Research On The Ktp Crystal Applied In Thg Of Nd:yan 1319nm Laser

Solid-state-laser has wide application prospect and great potential value because of its small size, compact structure, long life, high efficiency and some other advantages. Solid-state blue laser has a lot of important applications in many fields such as bio-engineering, large-screen laser show, laser medicine, under-water communications and so on. KTP crystal, as a good overall performance nonlinear optical crystal, has extremely important theoretical and practical significance applying in THG. of 1319nm laserIn this thesis, the theoretical analysis had been carried out for the third harmonic generation (THG) of Nd: YAG 1319nm laser to produce 440nm blue laser using KTP crystal at room temperature and the problems appearing in the expirment also had been studied and.solved In the experiment, a solid-state-laser LD end-pumped Nd: YAG / KTP / KTP was used as experimental device. and the cavity was straight.Main content:(1) The main performance of Nd: YAG and KTP crystals used in the experiment were introduced, and the advantages of KTP crystal used in the THG of 1319nm laser were also explained.(2)According to phase-matching theory of the biaxial crystal, the phase matching angle and the size of the effective nonlinear coefficient of the KTP crystals applying in SHG and THG for 1319nm laser were calculated. From these, we identified the cutting angles of the two KTP crystals.(3) The walk-off situation of the laser in the process of SHG and THG was calculated and analyzed. An approach of how to compensate walk-off and reduce the size of walk-off angle was proposed and discussed in detail. Experimental effection was obvious before and after the compensation.(4) The methods of rotating the crystal and adjusting the temperature had been carried out to find out the optimum phase matching angle and the operating temperature of the KTP crystal for THG. After re-cutting, the beam intensity of outputting 440nm blue laser had a significant improvementInnovation:The idea of KTP crystal applied in THG for 1319nm laser by the mode of critical phase matching at room temperature conditions was proposed for the first time. The key parameters of KTP crystal were calculated by computer programming for the first time,such as phase matching angle, effective nonlinear coefficient, walk-off angle, interaction length, divergence angle and the allowed angle of KTP By the experiment we had designed,the optimum phase matching angle(experimental value) of the KTP crystal used in THG of 1319nm laser were finaliy found out.