SPIE Defense + Security最新文献

{"title":"Contributions from coherent and incoherent lattice excitations to ultrafast optical control of magnetic anisotropy of metallic films","authors":"V. N. Kats, T. Linnik, A. S. Salasyuk, A. Rushforth, Mu Wang, Peter Wadely, A. Akimov, S. Cavill, V. Holý, A. Kalashnikova, A. Scherbakov","doi":"10.1117/12.2238020","DOIUrl":"https://doi.org/10.1117/12.2238020","url":null,"abstract":"Spin-lattice coupling is one of the most prominent interactions mediating response of spin ensemble to ultrafast optical excitation. Here we exploit optically generated coherent and incoherent phonons to drive coherent spin dynamics, i.e. precession, in thin films of magnetostrictive metal Galfenol. We demonstrate unambiguously that coherent phonons, also seen as dynamical strain generated due to picosecond lattice temperature raise, give raise to magnetic anisotropy changes of the optically excited magnetic _lm; and this contribution may be comparable to or even dominate over the contribution from the temperature increase itself, considered as incoherent phonons.","PeriodicalId":222501,"journal":{"name":"SPIE Defense + Security","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130231705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A wavelet contrast metric for the targeting task performance metric","authors":"Bradley L. Preece, Eric A. Flug","doi":"10.1117/12.2223855","DOIUrl":"https://doi.org/10.1117/12.2223855","url":null,"abstract":"Target acquisition performance depends strongly on the contrast of the target. The Targeting Task Performance (TTP) metric, within the Night Vision Integrated Performance Model (NV-IPM), uses a combination of resolution, signal-to-noise ratio (SNR), and contrast to predict and model system performance. While the dependence on resolution and SNR are well defined and understood, defining a robust and versatile contrast metric for a wide variety of acquisition tasks is more difficult. In this correspondence, a wavelet contrast metric (WCM) is developed under the assumption that the human eye processes spatial differences in a manner similar to a wavelet transform. The amount of perceivable information, or useful wavelet coefficients, is used to predict the total viewable contrast to the human eye. The WCM is intended to better match the measured performance of the human vision system for high-contrast, low-contrast, and low-observable targets. After further validation, the new contrast metric can be incorporated using a modified TTP metric into the latest Army target acquisition software suite, the NV-IPM.","PeriodicalId":222501,"journal":{"name":"SPIE Defense + Security","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123760170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated mid-infrared photonic circuits for label-free biochemical sensing","authors":"P. Lin","doi":"10.1117/12.2227049","DOIUrl":"https://doi.org/10.1117/12.2227049","url":null,"abstract":"A chip-scale biochemical sensor was developed using mid-Infrared (mid-IR) transparent silicon nitride (SiN) optical waveguides. The label free detection was conducted at λ = 2.70 - 2.81 μm because these spectral regions overlap with the characteristic glucose absorption associated with O-H stretches. Strong intensity attenuation at λ > 2.73 μm was found for the SiN waveguide covered by glucose and a detection limit less than 0.5 ng was experimentally demonstrated. The observed high sensitivity is attributed to a long mid-IR - glucose interaction length owning to the waveguide geometry and an increased sensing surface from the pedestal structure.","PeriodicalId":222501,"journal":{"name":"SPIE Defense + Security","volume":"136 13","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131747476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of the auger recombination rate in P+N−n−N−N HgCdTe detectors for HOT applications","authors":"J. Schuster, W. Tennant, E. Bellotti, P. Wijewarnasuriya","doi":"10.1117/12.2224383","DOIUrl":"https://doi.org/10.1117/12.2224383","url":null,"abstract":"Infrared (IR) photon detectors must be cryogenically cooled to provide the highest possible performance, usually to temperatures at or below ~ 150K. Such low operating temperatures (Top) impose very stringent requirements on cryogenic coolers. As such, there is a constant push in the industry to engineer new detector architectures that operate at higher temperatures, so called higher operating temperature (HOT) detectors. The ultimate goal for HOT detectors is room temperature