Research On All-solid-state Single-frequency And Intracavity Frequency-doubled Ultraviolet Pr:YLF Lasers

All-solid-state laser pumped by laser diode(LD)is widely used in scientific and industrial applications,because of its advantages such as small size,compact structure,stable performance,good beam quality and long service life.Trivalent praseodymium ions(Pr3+)offers strong radiation transition in the visible spectrum range,and it also makes it possible to get ultraviolet light with only one frequency conversion.Pr3+doped Lithium-Yttrium-Fluoride(Pr:YLF)crystal,as the most excellent mixing Pr3+material,can achieve high power laser output in many visible spectrums.Pr:YLF have broad application prospects in laser display,biological detection,quantum communication,optical holography and other fields.In this paper,we used Pr:YLF crystal as the gain medium,and studied the output characteristics of orange single-frequency laser and red intracavity frequency-doubled ultraviolet laser.The research content mainly includes the following parts:(1)The physical and chemical properties of Pr:YLF crystal are introduced.The absorption spectrum and emission spectrum of Pr:YLF crystal are analyzed base on the energy level structure.The four-level system is introduced,and the output characteristics of Pr:YLF crystal are discussed base on the four-level rate equation.(2)Orange single-frequency Pr:YLF laser was achieved.Using Pr:YLF crystal as the gain medium,the single-frequency laser output of 607nm is achieved through the combination frequency selection method of two eatlons.The maximum output power is 175mW,the slope efficiency is 16.6%,and the measured linewidth is about 6MHz.And the 604nm single-frequency laser is achieved by tuning the eatlons.The maximum output power is 91mW,slope efficiency is 8.9%,and the measurement line width is about 22MHz.(3)The all-solid-state intracavity frequency-doubled Pr:YLF ultraviolet laser was carried out.The thermal effect of the Pr:YLF crystal is explained and the focal length of the thermal lens at the highest power is calculated.Base on transmission matrix theory,a stable resonant cavity is designed and optimized,and there are fitting spot size at both laser crystal and nonlinear crystal.Using the V-cavity structure and LBO as nonlinear crystal,high-power 320nm ultraviolet laser is realized.The maximum power output is 1.01W when the absorbed pump power is 7.8W,and the stability is 1.4%after 1.5 hours of operation.