基于差频产生的中红外飞秒激光技术研究

Research on mid-infrared femtosecond laser technology based on difference frequency generation

针对国内中红外激光光源光谱范围小、脉冲宽度宽等问题,开展了基于差频(DFG)产生的中红外飞秒激光技术研究。差频产生的中红外飞秒激光具有光谱范围宽、脉宽窄等优势。研究了差频技术中选用不同的非线性晶体对产生的中红外激光的影响,在此基础上搭建了一套基于差频技术的、利用PPLN晶体产生的中红外激光的产生系统,利用光栅对压缩脉宽,实现飞秒激光输出。最终获得了波长范围在2.9~4.7μm的中红外飞秒激光,在中心波长3.2μm处获得了最高10.46 mW的输出光平均功率。研究结果为中红外激光光谱测量技术在大气监测、燃烧场组分探测等的应用提供了参考。

Aiming at the narrow spectral range and wide pulse width of domestic mid-infrared laser sources,research on mid-infrared femtosecond laser technology based on difference frequency generation(DFG)was carried out.The mid-infrared femtosecond laser generated based on DFG has the advantages of a wide spectral range and narrow pulse width.The influence of different nonlinear crystals on the generated mid-infrared laser in DFG was studied.On this basis,a mid-infrared laser generation system based on DFG using a PPLN crystal was conducted.Further,this system used grating pairs to compress the pulse width to achieve femtosecond laser output.Finally,a mid-infrared femtosecond laser with a tunable wavelength range of 2.9~4.7μm was observed,and the highest average output light power of 10.46 mW was obtained at a central wavelength of 3.2μm.The research results provide a reference for the application of mid-infrared laser spectroscopy measurement technology in atmospheric monitoring,combustion field component detection,etc.