Research On The Measurement Of Ultrashort Pulse Based On Frequency-resolved Optical Gating

Since the laser have been invented in the 1960 s,the output performance of laser have been improving.The pulse peak power of laser have been increased from kilowatt(103W)to petawatt(1015W),pulse width of laser have been increased from nanosecond(ns)and picosecond(ps)to femtosecond(fs)and even attosecond(as).Through decades of development,ultrashort pulses including picosecond pulse and femtosecond pulse have played an important role in social application and scientific research.The development of laser pulse also put forward higher requirements for pulse measurement technology,and promoted the development of laser pulse measurement technology to some extent.At present,ultrashort pulse measurement technology is mainly based on optic measurement methods.The most widely used measurement methods are Autocorrelation,Frequency-Resolved Optical Gating(FROG)and Spectral Phase Interferometry for Direct Electric-field Reconstruction(SPIDER).Each of the three methods has advantages and disadvantages.Combined with the specific measurement requirements of the laboratory,I built an ultrashort pulse measurement system based on FROG.The main research contents of this article are as follows:(1)Investigated the development and application of ultrashort pulse,introduced the importance and development of ultrashort pulse measurement technology,and described the application value of ultrashort pulse measurement technology.(2)Simulated the measurement mechanism of FROG measurement technology,researched the generation of two-dimensional traces and the reconstruction process of pulse width and phase information,analyzed the ambiguity in the direction of chirp of FROG theoretically.Proved the feasibility of FROG measurement technology from a theoretical perspective.(3)Expounded the design of experimental structures,the selection of requency-doubling crystals,the generation principle of delay,and the design of portability experimentally.Built a SHG-FROG measurement system successfully and obtain good measurement results after applied SHG-FROG measurement system to the femtosecond laser pulses of laboratory.(4)Analyzed the experimental data and obtained the experimental results,compared with the results measured by the intensity Autocorrelation,proved the accuracy of the SHG-FROG measurement device.Summarized the advantages and disadvantages of the SHG-FROG measurement system and giving a corresponding solutions for the disadvantages.