operation. While this is not currently possibly for photon detectors, significant increases in Top are nonetheless beneficial in terms of reduced size, weight, power and cost (SWAP-C). The most common HgCdTe IR detector architecture is the P+n heterostructure photodiode (where a capital letter indicates a wide band gap relative to the active layer or “AL”). A variant of this architecture, the P+N−n−N−N heterostructure photodiode, should have a near identical photo-response to the P+n heterostructure, but with significantly lower dark diffusion current. The P+N−n−N−N heterostructure utilizes a very low doped AL, surrounded on both sides by wide-gap layers. The low doping in the AL, allows the AL to be fully depleted, which drastically reduces the Auger recombination rate in that layer. Minimizing the Auger recombination rate reduces the intrinsic dark diffusion current, thereby increasing Top. Note when we use the term “recombination rate” for photodiodes, we are actually referring to the net generation and recombination of minority carriers (and corresponding dark currents) by the Auger process. For these benefits to be realized, these devices must be intrinsically limited and well passivated. The focus of this proceeding is on studying the fundamental physics of the intrinsic dark currents in ideal P+N−n−N−N heterostructures, namely Auger recombination. Due to the complexity of these devices, specifically the presence of multiple heterojunctions, numerical device modeling techniques must be utilized to predict and understand the device operation, as analytical models do not exist for heterojunction devices.","PeriodicalId":222501,"journal":{"name":"SPIE Defense + Security","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125259394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on biomimetic underwater vehicles for underwater ISR","authors":"P. Szymak, T. Praczyk, K. Naus, B. Szturomski, M. Malec, M. Morawski","doi":"10.1117/12.2225587","DOIUrl":"https://doi.org/10.1117/12.2225587","url":null,"abstract":"Autonomous Biomimetic Underwater Vehicles BUVs driven by an undulating propulsion are a new branch in an area of an underwater robotics. They imitate both the construction and kinematics of a motion of underwater living organisms, e.g. fishes. Such vehicles have several features crucial from the point of view of military applications, e.g. larger secrecy and potential range of operation. The paper presents results of the research on BUVs carried out within two (Polish and EDA) projects both led by Polish Naval Academy. At the beginning, the initial efforts in building Polish BUV called CyberFish are included. Then, selected results of the tests of subsystems, e.g. navigational and 3D model of BUV built within national project are described. Next, the initial research achieved in the international project are showed. At the end, the schedule of the research planned to carry out within both projects is inserted. The paper is mainly focused on the hardware development of the BUVs.","PeriodicalId":222501,"journal":{"name":"SPIE Defense + Security","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115576134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recent development of SWIR focal plane array with InGaAs/GaAsSb type-II quantum wells","authors":"H. Inada, K. Machinaga, Sundararajan Balasekaran, K. Miura, T. Kawahara, M. Migita, K. Akita, Y. Iguchi","doi":"10.1117/12.2229591","DOIUrl":"https://doi.org/10.1117/12.2229591","url":null,"abstract":"HgCdTe (MCT) is predominantly used for infrared imaging applications even in SWIR region. However, MCT is expensive and contains environmentally hazardous substances. Therefore, its application has been restricted mainly military and scientific use and was not spread to commercial use. InGaAs/GaAsSb type-II quantum well structures are considered as an attractive material for realizing low dark current PDs owing to lattice-matching to InP substrate. Moreover, III-V compound material systems are suitable for commercial use. In this report, we describe successful operation of focal plane array (FPA) with InGaAs/GaAsSb quantum wells and mention improvement of optical characteristics. Planar type pin-PDs with 250-pairs InGaAs(5nm)/GaAsSb(5nm) quantum well absorption layer were fabricated. The p-n junction was formed in the absorption layer by the selective diffusion of zinc. Electrical and optical characteristics of FPA or pin-PDs were investigated. Dark current of 1μA/cm2 at 210K, which showed good uniformity and led to good S/N ratio in