Research Of LD Side Pumped Nd:YAG Solid Laser Cavity

Laser-marking is the most advanced technology in the products-marking industry, wildly used in steel, automobiles, electronics, aerospace, machinery, metallurgy, shipbuilding and other related processing areas. Laser can print various characters, symbols and patterns on the plat surface or cambered surface, so high-speed laser marking can realize the real-time marking on the product assembly line, with the advantage of highly marking accuracy, fast processing speed, and so on. Currently the main lasers used in laser-marking are Nd:YAG laser and CO2 laser, especially the Nd:YAG laser is suit for the high-definition marks in the metal material, 50W LD side-pumped Nd:YAG laser is with the highest demand in the laser-marking machine market at present, so the content of this paper presents and completes the 50W LD side-pumped Nd:YAG laser design and related parameters research.The first part of this thesis is the design of LD side-pumped Nd:YAG laser resonant, we analysis the thermal effect of LD side-pumped Nd:YAG crystal with detail, to get the formula of the thermal focal length. Then based on the cavity model with thermally effect and the Gaussian beam transfer matrix principle we establish the LD side-pumped Nd:YAG resonator model with the crystal thermal effect and analysis the influence of the crystal parameters, the thermal focus length, the cavity parameters on the laser output power.The second part is 50W LD side-pumped Nd:YAG laser structure design, according to the design requirements of the output power we can calculated the parameters of laser crystal, according to the stable range of the cavity we can get the appropriate cavity length and the best transmissivity of the output coupler.In the third part, based on the thermal lens cavity model and light transmission ABCD matrix, we analysis the cavity stability area, the Gaussian beam transmission rule inside resonator and the beam radius on the surface of output mirror and crystal, with different cavity structure such as plane-plane cavity, plane-convex cavity and plane-concave cavity, so we can get the best resonator structure with the most stable cavity range, the biggest output power or the smallest output beam divergence angle.Finally we experimentally analysis the influence of the cavity length of plane-plane symmetrical resonator, the cooling temperature of the laser crystal and the transmissivity of output mirror on the laser output power, so the best cavity length, cooling temperature and transimissity of output can be got from the experiment results.