Optimum laser configurations are presented to achieve high illumination uniformity with directly driven inertial confinement fusion targets.Assuming axisymmetric absorption pattern of individual laser beams,theoretica...Optimum laser configurations are presented to achieve high illumination uniformity with directly driven inertial confinement fusion targets.Assuming axisymmetric absorption pattern of individual laser beams,theoretical models are reviewed in terms of the number of laser beams,system imperfection,and laser beam patterns.Utilizing a self-organizing system of charged particles on a sphere,a simple numerical model is provided to give an optimal configuration for an arbitrary number of laser beams.As a result,such new configurations as“M48”and“M60”are found to show substantially higher illumination uniformity than any other existing direct drive systems.A new polar direct-drive scheme is proposed with the laser axes keeping off the target center,which can be applied to laser configurations designed for indirectly driven inertial fusion.展开更多
Ramp-wave compression experiment to balance the high compression pressure generation in aluminum and x-ray blanking effect in transparent window is demonstrated with an imaging velocity interferometer system for any r...Ramp-wave compression experiment to balance the high compression pressure generation in aluminum and x-ray blanking effect in transparent window is demonstrated with an imaging velocity interferometer system for any reflector （VISAR） on ShenGuang-Ⅲprototype laser facility. The highest pressure is about 500 GPa after using the multilayer target design Al/Au/Al/LiF and -10^13 W//cm2 laser pulse illuminated on the planar Al target, which generates the spatial uniformity to 〈1% over 500 μm on the ablation layer. A 2-μm-thick Au layer is used to prevent the x-ray from preheating the planar ablation Al layer and window material LiF. The imaging VISAR system can be used to record the abrupt loss of the probe beam （λ= 532 nm） caused by absorption and reflection of 20-μm, 30-μm and 40-μm-thick Al, i.e., the blanking effect. Although there are slight shocks in the target, the peak pressure 500 GPa, which is the highest data up to now, is obtained with ramp-wave compression.展开更多
An optimized setup for fiber optic injection of a kilowatt peak power laser diode stack emitting in the SWIR spectral range is proposed. Starting from a fast axis collimated (FAC) and slow axis collimated (SAC) 15 bar...An optimized setup for fiber optic injection of a kilowatt peak power laser diode stack emitting in the SWIR spectral range is proposed. Starting from a fast axis collimated (FAC) and slow axis collimated (SAC) 15 bars, 19 emitters off the shelf laser diode stack, the beam is transformed using spatial beam combining and polarization coupling. Both techniques integrated in a compact design enable to couple the kilowatt level beam into a standard 600 μm core, 0.22 numerical aperture (NA) multimode optical fiber. An application in the field of long range SWIR laser illuminator for gated viewing is presented. A comparison between two illuminators is realized both based on the same laser diode stack but one using beam parameter product (BPP) reduction and one without. It could be demonstrated that BPP reduction is the best way for efficient, narrow divergence and compact semi-conductor based laser illuminators design and realization. The global laser illuminator efficiency could be improved by 75% for the narrowest divergences thanks to this approach.展开更多
With the rapid development of laser technology,laser as the light source of night vision illuminating can realize long-distance and clear imaging,which has been widely used in laser active illuminating field.A high-po...With the rapid development of laser technology,laser as the light source of night vision illuminating can realize long-distance and clear imaging,which has been widely used in laser active illuminating field.A high-power diode laser with a wavelength of 808 nm was designed as the laser active illuminating source,and the output power of no less than100 W was obtained by spatial beam multiplexing,polarization multiplexing,and high efficiency fiber coupling techniques.In view of the beam homogenization of illuminating source,a novel beam homogenization system based on waveguide is proposed in this work.A square spot with a horizontal divergence angle of 40°,a vertical divergence angle of 10°,and an illuminating power ratio of 4:1 was obtained by a collimating lens.Comparing with the traditional circular illuminating beam,the square illuminating beam can match the illuminating angle of CCD camera better,and the energy utilization rate is higher.In addition,by optimizing the structure of waveguide and collimating lens,the illuminating angle can be changed to meet the illuminating requirements under different conditions theoretically.展开更多
The integration between vertical-cavity surface-emitting lasers and metasurfaces has been demonstrated to enable on-chip high-angle illumination for total internal reflection and dark-field microscopy. Such an ultraco...The integration between vertical-cavity surface-emitting lasers and metasurfaces has been demonstrated to enable on-chip high-angle illumination for total internal reflection and dark-field microscopy. Such an ultracompact combined laser-beam shaper system provides a versatile illumination module for high-contrast imaging, thus leveraging biophotonics and lab-on-a-chip devices and facilitating life-science applications.展开更多
为提高跟踪测量系统对暗弱目标的探测能力，设计一套自动化激光主动照明光学系统，对跟踪测量视场范围进行主动辅助照明。该系统在0．2～5 km 距离处的照明直径均为10 m，计算出其在－20℃及＋45℃的温度调焦量，照明仿真结果表明系统...为提高跟踪测量系统对暗弱目标的探测能力，设计一套自动化激光主动照明光学系统，对跟踪测量视场范围进行主动辅助照明。该系统在0．2～5 km 距离处的照明直径均为10 m，计算出其在－20℃及＋45℃的温度调焦量，照明仿真结果表明系统照明不均匀性＜15％。通过研究系统像差对照明均匀性的影响，以及对设计的调光组进行分析，得到调光组移动量与照明距离之间的理论关系，表明自动调节调光组位置即可实现不同照明距离处的均匀照明。设计和分析结果表明，该主动照明系统能够自动调节调光组位置，实现跟踪测量视场内的均匀照明，有利于跟踪测量系统对于暗弱目标的探测。展开更多
基金This work was supported by the Japan Society for the Promotion of Science(JSPS).