SWIR region, was obtained. Further, we could successfully reduce of stray light in the cavity of FPA with epoxy resin. As a result, the clear image was taken with 320x256 format and 7% contrast improvement was achieved. Reliability test of 10,000 heat cycles was carried out. No degradations were found in FPA characteristics of the epoxy coated sample. This result means FPA using InGaAs/GaAsSb type-II quantum wells is a promising candidate for commercial applications.","PeriodicalId":222501,"journal":{"name":"SPIE Defense + Security","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126739278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A 640×512-20μm dual-polarity ROIC for MWIR and LWIR hybrid FPAs","authors":"S. Eminoglu, O. S. Incedere, Nusret Bayhan, M. Isikhan, S. T. Soyer, C. M. B. Ustundag, S. Kocak, Ozge Turan, U. Eksi, T. Akin","doi":"10.1117/12.2224743","DOIUrl":"https://doi.org/10.1117/12.2224743","url":null,"abstract":"This paper reports the development of a new dual-polarity Direct-Injection (DI) Readout Integrated Circuit (ROIC), called MT6420DDA, designed to support back-to-back connected photodiodes with a single contact per pixel using dual pixel input circuitries suitable for both p-on-n and n-on-p type detectors. The ROIC has a format of 640 × 512 (VGA) and a pixel pitch of 20μm, and can be used to build dual-color or dual-band FPAs working in the MWIR and/or LWIR bands. The ROIC supports snapshot operation with Integrate-then-Read (ITR) and Integrate-while-Read modes (IWR). MT6420DDA has a system-on-chip architecture, with programmable biasing, timing, and configuration. The ROIC supports 2, 4, and 8-output modes at pixel output rates up to 12.5 MHz per output. It runs on 3.3 V analog and 1.8 V digital supplies, and dissipates less than 135 mW in the 4-output mode at 10 MHz. The ROIC has separate programmable full well capacitance values of 1.5 Me-, 3.0 Me-, and 6.0 Me- for both polarities in the high-gain (HG), mid-gain (MG), and low-gain (LG) modes. The ROIC supports two type of polarity switching modes as PSBF (Polarity Switching between Frames) and PSWF (Polarity Switching within Frames). In the PSBF modes, an alternating input polarity is used for each detector type for each frame during each integration period, possibly with different full-well and integration time settings. In the PSWF mode, both type of pixels are exposed almost simultaneously, where detector current is integrated in a time multiplexed manner using the two separate integration capacitors of the pixel input circuitry. The PSBF mode is simple, but the time stamp for each image frame is different. The PSWF mode is complex, but results in a pseudo simultaneous registration of images for each color or spectral band. The ROIC has been developed for cryogenic operation down to 65K with an input referred noise level of less than 470 e- rms in the low-gain (LG) mode at 77K. The MT6420DDA ROIC has been fabricated on 200 mm wafers containing a total of 89 parts with typically 75 working parts. Mikro-Tasarim provides tested ROIC wafers and offers compact test electronics and software for its ROIC customers to shorten their FPA and camera development cycles. MT6420DDA can also be used together with MTAS1410X8, an 8-channel ASIC from Mikro-Tasarim, that can be used to drive the FPA and digitize its analog outputs to build compact and low-noise Integrated-Detector-Dewar-Cooler-Assembly (IDDCA) units and camera cores.","PeriodicalId":222501,"journal":{"name":"SPIE Defense + Security","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122269903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Precision optical navigation guidance system","authors":"D. Starodubov, K. McCormick, P. Nolan, D. Johnson, M. Dellosa, L. Volfson, A. Fallahpour, A. Willner","doi":"10.1117/12.2224326","DOIUrl":"https://doi.org/10.1117/12.2224326","url":null,"abstract":"We present the new precision optical navigation guidance system approach that provides continuous, high quality range and bearing data to fixed wing aircraft during landing approach to an aircraft carrier. The system uses infrared optical communications to measure range between ship and aircraft with accuracy and precision better than 1 meter at ranges more than 7.5 km. The innovative receiver design measures bearing from aircraft to ship with accuracy and precision better than 0.5 mRad. The system provides real-time range and bearing updates to multiple aircraft at rates up to several kHz, and duplex data transmission between ship and