227-W output all-fiberized Tm-doped fiber laser at 1908 nm

In this paper, we report that a diode-pumped thulium-doped double clad silica fiber laser can provide powers of up to 227 W at 1908 nm, corresponding to a slope efficiency of 54.3%, and an optical-to-optical efficiency of 51.2%. The output power, to the best of our knowledge, is the highest output at 1908 nm. The beam quality M2 factor is about 1.56. Also discussed in this paper is the dependence of the laser performance on fiber length.     

Pre-pumped passively Q-switched Nd:YAG/Cr:YAG microchip laser

A pre-pumped passively Q-switched Nd:YAG/Cr: YAG microchip laser is demonstrated with a peak power of 7.5 kW at pulse repetition rate of serveral kilohertzs. The full-width at half-maximum (FWHM) is 734 ps, and the pulse energy is 5.5 μJ with a fundamental spatial mode. In this system, the pre-pumped microchip laser of Nd: YAG/Cr: YAG wafer which is bonded through the thermal-bonding technique has achieved a time jitter value of 12 μs and a Q-switched amplitude instability of 1.26% (1δ) through the pre-pumped modulation technique.     

基于Phong模式的分裂Monte Carlo模拟红外室内信道脉冲响应函数

介绍了基于Phong模式的Monte Carlo方法.该方法能够对红外室内通信的重要性能参数—— 信道脉冲响应函数进行快速有效的计算，可应用于包括漫反射、镜面反射以及粗糙度介于这 两种反射之间的表面反射情形的信道中.相对于经典的有限元法，在高次反射时具有更为明 显的优势，不但计算速度快，而且计算结果也更接近真实信道环境.该方法的使用，能够为 设计高性能红外系统提供更为可靠的参数. 关键词： 红外室内通信 脉冲响应函数 分裂Monte Carlo Phong 模式     

一步法制备纳米氧化锌的形成机理

以氯化锌和氢氧化钠为原料,采用直接水解一步法制备了针状和球形纳米氧化锌.借助于XRD、TEM等测试手段,对纳米氧化锌粉体的制备条件和其对粒度、形貌的影响进行了分析研究.利用负离子配位多面体生长基元理论模型,解释了直接水解合成氧化锌纳米晶体的形成机理和生长习性.研究结果表明,一步法直接合成纳米氧化锌的结晶过程遵循溶解-结晶-聚集生长机理模型;ZnO为极性晶体,具有极性生长特性,其成核过程包括均相成核和非均相成核.     

Multi-coupler side-pumped Yb-doped double-clad fiber laser

The side-coupler of angle polished method, using angle-polished multimode fiber and optical adhesive, is used to efficiently pump an Yb-doped double-clad fiber laser. The maximum coupling efficiency of 78.6% is achieved by the side-coupler for a multimode fiber with a circular core of 200μm and a double-clad fiber with a 350/400μm D-shaped inner cladding. While laser diodes (LDs) with three side-couplers are simultaneously used as pump sources, maximum output power of 1.38 W and slope efficiency of 48.9% are demonstrated in the fiber laser system.     

All-fiber linearly polarized laser oscillator by fiber coiling loss control

In this paper,we demonstrate an all-fiber linearly polarized fiber laser oscillator.The single polarization of the oscillator is achieved through the careful designing of the active fiber coiling.The relationship between fiber coiling diameter and polarization extinction ratio and optical efficiency is studied,whose results lead to an optimized system.The thermal management of the oscillator is also refined,which allows the oscillator to reach a maximum output power of44.1 W with an optical-to-optical efficiency of 57.9%.A high average polarization extinction ratio of 21.6 d B is achieved during a 2-hour stability test.The oscillator also owns a narrow 3-d B bandwidth of 0.1 nm,as well as near-diffraction-limit beam quality of M~2~ 1.14.     

Laser diode end-pumped Nd：YVO4 regenerative amplifier for picosecond pulses

A diode dual-end-pumped Nd:YVO4 regenerative amplifier is reported. The influence of the cavity stability on the performance of the regenerative amplifier is studied. The experimental results match well with the analysis at high pump power. The mode locking seed pulses with 15 ps pulse width and 10 nJ single pulse energy at 86 MHz are amplified up to 4.7 mJ at 1 kHz, corresponding to the maximum amplification about 0.5 × 106 , by our regenerative amplifier. And an average power of 4.7 W is obtained at the repetition rate from 1 kHz to 10 kHz.     

气相色谱法测定二咖啡酰奎尼酸原料药中的有机溶剂残留量

以1,2-二氯乙烷作为内标,气相色谱法定量检测二咖啡酰奎尼酸原料药中7种有机溶剂残留量。色谱柱：DB-624,30m×0.32mm×1.8μm,载气为H2,检测器为FID,采用程序升温的方法。7种残留溶剂的线性关系良好（r〉0.9914）,回收率为92.5%—98.5%,最小检出限量均为0.01%。本方法简便、灵敏、准确,可用于二咖啡酰奎尼酸原料药残留溶剂的质量控制。     

GaAs被动调Q兼输出耦合Nd∶YVO4激光特性研究

利用可饱和吸收半导体GaAs作为被动调Q元件和F-P输出耦合镜,实现了半导体激光器(LD)抽运Nd:YVO4激光调Q运转,获得脉宽度为47ns,重复频率为1183kHz,平均功率为430 mW,光束质量为M2=1.13的TEM00激光基横模输出,调Q抽运阈值为1700mW.并数值求解了含有GaAs被动调Q兼输出耦合的速率方程,分析了GaAs被动调Q机理以及脉宽宽度、重复频率、平均功率随抽运速率、腔长的变化关系,理论与实验结果相一致.为多功能综合型微型调Q固体激光器提供了简单有效的方法.     

A passively Q-switched diode pumped Yb:YAG microchip laser

A passively Q-switched diode pumped Yb:YAG microchip laser with Cr4+:YAG saturable absorber mirror is reported. The TEMoo laser pulses are obtained with 1,7-uJ pulse energy, 15-ns pulse width, 0.11-kW peak power, and a repetition rate of 2.2 kHz at 1049 nm. The doped concentration and dimension of Yb:YAG microchip crystal are 10 at.-% and 5×0.6 mm2, respectively.