华中光电技术研究所- 武汉光电国家研究中心, 湖北 武汉 430223
光电跟踪仪光轴平行性要求与跟踪瞄准精度、激光测距传感器照射激光光束发散角、激光回波接收系统探测视场有关, 尤其是对于小目标, 还与激光测距作用距离和探测概率有关。从光电跟踪仪激光测距原理和指标要求出发, 分析照射光束能量分布特点, 考虑温度、振动等环境因素和变调焦引起的光轴稳定性误差, 提出了光电跟踪仪光轴平行性要求的计算方法。同时根据工程实践考虑光电传感器原位更换和现场标校的维修性, 建立了光轴平行性误差分配模型, 讨论了各随机误差项、各标校残余误差项的一般控制要求和估计方法, 为光电跟踪仪设计分析、制造工艺、维修性改进提供参考。
光电跟踪仪 光轴平行性 激光测距 跟踪瞄准 光束发散角 optoelectronic tracker optical axis parallelism laser ranging tracking and targeting beam divergence angle
强激光与粒子束
2023, 35(3): 034003
强激光与粒子束
2022, 34(5): 054002
1 盐城师范学院物理与电子工程学院, 江苏省智能光电器件与测控工程研究 中心, 江苏 盐城 224002
2 江苏省大气探测激光雷达技术军民融合创新平台, 江苏 盐城 224002
马赫-曾德尔干涉仪 (MZI) 具有光学能量利用率高、便于视场展宽等优点, 在光学滤波、鉴频等方面具有广泛的应用。然而, 在实际应用中 MZI 频谱会受到各种因素的影响而导致性能下降。从理论上导出了在考虑入射光发散角 2θ0 和谱宽 Δν 的影响下, MZI 干涉频谱的理论表达式, 并定量分析了其对 MZI 频谱的影响。结果表明: MZI 的光程差 l 越大, 其频谱受 Δν 的影响越显著, l 与入射光波长 λ 比值越大, 其频谱受 θ0 的影响越显著; 当 λ=355 nm, l=3 cm时 (第 1 种情形), Δν=10 GHz 和 θ0=4.5 mrad 将分别使条纹对比度 K 降至 2.8% 和 16.3%; 当 λ=532 nm, l=59 cm 时 (第 2 种情形), Δν=0.5 GHz 和 θ0=1.25 mrad 将分别使 K 降至 3.2% 和 15%。 为减小发散角的影响, 从理论上进一步研究了棱镜式视场展宽技术。结果表明: 若补偿棱镜厚度 d 和折射率 n 满足 d=nl/(n-1), 对应第 1 种情形, θ0=50 mrad 时 K 仍高于 93.1%,θ0=70 mrad 时 K 将降至 33.3%; 在第 2 种情形下, θ0=25 mrad时 K 仍高于94.0%, θ0=35 mrad 时 K 将降至 37.6%。若 d 依据不同 θ0 取不同最优值时,在第 1 种情形下, θ0=70 mrad 时 K 仍高于 92.1%; 而在第 2 种情形下, θ0=35 mrad 时 K 仍高于 94.4%。
光谱学 马赫-曾德尔干涉仪 光束发散角 谱宽 视场展宽 条纹对比度 spectroscopy Mach-Zehnder interferometer beam divergence angle spectral linewidth field-widening fringe contrast
Author Affiliations
Abstract
1 Laboratory of Solid State Optoelectronics Information Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
2 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
3 College of Future Technology, University of Chinese Academy of Sciences, Beijing 101408, China
4 State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
We design a 645 nm laser diode (LD) with a narrow vertical beam divergence angle based on the mode expansion layer. The vertical beam divergence of 10.94° at full width at half-maximum is realized under 1.5 A continuous-wave operation, which is the smallest vertical beam divergence for such an LD based on the mode expansion layer, to the best of our knowledge. The threshold current and output power are 1.07 A and 0.94 W, limited by the thermal rollover for the 100 µm wide and 1500 µm long broad area laser, and the slope efficiency is 0.71 W/A. The low coherence device is fabricated with the speckle contrast of 3.6% and good directional emission. Such 645 nm LDs have promising applications in laser display.
