用轴棱锥实现可改变的局域空心光束

Generation of Adjustable Bottle Beams Using an Axicon

理论和实验研究了利用轴棱锥-透镜系统产生的局域空心光束,分析了局域空心光束的演变过程,由简单的几何光学结构和近轴光线追迹的方法进行模拟。研究结果表明,局域空心光束的暗中空区域不仅与聚焦透镜的焦距有关,而且与光阑半径以及聚焦透镜到轴棱锥间的距离有关;对于给定的轴棱锥,局域空心光束的横向暗斑尺寸与焦距成正比,并且其纵向暗斑尺寸与聚焦透镜到轴棱锥间的距离以及光阑半径成反比。这些结果表明,改变聚焦透镜的焦距和聚焦透镜到轴棱锥间的距离以及光阑半径,可有效地改变局域空心光束的暗中空区域。

The bottle beams generated by using a conical-lens system are investigated theoretically and experimentally. The evolutions, of bottle beams are illustrated simply by using geometrical structures and the paraxial ray tracing. Our study results show that the bottle beams with a dark focus surrounded by regions of higher intensity, are dependent not only on the focal length of the focal lens, but also on the radius of limiting aperture and the distance between the axicon and the lens. For a fixed axicon, we show that the radius of the dark focus of the bottle beam is proportional to the focal length of the focal lens. And the longitudinal length of the dark focus is inverse proportional to the distance between the axicon and the lens and the radius of limiting aperture. It is shown that by changing the focal length of focal lens and the distance between the axicon and the lens, the center of dark of the bottle beams can be altered effectively.