deposited strontium titanate films on the resistive switching of Pt/STO/TiN devices

    SciTech Connect

    Aslam, N.; Rodenbücher, C.; Szot, K.; Waser, R.; Hoffmann-Eifert, S.; Longo, V.; Roozeboom, F.; Kessels, W. M. M.

    2014-08-14

    The resistive switching (RS) properties of strontium titanate (Sr{sub 1+x}Ti{sub 1+y}O{sub 3+(x+2y)}, STO) based metal-oxide-metal structures prepared from industrial compatible processes have been investigated focusing on the effects of composition, microstructure, and device size. Metastable perovskite STO films were prepared on Pt-coated Si substrates utilizing plasma-assisted atomic layer deposition (ALD) from cyclopentadienyl-based metal precursors and oxygen plasma at 350 °C, and a subsequent annealing at 600 °C in nitrogen. Films of 15 nm and 12 nm thickness with three different compositions [Sr]/([Sr] + [Ti]) of 0.57 (Sr-rich STO), 0.50 (stoichiometric STO), and 0.46 (Ti-rich STO) were integrated into Pt/STO/TiN crossbar structures with sizes ranging from 100 μm{sup 2} to 0.01 μm{sup 2}. Nano-structural characterizations revealed a clear effect of the composition of the as-deposited STO films on their crystallization behavior and thus on the final microstructures. Local current maps obtained by local-conductivity atomic force microscopy were in good agreement with local changes of the films' microstructures. Correspondingly, also the initial leakage currents of the Pt/STO/TiN devices were affected by the STO compositions and by the films' microstructures. An electroforming process set the Pt/STO/TiN devices into the ON-state, while the forming voltage decreased with increasing initial leakage current. After a RESET process under opposite voltage has been performed, the Pt/STO/TiN devices showed a stable bipolar RS behavior with non-linear current-voltage characteristics for the high (HRS) and the low (LRS) resistance states. The obtained switching polarity and nearly area independent LRS values agree with a filamentary character of the RS behavior according to the valence change mechanism. The devices of 0.01 μm{sup 2} size with a 12 nm polycrystalline stoichiometric STO film were switched at a current compliance of 50 μA with

  8. Defect trajectories and domain-wall loop dynamics during two-frequency switching in a bistable azimuthal nematic device.

    PubMed

    Davidson, A J; Brown, C V; Mottram, N J; Ladak, S; Evans, C R

    2010-05-01

    Bistable azimuthal nematic alignment textures have been created in micrometer-scale channels for which one sidewall is smooth and straight and the other possesses a symmetric sawtooth morphology. The optical textures have been observed during dynamic switching between the two stable states in response to dual frequency ac waveform driving of a highly dispersive nematic liquid crystal. The switching processes involves collapsing of filamentlike director reorientation (tilt-wall) loops and the associated motion and annihilation of surface defects along and close to the edge at the sawtooth sidewall. The predictions from both the n-director-based Ericksen-Leslie theory and the Q-tensor theory are in good agreement with the experimental observations.

  9. Defect trajectories and domain-wall loop dynamics during two-frequency switching in a bistable azimuthal nematic device

    NASA Astrophysics Data System (ADS)

    Davidson, A. J.; Brown, C. V.; Mottram, N. J.; Ladak, S.; Evans, C. R.

    2010-05-01

    Bistable azimuthal nematic alignment textures have been created in micrometer-scale channels for which one sidewall is smooth and straight and the other possesses a symmetric sawtooth morphology. The optical textures have been observed during dynamic switching between the two stable states in response to dual frequency ac waveform driving of a highly dispersive nematic liquid crystal. The switching processes involves collapsing of filamentlike director reorientation (tilt-wall) loops and the associated motion and annihilation of surface defects along and close to the edge at the sawtooth sidewall. The predictions from both the n -director-based Ericksen-Leslie theory and the Q -tensor theory are in good agreement with the experimental observations.

  10. Defect trajectories and domain-wall loop dynamics during two-frequency switching in a bistable azimuthal nematic device.