aircraft.","PeriodicalId":222501,"journal":{"name":"SPIE Defense + Security","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127841872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Controlling magnetism by ultrashort laser pulses: from fundamentals to nanoscale engineering","authors":"D. Bossini, T. Rasing","doi":"10.1117/12.2225199","DOIUrl":"https://doi.org/10.1117/12.2225199","url":null,"abstract":"From the discovery of sub-picosecond demagnetization over a decade ago [1] to the recent demonstration of magnetization reversal by a single 40 femtosecond laser pulse [2], the manipulation of spins by ultra-short laser pulses has become a fundamentally challenging topic with a potentially high impact for future spintronics, data storage and manipulation and quantum computation [3]. It was realized that the femtosecond laser induced all-optical switching (AOS) as observed in ferrimagnets exploits the laser induced strongly non-equilibrium dynamics and the antiferromagnetic exchange interaction between their sublattices [4-6]. This opens the way to engineer new magnetic materials for AOS [7,8], though for real applications nanoscale control of inhomogeneities appears to be relevant [9]. Besides the intruiging technological implications of these observations, they broadened remarkably the frontiers of our fundamental knowledge of magnetic phenomena. The laser driven out-of-equilibrium states cannot be described in term of the well-established thermodynamical approach, which is based on the concepts of equilibrium and adiabatic transformations. Theoretical efforts, although in their infancy, have already demonstrated [5,6] that light-induced spin dynamics on the (sub)-picosecond time scale results in phenomena utterly forbidden in a thermodynamical framework. Another challenge is how to bring the optical manipulation of magnetic media to the required nanoscale. This is clearly a key element for the perspectives in terms of magnetic recording. In addition, it would allow to explore a novel regime of spin dynamics, since the investigation of magnets on the femtosecond time-scale and the nanometer length-scale simultaneously is unexplored. One experimental approach which may be successful makes use of wave-shaping techniques [10]. Recent results with engineered hybrid magnetic materials and nanofocusing via a plasmonic antenna showed the practical potential of AOS: the magnetization of domains as small as 50 nm was repeatedly reversed by a single laser pulse [11]. The process was fully deterministic, implying that each laser pulse totally reversed the magnetization of the domain in a reproducible way. Employing antennas provided another significant benefit, by decreasing the threshold laser energy required for the AOS to occur.","PeriodicalId":222501,"journal":{"name":"SPIE Defense + Security","volume":"24 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123574694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advanced concepts for high-power, short-pulse CO2 laser development","authors":"D. Gordon, V. Hasson, H. V. von Bergmann, Yu-Hsin Chen, A. Schmitt-Sody, J. Peñano","doi":"10.1117/12.2223835","DOIUrl":"https://doi.org/10.1117/12.2223835","url":null,"abstract":"Ultra-short pulse lasers are dominated by solid-state technology, which typically operates in the near-infrared. Efforts to extend this technology to longer wavelengths are meeting with some success, but the trend remains that longer wavelengths correlate with greatly reduced power. The carbon dioxide (CO2) laser is capable of delivering high energy, 10 micron wavelength pulses, but the gain structure makes operating in the ultra-short pulse regime difficult. The Naval Research Laboratory and Air Force Research Laboratory are developing a novel CO2 laser designed to deliver ~1 Joule, ~1 picosecond pulses, from a compact gain volume (~2x2x80 cm). The design is based on injection seeding an unstable resonator, in order to achieve high energy extraction efficiency, and to take advantage of power broadening. The unstable resonator is seeded by a solid state front end, pumped by a custom built titanium sapphire laser matched to the CO2 laser bandwidth. In order to access a broader range of mid infrared wavelengths using CO2 lasers, one must consider nonlinear frequency multiplication, which is non-trivial due to the bandwidth of the 10 micron radiation.","PeriodicalId":222501,"journal":{"name":"SPIE Defense + Security","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115360383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}