为了克服放大自发辐射在飞秒激光放大器中对放大脉冲的影响,将增益介质掺钛蓝宝石晶体从腔内束腰位置处移至腔内光斑最大处是一个有效的办法.设计并实验了此种新型大焦斑直线形折叠腔.计算了腔内的光斑尺寸与腔结构参数的关系,得出了腔内光斑尺寸分部图,系统实验了输出功率与腔结构参数:曲面镜半径,输出耦合镜透射率,腔长等的关系,并进行了理论验证.本文为进一步将其做成新型、高效、低噪声再生放大器提供了必要的依据.

In order to overcome the influence of amplified spontaneous emission (ASE) on the amplified pulse in the femtosecond laser amplifier, it is an effective way to move the Ti∶sapphire from the waist in the cavity to where the size of the beam is largest. The experiments are carried out on such a new-style folded linear Ti∶sapphire amplifier cavity with the large beam size. The relationship between the beam size and the cavity parameters is calculated and the beam size distribution in the cavity is provided. The systemic experiments are done on the relationship between the output power and the cavity parameters such as the radius of the curved mirror, the reflectivity of the output mirror, the length of the two arms and so on.