    PubMed

    Davidson, A J; Brown, C V; Mottram, N J; Ladak, S; Evans, C R

    2010-05-01

    Bistable azimuthal nematic alignment textures have been created in micrometer-scale channels for which one sidewall is smooth and straight and the other possesses a symmetric sawtooth morphology. The optical textures have been observed during dynamic switching between the two stable states in response to dual frequency ac waveform driving of a highly dispersive nematic liquid crystal. The switching processes involves collapsing of filamentlike director reorientation (tilt-wall) loops and the associated motion and annihilation of surface defects along and close to the edge at the sawtooth sidewall. The predictions from both the n-director-based Ericksen-Leslie theory and the Q-tensor theory are in good agreement with the experimental observations. PMID:20866252

  11. Multilevel unipolar resistive switching with negative differential resistance effect in Ag/SiO2/Pt device

    NASA Astrophysics Data System (ADS)

    Sun, Haitao; Liu, Qi; Long, Shibing; Lv, Hangbing; Banerjee, Writam; Liu, Ming

    2014-10-01

    In this paper, we report a multilevel unipolar resistive switching (RS) phenomenon with negative differential resistance (NDR) effect in Ag/SiO2/Pt sandwich structure. After positive electroforming process with low compliance current (ICC, 10 nA), a conductive filament consisting of isolated Ag nanocrystals is formed inside SiO2 layer. Then, an abnormal unipolar resistive switching (RESET voltage is larger than SET voltage) with NDR effect is obtained under negative voltage sweep without ICC. Based on I-V fitting and temperature dependence of the resistance results, we suggest that the abnormal unipolar RS is dominated by the charging/discharging of carriers in Ag nanocrystals. In addition, we demonstrate that the unipolar RS exhibits good performances, including large Roff/Ron ratio, high uniformity, long retention time, and multilevel storage potential.

  12. Graphene-Modified Interface Controls Transition from VCM to ECM Switching Modes in Ta/TaOx Based Memristive Devices.

    PubMed

    Lübben, Michael; Karakolis, Panagiotis; Ioannou-Sougleridis, Vassilios; Normand, Pascal; Dimitrakis, Panagiotis; Valov, Ilia

    2015-10-28

    By modification of the electrode-solid-electrolyte interface with graphene, transit from valence change memories (VCM) to electrochemical metallization memories (ECM) in the cell Ta(C)/Ta2 O5 /Pt is demonstrated, thus, bridging both mechanisms. The ECM operation is discussed in the light of Ta-cation mobility in TaOx . The crucial role of electrochemical processes and moisture in the resistive switching process is also highlighted.

  13. Radiation sensitive solid state switch

    NASA Technical Reports Server (NTRS)

    Hutto, R. J. (Inventor)

    1973-01-01

    A mechanically operable solid state switch suited for use in achieving a variable circuit-switching function is described. This switch is characterized by an annular array of photoresponsive switching devices, disposed in communication with an included source of radiation, and a plurality of interchangeable, mechanically operable interrupter disks. Each disk has a predetermined pattern of transparent and opaque portions. Operative displacement of each disk serves to make and break selected electrical circuits through the photo responsive devices of said array.

  14. Modulation of surface trap induced resistive switching by electrode annealing in individual PbS micro/nanowire-based devices for resistance random access memory.

    PubMed

    Zheng, Jianping; Cheng, Baochang; Wu, Fuzhang; Su, Xiaohui; Xiao, Yanhe; Guo, Rui; Lei, Shuijin

    2014-12-10

    Bipolar resistive switching (RS) devices are commonly believed as a promising candidate for next generation nonvolatile resistance random access memory (RRAM). Here, two-terminal devices based on individual PbS micro/nanowires with Ag electrodes are constructed, whose electrical transport depends strongly on the abundant surface and bulk trap states in micro/nanostructures. The surface trap states can be filled/emptied effectively at negative/positive bias voltage, respectively, and the corresponding rise/fall of the Fermi level induces a variation in a degenerate/nondegenerate state, resulting in low/high resistance. Moreover, the filling/emptying of trap states can be utilized as RRAM. After annealing, the surface trap state can almost be eliminated completely; while most of the bulk trap states can still remain. In the devices unannealed and annealed at both ends, therefore, the symmetrical back-to-back Fowler-Nordheim tunneling with large ON/OFF resistance ratio and Poole-Frenkel emission with poor hysteresis can be observed under cyclic sweep voltage, respectively. However, a typical bipolar RS behavior can be observed effectively in the devices annealed at one end. The acquirement of bipolar RS and nonvolatile RRAM by the modulation of electrode annealing demonstrates the abundant trap states in micro/nanomaterials will be advantageous to the development of new type electronic components.

