Thermal Effect Study Of A Grazing-incidence Slab Amplifier

With the rapid development of Diode Pump Solid State Laser(DPSSL) technology, especially the development of diode pumped slab laser, the output power of solid-state laser has been further improved, and also the beam quality has been improved dramatically. Because Diode Pump Slab Solid State Laser has the advantage of compact structure, high efficiency, good quality, et al, the application prospect is very wide in the field of industry, and Diode Pump Slab Solid State Laser is the research hotspot in the field of laser. However, with the improvement of pump power, the thermal effect of the laser medium become an important factor of limiting high output power and high beam quality. So the study of the thermal effect of laser medium in laser has very important theory significance and actual reference value. In this paper, aiming at the cascade amplifier system, we made a detailed and systematic theoretical analysis and numerical simulation for the thermal effect of laser medium in a grazing- incidence slab amplifier. This paper include following respects:(1)It has analyzed the research status of slab laser amplifier at home and abroad, the thermal effect of laser medium is still the key factor of limiting the high output power and high beam quality. Aim a grazing-incidence slab laser, under the condition of considering end-face deformation and pump face deformation, the corresponding thermodynamics model was established. The formula derivation and analysis of the distribution of temperature field and stress field, wavefront aberration, and thermal lensing effect was carried out.(2)The numerical simulation of the thermal effect of a grazing-incidence slab amplifier is demonstrated. Using COMSOL and MATLAB software, we simulated the temperature distribution in conditions of different pump power, different slab thickness and different pump area, also simulated the stress field distribution under certain conditions, and also simulated the influence of different pump power, different pump area, different slab thickness, and different incident angle to the wavefront aberration and thermal lens effect. And we also made the corresponding measurement.(3) We put forward a newly type of composite structure of reducing the thermal effect. The numerical simulation of the thermal effect of a grazing-incidence composite slab amplifier is demonstrated. Under the certain conditions, we simulated the influence of different bonding layer thickness to the temperature distribution, medium deformation, wavefront aberration and thermal lens effect. The simulation results show that through bonding the undoped crystal on the pump face can effectively weaken the thermal effect in a grazing-incidence slab amplifier.Through the systematically theoretical analysis and numerical simulation for a grazing-incidence slab amplifier, we know the seriousness and urgency of thermal effect, at the same time we also recognize the origins of thermal effect deeply. These analysis and simulation results provide a reference basis in predicting the thermal effect, weakening or eliminating thermal effect.