激光同步辐射作为阿秒X射线辐射源的特性研究

 研究了逆流相对论电子与激光脉冲相互作用获得激光同步辐射的频率上移、微分散射截面等特性。发现逆流相对论电子与短脉冲激光相互作用，可以获得阿秒X射线辐射脉冲。短脉冲激光条件下得到的后向散射光的频率上移与长脉冲激光条件下得到的后向散射光的频率上移是完全一致的，同时发现随着入射电子初始能量的增加，散射光的准直性越来越好，后向散射光脉冲的脉宽越来越短。     

采用光谱展宽技术的钛宝石飞秒激光放大器

报道了飞秒激光啁啾脉冲放大器中的激光脉冲光谱展宽技术，实验中使用了几种光谱展宽元件，结果表明使用激光光谱展宽元件能有效地将飞秒激光脉冲 光谱展宽，抑制了飞秒激光放大器中常见的激光脉冲光谱增益窄化现象，从飞秒放大系统的振荡级输出28fs种子脉冲，放大后得到了重复频率为10Hz、峰值功率为1．6TW、脉冲宽度37．5fs的超短强飞秒激光脉冲 。     

A Quenched Dye Laser Pumped by a KrF Excimer Laser

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激光在烟幕中传输的蒙特卡罗模拟

建立蒙特卡罗计算模型,模拟计算1.06μm脉冲激光在石墨烟幕中的传输.分析透过率与石墨粒子粒径、烟幕浓度、烟幕厚度的关系,用卷积方法计算一定宽度的脉冲激光穿过烟幕后的波形,数值仿真δ脉冲和矩形脉冲激光在各种石墨烟幕中的时间展宽特性.模拟结果表明:石墨粒子存在一最佳半径(0.16μm),该半径的石墨粒子烟幕不仅使激光能量衰减最强,而且产生的时间展宽也最显著;激光脉冲宽度越小,其波形变化和时间展宽越显著,微秒量级脉宽的激光脉冲穿过烟幕后波形变化和时间展宽效应不明显.     

Laser pulse optimization for practical laser drilling

Laser drilling is a common commercially developed technique for material processing. From the application viewpoint, it is the end product for a laser system, for instance a drilled hole, that matters. Laser pulse profile is the most important parameter controlling the laser hole drilling process. An efficient and practical method is therefore needed to develop a relationship between the pulse parameters and the depth of hole produced in a known material. In the present study, dimensionless groups are developed to optimize laser pulse parameters to give information on workpiece materials. Consequently, an optimal laser pulse for drilling an aluminum workpiece is predicted.     

Higher-Derivative Gravitational Coupling Between Laser Beams

The gravitational field due to laser pulse traveling along a straight waveguide with a velocity v < c is considered in the framework of higher-derivative theory of gravitation. The deflection of a probe laser pulse propagating in the vicinity of a high-power laser pulse is discussed. It is shown from a numerical comparison that the deflection of the probe laser pulse predicted by higher-derivative theory of gravitation is much less than the prediction of general relativity if the wavelength of the laser pulse is smaller than the range of the additional force.     

Laser pulse spectral shaping based on electro-optic modulation

A new spectrum shaping method, based on electro-optic modulation, to alleviate gain narrowing in chirped pulse amplification （CPA） system, is described and numerically simulated. Near-Fourier transform-limited seed laser pulse is chirped linearly through optical stretcher. Then the chirped laser pulse is coupled into integrated waveguide electro-optic modulator driven by an aperture-coupled-stripline （ACSL） electricalwaveform generator, and the pulse shape and amplitude are shaped in time domain. Because of the direct relationship between frequency interval and time interval of the linearly chirped pulse, the laser pulse spectrum is shaped correspondingly. Spectrum-shaping examples are modeled numerically to determine the spectral resolution of this technique. The phase error introduced in this method is also discussed.     

