Development of novel Nd-doped vanadate single crystals for ultra-short pulse lasers

为研制以半导体激光器为泵浦光源的超短脉冲激光系统，采用浮区法生长了新型的Nd：LaVO4单晶，并对其光谱特性进行了研究。晶体是沿着光学弹性轴之一的Z轴生长的，具有光学高质量，没有任何宏观缺陷。晶体的吸收光谱和发射光谱表现为异常展宽的吸收峰和发射峰，沿各弹性轴的光学各向异性不明显。当考虑单模振荡时，获得了76%的高斜率效率，接近理论值。通过多模振荡获得了14 nm的展宽激光光谱，从而有可能获得小于300飞秒的超短脉冲。

Novel single crystals of Nd : LaVO4 were grown by the floating zone method and their spectral properties were investigated aiming for development of an ultra-short pulse laser system using a laser diode as a pumping source. The crystals were grown along Z-axis, which is one of the optical elasticity axes, and they were of optically high quality without any macroscopic defects. The absorption and emission spectra showed unusually broadened peaks as a Nd-doped crystals, and their optical aisotropy along each elasticity axis is not significant. When single-mode oscillation was examined, a high slope efficiency of 76 %, which is close to theoretical one, was obtained. A broadened laser spectrum of 14 nm was obtained by multi-mode oscillation, and it is accordingly possible to achieve an ultra-short pulse less than 300 femtosecond.