  15. Large optical nonlinearity of ITO nanorods for sub-picosecond all-optical modulation of the full-visible spectrum

    NASA Astrophysics Data System (ADS)

    Guo, Peijun; Schaller, Richard D.; Ocola, Leonidas E.; Diroll, Benjamin T.; Ketterson, John B.; Chang, Robert P. H.

    2016-09-01

    Nonlinear optical responses of materials play a vital role for the development of active nanophotonic and plasmonic devices. Optical nonlinearity induced by intense optical excitation of mobile electrons in metallic nanostructures can provide large-amplitude, dynamic tuning of their electromagnetic response, which is potentially useful for all-optical processing of information and dynamic beam control. Here we report on the sub-picosecond optical nonlinearity of indium tin oxide nanorod arrays (ITO-NRAs) following intraband, on-plasmon-resonance optical pumping, which enables modulation of the full-visible spectrum with large absolute change of transmission, favourable spectral tunability and beam-steering capability. Furthermore, we observe a transient response in the microsecond regime associated with slow lattice cooling, which arises from the large aspect-ratio and low thermal conductivity of ITO-NRAs. Our results demonstrate that all-optical control of light can be achieved by using heavily doped wide-bandgap semiconductors in their transparent regime with speed faster than that of noble metals.

  16. Large optical nonlinearity of ITO nanorods for sub-picosecond all-optical modulation of the full-visible spectrum

    PubMed Central

    Guo, Peijun; Schaller, Richard D.; Ocola, Leonidas E.; Diroll, Benjamin T.; Ketterson, John B.; Chang, Robert P. H.

    2016-01-01

    Nonlinear optical responses of materials play a vital role for the development of active nanophotonic and plasmonic devices. Optical nonlinearity induced by intense optical excitation of mobile electrons in metallic nanostructures can provide large-amplitude, dynamic tuning of their electromagnetic response, which is potentially useful for all-optical processing of information and dynamic beam control. Here we report on the sub-picosecond optical nonlinearity of indium tin oxide nanorod arrays (ITO-NRAs) following intraband, on-plasmon-resonance optical pumping, which enables modulation of the full-visible spectrum with large absolute change of transmission, favourable spectral tunability and beam-steering capability. Furthermore, we observe a transient response in the microsecond regime associated with slow lattice cooling, which arises from the large aspect-ratio and low thermal conductivity of ITO-NRAs. Our results demonstrate that all-optical control of light can be achieved by using heavily doped wide-bandgap semiconductors in their transparent regime with speed faster than that of noble metals. PMID:27682836

  17. Tunable Multi-switching in Plasmonic Waveguide with Kerr Nonlinear Resonator.

    PubMed

    He, Zhihui; Li, Hongjian; Zhan, Shiping; Li, Boxun; Chen, Zhiquan; Xu, Hui

    2015-10-29

    We propose a nanoplasmonic waveguide side-coupled with bright-dark-dark resonators in our paper. A multi-oscillator theory derived from the typical two-oscillator model, is established to describe spectral features as well as slow-light effects in bright-dark-dark structures, and confirmed by the finite-difference time domain (FDTD). That a typical plasmon induced transparency (PIT) turns to double PIT spectra is observed in this waveguide structure. At the same time, multi-switching effects with obvious double slow-light bands based on double PIT are also discovered in our proposed structure. What's more, dynamically tuning the multi-switching is achieved by means of filling Fabry-Perot resonators with the Kerr nonlinear material Ag-BaO. These results may have applications in all-optical devices, moreover, the multi-oscillator theory may play a guiding role in designing plasmonic devices.

