Laser-diode-pumped Cr4+,Nd3+: YAG with self-Q-switched laser output of 1.4 W

By use of a laser diode as a pump source, a self-Q-switched laser from a Cr,Nd:YAG crystal is demonstrated. The output Q-switched traces are very stable, the threshold pump power is 3.5 W, the pulse duration is 50 ns, and the slope efficiency is as high as 20%. In addition, the pulse width remains constant while the pulse repetition rate Varies with pump power. (C) 2000 Optical Society of America OCIS codes: 140.0140, 140.2020, 140.3380, 140.3480, 140.3540, 140.3580.

A passively mode-locked diode-end-pumped Nd : YAG laser with a semiconductor saturable absorber mirror grown by metal organic chemical vapour deposition

We report the experimental results of a mode-locked diode-end-pumped Nd:YAG laser with a semiconductor saturable absorber mirror (SESAM) from which we achieved a 10 ps pulse duration at 150 MHz repetition rate. The SESAM was grown by metal organic chemical vapour deposition at low temperature. The recovery time was measured to be 0.5 ps, indicating the potential pulse compression to sub-picoseconds.

长波长半导体可饱和吸收镜的研制及其在固体激光器被动锁模和调Q中的应用

介绍了国际上流行的长波长半导体可饱和吸收镜的研制方法及其在固体激光器被动锁模和被动调Q中所起的作用,并分别就Cr4+:YAG,Cr:Forsterite等激光器进行了阐述.

NCMAS系统熔体结构和动力学性质压力效应的分子动力学研究

Molecular dynamics simulations were used to study the pressure dependence of the structure and the dynamic properties of forsterite melt (Mg_2SiO_4), diopside melt (CaMgSi_2O_6), anorthite melt (CaAl_2Si_2O_8), jadite melt (NaAlSi_2O_6) and albite melt (NaAlSi3O8) from 0 GPa to 25 GPa at about 2000 K and the following conclusions have been reached. Firstly, the ratio of NBO to T (NBO and T denote the content of non-bridging oxygen and the total content of Si~(4+) and Al~(3+) respectively) is closely related to the pressure and the composition of the melts. It decreases monotonously in forsterite, diopside and anorthite melts while increases at the initial stage and then decreases in jadite and albite melts with increasing pressure. At a fixed pressure, the shear viscosity of the melts decreases with increasing NBO/T and the variation rate is almost 150 times higher in fully polymerized melts than that in de-polymerized melts in comparison with anorthite melts. Secondly, it is generally accepted that the formation of the Si and A1 will promote the diffusion of the network-forming ions. The hypothesis is frequently employed to explain the emergence of the maximum self-diffusion coefficient of the network-forming ions in fully polymerized melts. However, I detected that the pressure corresponding to the peak of the self-diffusion coefficient of the network-forming ions is lower than that corresponding to the maximum content of Si and A1, and that there exists an approximately linear relationship between the self-diffusion coefficient of the ions and the breaking frequency of the bonds under a given pressure, which is different from the present understanding about the mechanism of self-diffusion. Thirdly, the relationship between the self-diffusion coefficient of Si~(4+), Al~(3+) and O~(2-) and the shear viscosity of the melts evolves from the Stokes-Einstein equation and Sutherland-Einstein equation to the Eyring equation with increasing pressure. And the key to obtain self-diffusion coefficient from shear viscosity under difference pressures is to determine A. in the Eyring equation. For Si~(4+) and O~(2-), this could be done using the linear relationship between A, and NBO% in anorthite melts. However, this method is inapplicable in other kinds of melts.