Thermal Effect Of Microchip Solid-state Laser By Diode Laser End-pumped

Solid laser of semiconductor pumped was born in twentieth Century sixty.As early as1962,the first laser diode was born soon,Keyes et al. in America MIT laboratory used it as a pump source of solid state laser and realizes quasi-continuous laser output. Compared with traditional solid state laser, the laser diode pumped solid-state laser(DPSSL) has its significant advantage,main show is its high overall efficiency,high frequency and power stability,long service life,small volume,nice beam quality,and the multiplicity of the cavity forms. So it is widely used in industry,national defense,communications,medical and scientific research.With the development of the DPL applications, people on the laser output power and beam quality of the increasingly high demand. With the output power of the laser in the laser crystal is greatly improved, will produce the serious thermal effects, thermal effects that reduce the efficiency of the laser system, the beam quality becomes worse, and even lead to damage of the laser crystals, especially for the end pumped solid-state laser, the pump is usually focused on a small spot thus, thermal power density laser range is very large, therefore it is very important to study the thermal effect. This paper researches the thermal effect of the microchip laser on the fundamental theory of laser diode pumped solid-state laser,in the previous study,People usually regarded the thermal-conductivity coefficient of Yb:YAG laser crystal as a constant,but in this paper,through the author reading the literatures carefully and depth study founded that : the thermal-conductivity coefficient of Yb:YAG crystal is a varied function with the temperature changes,and so do the thermal-expansion coefficient. Thus the research results will be more accurate, This paper will research the thermal effect of the Yb:YAG microchip crystal through the two innovation,The main contents are:1. reviewed the historical development of the laser diode pumped solid-state laser,introduced the domestic and foreign research present situation and the direction of development and research hot spot of DPSSL,described the pumped ways of laser diode,proposed methods for reducing the thermal effect,and elaborated on the characteristics and the work characteristics of Yb:YAG crystal.2. Studyed on thermal effect of round and square Yb:YAG microchip crystal by laser diode end pumped, considering the thermal-conductivity coefficient of Yb:YAG crystal is a varied function with the temperature changes in the study,then establish the model,present the boundary conditions,apply mathematics method and mathematics software for calculating the temperature field of Yb:YAG crystal, the general analytical expressions for the temperature field are obtained. use mathematic software to simulate,analysis the temperature field of Yb:YAG microchip laser on thedifferent pump power, beam radius, different order and other factors.3.Study on thermal effect of pulsed laser diode end pumped Yb:YAG microchip crystal in the same way. Through solving the heat conduction equation to obtain the temperature expression.Quantitative analysis the effect of temperature field with different pump power,spot radius,super Gauss order and pulse width,and the temperature field change rule in the non steady state periodic pulse process and quasi thermal equilibrium state. if apply this method to the study of other laser thermal effects, it can be provide theoretical basis for effectively solving the problems of thermal effect in the process of diode pumped.