采用光学空间滤波方法,对基于变形镜生成的贝塞尔光束的质量进行改善。设计了一种环形滤波器,在贝塞尔光束的空间谱平面上滤除由变形镜圆顶误差引起的频谱分量,使贝塞尔光束的轴向光强分布更加均匀;设计了扇形和环形组合的滤波器,将圆对称的贝塞尔光束整形成椭圆贝塞尔光束,其主瓣的长短轴之比约为1.72,轴向光强半峰全宽达到247 mm,具有良好的无衍射特性。提出的空间滤波方法可有效提高基于变形镜生成的贝塞尔光束的性能,有利于其应用。

In this study, we employ optical spatial filtering to improve the quality of the Bessel beam generated by a deformable mirror. An annular filter is designed to filter the spectral components produced by the round tip error of the deformable mirror on the spatial spectrum plane of the generated Bessel beam, making the axial intensity distribution of the Bessel beam increasingly uniform. Furthermore, a filter that combines a sectorial filter and an annular filter is designed, which directly transforms a circularly symmetric Bessel beam into an elliptic Bessel beam. The aspect ratio of the main lobe of the generated elliptical Bessel beam is approximately 1.72. The axial full width at half maximum exhibits a maximum of 247 mm, denoting an excellent non-diffraction property. The proposed optical spatial filtering method can effectively improve the performance of the Bessel beam generated by a deformable mirror and advance its applications.