Abstract
The transverse focal shift (TFS) is a phenomenon that the maximum of a focused field does not occur at the geometrical focus, but is moved a short distance transversely in the focal plane. In this paper, the TFS of vortex beams in a high numerical aperture system is investigated. Four typical types of incident vortex beams are selected and the intensity distributions and the vortices behaviors in the focal region are discussed analytically and numerically. It is found that there are three main parameters, the topological charge, the initial positions of the vortices, and the semiaperture angle influencing the TFS in different ways, and the TFS even can be observed when the vortices annihilate in the focal plane. Our results also show that the intensity maximum can move from the y-axis, x-axis to the geometrical focus, or move from +y-axis to-y-axis in different cases, which may have implications in optical trapping.
| Original language | English |
|---|---|
| Article number | 8264749 |
| Pages (from-to) | 1-18 |
| Number of pages | 18 |
| Journal | IEEE Photonics Journal |
| Volume | 10 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 23 Jan 2018 |
Funding
Manuscript received December 14, 2017; revised January 11, 2018; accepted January 15, 2018. Date of publication January 23, 2017; date of current version February 6, 2018. This work was supported by the National Natural Science Foundation of China (11504296, 11604264) and Natural Science Basic Research Plan in Shaanxi Province of China (2016JQ1011, 2016JQ1021). Corresponding author: Xiaoyan Pang (email: [email protected]).
| Funders | Funder number |
|---|---|
| Natural Science Basic Research Plan in Shaanxi Province of China | 2016JQ1021, 2016JQ1011 |
| National Natural Science Foundation of China | 11604264, 11504296 |
Keywords
- diffraction theory
- optical vortex
- Singular optics
- transverse focal shift
