Research On Ladder Doped Crystals In Solid-state Laser

How to effectively control the laser thermal effect of laser research has become one of the key. The thermal effect of laser crystal is determined by crystal heat consumption, the nature of the crystal itself and crystal cooling methods together. Both the spatial distribution of the pump source and the absorption properties of crystal decides the spatial distribution of the absorbed pump light in the crystal and the heat consumption. The pump light absorption in crystal depends on the concentration of crystals doped and other crystal properties. Traditional laser crystal is uniform doping,crystals absorb the pump light exponential decay along the length, causes non-uniform vertical temperature distribution. Crystal face thermal effect serious, and the absorption efficiency reduces along the length. The absorption efficiency and temperature distribution is inconsistency.This paper mainly discusses the nature of crystal doping concentration effect on the absorption of pump light. For uneven thermal effects longitudinal distribution caused by absorption, the paper puts forward the idea of Sub-thermal effects. According to the relationship between the crystal doping concentration and the laser pump light absorption, gives the ladder doped crystal. With LD end-pumped Nd:YAG solid-state laser by example, in the actual production process conditions, to discuss the numbers of laser crystal, the doping concentration and the length of the ladder doped crystal, so that each laser crystal absorbed thermal power and thermal lens focus is equal, the total thermal lens focal length of a larger. Based on this, puts forward the gradient doped crystal. Finally, to simulate and analyze of the crystal temperature distribution and thermal lens focus changes. The results shows that, compared with the uniformly doped crystals, using ladder doped crystals and gradient doped crystal, pump light absorption power density is more evenly distributed along the longitudinal, laser crystal temperature significantly lower, and the more uniform temperature distribution along the longitudinal, end deformation significantly smaller, thermal lens effect to improve.The paper discusses the output characteristics of the laser crystal at last. The paper discusses how the saturation absorption and the decrease of stimulated emission impacts on the output power, and analyzes the improvement of output characteristics after using ladder doped crystal.