  18. All-optical NRZ-to-RZ data format conversion with optically injected laser diode or semiconductor optical amplifier

    NASA Astrophysics Data System (ADS)

    Lin, Gong-Ru; Chang, Yung-Cheng; Yu, Kun-Chieh

    2006-09-01

    By injecting the optical NRZ data into a Fabry-Perot laser diode (FPLD) synchronously modulated at below threshold condition or a semiconductor optical amplifier (SOA) gain-depleted with a backward injected clock stream, the all-optical non-return to zero (NRZ) to return-to-zero (RZ) format conversion of a STM-64 date-stream for synchronous digital hierarchy (SDH) or an OC-192 data stream for synchronous optical network (SONET) in high-speed fiber-optic communication link can be performed. Without the assistance of any complicated RF electronic circuitry, the output RZ data-stream at bit rate of up to 10 Gbit/s is successfully transformed in the optically NRZ injection-locked FPLD, in which the incoming NRZ data induces gain-switching of the FPLD without DC driving current or at below threshold condition. A power penalty of 1.2 dB is measured after NRZ-to-RZ transformation in the FPLD. Alternatively, the all-optical 10Gbits/s NRZ-to-RZ format conversion can also be demonstrated in a semiconductor optical amplifier under a backward dark-optical-comb injection with its duty-cycle 70%, which is obtained by reshaping from the received data clock at 10 GHz. The incoming optical NRZ data-stream is transformed into a pulsed RZ data-stream with its duty-cycle, rms timing jitter, and conversion gain of 15%, 4ps, and 3dB, respectively. In contrast to the FPLD, the SOA based NRZ-to-RZ converter exhibits an enhanced extinction ratio from 7 to 13 dB, and BER of 10 -13 at -18.5 dBm. In particular, the power penalty of the received RZ data-stream has greatly improved by 5 dB as compared to that obtained from FPLD.

  19. Resistive switching memory devices based on electrical conductance tuning in poly(4-vinyl phenol)-oxadiazole composites.

    PubMed

    Sun, Yanmei; Miao, Fengjuan; Li, Rui; Wen, Dianzhong

    2015-11-28

    Nonvolatile memory devices, based on electrical conductance tuning in thin films of poly(4-vinyl phenol) (PVP) and 2-(4-tert-butylphenyl)-5-(4-biphenylyl)-1,3,4-oxadiazole (PBD) composites, are fabricated. The current-voltage characteristics of the fabricated devices show different electrical conductance behaviors, such as the write-once read-many-times (WORM) memory effect, the rewritable flash memory effect and insulator behavior, which depend on the content of PBD in the PVP + PBD composites. The OFF and ON states of the WORM and rewritable flash memory devices are stable under a constant voltage stress or a continuous pulse voltage stress at a read voltage. The memory mechanism is deduced from the modeling of the nature of currents in both states in the devices. PMID:26490192

  20. Frequency-time coherence for all-optical sampling without optical pulse source

    PubMed Central

    Preußler, Stefan; Raoof Mehrpoor, Gilda; Schneider, Thomas

    2016-01-01

    Sampling is the first step to convert an analogue optical signal into a digital electrical signal. The latter can be further processed and analysed by well-known electrical signal processing methods. Optical pulse sources like mode-locked lasers are commonly incorporated for all-optical sampling, but have several drawbacks. A novel approach for a simple all-optical sampling is to utilise the frequency-time coherence of each signal. The method is based on only using two coupled modulators driven with an electrical sine wave. Since no optical source is required, a simple integration in appropriate platforms, such as Silicon Photonics might be possible. The presented method grants all-optical sampling with electrically tunable bandwidth, repetition rate and time shift. PMID:27687495

  1. All-optical virtual private network and ONUs communication in optical OFDM-based PON system.

    PubMed

    Zhang, Chongfu; Huang, Jian; Chen, Chen; Qiu, Kun

    2011-11-21

    We propose and demonstrate a novel scheme, which enables all-optical virtual private network (VPN) and all-optical optical network units (ONUs) inter-communications in optical orthogonal frequency-division multiplexing-based passive optical network (OFDM-PON) system using the subcarrier bands allocation for the first time (to our knowledge). We consider the intra-VPN and inter-VPN communications which correspond to two different cases: VPN communication among ONUs in one group and in different groups. The proposed scheme can provide the enhanced security and a more flexible configuration for VPN users compared to the VPN in WDM-PON or TDM-PON systems. The all-optical VPN and inter-ONU communications at 10-Gbit/s with 16 quadrature amplitude modulation (16 QAM) for the proposed optical OFDM-PON system are demonstrated. These results verify that the proposed scheme is feasible.