激光二极管抽运的GaAs被动Q开关Nd：YVO4激光器

利用固体可饱和吸收体砷化镓（GaAs）作为被动调Q元件，实现了激光二极管抽运平－凹腔掺钕钒酸钇（Nd:YVO4）激光调Q运转，详细测量了砷化镓被动调QNd:YVO4激光输出特性，获得脉宽15ns，重复频率470kHz，光束质量M^2=1.31的激光输出，调Q激光运转阈值为500mW，并数值求解了砷化镓被动调Q速率方程，讨论了被动调Q机理以及调Q脉冲宽度和脉冲重复频率对抽运速率的依赖关系，理论计算结果与实验结果相一致。     

超短脉冲光纤激光器新进展及其应用

超短脉冲光纤激光器是目前激光技术研究领域中最具有活力的研究课题．有着巨大的应用前景。本文介绍超短脉冲光纤激光器的发展概况及最新进展，论述掺稀土超短脉冲光纤激光器原理，对其关键技术及多种新型技术方案做了介绍和比较，分析超短脉冲激光器的应用前景及发展趋势。     

主控抽运被动调Q激光器和输出特性

对脉冲抽运与增益预抽运的微腔Cr4+:YAG/Nd:YAG被动调Q激光器的稳定性进行了理论和实验研究。结果表明在抽运时抽运脉宽和重复率较大的情况下,输出激光脉冲相对于抽运脉冲抖动范围明显加大。针对此情况,采用压缩抽运脉宽和降低重复率的方法获得了波长为1.06 μm、脉宽为3.8 ns、单脉冲能量为65 μJ、相对抽运脉冲的抖动范围小于0.8 μs的激光输出。同时分析了增益预抽运的优势和缺点。     

Laser thermoprobe

Time-resolved thermal profiles produced in a thin film of Al by a pulse of energy from a GaAs laser have been measured by a laser thermoprobe, consisting of an Ar⁺ laser and a thin film of CdS evaporated onto the Al. A spatial resolution of 0.5 μm and a temporal resolution of 10 nsec were achieved. The measurement is in good agreement with a three-dimensional heat flow calculation.     

Laser amplifier design

Often one wants a laser amplifier system to produce an output pulse of a specific form, e.g., time shape, energy, etc. Given any potential amplifier configuration one needs to find the proper input pulse which, when propagated through the amplifier system, results in the desired output pulse. Efficient operation of the amplifier (large energy extraction) usually implies that the response of the laser medium is nonlinear, which makes such a calculation very tedious if attempted on a hit and miss basis. Here we discuss a procedure which enables one to systematically generate the proper input pulse. Once the input is known it is straightforward to determine whether the amplifier configuration is suitable.     

LD抽运角锥棱镜腔电光调Q固体激光器

利用角锥棱镜的退偏效应实现了电光调Q固体激光器的偏振耦合输出.器件采用热传导冷却半圆柱面LD阵列侧向泵浦Nd:YAG泵浦几何,获得在20 Hz运行条件下,脉冲能量163 mJ/pulse、脉冲宽度6.5 ns、发散角3.5 mrad、能量稳定性土2.8%、光光效率16.7%的理想性能.与传统平行平面腔相比,具有效率高、峰值功率大、输出能量和脉宽可调,且输出稳定等优点.     

高功率激光装置前端系统激光脉冲的时间整形及修正技术

针对激光惯性约束聚变实验研究对高功率激光驱动器前端系统复杂时间形状种子激光脉冲的需求,应用孔径耦合带状线集成波导整形系统设计了满足需要的前端整形激光脉冲。用一种新方法精确计算了孔径耦合带状线电脉冲整形器的耦合系数和孔径宽度的数值关系,并针对高衬比度整形激光脉冲的需求,提出了高衬比度双极型集成波导整形系统方案。由该系统可以得到100 ps脉冲前沿、1～3 ns脉冲宽度可调、高衬比度(大于100:1)、光滑无纹波调制、可精确满足神光Ⅱ八路及第九路装置需求的前端整形激光脉冲。     

