In this letter, we develope a control and image processing system for Streak Tube Imaging Lidar (STIL). In the system, the data acquisition card control and the software interface are programmed in Visual Basic (VB) while the image processing is finished by MATLAB. A STIL imaging experiment is carried out in the laboratory. We obtained the intensity and range images of targets with pseudo color by image processing and reconstruction for a set of raw streak images of targets at different distances acquired by STIL. The range resolution is better than 2 centimeters.

A numerical simulation is performed to study the far-field diffraction properties of planar diamond waveguides. The far-field intensity distributions of a planar air waveguide and a diamond waveguide with different distances are given by numerical calculations. In the experiment, the diffraction patterns on the screen with different distances are recorded using a He-Ne laser as the light source, wherein the laser beam is coupled with and propagates in the diamond waveguide. The simulation results are found to be consistent with the experimental ones.

建立了绿光水下激光传输的发射和接收实验系统，在威海近岸海域对调制激光信号在水下的传输特性进行了实验研究。系统以光电倍增管作为探测器，在不同接收负载情况下，观测了不同传输距离下绿光脉冲信号的接收波形。实验结果表明，大的接收负载有助于提高探测距离，采用1 MΩ接收负载时的最大探测距离为26 m。根据实验数据拟合不同距离处的接收光强，激光在海水中的传输信号强度呈e指数衰减趋势，其衰减系数为0.5 m-1,可以推断在浑浊度较小的海域光传输距离会增加。

In this letter, numerical simulation and experimental study of a radial-slab solid-state laser are presented. The laser includes four crossing-slabs pumped by four Xe flashlamps. The numerical simulation of coherent intensity in the near field and the far field indicates that the laser with the structure can improve the quality of output beam compared with incoherent beam combination. The radial-slab solid-state laser is fabricated, and initial experiments are carried out at a pulse repetition of 1 Hz. Nine beams in the near field and one combined beam in the far field are obtained in our initial experiment. The experimental results are consistent with the numerical analysis in the coherent condition. The results show that coherent beam combination is obtained by this laser.

A new method for laser-frequency stabilization by controlling the pulse setup time is presented. The frequency-stabilization system monitors the pulse setup time continuously, and controls it by adjusting the cavity length. Laser frequency is stabilized to the center of the gain curve when the setup time is the shortest. The system is used to stabilize a radio-frequency-excited waveguide CO2 laser tuned by grating, and the shift of laser frequency is estimated to be less than §25 MHz for an extended period. The system has the advantages of compact structure, small volume, and low cost. It can be applied for frequency stabilization of other kinds of pulsed lasers with adjustable cavity.

设计并研制了以全金属射频波导CO2激光器为抽运源的太赫兹(THz)激光器,其中THz激光工作气体为CH3OH气体,在波长为9.69 μm的P9(36)支CO2脉冲激光抽运情况下,获得了脉冲THz激光输出。实验上测量了脉冲抽运光及THz激光波形及重复频率,抽运光由宽带室温HgCdTe探测器测试,最高重复频率为5 kHz。THz激光由热释电探测器接收,由于受探测器限制,实验上测量的THz激光波形失真,最高重复频率为1 kHz。另外研究了输出THz激光强度与工作气压的关系,测出此系统最佳工作气压为10 Pa左右。研制的THz激光器为全金属结构,不用水冷,具有结构简单、体积小的优点,可以为相关研究提供参考。

Optically pumped terahertz (THz) lasers with high pulse repetition frequency are designed. Such a laser includes two parts: the optically pumping laser and the THz laser. The structures of the laser are described and analyzed. The rate equations for the pulsed THz laser are given. The kinetic process and laser pulse waveform for this kind of laser are numerically calculated based on the theory of rate equations. The theoretical results give a helpful guide to the research of such lasers.