  2. Frequency-time coherence for all-optical sampling without optical pulse source

    NASA Astrophysics Data System (ADS)

    Preußler, Stefan; Raoof Mehrpoor, Gilda; Schneider, Thomas

    2016-09-01

    Sampling is the first step to convert an analogue optical signal into a digital electrical signal. The latter can be further processed and analysed by well-known electrical signal processing methods. Optical pulse sources like mode-locked lasers are commonly incorporated for all-optical sampling, but have several drawbacks. A novel approach for a simple all-optical sampling is to utilise the frequency-time coherence of each signal. The method is based on only using two coupled modulators driven with an electrical sine wave. Since no optical source is required, a simple integration in appropriate platforms, such as Silicon Photonics might be possible. The presented method grants all-optical sampling with electrically tunable bandwidth, repetition rate and time shift.

  3. All-optical XOR and OR logic gates based on line and point defects in 2-D photonic crystal

    NASA Astrophysics Data System (ADS)

    Goudarzi, Kiyanoosh; Mir, Ali; Chaharmahali, Iman; Goudarzi, Dariush

    2016-04-01

    In this paper, we have proposed an all-optical logic gate structure based on line and point defects created in the two dimensional square lattice of silicon rods in air photonic crystals (PhCs). Line defects are embedded in the DX and DZ directions of the momentum space. The device has two input and two output ports. It has been shown analytically whether the initial phase difference between the two input beams is π/2, they interfere together constructively or destructively to realize the logical functions. The simulation results show that the device can acts as a XOR and an OR logic gate. It is applicable in the frequency range of 0-0.45 (a/λ), however we set it at (a/λ=) 0.419 for low dispersion condition, correspondingly the lambda is equal to 1.55 μm. The maximum delay time to response to the input signals is about 0.4 ps, hence the speed of the device is about 2.5 THz. Also 6.767 dB is the maximum contrast ratio of the device.

  4. Switching Power Universality in Unipolar Resistive Switching Memories

    PubMed Central

    Kim, Jongmin; Jung, Kyooho; Kim, Yongmin; Jo, Yongcheol; Cho, Sangeun; Woo, Hyeonseok; Lee, Seongwoo; Inamdar, A. I.; Hong, Jinpyo; Lee, Jeon-Kook; Kim, Hyungsang; Im, Hyunsik

    2016-01-01

    We investigate the resistive switching power from unipolar resistive switching current-voltage characteristics in various binary metal oxide films sandwiched by different metal electrodes, and find a universal feature (the so-called universality) in the switching power among these devices. To experimentally derive the switching power universality, systematic measurements of the switching voltage and current are performed, and neither of these correlate with one another. As the switching resistance (R) increases, the switching power (P) decreases following a power law P ∝ R−β, regardless of the device configurations. The observed switching power universality is indicative of the existence of a commonly applicable switching mechanism. The origin of the power universality is discussed based on a metallic filament model and thermo-chemical reaction. PMID:27033695

  5. All-optical buffer based on temporal cavity solitons operating at 10 Gb/s

    NASA Astrophysics Data System (ADS)

    Jang, Jae K.; Erkintalo, Miro; Schröder, Jochen; Eggleton, Benjamin J.; Murdoch, Stuart G.; Coen, Stéphane

    2016-10-01

    We demonstrate the operation of an all-optical buffer based on temporal cavity solitons stored in a nonlinear passive fiber ring resonator. Unwanted acoustic interactions between neighboring solitons are suppressed by modulating the phase of the external laser driving the cavity. A new locking scheme is presented that allows the buffer to operate with an arbitrarily large number of cavity solitons in the loop. Experimentally, we are able to demonstrate the storage of 4536 bits of data, written all-optically into the fiber ring at 10 Gb/s, for 1 minute.

  6. Cascaded all-optical operations in a hybrid integrated 80-Gb/s logic circuit.

    PubMed

    LeGrange, J D; Dinu, M; Sochor, T; Bollond, P; Kasper, A; Cabot, S; Johnson, G S; Kang, I; Grant, A; Kay, J; Jaques, J

    2014-06-01

    We demonstrate logic functionalities in a high-speed all-optical logic circuit based on differential Mach-Zehnder interferometers with semiconductor optical amplifiers as the nonlinear optical elements. The circuit, implemented by hybrid integration of the semiconductor optical amplifiers on a planar lightwave circuit platform fabricated in silica glass, can be flexibly configured to realize a variety of Boolean logic gates. We present both simulations and experimental demonstrations of cascaded all-optical operations for 80-Gb/s on-off keyed data.

