All-solid-state Contiuous Wave Nd: YAG 473nm Laser

Diode-pumped solid-state laser has been paid more attention for its advantages. Green, red, blue and ultraviolet solid-state lasers have attracted many scientists. Blue laser is very valuable for military , communication, high-density optical storage , information, colorful display of laser % colorful printing and biochemistry. For example, blue laser of 475nm can be used for seabed research and communication of submarine. In recent years more and more attention has been given to solid-state blue laser, but its development is more slow than green, red all-solid-state laser. In this dissertation, the technique has been adopted for 473 nm blue laser with doubling 946 nm of Nd:YAG. Not only exhaustive theory but also experiment of it has been given in this paper. The main continents can be summarized as follows.The analyses given in this paper to quasi-three-level for 946 nm laser are complete. The relation between 946 nm laser transmission and optimal crystal length has been derived from the rate equations describing the population inversion and the photon density in the laser cavity in the steady-state case. The minimal claims to coating have been given on the base of contrasting 946 nm transmission with 1064 nm transmission in the condition of different cavity losses and how the pump beam radius in the laser crystal and optimal crystal length affect the laser threshold and output power of 946 nm laser has been given as well. All the discussion above will be useful for efficient 946 nm laser operation at room temperature. The methold applied in this paper will be enlightening for such low gain and quasi-three-lever or three-lever systems.The characteristics of different nonlinear crystals for frequency-doubled Nd:YAG 946 nm laser have been compared, A biaxial crystal, LBO, has been chosen for frequency doubling in our experiment. According to this, the phase-matching conditions, effective nonlinear coefficients, acceptances of angle and wavelength for biaxial' crystals have beendiscussed in detail.Thermal lens effect is an important factor which affects the quality of laser beam and the amount of output power. Because of high threshold of 946 nm laser, severe thermal lens effect will appear when the 946 nm laser operations. In the consideration of thermal lens effect, the- optimized folding cavity has been devised. The relation between thermal lens effect and the radius of laser beam waist has been given as well.The experiment of intracavity doubling of a 946 nm Nd:YAG laser with an LBO crystal has been done at room temperature. A continuous wave 473 nm laser is obtained with 235mW output power at a pump power of 20W. The laser beam quality of 473 nm is good as well. Advise for further improvement has been given in the end.