Research On Narrow Pulse Width High Peak Power 456nm All Solid-state Laser

LD pumped solid-state pulsed blue laser has very important application prospects in underwater communication detection,precision machining,radar and laser medicine.A 456nm pulsed solid-state laser with narrow pulse width and peak power is studied theoretically and experimentally.The main research content of this paper is as follows:Firstly,the theory of LD pumped Nd:Gd VO₄ laser and thermal lens effect are analyzed theoretically.The output threshold formula and output slop efficiency formula are derived to determine the parameters of Nd:Gd VO₄ crystal.In order to improve the accuracy of the calculation of thermal lens effect,the optical field distribution of LD pump source was experimentally measured.On this basis,a crystal heat distribution model was established according to the heat conduction equation,and the focal length of thermal lens was experimentally measured by the planar-parallel-resonator method,which further verified the accuracy of the theoretical model of thermal lens focal length and provided a theoretical basis for the design of laser resonator.Obtaining high performance 912 nm laser output is the basis of efficient frequency doubling to produce 456 nm laser.Based on the acousto-optic Q-switching theory,the output of the 912 nm Nd:Gd VO₄ acousto-optic Q-switched laser is simulated and analyzed,and the factors affecting the pulse width and peak power of the laser output are obtained,so as to optimize the parameters of the 912 nm acousto-optic Q-switched laser.Finally,the optimal output of 912 nm laser was obtained at the pump power of 47 W with a repetition frequency of 10 k Hz.The average output power was 1760 m W,the pulse width was 10.45 ns,and the corresponding peak power was 16.84 k W.At last,based on the above research basis of 912 nm Nd:Gd VO₄acousto-optical Q-switched laser,an optimization study was carried out to obtain 456 nm laser by frequency doubling of LBO crystals outside the straight cavity and inside the V cavity respectively.A456 nm pulsed laser with an average output power of 402.4 m W,a pulse width of 8.65 ns,and a corresponding peak power of 4.64 k W were obtained by using a direct cavity with an extra cavity frequency doubling method with a repetition frequency of 10 k Hz and a pump power of 47 W.Based on mode matching,an ABCD optical transmission matrix combined with the resonant cavity stability condition was used to optimize the V-cavity intracaverity frequency doubling of 456 nm laser.The pulse width was 57.5 ns and the average output power was 775m W under the pump power of 10 k Hz and 42 W repetition rates.The 456 nm laser output has a peak power of 1.347 k W.