基于声光调制的频移反馈激光器是目前研究的热点,它可以生成一串频率间隔相同的谐波。为了生成多频激光,采用移频反馈激光器的方法,设计了一种全光纤式移频-放大反馈环路,建立了基于频移反馈腔的激光外差相关理论模型,并进行了数值仿真。同时,在环路中引入光纤放大器,研究了增益系数对各阶次谐波相应强度的影响,验证了不同增益系数对各阶次频率的选择作用。结果表明,利用频移反馈回路,实现了数倍于基频的高频调制,最高调制频率可达4GHz。这为新体制高频调制激光的研究奠定了理论及实验基础。

传统的光学镜头探测主要基于回波强度(猫眼效应)来实现,但对于微型镜头而言,反射回波中存在明显的衍射现象,因此对微型镜头光阑衍射效应的研究成为一个重要的研究方向。基于角谱衍射理论,研究了微型镜头对辐照激光的空间调制特性,推导了回波光场分布的公式;仿真研究了探测距离、入射角度和光阑直径对衍射光场分布的影响,以及不同光阑直径时的最大可探测入射角,并利用搭建的激光主动探测系统对回波衍射现象进行了探测。结果表明,实际探测的衍射图样与仿真图样吻合得较好,所提理论能够准确地预测微型镜头探测回波的衍射现象。

针对利用光纤延时自差系统获得双频拍频光的方法, 建立了激光源强度起伏和相位噪声对拍频光功率谱影响的理论模型, 并基于该模型进行了数值分析和模拟。结果表明, 短延时差比长延时差更有利于减小激光器的噪声干扰。当延时差小于激光相干时间时, 激光线宽越大, 强度起伏越大, 信号的信噪比越低。当延时差远大于激光相干时间时, 激光器的相位噪声成为拍频光信号展宽的主要来源, 且相位噪声越大, 拍频光信号功率越小; 强度起伏也有一定的展宽效应, 但对于拍频信号功率有增大作用。在长延时情况下, 拍频光信号功率和线宽随两个频率光的延时差呈余弦规律变化, 存在最佳工作点。

根据全光纤激光雷达特性设计与优化发射和接收光学系统。针对全光纤激光雷达光学系统中的激光高斯传输特性、扩展目标特性和光纤收发特性，修正激光雷达方程中的发射天线增益和目标反射截面，引入光纤接收效率参数。修正后的发射天线增益与目标处光斑大小的平方成反比，漫反射目标的雷达反射截面取决于目标反射率和激光入射角。实验探究了回波功率与接收光纤芯径的关系，得到了最佳光纤芯径。修正后的激光雷达方程可准确计算光纤收发条件下激光的回波功率，为后续的信号处理提供精确的理论支持。

采用一种新型的Nd∶YVO4/YVO4复合晶体,利用V型折叠腔,研究了高功率激光二极管端面泵浦的Nd∶YVO4/YVO4复合晶体激光器基频1.06 μm及倍频532 nm激光的输出特性.当泵浦功率为24.6 W时,获得1.06 pm激光的最大输出功率为11.7 W,光-光转换效率为48%.当泵浦功率为17 W时,获得了5.32 W的绿光输出,光-光转换效率达到31.3%.

Thermal effects control is very critical in highly scaling the output power of diode-pumped solid-state lasers to a few watts especially for end pumping configuration. Low temperature reservation of the pumping surface and the crystal could be adopted to reduce thermal effects and improve laser performance. Diffusion bonding crystal has been demonstrated to be an effective method to relieve the thermal lensing theoretically based on the numerical heat analysis to the end-pumped anisotropic laser crystal. The temperature distribution in Nd:YVO4/YVO4 composite crystal was analyzed before the end-pumped Nd:YVO4/YVO4 composite crystal laser with V cavity was designed and set up. The maximum output powers of 9.53 W at 1064 nm, 5.01 W at 532 nm were obtained while the pumping power was 17 W. The highest optical to optical conversion efficiencies were up to 59.1% at 1064 nm and 34.4% at 532 nm, respectively.

Thermal effect in crystals is the main obstacle blocking diode-pumped solid state laser to get high and stable output power. Diffusion bonding crystal has been demonstrated to be an effective method to relieve the thermal lensing theoretically based on the numerical heat analysis to the end-pumped anisotropic laser crystal. The temperature distributions in Nd:YVO4/YVO4 composite crystal and conventional crystal were analyzed and compared. The end-pumped Nd:YVO4/YVO4 composite crystal laser was designed and set up with z-cavity. The maximum output powers of 9.87 W at 1064 nm and 6.14 W at 532 nm were obtained at the incident pump power of 16.5 W. The highest optical-optical conversion efficiencies were up to 59.8% at 1064 nm and 37.2% at 532 nm respectively.

在高功率激光二极管(LD)抽运的情况下, 对比分析了Nd:YVO4/YVO4复合晶体和Nd:YVO4单一晶体的激光特性。实验证明, 复合晶体能够有效地降低晶体内的温度梯度, 减小由端面变形带来的热透镜效应, 获得比单一晶体高出许多的输出功率。采用Z型折叠腔, 研究了Nd:YVO4/YVO4复合晶体KTP倍频特性, 当抽运功率为17 W时, 获得了6.23 W的绿光输出, 抽运光到绿光的转换效率高达37%。