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This article is cited in 1 scientific paper (total in 1 paper)
OPTO-IT
Tightly focused laser light with azimuthal polarization and singular phase
V. V. Kotlyarab, A. G. Nalimovab a Samara National Research University, Samara, Russia
b Image Processing Systems Institute îf RAS, – Branch of the FSRC “Crystallography and Photonics” RAS, Samara, Russia
Abstract:
Using simplified Richards-Wolf formulas we show that laser light with azimuthal polarization and singular phase can produce a smaller focal spot than that from a laser beam with radial polarization, other conditions remaining the same. It is numerically shown that when focusing an azimuthally polarized laser beam with phase singularity using a zone plate a 1.3 times smaller focal spot can be attained than when an aplanatic lens is used. A spiral phase plate can be replaced with a phase step with a $\pi$-phase shift. In this case the subwavelength focal spot from a laser beam with azimuthal polarization, which is formed near the zone plate surface, loses circular symmetry, while becoming smaller and acquiring an elliptical form with radiuses of $0.273\lambda$ and $0.314\lambda$ ($NA = 1$).
Keywords:
zone plate, polarization conversion, diffraction grating.
Received: 30.09.2016 Accepted: 21.10.2016
Citation:
V. V. Kotlyar, A. G. Nalimov, “Tightly focused laser light with azimuthal polarization and singular phase”, Computer Optics, 40:5 (2016), 642–648
Linking options:
https://www.mathnet.ru/eng/co288 https://www.mathnet.ru/eng/co/v40/i5/p642
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