Long range 3D imaging is a key technology for future target acquisition and ID. Dstl have demonstrated high resolution 3D image acquisition of representative vehicle targets at a range of 1.4 km in daylight, using currently available visible band technology. With modern GPS timing capabilities, it should also be possible to separate laser and camera by some considerable distance, enabling long baseline bistatic lidar or distributed sensing to be achieved. Preliminary results from an exploration of this concept will also be shown.
{"title":"Long range 3D imaging and bistatic lidar using high resolution SPAD camera","authors":"P. Soan, A. Walton","doi":"10.1117/12.2639330","DOIUrl":"https://doi.org/10.1117/12.2639330","url":null,"abstract":"Long range 3D imaging is a key technology for future target acquisition and ID. Dstl have demonstrated high resolution 3D image acquisition of representative vehicle targets at a range of 1.4 km in daylight, using currently available visible band technology. With modern GPS timing capabilities, it should also be possible to separate laser and camera by some considerable distance, enabling long baseline bistatic lidar or distributed sensing to be achieved. Preliminary results from an exploration of this concept will also be shown.","PeriodicalId":52940,"journal":{"name":"Security and Defence Quarterly","volume":"43 1","pages":"1227402 - 1227402-15"},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79665490","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}
Recently the authors proposed a new angle measurement technology based on the use of the two-dimensional scales. The rotation angle measurement is based on measuring the rotation of the pattern image on the sensor of a digital camera. The report presents the results of generalization of the developed earlier technology of angular measurements using a two-dimensional scale to measurements of linear displacements. It is shown that using a simple optical-digital system with a physical resolution, for example, of the order of several micrometers, it is possible to measure angles with an error of one thousandth of an arc second and linear displacements with an error of a fraction of a nanometer.
{"title":"The use of two-dimensional scales for measuring angle and linear displacement","authors":"A. Korolev, A. Lukin, Y. Filatov, V. Venediktov","doi":"10.1117/12.2635920","DOIUrl":"https://doi.org/10.1117/12.2635920","url":null,"abstract":"Recently the authors proposed a new angle measurement technology based on the use of the two-dimensional scales. The rotation angle measurement is based on measuring the rotation of the pattern image on the sensor of a digital camera. The report presents the results of generalization of the developed earlier technology of angular measurements using a two-dimensional scale to measurements of linear displacements. It is shown that using a simple optical-digital system with a physical resolution, for example, of the order of several micrometers, it is possible to measure angles with an error of one thousandth of an arc second and linear displacements with an error of a fraction of a nanometer.","PeriodicalId":52940,"journal":{"name":"Security and Defence Quarterly","volume":"53 1-2 1","pages":"1227410 - 1227410-8"},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77938543","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}
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
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.
{"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}
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.
{"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}
J. Buquet, S.-G. Beauvais, J. Parent, P. Roulet, S. Thibault
The next generation of sUAS (small Unmanned Aircraft Systems) for automated navigation will have to perform in challenging conditions, bad weather, high and low temperature and from dusk-to-dawn. The paper presents experimental results from a new wide-angle vision camera module specially optimized for low-light. We present the optical characteristics of this system as well as experimental results obtained for different sense and avoid functionalities. We also show preliminary results using our camera module images on neural networks for different scene understanding tasks.
{"title":"Next-generation of sUAS 360 surround vision cameras designed for automated navigation in low-light conditions","authors":"J. Buquet, S.-G. Beauvais, J. Parent, P. Roulet, S. Thibault","doi":"10.1117/12.2639024","DOIUrl":"https://doi.org/10.1117/12.2639024","url":null,"abstract":"The next generation of sUAS (small Unmanned Aircraft Systems) for automated navigation will have to perform in challenging conditions, bad weather, high and low temperature and from dusk-to-dawn. The paper presents experimental results from a new wide-angle vision camera module specially optimized for low-light. We present the optical characteristics of this system as well as experimental results obtained for different sense and avoid functionalities. We also show preliminary results using our camera module images on neural networks for different scene understanding tasks.","PeriodicalId":52940,"journal":{"name":"Security and Defence Quarterly","volume":"192 1","pages":"122740L - 122740L-12"},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72757319","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}
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.
{"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}
Daniel F. Pereira, N. Silva, Margarida Almeida, Armando N. Pinto
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.
{"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}
Francesco Malanga, G. Acconcia, S. Farina, M. Ghioni, I. Rech
In this work, we present the configurable Fast-Time-to-Amplitude Converter (FTAC), a versatile and completely integrated multichannel timing device constituted by 8 high-performance Time-to-Amplitude Converters (TACs) and a smart front-end logic. The designed converter can not only provide state-of-the-art performance in terms of conversion frequency (up to 100Mcps) and timing precision (down to 1.1ps rms, i.e. 2.6 ps Full Width at Half Maximum), but also a unique flexibility to the end user, who can select the most suitable configuration for its specific requirements. Above all, this chip gives the possibility of using the 8 channels separately, as a building block of a multichannel system, or combining the internal converters to reach picosecond precision, that could open the way to on-field exploitation of Super Conducting Nanowire Single Photon Detectors (SNSPDs). The chip provides 11 different configurations among which select the best option in terms of a combination of parallel channels, speed and timing precision.
