Experiments and simulations of QCW Yb:YAG laser with consideration of transient temperature

Abstract The effects of transient temperature variation of gain medium on quasi-three-level microchip laser were investigated. Firstly, the dynamic behavior with temperature variation and the characteristic of the output power were reported. The numerical simulation results revealed not only the dynamics characteristic of lasing levels, but also the relationship between pump pulse width and output power in equivalent duty cycle. The increments of output power deviated significantly from linear increasing with the pump pulse width. The characteristic of the output power with different duty cycle was compared. Because the heat load was rising with the increase of the duty cycle and high heat load reduced population inversion density, the optical-to-optical efficiency of 9.7% at 50% duty cycle was lower than optical-to-optical efficiency of 15.6% at 7% duty cycle. The calculated and experimental pump power thresholds for output of 1030 nm were discussed. Particularly, the output power calculated by the model with the addition of temperature terms was significantly lower than that simulated by the model without temperature terms. Experimental results have shown a good agreement with the theoretical predictions.