Design And Fabrication Of Laser Pulse Compression Based On Transmission Grating

Laser pulse compression is one of the key components of chirped pulse amplification system. Pulse compression grating can be classified into reflection pulse compression grating and transmission pulse compression grating. Reflection pulse compression grating have been widely used in chirped pulse amplification system. With the improvement of manufacturing technology, transmission grating have been paid great attention. Fused silica transmission grating have advantages of high diffraction efficiency, high damage threshold, long life and no shelter. Fused silica transmission grating will play an important role in the ultra short laser pulse compression system.The design and fabrication of pulse compression grating are investigated theoretically and experimentally in this paper.The main contents are as follows:Firstly, the developing background of ultra-intensity and ultra-short pulse, the process of the research on pulse compression grating are presented. The theory of chirped pulse amplification is described in detail. Analytical phase expressions are presented for an Offner stretcher and transmission grating compressor based on ray tracing and apply them to analyze a chirped-pulse-amplification(CPA) system. Besides, an optimization method to extract high-fidelity amplified pulse is proposed by controlling the phase of the entire system.Rigorous coupled wave theory is used for design transmission grating, and the maximum diffraction efficiency is over 98%. In order to decrease the reflection of substrate, we creatively propose that high frequency grating can be used to replace anti-reflection coating, and the transmittance of high frequency transmission grating is above 99.9%.The deep-etched fused silica transmission grating(1250lp/mm) is fabricated by holographic recording and ion beam etching, the absolute efficiency is about to 98%(@808nm). In order to replace anti-reflection coating, the transmission grating(2100lp/mm)is fabricated on the bottom of substrate. At last, the deep-etched grating and high frequency grating are integrated in a fused quartz substrate(Φ65mmx1mm), and the diffraction efficiency of fused silica transmission grating is near to 98% in the experiment. Experimental results are coincident with the theoretical analysis.