钛宝石飞秒激光器用色散补偿Gires-Tournois镜的研究

A Gires-Tournois mirror for dispersion compensation in the Ti-sapphire laser system

根据钛宝石飞秒激光器的色散补偿要求设计了单次反射平均补偿量为-60fs2的GT(Gires-Tournois)镜,采用离子束辅助沉积技术结合光学监控技术制作了器件.用分光光度计对650—950nm波段薄膜反射率进行测试,结果表明反射率测试曲线与设计曲线十分符合,同时利用白光干涉系统对群延迟色散进行了测试,测试结果与设计符合得很好,实际的色散曲线振荡基本控制在±20fs2以内.应用该GT镜进行钛宝石飞秒激光系统的色散补偿,取得了很好的锁模效果,得到了29fs的超短脉冲.

A Gires-Tournois（ GT） mirror with a group delay dispersion （ GDD） of-60 fs2 in one reflection was designed according to the requirement of dispersion compensation in the Ti-sapphire femtosecond laser system. It was manufactured by ion assisted deposition combined with the optical monitoring in transmission. The reflectance of the mirror was measured by a spectrophometer working in the range from 650 nm to 950 nm with a resolution of 1 nm. The results were consistent with the design. Furthermore,a home-made white light interferometry system was employed to test the reflection GDD and the result also agreed well with the design. The experimental GDD oscillation was less than ± 20 fs2. The GT mirror was applied in the Ti-sapphire femtosecond laser system and a good clamping result was obtained. Finally a 29 fs ultra-short pulse was acquired.