Studies on Nonlinear Physics and Application Technology of Thin-Slice Solid-State Lasers with Coated End Mirrors

通过对激光二极管(LD)泵浦的薄片固体激光器的非线性物理和应用技术的研究，取得了以下主要成果。LD泵浦的薄片固体激光器中的图案形成(1)系统地研究了LD泵浦的大口径薄片固体激光器中反射端的表面粗糙度和泵浦光束光斑尺寸对激光图案形成的影响。实验上发现了类似于量子台球模、复合晶格模和散斑模等奇特的激光模式。(2)在常规激光晶体中发现了局域横模的偏析以及伴随的包含混沌的高速强度调制。：YAG陶瓷激光器，平均晶粒度为几十微米。这些现象在理论上都得到了很好的再现。(3)用以下方法解决了陶瓷激光器中的固有问题：(1)学习直径足够大的Ince-Gauss型激光模的选择激励…更多的颗粒尺寸；(Ii)使用平均颗粒尺寸为几微米的微晶陶瓷激光器。在这两种情况下，(4)发展了微芯片固体激光器高次高斯模的Lapumping方法，并通过操控小粒子的运动实现了各种新型光涡的形成。2.LD-Pumecl自混合薄片固体激光测量(1)通过改进移频反馈装置，将光学灵敏度提高了两个数量级。(2)实现了1-nm振幅的实时振动测量和对粒径在80-500mN范围内浓度小于1ppm的水中小颗粒的快速测量。利用自行研制的载频复用法，实现了1 nm振幅的三维实时测振。利用调频解调电路实时捕捉到了布朗粒子的整体动力学信息。(3)将自混合激光测量技术应用于流体流动测量，成功地实现了流体速度和动态粘度的快速测量。对于262-纳米聚苯乙烯乳胶球，在0.01ppm的浓度限制下，对流动中的小颗粒进行了检测。较少

The following main results have been obtained through studies on nonlinear physics and application technology using laserdiode (LD) pumped thin-slice solid-state lasers.1. Pattern formations in LD-pumped thin-slice solid-state lasers(1) Effects of surface roughness of reflective ends and pump-beam spot size on lasing pattern formations were studied systematically in wide-aperture thin-slim solid-state lasers with LD pumping. Such curious lasing patterns as quantum billiard-like modes, composite lattice modes and speckle modes were found experimentally.(2) Segregations into local transverse modes' and associated high-speed intensity modulations inclnding chaos were found in conventional Nd. : YAG ceramic lasers whose average grain size is several tens of microns. These phenomena were well reproduced theoretically.(3)The inherent problem in ceramic lasers was solved in the following way (i) The selective excitation of Ince-Gaussian lasing modes with learn diameters sufficiently larger th … More an grain sizes ; (ii) The use of micro-grained ceramic lasers with average grain size of few microns. In both cases, stable oscillations without segregations into local modes were realized.(4)The Lapumping method for controlled generations of higher order Ince-Gaussian modes in microchip solid-state lasers was developed and formation of various types of novel optical vortices was realized toward manipulating motions of small paricles.2.LD-pumecl self-mixing thin-slice solid-state laser metrology(1) We increased the optical sensitivity by two-orders of magnitude by improving devices in the frequency-shift feedback scheme.(2) We realized real-time vibrometry of 1-nm amplitude and quick sizing of small particles in water whose concentration is below 1 ppm in the particle diameter range of 80-500mn. The three-dimensional real-time vibrometry of 1-nm-amplitude was realized by usinghe carrierfrequency multiplexing method which we developed. The overall dynamics of Brownian particles was captured for the fa-A time by the FM demodulation circuit.(3) We applied our self-mixing laser metrology to flow measurements and quick measurements of flow velocity and dynamic viscosity were successfully demonstrated. Also, the detection of small particles in the flow was done under the concentration limit of 0.01ppm for 262-nmpolystyrene latex spheres. Less