高功率LD抽运Tm:YAG激光模块的设计与优化

Three LD Bar strips (Focus Light, USA) are symmetrically distributed around a ceramic diffuse reflector surface with a 120° angle, with an inner diameter of 5.5mm and a thickness of 0.5mm. Each LD Bar strip has a maximum output power of approximately 220W, allowing the laser module to provide a maximum pumping power of 660W. The fast-axis divergence angle of the LD is 35°, and the distance between the emitting surface and the crystal rod axis is 6mm, ensuring that almost all pumping light can be directly absorbed by the crystal, improving absorption efficiency. Tm:YAG has two absorption bands, located near 781nm and 785nm [15]. The center wavelength of the LD Bar strip we selected is 780.5nm at maximum driving current, and the emission spectral line has a full width at half maximum (FWHM) of approximately 1.7nm. Therefore, the Tm:YAG's wider 781nm absorption band can be matched within a larger range of driving current variations.