Research On All-solid-state Continuous Wave Single Frequency 266 Nm Laser

Continuous wave single frequency 266 nm ultraviolet laser has the advantages of concentrated energy distribution and high processing resolution.It has important application value in cutting-edge high-end fields such as high-capacity information storage,high-resolution spectral monitoring,semiconductor material defect detection,and high-precision ultraviolet lithography.In recent years,it has become one of the research hotspots in the field of ultraviolet laser at home and abroad.In response to the application requirements of continuous wave ultraviolet 266 nm laser in measurement and measurement,a systematic study on the characteristics of continuous wave single frequency 266 nm laser has been conducted theoretically and experimentally,focusing on nonlinear frequency transformation,optical impedance matching theory,and Hansch-Couillaud(H-C)frequency locking key technologies.The aim is to achieve high beam quality,high power,and high stability of continuous wave single frequency 266 nm laser output.The main content of the paper is as follows:The first chapter introduces the main applications of single frequency continuous wave 266 nm laser in industrial processing,scientific research,and other fields,lists the main ways to achieve continuous wave single frequency 266 nm laser output,compares in detail the commonly used optical nonlinear crystals for fourth harmonic nonlinear frequency conversion,summarizes the research progress of continuous wave single frequency 266 nm laser at home and abroad,and elaborates on the main research work of this paper.Chapter 2 introduces the main technical approaches to achieve single frequency laser operation at fundamental frequency 1064 nm,and compares in detail the optical characteristics of commonly used gain crystals Nd:YAG and Nd:YVO4 in the 1064 nm band.We selected Nd:YVO4 laser crystal as the gain crystal to study the characteristics of continuous wave single frequency 1064 nm laser.At an absorbed pump power of 21 W,a continuous wave single frequency laser output of up to 8.38 W was obtained,with a slope efficiency of 39.9%,a line width of 30 MHz,a power instability of 0.451%at 3.5 hours,and laser beam quality of Mx2=1.204 and My2=1.280,respectively.Chapter 3 introduces the principle of nonlinear frequency doubling and phase matching technology,and derives the analytical equation of frequency doubling conversion efficiency.On this basis,an intracavity frequency doubling 532 nm continuous wave laser experiment based on KTP crystal was carried out,achieving a 4.8 W 532 nm laser output with an optical to optical conversion efficiency of 18.4%,long-term power instability of 0.75%,and beam quality of Mx2=1.492 and My2=1.415.Chapter 4 provides a detailed introduction to the basic principles of H?nsch-Couillaud(HC)frequency locking and Pound-Rever-Hall(PDH)frequency locking,and analyzes their respective advantages and disadvantages.Starting from the theory of optical impedance matching,the optimal transmittance of the input mirror was derived.Based on the four mirror ring frequency doubling cavity structure,the characteristics of a continuous wave single frequency 266 nm laser were studied.BBO crystal was used as a nonlinear crystal,and combined with H-C frequency locking technology,stable continuous wave 266 nm excitation output was achieved.A single frequency continuous wave 266 nm stable laser output with a power of 1.2 W was obtained at a fundamental frequency optical power of 4.9 W.The frequency doubling efficiency was 24.9%,the beam quality factor M2<1.6,and the laser linewidth was less than 1 MHz.