  7. All-optical logic gate based on transient grating from disperse red 1 doped organic-inorganic hybrid films with an improved figure of merit

    SciTech Connect

    Gao, Tianxi; Que, Wenxiu Shao, Jinyou; Wang, Yushu

    2015-10-21

    Azobenzene dyes have large refractive index near their main resonance, but the poor figure of merit (FOM) limits their potential for all-optical applications. To improve this situation, disperse red 1 (DR1) molecules were dispersed in a sol-gel germanium/Ormosil organic-inorganic hybrid matrix. Z-scan measurement results showed a good compatibility between the dopant and the matrix, and also, an improved FOM was obtained as compared to the DR1/polymer films reported previously. To demonstrate the all-optical signal processing effect, a cw Nd:YAG laser emitting at 532 nm and a He-Ne laser emitting at 632.8 nm were used as pump and probe beams, respectively. DR1 acts as an initiator of the photo-induced transient holographic grating, which is attributed to the trans-cis-trans photoisomerization. Thus, a three inputs AND all-optical logic gate was achieved by using choppers with different frequencies. The detailed mechanism of operation is discussed. These results indicate that the DR1 doped germanium/Ormosil organic-inorganic hybrid film with an improved FOM has a great potential in all-optical devices around its main resonance.

  8. Manually operated coded switch

    DOEpatents

    Barnette, Jon H.

    1978-01-01

    The disclosure relates to a manually operated recodable coded switch in which a code may be inserted, tried and used to actuate a lever controlling an external device. After attempting a code, the switch's code wheels must be returned to their zero positions before another try is made.

  9. Synthesis of Mn0.04Cu0.05Zn0.91O nanorod and its application in optoelectronic switching device

    NASA Astrophysics Data System (ADS)

    Layek, Animesh; Middya, Somnath

    2016-05-01

    The optical absorption of ZnO nanorod had been reduced by introducing Mn as doping element. In this present study the optical absorption of ZnO nanorod has been improved by simultaneous doping of the element Mn and Cu. The hydrothermal reaction was adopted for the synthesis. The electrical conductivity and the optical band gap of the Mn0.04Cu0.05Zn0.91O were measured as 1.16 × 10-3Scm-1 and 3.07eV respectively, assigned the semiconductor behavior. The light induced rectification in time dependent current response characteristic of Al/ Mn0.04Cu0.05Zn0.91O/ITO was investigated to check the performance of the composite in opto-electronic switching device.

  10. Magnetic induction measurements using an all-optical {sup 87}Rb atomic magnetometer

    SciTech Connect

    Wickenbrock, Arne; Tricot, François; Renzoni, Ferruccio

    2013-12-09

    In this work we propose, and experimentally demonstrate, the use of a self-oscillating all-optical atomic magnetometer for magnetic induction measurements. Given the potential for miniaturization of atomic magnetometers, and their extreme sensitivity, the present work shows that atomic magnetometers may play a key role in the development of instrumentation for magnetic induction tomography.

  11. All-optical magnetization reversal by circularly polarized laser pulses: Experiment and multiscale modeling

    NASA Astrophysics Data System (ADS)

    Vahaplar, K.; Kalashnikova, A. M.; Kimel, A. V.; Gerlach, S.; Hinzke, D.; Nowak, U.; Chantrell, R.; Tsukamoto, A.; Itoh, A.; Kirilyuk, A.; Rasing, Th.

    2012-03-01

    We present results of detailed experimental and theoretical studies of all-optical magnetization reversal by single circularly-polarized laser pulses in ferrimagnetic rare earth—transition metal (RE-TM) alloys GdxFe90-xCo10 (20%all-optically driven linear reversal can be modeled as a result of a two-fold impact of the laser pulse on the medium. First, due to absorption of the light and ultrafast laser-induced heating, the medium is brought to a highly nonequilibrium state. Simultaneously, due to the ultrafast inverse Faraday effect the circularly polarized laser pulse acts as an effective magnetic field of the amplitude up to ˜20 T. We show that the polarization-dependent reversal triggered by the circularly polarized light is feasible only in a narrow range (below 10%) of laser fluences. The duration of the laser pulse required for the reversal can be varied from ˜40 fs up to at least ˜1700 fs. We also investigate experimentally the role of the ferrimagnetic properties of GdFeCo in the all-optical reversal. In particular, the optimal conditions for the all-optical reversal are achieved just below the ferrimagnetic compensation temperature, where the magnetic information can be all-optically written by a laser pulse of minimal fluence and read out within just 30 ps. We argue that this is the fastest write-read event demonstrated for magnetic recording so far.