文摘Optimum laser configurations are presented to achieve high illumination uniformity with directly driven inertial confinement fusion targets.Assuming axisymmetric absorption pattern of individual laser beams,theoretical models are reviewed in terms of the number of laser beams,system imperfection,and laser beam patterns.Utilizing a self-organizing system of charged particles on a sphere,a simple numerical model is provided to give an optimal configuration for an arbitrary number of laser beams.As a result,such new configurations as“M48”and“M60”are found to show substantially higher illumination uniformity than any other existing direct drive systems.A new polar direct-drive scheme is proposed with the laser axes keeping off the target center,which can be applied to laser configurations designed for indirectly driven inertial fusion.
基金Supported by the National Natural Science Foundation of China under Grant No 11305160
文摘Ramp-wave compression experiment to balance the high compression pressure generation in aluminum and x-ray blanking effect in transparent window is demonstrated with an imaging velocity interferometer system for any reflector （VISAR） on ShenGuang-Ⅲprototype laser facility. The highest pressure is about 500 GPa after using the multilayer target design Al/Au/Al/LiF and -10^13 W//cm2 laser pulse illuminated on the planar Al target, which generates the spatial uniformity to 〈1% over 500 μm on the ablation layer. A 2-μm-thick Au layer is used to prevent the x-ray from preheating the planar ablation Al layer and window material LiF. The imaging VISAR system can be used to record the abrupt loss of the probe beam （λ= 532 nm） caused by absorption and reflection of 20-μm, 30-μm and 40-μm-thick Al, i.e., the blanking effect. Although there are slight shocks in the target, the peak pressure 500 GPa, which is the highest data up to now, is obtained with ramp-wave compression.
文摘An optimized setup for fiber optic injection of a kilowatt peak power laser diode stack emitting in the SWIR spectral range is proposed. Starting from a fast axis collimated (FAC) and slow axis collimated (SAC) 15 bars, 19 emitters off the shelf laser diode stack, the beam is transformed using spatial beam combining and polarization coupling. Both techniques integrated in a compact design enable to couple the kilowatt level beam into a standard 600 μm core, 0.22 numerical aperture (NA) multimode optical fiber. An application in the field of long range SWIR laser illuminator for gated viewing is presented. A comparison between two illuminators is realized both based on the same laser diode stack but one using beam parameter product (BPP) reduction and one without. It could be demonstrated that BPP reduction is the best way for efficient, narrow divergence and compact semi-conductor based laser illuminators design and realization. The global laser illuminator efficiency could be improved by 75% for the narrowest divergences thanks to this approach.
基金supported by the National Natural Science Foundation of China(NSFC)(No.61991433)Pilot Project of CAS(No.XDB43030302)+3 种基金Equipment Pre-research(No.2006ZYGG0304)Key Research and Development Project of Guangdong Province(No.2020B090922003)R&D Program of Jilin Province(No.20190302042GX)Local Cooperation Projects of Chinese Academy of Sciences(No.2021SYHZ0012)。
文摘With the rapid development of laser technology,laser as the light source of night vision illuminating can realize long-distance and clear imaging,which has been widely used in laser active illuminating field.A high-power diode laser with a wavelength of 808 nm was designed as the laser active illuminating source,and the output power of no less than100 W was obtained by spatial beam multiplexing,polarization multiplexing,and high efficiency fiber coupling techniques.In view of the beam homogenization of illuminating source,a novel beam homogenization system based on waveguide is proposed in this work.A square spot with a horizontal divergence angle of 40°,a vertical divergence angle of 10°,and an illuminating power ratio of 4:1 was obtained by a collimating lens.Comparing with the traditional circular illuminating beam,the square illuminating beam can match the illuminating angle of CCD camera better,and the energy utilization rate is higher.In addition,by optimizing the structure of waveguide and collimating lens,the illuminating angle can be changed to meet the illuminating requirements under different conditions theoretically.
文摘The integration between vertical-cavity surface-emitting lasers and metasurfaces has been demonstrated to enable on-chip high-angle illumination for total internal reflection and dark-field microscopy. Such an ultracompact combined laser-beam shaper system provides a versatile illumination module for high-contrast imaging, thus leveraging biophotonics and lab-on-a-chip devices and facilitating life-science applications.
文摘为提高跟踪测量系统对暗弱目标的探测能力，设计一套自动化激光主动照明光学系统，对跟踪测量视场范围进行主动辅助照明。该系统在0．2～5 km 距离处的照明直径均为10 m，计算出其在－20℃及＋45℃的温度调焦量，照明仿真结果表明系统照明不均匀性＜15％。通过研究系统像差对照明均匀性的影响，以及对设计的调光组进行分析，得到调光组移动量与照明距离之间的理论关系，表明自动调节调光组位置即可实现不同照明距离处的均匀照明。设计和分析结果表明，该主动照明系统能够自动调节调光组位置，实现跟踪测量视场内的均匀照明，有利于跟踪测量系统对于暗弱目标的探测。
