We reported pump uniformity study of a side-pumped DPSS laser, which produced CW output of 30 W with a proper uniform pumping. An JR camera was employed to study the pump energy distribution as well as the thermal effect inside the laser crystal. Theoretically simulated energy distributions were compared with the experimentally measured JR images. Jt is found that the JR imaging technology is an effective method to study pump uniformity of side-pumped DPSS lasers, and uniform pumping is very essential to achieve a good beam quality and a wider stable operating range for high-power DPSS lasers.
Thermal conductivity and expansion coefficient of YAG laser crystals vary greatly with temperature. In order to obtain an accurate solution, finite element analysis is employed to solve the heat equation. By comparing the finite element analysis with the conventional analytical analysis, we found the temperature difference between finite element analysis and conventional analytical analysis is small and the conventional analytical solution for temperature is still available; the stress difference between finite element analysis and conventional analytical analysis is large, so we need treat the thermal conductivity and the expansion coefficient as non-constants when calculating the stresses in laser rods.
Q-switched operation is very common and important for diode- pumped solid-state lasers. In this paper, we reported a novel use of GaAs wafers as Q-switch elements as well as output couplers for DPSS lasers. A pulse duration of 2.6 ns at the wavelength of 1064 nm was obtained from a diode- pumped and passively Q-switched Nd:YVO4 laser using a piece of GaAs wafer as the saturable absorber as well as the output coupler. The transmissivity and the absorption coefficient of different wafers were studied. The experimentally measured results indicated that the transmissivity of different GaAs wafers varied from as low as approximately 32% to as high as approximately 75%. It was found that some of those wafers showed Fabry-Perot effect and it could affect the effective transmissivity and produce lower transmission, and thus shorten the pulse duration and stabilize the laser operation.