在这项工作中，我们提出了可配置的快速时间-幅度转换器(FTAC)，这是一个由8个高性能时间-幅度转换器(tac)和一个智能前端逻辑组成的多功能和完全集成的多通道时序器件。设计的转换器不仅可以提供最先进的转换频率(高达100Mcps)和定时精度(低至1.1ps rms，即2.6 ps Full Width at Half Maximum)方面的性能，而且还为最终用户提供了独特的灵活性，他们可以根据其特定要求选择最合适的配置。最重要的是，该芯片提供了单独使用8通道的可能性，作为多通道系统的构建块，或者结合内部转换器达到皮秒精度，这可能为超导纳米线单光子探测器(SNSPDs)的现场开发开辟道路。该芯片提供了11种不同的配置，在并行通道、速度和定时精度的组合方面选择最佳选项。
{"title":"Configurable multichannel time-to-amplitude converter for advanced TCSPC applications","authors":"Francesco Malanga, G. Acconcia, S. Farina, M. Ghioni, I. Rech","doi":"10.1117/12.2636027","DOIUrl":"https://doi.org/10.1117/12.2636027","url":null,"abstract":"In this work, we present the configurable Fast-Time-to-Amplitude Converter (FTAC), a versatile and completely integrated multichannel timing device constituted by 8 high-performance Time-to-Amplitude Converters (TACs) and a smart front-end logic. The designed converter can not only provide state-of-the-art performance in terms of conversion frequency (up to 100Mcps) and timing precision (down to 1.1ps rms, i.e. 2.6 ps Full Width at Half Maximum), but also a unique flexibility to the end user, who can select the most suitable configuration for its specific requirements. Above all, this chip gives the possibility of using the 8 channels separately, as a building block of a multichannel system, or combining the internal converters to reach picosecond precision, that could open the way to on-field exploitation of Super Conducting Nanowire Single Photon Detectors (SNSPDs). The chip provides 11 different configurations among which select the best option in terms of a combination of parallel channels, speed and timing precision.","PeriodicalId":52940,"journal":{"name":"Security and Defence Quarterly","volume":"35 1","pages":"122740E - 122740E-4"},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74028035","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}
J. David, X. Jin, H. Lewis, B. Guo, Seunghyun Lee, Hyemin Jung, S. Kodati, B. Liang, S. Krishna, J. Campbell
Avalanche photodiodes (APDs) capable of operating at telecommunication wavelengths usually utilize an InGaAs absorber and a multiplication region of InP or InAlAs. Since the electron and hole ionization coefficients (α and β respectively) in these multiplication regions are very similar they suffer from high excess noise, limiting their sensitivity. In recent years, there have been a number of reports of Sb containing III-V semiconductor alloys that appear to show very low excess noise characteristics, similar to or better than that obtained in silicon. These reports show that AlInAsSb grown on GaSb appears to show a β/α ratio of ~0.015. Both AlAsSb and Al0.85Ga0.15As0.56Sb0.44 grown lattice matched on InP also show β/α values that vary from 0.005-0.01. The exception to this appears to be AlGaAsSb grown lattice matched on GaSb where a β/α ratio of ~2.5 has been seen. This paper reviews the published results in this area.
{"title":"Avalanche multiplication and excess noise characteristics in antimony-based avalanche photodiodes","authors":"J. David, X. Jin, H. Lewis, B. Guo, Seunghyun Lee, Hyemin Jung, S. Kodati, B. Liang, S. Krishna, J. Campbell","doi":"10.1117/12.2640257","DOIUrl":"https://doi.org/10.1117/12.2640257","url":null,"abstract":"Avalanche photodiodes (APDs) capable of operating at telecommunication wavelengths usually utilize an InGaAs absorber and a multiplication region of InP or InAlAs. Since the electron and hole ionization coefficients (α and β respectively) in these multiplication regions are very similar they suffer from high excess noise, limiting their sensitivity. In recent years, there have been a number of reports of Sb containing III-V semiconductor alloys that appear to show very low excess noise characteristics, similar to or better than that obtained in silicon. These reports show that AlInAsSb grown on GaSb appears to show a β/α ratio of ~0.015. Both AlAsSb and Al0.85Ga0.15As0.56Sb0.44 grown lattice matched on InP also show β/α values that vary from 0.005-0.01. The exception to this appears to be AlGaAsSb grown lattice matched on GaSb where a β/α ratio of ~2.5 has been seen. This paper reviews the published results in this area.","PeriodicalId":52940,"journal":{"name":"Security and Defence Quarterly","volume":"88 1","pages":"122740A - 122740A-12"},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74043834","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}
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
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.
{"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}
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