Research On Passively Q-switched Laser Based On Yb,Ho:LuVO₄ Crystal

2?m pulsed laser has great application value due to its unique advantages.In recent years,with the development of 2?m pulsed laser technology,Yb,Ho co-doped crystals have become a research hotspot due to their great research value in the field of 2?m lasers.Based on this situation,this thesis has conducted an in-depth study of Yb,Ho:Lu VO₄ crystal passive Q-switched lasers.The laser uses Yb,Ho:Lu VO₄material as the laser crystal and three saturable absorbers of MoS₂,BP and BP-MoS₂prepared from MoS₂ and BP materials were used as passive Q-switched devices.Firstly,three kinds of saturable absorbers of MoS₂,BP and BP-MoS₂ were prepared using MoS₂ material and BP material.Their properties were characterized by scanning electron microscopy,Raman spectroscopy and other techniques.Three saturable absorbers of MoS₂,BP and BP-MoS₂ were obtained with modulation depths of 9.5%,11.3%and 12.9%,respectively.Secondly,the absorption spectra of different axial cutting Yb,Ho:Lu VO₄crystals were analyzed in depth,and the optimal pump wavelength of different axial cutting crystals was determined.Based on the theory of spectroscopy,the mechanism of energy level transition in the 2?m band of Yb,Ho:Lu VO₄ crystal was deeply studied,and the energy level transition rate equation was established.Finally,in the experiment,the output performance of Yb,Ho:Lu VO₄ crystal passively Q-switched lasers were studied when three saturable absorbers of MoS₂,BP and BP-MoS₂ as passive Q-switched devices.When the MoS₂ saturable absorber was used as passive Q-switched device,the average output power and center output wavelength of Yb,Ho:Lu VO₄ crystal passively Q-switched laser are 268m W and2055.4nm,respectively,corresponding to the pulse width of 1.89?s and the repetition frequency of 36.96k Hz,and the beam quality factors in the x-axis direction and y-axis direction of the output laser are 1.10 and 1.11,respectively.When the BP saturable absorber was used as the passive Q-switched device,the average output power and the center output wavelength of the Yb,Ho:Lu VO₄ crystal passively Q-switched laser are 249m W and 2056.6nm,respectively.The corresponding pulse width is 2.34?s,the repetition frequency is 25.27k Hz,and the beam quality factors in the x-axis direction and y-axis direction of the output laser are both 1.07.When the BP-MoS₂ saturable absorber was used as the passive Q-switched device,the average output power and center output wavelength of the passively Q-switched Yb,Ho:Lu VO₄ crystal laser are 297m W and 2056.3nm,corresponding to the pulse width of 1.88?s and the pulse repetition frequency of 21.35k Hz,and the beam quality factors in the x-axis direction and y-axis direction of the output laser are 1.08 and1.06,respectively.