beam divergence laser diode speckle laser display Chinese Optics Letters
2021, 19(10): 101401
Author Affiliations
Abstract
National Key Laboratory of Tunable Laser Technology, Institute of Optoelectronics, Department of Electronics Science and Technology, Harbin Institute of Technology, Harbin 150080, China
In this Letter, we firstly, to the best of our knowledge, demonstrated the influence of pre-pulse current and delay time on the intensity of a discharge pumped Ne-like Ar soft X-ray laser operating at 46.9 nm by employing an alumina capillary having an inner diameter of 4.8 mm. Specifically, the delay time was changed from 8 to 520 μs in small intervals. The pre-discharge current was increased from 25 A to 250 A through small steps, while keeping the main discharge current constant. Usually, a small pre-discharge current is applied to an Ar-filled capillary to attain a plasma column having sufficient pre-ionization before the injection of the main current. The pre-discharge current of 140 A was declared the best current to obtain lasing with a 4.8 mm diameter capillary. The laser spots were captured at best time delays for the pre-discharge currents of 25, 45, 80, 140, and 250 A, which support the experimental results. We observed that by applying the pre-discharge current of 140 A, the laser spot exhibits small divergence, higher symmetry, and uniformity, which is clear evidence of strong amplification. The laser spot obtained at 140 A is cylindrically symmetric and has a better structure than those reported by all other groups in the literature. Hence, the laser spot indicates that the laser beam is highly focusable and beneficial for the applications of the 46.9 nm laser. Results of this Letter might open a new way to enhance applications of a 46.9 nm capillary discharge soft X-ray laser.
Z-pinch pre-discharge kink instabilities beam divergence Chinese Optics Letters
2020, 18(11): 111403
1 中国科学院半导体研究所 集成光电子国家重点实验室,北京 100083
2 中国科学院大学 材料科学与光电工程中心,北京 100083
理论仿真和实验制备了AlGaInAs/InP材料1.55 μm小发散角量子阱激光器.为了扩展近场光场并减小内损耗,将一个非对称模式扩展层插入到外延结构的下盖层当中.仿真结果表明,该模式扩展层除了少量增加激光器阈值电流以外,在不影响激光器其它性能的情况下能显著减小激光器的垂直远场发散角.实验结果与理论仿真高度吻合.成功制备出脊宽4 μm,腔长1000 μm的脊波导小发散角激光器.在端面未镀膜的情况下,该激光器阈值电流为56 mA,输出功率为17.38 mw@120 mA,斜率效率可以达到0.272 W/A.实验测得垂直远场发散角为29.6°,相比较传统激光器减小了约35.3%.
铟磷基激光器 发散角 光场分布 InP-based lasers beam divergence intensity distribution 红外与毫米波学报
2019, 38(4): 04412
1 武汉大学 电子信息学院,湖北 武汉 430072
2 昆明理工大学 理学院,云南 昆明 650051
植被树高是生物量评估和森林生态监测的重要参数,但是大区域的植被树高数据获取困难.由大光斑星载激光测高系统森林回波可反演大区域植被树高,然而大坡度山区的植被和地面回波混叠严重,难以准确提取波形参数反演植被树高.为此建立森林目标回波的解析模型,推导出从混叠回波中分离植被和地面回波的必要条件,指出导致回波混叠的因素除了目标粗糙度和坡度,还有发射脉冲的发散角.分析了地表粗糙度和地形坡度对植被冠层回波的展宽效应及其对波形分解的影响,通过比较实测GLAS波形和仿真回波波形,验证了压缩光束发散角可降低森林回波对大坡度地形的敏感性.对于卫星轨道高度在500~600 km之间时,激光测高仪光束发散角一般在40~60 μrad,更有利于森林植被树高的反演.所得结论为提高大坡度山地森林树高反演精度,从星载激光测高仪的系统设计角度提供了有意义的参考.
星载激光测高仪 光束发散角 光斑直径 森林回波 satellite laser altimeter beam divergence angle footprint diameter forest echo
北京卫星信息工程研究所 天地一体化信息技术国家重点实验室, 北京 100086
在自由空间激光通信(FSO)系统中, 瞄准误差和大气湍流严重影响系统通信链路, 是链路性能恶化的两大主要因素。通过对联合信道的理论分析, 建立了信道模型, 并利用Meijer G函数推导出了直接探测系统和相干探测系统平均信道容量的表达式。通过在Matlab中的仿真结果可知, 在给定瞄准误差和大气湍流的条件下, 信号光的光束束散角并非越小越好, 而是存在最优束散角, 该束散角不仅可以保证系统性能良好, 而且使得发射系统功率取得最小值, 并且采用相干探测系统可以抑制大气湍流对系统的影响, 有效提高系统的性能。
激光通信 最优束散角 瞄准误差 Gamma-Gamma大气湍流 平均信道容量 laser communication optimal beam divergence angle pointing error Gamma-Gamma atmospheric turbulence average channel capacity