Security and Defence Quarterly最新文献_第6页

Long range 3D imaging and bistatic lidar using high resolution SPAD camera 采用高分辨率SPAD相机的远程三维成像和双基地激光雷达

Security and Defence Quarterly Pub Date : 2022-11-04 DOI: 10.1117/12.2639330

P. Soan, A. Walton

引用次数: 0

The use of two-dimensional scales for measuring angle and linear displacement 使用二维尺度测量角度和直线位移

Security and Defence Quarterly Pub Date : 2022-11-04 DOI: 10.1117/12.2635920

A. Korolev, A. Lukin, Y. Filatov, V. Venediktov

引用次数: 0

GaN laser diodes for cold-atom sensing, optical atomic clocks and precision metrology 用于冷原子传感、光学原子钟和精密计量的氮化镓激光二极管

Security and Defence Quarterly Pub Date : 2022-11-04 DOI: 10.1117/12.2632992

S. Najda, P. Perlin, T. Suski, S. Stanczyk, A. Kafar, M. Leszczynski, D. Schiavon, T. Slight, S. Gwyn, S. Watson, A. Kelly, M. Knapp, M. Haji

{"title":"GaN laser diodes for cold-atom sensing, optical atomic clocks and precision metrology","authors":"S. Najda, P. Perlin, T. Suski, S. Stanczyk, A. Kafar, M. Leszczynski, D. Schiavon, T. Slight, S. Gwyn, S. Watson, A. Kelly, M. Knapp, M. Haji","doi":"10.1117/12.2632992","DOIUrl":"https://doi.org/10.1117/12.2632992","url":null,"abstract":"Quantum technologies containing key GaN laser components will enable a new generation of precision sensors, optical atomic clocks and secure communication systems for many applications such as next generation navigation, gravity mapping and timing since the AlGaInN material system allows for laser diodes to be fabricated over a wide range of wavelengths from the U.V. to the visible. We report our latest results on a range of AlGaInN diode-lasers targeted to meet the linewidth, wavelength and power requirements suitable for quantum sensors such as optical clocks and cold-atom interferometry systems. This includes the [5s2S1/2-5p2P1/2] cooling transition in strontium+ ion optical clocks at 422 nm, the [5s21S0-5p1P1] cooling transition in neutral strontium clocks at 461 nm and the [5s2s1/2 – 6p2P3/2] transition in rubidium at 420 nm. Several approaches are taken to achieve the required linewidth, wavelength and power, including an extended cavity laser diode (ECLD) system and an on-chip grating, distributed feedback (DFB) GaN laser diode.","PeriodicalId":52940,"journal":{"name":"Security and Defence Quarterly","volume":"8 1","pages":"122740O - 122740O-9"},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81701514","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}

引用次数: 0

The Terahertz-based non-destructive evaluation of military-designated materials 军事指定材料的太赫兹非破坏性评估

Security and Defence Quarterly Pub Date : 2022-11-04 DOI: 10.1117/12.2636196

M. Strąg, W. Świderski

{"title":"The Terahertz-based non-destructive evaluation of military-designated materials","authors":"M. Strąg, W. Świderski","doi":"10.1117/12.2636196","DOIUrl":"https://doi.org/10.1117/12.2636196","url":null,"abstract":"With regards to composite materials, the need for noninvasive evaluation of their structures, components, or systems they form continues to rise. It relates to the fact that composites, due to their two-phased (at least) composition, are vulnerable to different damages arising during their manufacturing or their use. Thus, there is a need to non-destructively monitor such materials especially when they are used in safety applications such as e.g., bulletproof vests and their damage may pose a real threat. In the frame of this work, the use of the newly developed non-destructive testing (NDT) method based on the application of Terahertz (THz) radiation was presented. For this purpose, the series of samples without defects and with a defect in their interior was investigated. The samples were prepared as the soft insert of a bulletproof vest and one of them had intentionally introduced defect in the form of aramid fibers textile soaked in salty water. The results obtained using the THz imaging method were compared to the ones obtained using the conventional X-ray method. Overall, the potential of THz transmission measurements was demonstrated and a selected application using THz-based system was presented.","PeriodicalId":52940,"journal":{"name":"Security and Defence Quarterly","volume":"18 1","pages":"122740V - 122740V-6"},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82847373","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}

引用次数: 4

Next-generation of sUAS 360 surround vision cameras designed for automated navigation in low-light conditions 下一代sUAS 360环绕视觉相机专为低光条件下的自动导航而设计

Security and Defence Quarterly Pub Date : 2022-11-04 DOI: 10.1117/12.2639024

J. Buquet, S.-G. Beauvais, J. Parent, P. Roulet, S. Thibault

引用次数: 1

Comparison of compressive imaging and video techniques for threat detection applications 压缩成像和视频技术在威胁检测中的应用比较

Security and Defence Quarterly Pub Date : 2022-11-04 DOI: 10.1117/12.2636239

J. Limbach, C. Eisele

{"title":"Comparison of compressive imaging and video techniques for threat detection applications","authors":"J. Limbach, C. Eisele","doi":"10.1117/12.2636239","DOIUrl":"https://doi.org/10.1117/12.2636239","url":null,"abstract":"High performance imaging sensors are a fundamental requirement for many defense and security applications. The usually high cost of such sensors, however, prevents their broad deployment. Modern Computational Imaging approaches like Compressed Sensing (CS) promise cost efficient sensor architectures that might enable a wider usage of some sensor technologies. However, the technological potential for military applications still has to be verified. In order to test the capabilities of a CS-system for threat detection, a software framework for automated testing was implemented. The code contains different methods for scene modulation and image reconstruction. In our previous work, we studied the classic iterative optimization methods for image reconstruction with promising, but not completely satisfactory results. Therefore, we implemented another method. This CS video method is the ‘Fourier domain regularized inversion’ (FDRI) which promises real time single pixel video imaging. In the study presented here, we compare the rather new method with the already implemented optimization approaches regarding runtime, conventional image quality metrics and suitability for threat detection applications in different spectral bands.","PeriodicalId":52940,"journal":{"name":"Security and Defence Quarterly","volume":"51 1","pages":"122740F - 122740F-9"},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87473344","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}

