利用飞秒激光振荡器产生的脉冲对镀有铬层的玻璃和石英基片进行微加工,发现两种样品表面均有波纹状的微突起结构产生。这些微突起结构离开样品表面的高度为10～300 nm不等,并且随着激光功率的增大而增加,在一定功率下达到饱和状态。它们的形貌、尺寸和高度取决于入射飞秒激光的能流以及飞秒脉冲的参数。通过化学方法证明了这些微突起结构是由玻璃和石英的主要成分SiO2组成的,并非样品表面的铬元素。此外,通过选取适当的飞秒激光功率和样品加工速度,制作了两种不同周期和线宽的光栅结构,显示出飞秒激光振荡器良好的加工性能。

Periodic microripple structures were formed on the sample surface after micromachining on Cr-coated glass and fused silica by trains of femtosecond laser pulses from the oscillator. The heights of these microripple structures varied from 10 nm to 300 nm by increasing the laser power and saturated at a higher laser power. The morphology, sizes and heights of theses microstructures are depended on the irradiation fluences and parameters of the femtosecond laser pulses. Chemical methods proved that the microripple structures are composed of not chromium material but the substrate material of glass or fused silica. Furthmore, two kinds of grating with different periods and linewidths were fabricated by selecting the laser power and micromachining speed properly, which indicated the good micromachining performances of the femtosecond laser oscillator.