光束变换环形孔径激光谐振腔(BCAR)是适用于环形增益介质的高性能谐振腔,已成功应用到高能连续波HF化学激光器中。建立了光束变换环形孔径激光谐振腔镜面倾斜及非共轴的数学模型,在此基础上,使用积分和差分结合的计算方法,计算了失调腔的输出光场近场分布,分析了束变换环孔腔在镜面失调情况下的模式特征,以及对远场传输能力的影响。计算结果表明,非共轴偏移和紧束段倾斜将使输出光场的相位分布呈现剪切、扭曲现象,并且沿偏移方向出现相位跳变;随偏移量的增大,相位畸变严重,远场传输能力下降。不同的偏移方向对于输出光场影响差别很小。两者相比,非共轴偏移对输出光场质量的影响更为严重,而紧束段倾斜的影响相对而言非常小,表现在相位分布的扭曲现象不明显,谐振腔的能量抽取效率变化微弱。

Beam-converting annular resonator (BCAR) possesses outstanding characteristics of high extraction efficiency and near-diffractive beam quality. It is applied specially to annular HF/DF gain medium. In this paper, numerical model of rear cone misalignment and compact leg tilt is presented, and this numerical model has been used in physical optics code. The numerical result shows that the output power is insensitive to rear cone decentration and compact leg tilt, but beam quality is very sensitive to the decentration and tilt. The rear cone decentration and compact leg tilt can both result in a phase shear and twist on the optical field, and lead to phase jump and tilt along the misalignment direction. When the misalignments increase, the phase distribution of BCAR output field is twisted more severely. The directions of misalignments have little effects on the output field. Among these misalignments, rear cone decentration has more severe effect on the output field, and it must be controlled carefully in engineer.