Study On LD Side Pumped Nd: YLF All-solid-state Laser

All-solid-state lasers have a wide range of applications in industrial laser processing,scientific research,medical and other fields.In this paper,a LD side-pumped Nd: YLF all-solid-state laser is studied.Based on the anisotropic characteristics of Nd: YLF,the thermal effects of LD side-pumped anisotropic Nd: YLF crystal is analyzed.In order to improve the output beam quality of the Nd: YLF laser,a Gaussian aperture is inserted into the laser cavity.The theoretical simulation analysis of the laser output beam was performed using the self-reconstruction theory and the Collins formula.LD side-pumped Acousto-optic Q-switched Nd: YLF all-solid-state pulse laser was designedand the output characteristics of the laser are measured and analyzed.The specific research content is as follows:(1)Using the finite element analysis method,a theoretical simulation analysis of the thermal effects of LD side-pumped Nd: YLFcrystal under steady-state conditions is performed.A numerical model of heat source distribution in an LD side-pumped anisotropic Nd: YLF laser medium was established,and the effects of Nd: YLF thermal expansion coefficient anisotropy on the laser thermal effect distribution were discussed.Due to the anisotropy of the thermal expansion coefficient of the Nd: YLF crystal,the thermal deformation of the crystal will cause asymmetry in the x and y directions,which will affect the quality of the laser beam.(2)According to the self-reconstruction theory and Collins formula,the theoretical simulation analysis is performed on the output beam when there is no Gaussian aperture in the Nd: YLF laser cavity and the Gaussian aperture is inserted.After inserting a Gaussian aperture in the resonant cavity,the high-order-modes in the output laser beam is significantly suppressed.A comparative analysis is carried out through experiments.Through the experimental comparative analysis,the beam quality of LD side pumped Nd: YLF laser output beam was significantly improved when inserter gaussian aperture into the laser resonator cavity.(3)An LD side-pumped acousto-optic Q-switched Nd :YLF laser was designed experimentally,and the operating conditions such as output mirror transmittance and laser repetition rate were analyzed to influence the output characteristics of the LD side pumped Nd : YLF laser.Through experimental debugging and testing,when the output mirror transmittance T = 15%,the acousto-optic Q-switch repetition rate is 1kHz,and the LD pump power current is 19.5A,the maximum average power of the LD side pump Nd : YLF laser is obtained.It is 4.12 W,and the narrowest pulse width is 81.92 ns in the 1053 nm band laser output.In order to improve the quality of laser beam,the output laser beam quality is improved by inserting a gaussian aperture into the resonant cavity.