从理论和实验两方面分析测定了纳秒无衍射贝塞耳光脉冲的相关参量。由广义惠更斯-菲涅耳衍射积分理论出发给出了平行光通过轴棱锥后的光场分布、最大无衍射准直距离、最小中心光斑半径等参量的表达式,并进行相关参量的数值模拟。实验采用平-抗共振环(ARR)腔被动调Q Nd:YAG激光器和轴棱锥系统获得了高稳定的纳秒贝塞耳光脉冲,测定了其脉冲宽度、最大无衍射距离、横面光强分布及最小中心亮斑尺寸,实验结果与理论分析相吻合。利用胶片扫描法给出了光脉冲的截面光强分布精细结构,其分辨率远高于普通的光束分析仪。

Relative parameters of nanosecond diffraction-free Bessel laser pulse were theoretically analyzed and measured in experiments. The expressions of the optical intensity distribution behind an axicon illuminated by a plane wave, maximum diffraction-free distance, minimum central spot radius were given based on the generalized Huygens-Fresnel diffraction integral theory. Relative parameters were also theoretically simulated and calculated. In the experiment, high stability nanosecond Bessel laser pulses were generated by using a Q-switched Nd:YAG laser with a plane-antiresonant ring (ARR) resonator and an axicon system. The pulse duration, maximum diffraction-free distance, optical intensity in the cross-section and minimum central spot radius were measured. Experimental results were consistent with the theoretical analysis. The fine structure of the optical intensity in the laser beam cross-section was presented by film-scanning, and the resolution of the beam pattern is much higher than that in a laser parameter analyzer.