Ti:sapphire Laser Pumped Yb:YAG Laser with Cr4+:YAG as a Passive Q-switch

摘要：

The Ti: sapphire laser pumped Yb: YAG passively- Q- switched laser with Cr4 +: YAG as a saturable absorber experiment was performed. The Mira 900 tunable Ti:sapphire laser with an output power up to 1 W was used as a pump source. The optical pump system was composed of a spherical lens (f = 75 mm) for focusing the pump beam to a circular spot with a diameter of about 50μm, the pumping power was measured to be up to 920 mW. The laser cavity was configured to be semispherical, and was formed by the 50 mm curvature radius mirror Mi and the flat mirror M2. Mirror Mt, one face was coated for high transmission at 940 nm and the other face was coated for total reflection at 940 nm and 1.03 μm, was placed on the front of the input facet of the Yb: YAG crystal. The Yb: YAG gain medium is doped with 20 at. - ％ Yb3+, no concentration quenching of the upper-state lifetime has been observed in this crystal. The Yb: YAG gain element is 8 × 8 × 0.5 mm3 thick and is polished flat and paralld. It is coated on one face of the crystal for high transmission at 940 nm and at 1030 nm, the other surface of the crystal is coated for total reflection at 940 nm and at 1030 nm. Mirror M2 was coated for total reflection at 940 nm and reflectivity of 97％ at 1.03 μm acting as an output coupler. The overal cavity length is 23 cm. More than 90％ of the laser pumping power was absorbed by the Yb: YAG crystal. The laser operation was performed at 278 K by using the constant-temperature water-cooled circulation with a copper surface. The Cr4+: YAG saturable absorber was placed tightly dose to Yb: YAG sample. This provided a train of pulsesat 1.03 μm with a pulse duration (FWHM) decreasing from 0.6 μs to 0.4 μs and a repetition rate increasing from 20 kHz to 50 kHz. The maximum average power of 53 mW is attained when the pmping power is 730 mW. The slope efficiency is about 16％.

机标关键词：total reflection、saturable absorber、concentration quenching、slope efficiency、pulse duration、output coupler

所属期刊栏目：27

分类号：O4 ;TH7

在线出版日期：2008-08-04（万方平台首次上网日期，不代表论文的发表时间）

页数：共5页

页码：192