The 10 kW Level High Brightness Face-Pumped Slab Nd:YAG Amplifier with a Hybrid Cooling System

We demonstrate a high power, high brightness, slab amplifier based on face-pumped Nd:YAG slab gain modules,having a high efficient hybrid cooling system of the conduction cooling and forced convection cooling. Using a single gain module, a laser output power up to 4.5 kW with a remarkable optical-optical conversion efficiency of 51% is realized, indicating an excellent lasing performance of the Nd:YAG slab module. The amplifier operates at a repetition rate of 700 Hz and delivers a maximum average output power exceeding 10.5 kW with pulse duration of 150us. A good beam quality factor is measured to be β = 1.9. To the best of our knowledge, this is the highest brightness for a 10 kW level Nd:YAG slab amplifier.     

基于Nd∶YVO_4晶体四波段腔面膜的研制

黄光激光器作为一种接近人眼敏感区域的激光器在诸多领域都发挥着重要的作用,而谐振腔又是激光器中重要组成部分.本文以Nd∶YVO4(c-cut)晶体为基底,利用真空镀膜设备研制出四波段腔面膜.通过分析膜系设计过程中膜层电场强度和优化膜系,使膜层中驻波场强得到合理分布,从而在理论上减小膜层损伤的可能性;通过TFCalc软件对测试结果进行工艺反馈分析,经过多次模拟实验,发现在不同控制波长下,采用相同监控方法监测不同的膜厚比例系数,通过调整工具因子解决了光谱曲线漂移的问题,制备出膜层牢固、化学性能稳定、满足四个波段光谱输出的黄光激光器腔面膜.     

光学元件激光预处理技术研究进展及其应用

光学元件中的杂质和缺陷会引起其激光损伤阈值的大幅降低,现阶段这一问题已成为激光装置向高功率、高能量方向发展的“瓶颈”,亟待解决。在对光学元件激光损伤的研究中发现,用低于光学元件损伤阈值的激光对元件表面进行预处理,可以有效提高光学元件的抗激光损伤能力。对激光预处理技术的提出背景、定性作用机理、定量理论模型及国内外技术应用现状进行了概述。并且介绍了一种可在薄膜制备过程中进行原位实时激光预处理的新型薄膜制备技术。最后指出,激光预处理技术作为一种无污染,可有效改善光学薄膜、光学玻璃、光学晶体元件损伤阈值的最有效方法之一,其作用机理、实用化、仪器化还有待进一步发展。     

紫外日盲通信系统中滤光膜的研究

紫外日盲通信凭借其优良的光学特性被越来越多地应用在光学系统中。紫外日盲通信系统与常规通信系统相比,具有结构简单、虚警率低、灵敏度高、隐蔽性强等独特优势。为了满足紫外通信系统的技术要求,提高信号采集效率,需要一种日盲光谱滤光膜来保证其稳定工作。根据薄膜理论,选择合适的紫外薄膜材料,在设计方面通过对独立敏感度和误差分布的分析与修正,降低了膜层的敏感度,同时在薄膜制备过程中通过逆向测试分析法,解决了由于设备与控制误差导致的膜厚问题。制备的紫外滤光膜在240~280nm透射率为86%,290~360nm波段截止度小于0.2%,并通过了国军标的相关环境测试。     

智能眼镜影像系统宽光谱广角度分光膜的研制

依据光学薄膜理论,建立膜系优化评价函数,利用软件优化膜系,实现0°~75°入射宽光谱P光分光膜的设计.选择H4和MgF2作为高低折射率材料,采用电子束及离子辅助沉积技术,来制备该分光膜.通过对膜层厚度误差分析,用晶控片单独控制相对敏感度较高的膜层,解决了薄膜制备过程中不能精确控制膜厚误差的问题.运用逆向分析法对实验测试结果进行模拟分析,通过改变膜厚修正因子,使P光透射光谱曲线更加平滑.光谱测试表明P光垂直入射平均透过率为60.3%,满足系统使用要求.     

High Power Pulse Laser Reflection Sequence Combination with a Fast Steering Mirror

We propose and demonstrate a new approach for a high power pulse laser reflection sequence combination with a fast steering mirror(FSM). This approach possesses significant advantages for lasers combining with a variety of output power, wavelength, pulse duration, repetition rates and polarization. The maximum number of laser routes participating in combination principally depends on the FSM's adjustment time of the step response, lasers' repetition rates and pulse duration. A proof-of-principle experiment is performed with two 2-kW level pulsed beams. The results indicate that the combined beam has an excellent pointing stability with rms pointing jitter～8.5μrad. Meanwhile, a high combining efficiency of 98.6% is achieved with maintaining good beam quality.     

光学元件激光预处理技术研究进展及其应用

光学元件中的杂质和缺陷会引起其激光损伤阈值的大幅降低,现阶段这一问题已成为激光装置向高功率、高能量方向发展的“瓶颈”,亟待解决。在对光学元件激光损伤的研究中发现,用低于光学元件损伤阈值的激光对元件表面进行预处理,可以有效提高光学元件的抗激光损伤能力。对激光预处理技术的提出背景、定性作用机理、定量理论模型及国内外技术应用现状进行了概述。并且介绍了一种可在薄膜制备过程中进行原位实时激光预处理的新型薄膜制备技术。最后指出,激光预处理技术作为一种无污染,可有效改善光学薄膜、光学玻璃、光学晶体元件损伤阈值的最有效方法之一,其作用机理、实用化、仪器化还有待进一步发展。     

Theoretical and experimental studies on high-power laser-induced thermal blooming effect in chamber with different gases

High-power laser induced thermal blooming effects in a closed chamber with three different gases are investigated theoretically and experimentally in this work. In the theoretical treatment, an incompressible gas turbulent model is adopted. In the numerical simulation the gas refractive index as a function of both the temperature and pressure is taken into consideration. In the experimental study the pump-probe technology is adopted. A high-power 1064-nm fiber laser with maximum output power of 12 kW is used to drive the gas thermal blooming, and a 50-mW high-beam-quality 637-nm laser diode (LD) is used as a probe beam. The influences of the gas thermal blooming in the chamber on the probe beam wavefront and beam quality are analyzed for three different gases of air, nitrogen, and helium, respectively. The results indicate that nitrogen is well suitable for restraining thermal blooming effect for high-power laser. The measured data are in good agreement with the simulated results.     

多功能防油污减反膜的研制

为了改善光学镜头表面的耐污染性,选取新型抗油污含氟有机材料、氧化铟锡导电薄膜材料、TiAl合金以及SiO2做为中、高、低折射率镀膜材料.借助TFCalc软件进行膜系设计,采用离子源辅助沉积的方法,通过电子束真空镀膜设备进行制备.对比实验发现,不同的真空度环境以及不同的膜层厚度,对于薄膜的防油污性能的影响有所差异.通过对防油污性能的测试,不断优化沉积工艺参量,获得了在350~700nm波段平均理论反射率小于1%的宽带减反射膜.该薄膜具有憎水憎油抗污染能力,牢固度好,抗辐射能力强,可应用于军事、医疗、民用等各个领域.