Linearly polarized operation of Yb-doped fiber laser by Brewster's angle-polished fiber end

<正>A new method to obtain linear polarization operation by Brewster's angle-polished fiber end is demonstrated. By using the special polarization operation technique together with introducing a narrow-linewidth fiber grating into the laser cavity,a cladding-pumped linear polarization and single-transverse-mode (M~21.1) Yb-doped fiber laser with narrow linewidth whose full-width at half-maximm(FWHM) is less than 0.2 nm,is obtained in a simple configuration.The output power is up to 10 W which is continuouswave output at 1085 nm,and the slope efficiency is 63%with respect to the coupled pump power and 75%with respect to the absorbed pump power,respectively.The measured 21-dB polarization extinction ratio does not degrade with the output power.The simplicity of such an approach is highly beneficial for a number of applications,including the use of a fiber laser for the nonlinear wavelength conversion (especially for the intracavity frequency doubling) and for the coherent and spectral beam combination.     

High-energy nanosecond all-fiber Yb-doped amplifier

We demonstrate a high-energy,low-repetition-rate,all-fiber,1 064-nm Yb-doped fiber laser based on the master oscillator power amplifier structure.Pulse-pumping technology is used to suppress amplified spontaneous emission.A maximum output pulse energy of 5.97 mJ is obtained at 16-ns pulses with an M2of 2.9.     

复合金属纳米颗粒多孔硅的光学非线性特性

根据多孔硅中的量子限制效应和金属颗粒与电磁场相互作用的Mie理论及非线性光学的基本原理，提出了用于复合金属纳米颗粒多孔硅微结构的计算模型，分析了复合金属纳米颗粒多孔硅的非线性光学性质．计算了复合Ag(Au)纳米颗粒多孔硅的场增强因子，得到了在不同的金属颗粒含量时，复合体系的三阶极化率随入射光波长变化的关系，为制备具有强非线性光学效应的硅基材料及其应用提供了重要参考．     

多孔硅拉曼光谱的研究

采用电化学腐蚀的方法制备多孔硅。对不同实验条件下所得到的多孔硅的拉曼光谱进行了分析，确认多孔硅是具有纳米晶结构特征的材料，肯定了量子限制效应在多孔硅光致发光中的作用。     

All-fiber, high-average-power core-diameter nanosecond laser based on adjustment

Core-diameter adjustment, in analogy to doping management, is proposed in this letter for balancing thermal load and nonlinear effects. In this scheme, the core-to-cladding ratio increases with increasing core diameter along the direction of signal and pump propagation. An all-fiber-integrated Yb-doped master oscillator power amplification （MOPA） is successfully demonstrated. Two segments of fiber with different core diameters but same inner-cladding diameters and doping levels are spliced together and used as gain fibers in the last stage. A maximum average output power of 200 W at an overall slope efficiency of 71% is achieved from the MOPA with a pulse energy of 2 mJ and peak power as high as 80 kW.     

Frequency doubling of narrow-linewidth pulsed fiber laser

A pulsed master oscillator power amplifier system is constructed using a double-cladding polarized Ybdoped fiber and an all-fiber Q-switched narrow-linewidth pulsed laser used as seed laser.This system has a high repetition rate and provides a nanosecond pulsed laser with a narrow linewidth and linear polarization.Moreover,it generates amplified radiation with up to 14 W of average power,narrow linewidth(full-width at half-maximum is smaller than 0.12 nm),linear polarization at 1 080-nm wavelength,repetition rate of 51 kHz,and pulse duration of approximately 50 ns.Based on this pulsed amplified radiation,3.5 W of green laser,with an optical-to-optical efficiency of 27.3%,is obtained via single-pass frequency doubling using a noncritical phase matching KTP crystal.