超宽带近红外和蓝光飞秒激光脉冲产生的实验研究

增益介质中泵浦光束提供的软光阑效应对于实现克尔透镜稳定锁模及其超宽带光谱脉冲的产生具有非常重要的作用.实验上首先对半导体泵浦全固化钛宝石飞秒激光器的锁模动态特性进行了研究,在4 W绿光泵浦状态下获得了平均输出功率为570 mW、中心波长在794 nm～835 nm范围内调谐、光谱带宽最大可达135 nm的近红外光脉冲输出,其相应的时域变换极限脉冲宽度均小于10 fs.另外,将光束聚焦在超薄BBO晶体上,获得了中心波长在418 nm～429 nm之间调谐、光谱宽带时域变换极限小于15 fs的蓝光飞秒脉冲.

Generation of Ultra-broad-bandwidth Femtosecond Laser Pulses in Infrared and Blue Region

Soft gain aperture effect from pump beam size inside the laser crystal is crucial for obtaining stable Kerr lens mode-locking and generating ultrabroad-bandwidth pulses in Ti∶sapphire laser. Modelocking dynamics is experimentally investigated for a diode-pumped all-solid-state laser. At the pump power of 4 W,the femtosecond laser pulses tunable from 794 nm to 835 nm are generated with high output power of 570mW and extremely large bandwidths at the maximum of 135 nm,which can support the transform-limited pulse width in sub-10 fs time duration. Moreover,this laser is extended to blue pulses tunable from 418 nm to 429 nm by using a 260 μm-thick BBO crystal.The measured ultrabroad bandwidths are unprecedent in this spectral region,and their transformlimited pulse durations are sub-15 fs.