Tightly focused laser light with azimuthal polarization and singular phase
V.V. Kotlyar, A.G. Nalimov
Image Processing Systems Institute оf RAS, – Branch of the FSRC “Crystallography and Photonics” RAS, Samara, Russia,
Samara National Research University, Samara, Russia
Full text of article: English language.
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 π-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 0.273λ and 0.314λ (NA = 1).
zone plate, polarization conversion, diffraction grating.
Kotlyar VV, Nalimov AG. Tightly focused laser light with azimuthal polarization and singular phase. Computer Optics 2016; 40(5): 642-648. DOI: 10.18287/2412-6179-2016-40-5-642-648.
- Hao X, Kuang C, Wang T, Liu X. Phase encoding for sharper focus of the azimuthally polarized beam. Opt Lett 2010; 35(23): 3928-3930. DOI: 10.1364/OL.35.003928.
- Richards B, Wolf E. Electromagnetic diffraction in optical systems. II. Structure of the image field in an aplanatic systems. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 1959; 253(1274): 358-379. DOI: 10.1098/rspa.1959.0200.
- Cheng Z, Zhou Y, Xia M, Li W, Yang K, Zhou Y. Tight focusing of the azimuthally polarized light beam for a sharper spot. Optics & Laser Technology 2015; 73: 77-81. DOI: 10.1016/j.optlastec.2015.04.013.
- Li X, Venugopalan P, Ren H, Hong M, Gu M. Super-resolved pure-transverse focal fields with an enhanced energy density through focus of an azimuthally polarized first-order vortex beam. Opt Lett 2014; 39(20): 5961-5964. DOI: 10.1364/OL.39.005961.
- Khonina S.N., