非稳腔输出环状激光束的传输特性

本文从菲涅耳衍射积分公式出发研究了激光器非稳腔输出环状光束在空间的传输规律.由轴上光强的极值点位置给出了划分非稳腔传输空间的近场、中场和远场区域公式.理论计算结果表明,非稳腔输出端环状光束在中场区域激光能量逐渐向轴心方向转移,而在远场变为爱里型圆盘状光束的过程.在非稳腔脉冲TEA CO_2激光器上测得的实验结果与理论计算结果很好地符合.

Propagation properties of output annular beam from unstable laser resonator

The spatial propagation properties of output annular laser beam from an unstable resonator are studied based on Fresnel diffraction integral. According to the position of extreme value point of laser intensity on the axis, the formula used to divide the propagation space of output beam from unstable resonator into near field, middle field and far field is derived. The numerical calculation shows the variation process of output laser beam of unstable resonator from annular pattern on near field, with gradual transition of laser energy in the annular region to the beam's center, to Airy disk pattern on far field. The experimental results obtained in TEA pulsed CO2 laser with unstable resonator are in good agreement with theoretical results.