https://doi.org/10.1140/epjd/s10053-022-00434-2
Regular Article - Optical Phenomena and Photonics
Focal shift and focal switch of broadband hollow Gaussian beams passing through an aperture-lens system
1
School of Electronic Engineering, Xi’an University of Posts and Telecommunications, 710121, Xi’an, China
2
Xi’an Key Laboratory of Microwave Photonics and Optical Communication, Xi’an, China
Received:
1
April
2022
Accepted:
6
June
2022
Published online:
25
June
2022
In this paper, we deduce the approximate analytical formula for the distribution of axial intensity for broadband hollow Gaussian beams (HGBs) passing through an optical system with an aperture and a lens separated based on the Collins formula. Moreover, the focal shift and focal switch effect of broadband HGBs passing through the system is investigated in detail. As demonstrated by the numerical results, whether the focal switch of broadband HGBs occurs is primarily dependent on the size of the aperture, the effective Fresnel number, as well as the relative separation between the aperture and the lens. Furthermore, the bandwidth may have effects on the behavior of the focal switch and reduce the relative focal shift. In this paper, the focal shift of HGBs through a thin lens is recognized as a special case.
© The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature 2022
