高效率,窄脉冲1 198.5 nm Ba(NO3)2喇曼激光器

利用1064nm的Nd∶YAG激光抽运振荡腔内的硝酸钡晶体,获得高效率、窄脉冲的喇曼激光输出.硝酸钡晶体由水溶液降温法生长,长度为48 mm.喇曼振荡腔由对抽运光、一阶、二阶斯托克斯光有不同反射率的双色平面镜构成.当抽运光功率达到4.5 W时,获得最高的一阶斯托克斯喇曼激光功率为1.48 W,相应的转换效率为32.9%,并测得斜率效率为40%.由于受激喇曼散射的作用,喇曼脉冲光由抽运脉冲光的19.8 ns压缩为2.4 ns,获得的喇曼激光脉冲波形具有的“上升沿陡峭、下降沿缓慢”的特性,对其形成过程作了定性分析.测得喇曼激光的波长为1 198.5 nm,半峰全宽（FWHM）为1.2 nm.

High Efficiency, Short-pulse 1 198.5 nm Ba(NO3)2 Raman Laser

A high-efficiency, short-pulse 1 198.5 nm Raman laser was demonstrated by using stimulated Raman Scattering (SRS) in the barium nitrate (Ba(NO3)2) crystal which was pumped by a 1 064 nm Nd: YAG laser. With an incident pump power of 4.5 W, a maximum of 1.48 W Raman output power at a repetition rate of 30 Hz was obtained, corresponding to an overall optical-to-optical conversion efficiency of 32.9%. The slope efficiency was calculated as 40%.The pulse width of the Raman pulses was reduced to 2.4 ns compared to the pump pulse width of 19.3 ns. The typical Raman pulse had an asymmetric shape, with a very steep positive-going slope and an extended negative-going slope, the mechanism of which was also demonstrated with qualitative analysis. The wavelength of the Raman laser ( the first Stokes ) was measured to be 1 198.5 nm with FWHM of 1.2 nm.