Abstract
In most tight focusing systems with the incident wave of unique polarization (including the radial and azimuthal polarization), the polarization along the optical (central) axis (the propagation direction) is found to be uniform. In this paper, we will show that when there is an off-axis vortex in the incident field, the polarization state varies along the central optical axis and the polarization singularities, ‘C-points’ ‘L-points’ both can exist on axis. The polarization state is demonstrated to be mainly dependent on two parameters, the initial position of off-axis vortex and the Gouy phase of the axial field. Due to the special property of the Gouy phase, we find that moving the off-axis vortex can vary the polarization without changing its handedness. Especially, it is quite interesting to find that one direction of the linear polarization at the geometrical focus exactly corresponds to one position of the off-axis vortex.
Original language | English |
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Pages (from-to) | 50-55 |
Number of pages | 6 |
Journal | Optics Communications |
Volume | 421 |
DOIs | |
Publication status | Published - 15 Aug 2018 |
Funding
This work is supported by National Natural Science Foundations of China (NSFC) (No. 11504296) and Natural Science Basic Research Plan in Shaanxi Province of China (No. 2016JQ1011).
Funders | Funder number |
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National Natural Science Foundation of China | 11504296 |
Natural Science Foundation of Shaanxi Province | 2016JQ1011 |
Keywords
- Gouy phase
- Optical singularity
- Polarization
- Vortex beam