  12. Reusable fast opening switch

    DOEpatents

    Van Devender, John P.; Emin, David

    1986-01-01

    A reusable fast opening switch for transferring energy, in the form of a high power pulse, from an electromagnetic storage device such as an inductor into a load. The switch is efficient, compact, fast and reusable. The switch comprises a ferromagnetic semiconductor which undergoes a fast transition between conductive and insulating states at a critical temperature and which undergoes the transition without a phase change in its crystal structure. A semiconductor such as europium rich europhous oxide, which undergoes a conductor to insulator transition when it is joule heated from its conductor state, can be used to form the switch.

  13. Reusable fast opening switch

    DOEpatents

    Van Devender, J.P.; Emin, D.

    1983-12-21

    A reusable fast opening switch for transferring energy, in the form of a high power pulse, from an electromagnetic storage device such as an inductor into a load. The switch is efficient, compact, fast and reusable. The switch comprises a ferromagnetic semiconductor which undergoes a fast transition between conductive and metallic states at a critical temperature and which undergoes the transition without a phase change in its crystal structure. A semiconductor such as europium rich europhous oxide, which undergoes a conductor to insulator transition when it is joule heated from its conductor state, can be used to form the switch.

  14. Organic Materials For Optical Switching

    NASA Technical Reports Server (NTRS)

    Cardelino, Beatriz H.

    1993-01-01

    Equations predict properties of candidate materials. Report presents results of theoretical study of nonlinear optical properties of organic materials. Such materials used in optical switching devices for computers and telecommunications, replacing electronic switches. Optical switching potentially offers extremely high information throughout in compact hardware.

  15. Enhanced stability of complementary resistance switching in the TiN/HfOx/TiN resistive random access memory device via interface engineering

    NASA Astrophysics Data System (ADS)

    Zhang, H. Z.; Ang, D. S.; Yew, K. S.; Wang, X. P.

    2016-02-01

    This study shows that a majority (70%) of TiN/HfOx/TiN devices exhibit failed complementary resistance switching (CRS) after forming. In conjunction with the consistent observation of a large non-polar reset loop in the first post-forming voltage-sweep measurement, it is proposed that breakdown of the TiN/HfOx interfacial oxide layers (crucial in enabling CRS) and the accompanied formation of Ti filaments (due to Ti migration from the TiN cathode into the breakdown path) resulted in CRS failure and the observed non-polar reset behavior. This hypothesis is supported by the significant reduction or complete elimination of the large non-polar reset and CRS failure in devices with a thin Al2O3 layer incorporated at the TiN-cathode/HfOx or both TiN/HfOx interfaces. The higher breakdown field of the thin Al2O3 enables it to sustain the forming voltage until the forming process is interrupted, thus enabling CRS via oxygen exchange with the adjacent vacancy-type filament formed in the HfOx.

  16. Widely tunable monolithic dual-mode laser for W-band photonic millimeter-wave generation and all-optical clock recovery.

    PubMed

    Pan, Biwei; Guo, Lu; Zhang, Limeng; Lu, Dna; Huo, Li; Lou, Caiyun; Zhao, Lingjuan

    2016-04-10

    We demonstrate a monolithic dual-mode amplified feedback laser for photonic millimeter-wave generation and all-optical clock recovery. Dual-mode lasing with beating frequency around 100 GHz was realized by using a single-mode distributed feedback (DFB) laser with a short feedback cavity that was integrated by simple quantum-well intermixing technology. By tuning the bias currents of the laser sections, the beating-frequency can be continuously tuned from 75 to 109 GHz, almost covering the entire W-band (75-110 GHz). Furthermore, by using this device, an all-optical clock recovery for 100 Gbit/s return-to-zero on-off-keying signal was achieved with a timing jitter of 301 fs.

