非共焦离轴正支非稳腔光束特性研究

Study on the Characteristics of Non-confocal Off-axis Positive Branch Unstable Resonator

非稳腔拥有较大的模体积,良好的光束特性,因而在板条激光器中应用广泛。一般而言,板条激光器均采用的是共焦非稳腔结构,对非共焦腔结构研究较少。采用Rigrod分析法对非共焦非稳腔的功率提取效率进行分析,研究了腔长增加或者减小时,非共焦腔的光束特性,失调特性以及功率提取效率的变化。结果表明,腔长减小时,非共焦腔相比共焦腔,功率提取效率整体呈下降趋势;而当腔长增加150~210 mm时,非共焦腔的功率提取效率提升11%左右,抗失调特性相比共焦腔结构也提升10%以上。

The unstable resonator has a large mode volume and good beam characteristics, so it is widely used in the slab laser. Generally speaking, the slab laser adopts confocal unstable resonator, while there are few research on the structure of the non-confocal unstable resonator. In this paper, the power extraction efficiency of non-confocal resonator is analyzed by ‘Rigrod Analysis’. The beam characteristics and misalignment characteristics are investigated when the cavity length increased or reduced. The results show that when the cavity length decreased, the power extraction efficiency shows a downward trend. However, when the cavity length increased by 150 mm to 210 mm, the power extraction efficiency of the non-confocal resonator is increased about 11%, and the anti-misalignment is increased by more than 10% compared with the confocal resonator.