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Minimal focal spot obtained by focusing circularly polarized light
S.S. Stafeev 1,2, V.D. Zaitcev 1,2, V.V. Kotlyar 1,2

1 IPSI RAS – Branch of the FSRC "Crystallography and Photonics" RAS,
443001, Samara, Russia, Molodogvardeyskaya 151;
2 Samara National Research University, 443086, Samara, Russia, Moskovskoye Shosse 34

 PDF, 791 kB

DOI: 10.18287/2412-6179-CO-1247

Pages: 361-366.

Full text of article: Russian language.

Abstract:
In this paper, using the Richards-Wolf equations, we analyze focusing circularly polarized light with flat diffractive lenses. It is shown that as the numerical aperture of the lens increases, the size of the focal spot first decreases and then begins to grow. The minimum focal spot is observed at NA=0.96 (FWHM=0.55λ). With a further increase in the numerical aperture of the lens, the growth of the longitudinal component leads to an increase in the size of the focal spot. When the flat diffractive lens is replaced by an aplanatic lens, the size of the focal spot decreases monotonically as the numerical aperture of the lens increases.

Keywords:
tight focusing, Richards-Wolf formulas, polarization conversion, flat-top focus.

Citation:
Stafeev SS, Zaitsev VD, Kotlyar VV. Minimal focal spot obtained by focusing circularly polarized light. Computer Optics 2023; 47(3): 361-366. DOI: 10.18287/2412-6179-CO-1247.

Acknowledgements:
This work was supported by Russian Science Foundation under project No. 22-22-00265.

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