  17. Characterization of a Broadband All-Optical Ultrasound Transducer—From Optical and Acoustical Properties to Imaging

    PubMed Central

    Hou, Yang; Kim, Jin-Sung; Huang, Sheng-Wen; Ashkenazi, Shai; Guo, L. Jay; O’Donnell, Matthew

    2009-01-01

    A broadband all-optical ultrasound transducer has been designed, fabricated, and evaluated for high-frequency ultrasound imaging. The device consists of a 2-D gold nanostructure imprinted on top of a glass substrate, followed by a 3 μm PDMS layer and a 30 nm gold layer. A laser pulse at the resonance wavelength of the gold nanostructure is focused onto the surface for ultrasound generation, while the gold nanostructure, together with the 30 nm thick gold layer and the PDMS layer in between, forms an etalon for ultrasound detection, which uses a CW laser at a wavelength far from resonance as the probing beam. The center frequency of a pulse-echo signal recorded in the far field of the transducer is 40 MHz with -6 dB bandwidth of 57 MHz. The signal to noise ratio (SNR) from a 70 μm diameter transmit element combined with a 20 μm diameter receive element probing a near perfect reflector positioned 1.5 mm from the transducer surface is more than 10 dB and has the potential to be improved by at least another 40 dB. A high-frequency ultrasound array has been emulated using multiple measurements from the transducer while mechanically scanning an imaging target. Characterization of the device’s optical and acoustical properties, as well as preliminary imaging results, strongly suggest that all-optical ultrasound transducers can be used to build high-frequency arrays for real-time high-resolution ultrasound imaging. PMID:18986929

  18. All-optically driven system in ultrasonic wave-based structural health monitoring

    NASA Astrophysics Data System (ADS)

    Bi, Siwen; Wu, Nan; Zhou, Jingcheng; Zhang, Haifeng; Wang, Xingwei

    2016-04-01

    Ultrasonic wave based structural health monitoring (SHM) is an innovative method for nondestructive detection and an area of growing interest. This is due to high demands for wireless detection in the field of structural engineering. Through optically exciting and detecting ultrasonic waves, electrical wire connections can be avoided, and non-contact SHM can be achieved. With the combination of piezoelectric transducer (PZT) (which possesses high heat resistance) and the noncontact detection, this system has a broad range of applications, even in extreme conditions. This paper reports an all-optically driven SHM system. The resonant frequencies of the PZT transducers are sensitive to a variety of structural damages. Experimental results have verified the feasibility of the all-optically driven SHM system.

  19. Photonic integrated circuit for all-optical millimeter-wave signal generation

    SciTech Connect

    Vawter, G.A.; Mar, A.; Zolper, J.; Hietala, V.

    1997-03-01

    Generation of millimeter-wave electronic signals and power is required for high-frequency communication links, RADAR, remote sensing and other applications. However, in the 30 to 300 GHz mm-wave regime, signal sources are bulky and inefficient. All-optical generation of mm-wave signals promises to improve efficiency to as much as 30 to 50 percent with output power as high as 100 mW. All of this may be achieved while taking advantage of the benefits of monolithic integration to reduce the overall size to that of a single semiconductor chip only a fraction of a square centimeter in size. This report summarizes the development of the first monolithically integrated all-optical mm-wave signal generator ever built. The design integrates a mode-locked semiconductor ring diode laser with an optical amplifier and high-speed photodetector into a single optical integrated circuit. Frequency generation is demonstrated at 30, 60 and 90 Ghz.

  20. An all-optical vector atomic magnetometer for fundamental physics applications

    NASA Astrophysics Data System (ADS)

    Wurm, David; Mateos, Ignacio; Zhivun, Elena; Patton, Brian; Fierlinger, Peter; Beck, Douglas; Budker, Dmitry

    2014-05-01

    We have developed a laboratory prototype of a compact all-optical vector magnetometer. Due to their high precision and absolute accuracy, atomic magnetometers are crucial sensors in fundamental physics experiments which require extremely stable magnetic fields (e.g., neutron EDM searches). This all-optical sensor will allow high-resolution measurements of the magnitude and direction of a magnetic field without perturbing the magnetic environment. Moreover, its absolute accuracy makes it calibration-free, an advantage in space applications (e.g., space-based gravitational-wave detection). Magnetometry in precision experiments or space applications also demands long-term stability and well-understood noise characteristics at frequencies below 10-4 Hz. We have characterized the low-frequency noise floor of this sensor and will discuss methods to improve its long-time performance.