基于光子晶体光纤飞秒激光放大器的微纳加工系统

Micromachining System Based on Photonic Crystal Fiber Femtosecond Laser Amplifier

以掺镱大模面积光子晶体光纤(PCF)飞秒激光放大器为光源组建了一套结构紧凑且运行稳定的飞秒激光微纳加工系统,中心波长为1040 nm,重复频率50 MHz,最大平均功率16 W,光栅压缩后脉冲宽度85 fs。利用该套系统在硅片、金属薄膜(Cr膜、Al膜)上演示了微图案的刻划,并与采用重复频率1 kHz的固体钛宝石飞秒激光放大器的加工结果进行对比,发现利用新组建的加工系统进行微纳加工,由于单脉冲能量较小且便于调节,使得刻划微图案时边缘加工效果更容易控制,且避免了加工过程中未加工区域受到的污染,保护了制作衬底。显示了该套系统高重复频率和高平均功率的特性及其在改善微纳加工效果及明显提高加工效率方面的优势。

A compact and stable femtosecond laser micromachining system was founded based on Yb-doped largemode-area photonic crystal fiber （PCF） femtosecond laser amplifier, which outputs pulse with 1040 nm center wavelength, 50 MHz repetiton rate, 100 fs pulse width, 16 W maximal average power and 85 fs pulse duration after compressed by grating. Fabrication of micropatterns on silicon and metallic thin film （Cr, Al） was demonstrated by the system and the obtained micropatterns were compared with those fabricated by solid-state Ti： sappire femtosecond laser amplifier with 1 kHz repetition rate. It shows that due to the lower and easily adjusted single pulse energy of our high repetition rate femtosecond laser, the proposed system can effectively control the morphologies of micropatterns, and avoid contamination during micromachining, herein, protect the substrates. The characteristics of high repetition rate and high average power for the founded system are revealed to be advantageous for femtosecond micromachining in aspects of improving the fabrication outcome and promoting the efficiency.