引用次数: 1

Optimization of continuous variables quantum key distribution using discrete modulation 离散调制的连续变量量子密钥分配优化

Security and Defence Quarterly Pub Date : 2022-11-04 DOI: 10.1117/12.2638896

Daniel F. Pereira, N. Silva, Margarida Almeida, Armando N. Pinto

{"title":"Optimization of continuous variables quantum key distribution using discrete modulation","authors":"Daniel F. Pereira, N. Silva, Margarida Almeida, Armando N. Pinto","doi":"10.1117/12.2638896","DOIUrl":"https://doi.org/10.1117/12.2638896","url":null,"abstract":"Continuous Variables Quantum Key Distribution (CV-QKD) tackles the problem of the generation and distribution of cryptographic keys without assuming any computational limitations while employing standard telecom equipment. Gaussian Modulation (GM) theoretically maximizes the information a CV-QKD system is capable of transmitting while exhibiting a higher resistance to excess channel noise. However, GM-CV-QKD protocols put an extreme burden on the transmitter’s random number source and tend to be more susceptible to imperfect state preparation. Due to these difficulties, most experimental implementations of CV-QKD have used Discrete Modulation (DM). The closer the DM constellation approaches a GM one, the closer the theoretical performance of the associated system will be to the optimum value. To achieve this, high-cardinality constellations, coupled with probabilistic shaping, can be explored. However, choosing a too complex constellation will cause the modulation stage imperfections to again become apparent. Thus, the choice of the constellation format is not direct and is of high importance. In this work we present a methodology to determine the optimum constellation for a given DM-CV-QKD system, taking into account the limitations of the modulation stage, choosing from a variety of M-QAM and M-APSK constellations coupled with probabilistic shaping. Our obtained methodology will allow for the optimum modulation format for each specific system to be selected.","PeriodicalId":52940,"journal":{"name":"Security and Defence Quarterly","volume":"19 1","pages":"122740S - 122740S-7"},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73690380","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}

引用次数: 1

Configurable multichannel time-to-amplitude converter for advanced TCSPC applications 可配置的多通道时间-幅度转换器先进的TCSPC应用

Security and Defence Quarterly Pub Date : 2022-11-04 DOI: 10.1117/12.2636027

Francesco Malanga, G. Acconcia, S. Farina, M. Ghioni, I. Rech

引用次数: 0

Avalanche multiplication and excess noise characteristics in antimony-based avalanche photodiodes 锑基雪崩光电二极管的雪崩倍增和过量噪声特性

Security and Defence Quarterly Pub Date : 2022-11-04 DOI: 10.1117/12.2640257

J. David, X. Jin, H. Lewis, B. Guo, Seunghyun Lee, Hyemin Jung, S. Kodati, B. Liang, S. Krishna, J. Campbell

引用次数: 1

Imaging enhancement using multifunctional subwavelength structured windows 利用多功能亚波长结构窗增强成像

Security and Defence Quarterly Pub Date : 2022-11-04 DOI: 10.1117/12.2636219

M. Lee, R. Guillemet, A. Delboulbé, D. Jussey, J. Cholet, C. Arnoux, A. Banyasz, F. Hilbert, C. Monnereau, P. Baldeck, B. Loiseaux, P. Garabédian, P. Romero

{"title":"Imaging enhancement using multifunctional subwavelength structured windows","authors":"M. Lee, R. Guillemet, A. Delboulbé, D. Jussey, J. Cholet, C. Arnoux, A. Banyasz, F. Hilbert, C. Monnereau, P. Baldeck, B. Loiseaux, P. Garabédian, P. Romero","doi":"10.1117/12.2636219","DOIUrl":"https://doi.org/10.1117/12.2636219","url":null,"abstract":"We exploit micro-nano structuration to achieve multifunctional windows offering outstanding optical and fluidic properties to enhance the operation of surveillance or detection devices under rainy conditions. These windows are based on synthesis of an artificial index gradient for antireflection properties and improvement of their water repellency property thanks to their structuration at a subwavelength scale with controlled conical geometries. We demonstrate the realization of multifunctional germanium windows for LWIR camera, using two approaches: nanoimprint lithography, well-known for its very high resolution enabling applications from visible to thermal infrared domain, followed by etching techniques, and 3D direct laser writing based on Two-Photon Polymerization (TPP), which is of interest thanks to its ability to manufacture complex 3D structuration directly. Optical characterization shows the ability of such windows to improve optical transmission within 8-14μm spectral range, as compared to non-structured window. In terms of water repellency, the structured windows enable an increase of the contact angle up to 160° with a very low hysteresis. To evaluate the advantage of the multifunctional windows for imaging devices, the windows are integrated in front of a thermal infrared camera and images analysis shows that the camera sensitivity is increased for the nanoimprint window thanks to the multifunctional window and high water repellency in presence of water.","PeriodicalId":52940,"journal":{"name":"Security and Defence Quarterly","volume":"26 1","pages":"122740G - 122740G-11"},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85390803","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}

引用次数: 0