二极管激光侧泵浦单横模100Hz电光调Q激光器

介绍了二极管激光侧泵浦单横模１００Ｈｚ电光调Ｑ激光器的实验结果。泵浦源为一个线阵准连续１００Ｗ二极管激光器，激光工作介质为ＮｄＹＡＧ薄梯形板条，板条与泵浦源间用柱透镜耦合，ＫＤ＊Ｐ电光晶体调Ｑ。在１００Ｈｚ重复频率下，获得单脉冲能量２．３７ｍＪ，脉宽小于７ｎｓ，光束质量因子Ｍ２＝１．１的１．０６μｍ激光，光－光效率为８．５％，斜效率为１８．７％。     

基于光纤中SBS相位共轭的自调Q光纤激光器

分析了利用光纤中的受激布里渊散射(stimulated Brillouin scattering,SBS)相位共轭效应进行激光腔内调Q,产生ns量级脉冲激光的原理,并对利用该效应产生的激光脉冲波形和脉冲形成过程进行了数值模拟,得到的脉冲波形与SBS相位共轭反射率随时间变化曲线基本一致,表明利用光纤中的SBS相位共轭作用调Q具有可行性.据此,对采用单模光纤(single-mode fiber,SMF)作为SBS池的Er³⁺掺杂调Q光纤激光器进行实验研究.当单模光纤长度为1.5 m时,在45 mW的光抽运功率下得到脉宽约2.6ns,脉冲周期58.23ns,平均功率7.35mW的激光脉冲.进一步的研究表明:激光器中相位共轭镜的形成与SBS介质长度有关,SBS介质过长,斯托克斯线之间无固定的相位关系,不能形成相干叠加,SBS相位共轭腔不能形成;SBS介质过短,腔内正交偏振模光子寿命的改变使脉冲出现双峰现象.脉冲形成后其属性只与SBS动态属性有关.     

军用脉冲激光测距技术与研究现状

简要介绍了军用脉冲激光测距机的工作原理和应用现状，分析了脉冲激光测距机中各种激光源的优缺点，并对现阶段军用脉冲激光测距机的研究热点和未来的发展趋势作了相应阐述。     

激光导致的透明固体损伤模型

详细分析了描述激光导致损伤的"移动的损伤"模型,发现该模型不适用于常见的飞秒激光对绝缘性透明固体材料处理的情况(如:800nm的100fs激光脉冲,0.65NA紧聚焦系统),此时脉冲与物质间相互作用区域和聚焦系统的瑞利长度可以比拟.对模型做了改进,改进后的模型可以很好地预期飞秒激光脉冲在固体中产生损伤的时间和空间形态.     

一种基于增益调制技术的全光纤化脉冲Yb光纤激光器

以波长为975 nm的半导体激光器作为泵浦源,周期性地脉冲泵浦一个包含Yb掺杂光纤和光纤光栅对的Yb光纤激光器,实现了基于增益调制技术的全光纤化高功率Yb光纤激光器的稳定脉冲输出.在50 kHz重频下,采用20 W的泵浦功率和2.4 μs的泵浦脉冲宽度,获得了1 060 nm波长脉冲宽度仅100 ns的稳定脉冲激光输出,单脉冲激光能量约为20 μJ.以此作为脉冲激光种子进行功率放大,获得了性能稳定的全光纤结构高功率脉冲激光输出,放大后单脉冲能量超过200 μJ,激光放大器斜率效率达到60%.     

脉冲相干激光雷达测距信号研究

对脉冲激光雷达外差测距信号进行了研究，理论上，采用调Q激光脉冲的数值计算波形，研究了脉冲激光经远处目标漫反向后进行外差接收的波形及其傅里叶变换频谱成分。实验上，研究了可调谐电光调Q射频激励波导CO2激光器脉冲激光经目标反射后的外差波形及其傅里叶变换频谱成分，并计算了目标的距离，理论分析与实验结果一致。