High-Power Red Laser Double-End-Pumped By Laser-Diode-Arrays

Diode-pumped solid-state lasers (DPSSL) have been attracting great interest due to their many good advantages such as high efficiency, long lifetime, excellent beam quality, simple structure, high reliability, and compact size. They have been used widely in industry, military, medical treatment, information, scientific researches and many other fields. Moreover, high-power solid-state red lasers have a wide application in the fields such as biomedical technology, medical treatment and laser color display, and can also be applied to be pump source of femtosecond Kerr-lens mode-locked Cr:LiSAF lasers. This dissertation presents results of theoretical and experimental research on the laser-diode end-pumped solid-state red laser. The main contents are as follows:1. The development, characteristics and directions of DPSSL are summarized. Various laser materials are also introduced. Especially, the developments of solid-state red lasers are introduced in detail.2. Based on the rate-equation theory of four-level system, the expressions of field distribution function of pumping and oscillating light, pump power threshold, output power and slope efficiency are given. The theory of intracavity frequency doubling is also discussed, which provides theoretical principle for experiments.3. According to the transmission matrix theory, the resonator design of end-pumped four-mirror folded cavity Nd:YVO₄ solid-state laser is numerically simulated, the relations between the parameters of cavity and stability is analyzed, by which a conclusion is made that there are two stable regions of four-mirror folded cavity, whose range can be regulated by the length of each arms of cavity.4. According to the transmission matrix theory, the resonator design of the end-pumped intracavity-frequency-doubling Nd:YVO₄ solid-state laser, which has a four-mirror-folded cavity, was numerically simulated. The relations between the size and location of the beam waist for frequency doubling and parameters of cavity were analyzed.5. The structure and general properties of Nd:YVO₄ and Nd:GdVO₄ crystal are researched and discussed, and its important parameters are listed in the meantime; The physical and nonlinear characters of LBO crystal are introduced and its critical and non-critical phase-matched characters are analyzed.6. By using different lengths of Nd:YVO₄, Nd:GdVO₄ and LBO crystals and different type of phase-matching, the maximum quasi-continuous-wave output powers of 9.2W, 10.2W and 9.4W at 671nm has been separately obtained by intracavity frequency doubling, the corresponding optical conversion efficiencies were 14.6%, 13.0% and 12.9%, separately.