A picosecond widely tunable deep-ultraviolet laser for angle-resolved photoemission spectroscopy

We develop a picosecond widely tunable laser in a deep-ultraviolet region from 175 nm to 210 nm,generated by two stages of frequency doubling of a 80-MHz mode-locked picosecond Ti:sapphire laser.A β-BaB2O4 walk-off compensation configuration and a KBe2BO3F2 prism-coupled device are adopted for the generation of second harmonic and fourth harmonics,respectively.The highest power is 3.72 mW at 193 nm,and the fluctuation at 2.85 mW in 130 min is less than ±2%.     

高平均功率固体激光功率和光束质量关系研究进展

 固体激光的一个重大发展方向和目标是实现“三高”(高平均功率、高光束质量和高效率)激光同时输出,结合相关研究工作和进展,着重论述了固体激光输出功率和光束质量的关系,给出了功率升高、光束质量非线性下降是当前“三高”固体激光研究的一个基本科学技术问题。围绕这一基本问题,评述了一些重要技术途径和手段,并探讨了实现高平均功率高光束质量固体激光输出的可能有效途径。     

High Beam Quality Green Generation with Output 140W Based on a Thermally-Near-Unstable Flat-Flat Resonator

By using a diode-side-pumped Q-switched Nd:YAG rod laser based on a thermally-near-unstable fiat-fiat resonator, an intracavity-frequency-doubled green beam generation is investigated. Output power 140 W is obtained at a repetition rate of 10kHz and a pulse width of 110ns. The green beam quality factors Mx^2 and My^2, which are measured by a laser beam analyser, are 10.65 and 10.85, respectively, at output power of 124W.     

全固态激光器抽运的PPLN光参变振荡

用全固态1064nm调Q激光输出，抽运多周期PPLN，实现了宽调谐的准相位匹配光参变振荡，振荡阈值10．3μJ（脉宽22ns)，信号光最高输出平均功率为42．5mW，斜率效率为12．5％。     

Dark blue erenkov second harmonic generation in the two-layer-stacked hexagonal periodically poled MgO:LiNbO_3s

We report the dark blue nonlinearˇCerenkov radiation by the second harmonic generation(SHG)in a two-layer-stacked hexagonal periodically-poled-MgO:LiNbO3s(PPMgOLNs).Based on the direct wafer bonding of two target PPMgOLNs rotating around the axis perpendicular to the plane with an angle of 30°,twelve bright spots as twice of those in a single PPMgOLN are shown at each second-harmonicˇCerenkov ring.The experimental results agree with the theoretical ones and present a promising application in the fabrication of three-dimensional(3D)PPMgOLNs.     

Frequency stabilization of a laser-diode-module-pumped single-frequency Cr,Nd:YAG laser

A single-frequency passively Q-switched laser was constructed, in which a co-doped crystal served as an active element, a mode selector, and a passive Q-switch simultaneously. In order to obtain the frequency instability of 10-6, a stable single-frequency operation was presented and its characteristics were determined. The experimental results showed that the stable single frequency could be maintained for half an hour and the linewidth was approximately 530 MHz at a pump power of 13 W.     

Low-Threshold Mid-Infrared Optical Parametric Oscillator Using Periodically Poled LiNbO33

We report the generation of tunable mid-infrared optical pulses using all-solid-state pumped optical parametri coscillator in a periodically poled lithium niobate. Several ways were used to lower the threshold, resulting in a mean threshold as low as 6.5mW and an achievement of wavelength conversion in the 2.77-4.04μm spectral range. Continuous tuning range from 2.97 to 3.25μm was achieved. The maximum idler output power of 466mW at the wavelength of 3.41μm was obtained, which represents an optical-to-optical conversion efficiency of 19% from incident pump power to the idler output.     

High－Power Blue Light Generation by External Frequency Doubling of an Optical Parametric Oscillator ＊

We report on an all-solid-state high-power quasi-continuous blue light source by the frequency doubling of asignal wave from an optical parametric oscillator (OPO). A 50-mm-long LiB305 (LBO) crystal is used for theOPO, which is pumped by a diode-pumped Nd:YAG green laser (1OkHz, 50ns). Tunable blue emission in a newnonlinear crystal BiB306 (BiBO) is obtained with a wavelength range from 450 to 495 nm. The average power ofthe signal output is as high as 9.3 W from 924 to 970nm. The maximum output of the blue laser with the secondharmonic walk-off compensation is 1.3W average power at 470nm for 6.2W of OPO signal light at 940nm.     

初始啁啾对飞秒脉冲在光子晶体光纤中超连续谱产生的影响

采用分步傅里叶方法模拟了初始啁啾对光子晶体光纤中超连续谱产生的影响.根据光纤长度，将光子晶体光纤中脉冲的演化分成初始展宽、剧烈展宽和饱和展宽三个阶段.通过讨论啁啾脉冲和无初始啁啾脉冲在各阶段演化的区别，发现啁啾只在初始展宽和剧烈展宽阶段对光谱有影响，当β₂C<0时啁啾有利于光谱的展宽，当β₂C>0时则刚好相反，在饱和展宽阶段啁啾不再对光谱产生影响.要想利用啁啾脉冲来获得较宽的光谱，必须选择合适的光纤长度，使输出的脉冲处于剧烈展宽阶段.这为利用啁啾脉冲在光子晶体光 关键词： 超连续谱 光子晶体光纤 分步傅里叶法 啁啾     

Mid—Infrared Optical Parametric Oscillator Based on All—Solid—State—Pumped Periodically Poled LiNbO

We report the tunable mid-infrared generation with a periodically poled LinbO3(PPLN).Using an all-solid-state pumped Nd:YVO4 laser as the pump source and a PPLN nonlinear crystal with grating periods of 28.2-30.8μm,we have achieved wavelength conversion in the 2.90-4.05μm spectral range by period tuning.The use of confocal cavity design has brought a compact,all-solid-state configuration with an average output powers of idler up to -200mW.The maximum power of 277mW was obtained at the wavelength of 3.35um.