Study and Experiment of Parameters Related to Small Beam Diameter of High Power Nd:YAG Laser

This paper presents the study and experiment of parameters related to small beam diameter of high power Nd:YAG laser that greater than 50 W in continuous wave mode (CW) at wavelength 1064 nm. In this paper, two mirror conditions of optical cavity such as R1:750 mm, R2:1000000 mm and R1:508 mm, R2:1000000 mm are used to compare the laser performances of each Nd:YAG laser system. Here, using mirrors curvature radius of R1: 750 mm, R2: 1000000 mm obtains a smallest beam diameter at aperture diameter 1 mm, the maximum output power of 56.88 W at optical cavity length 260 mm and the small beam diameter is maintained about 1 mm at optical cavity length 260 − 450 mm. Furthermore, compared with using mirrors curvature radius of R1: 508 mm, R2: 1000000 mm, the optimum current to achieve the maximum output power is lower, the optimized temperature to achieve the diode-pumped wavelength 805.5 nm is higher, the beam propagation has smaller beam diameter of 1.71 mm, and it has better circularity of 91%. And the beam quality is also better. Therefore, it can be concluded that R1:750 mm, R2:1000000 mm is the appropriate mirror condition to achieve the small beam diameter of high power Nd:YAG laser for this research.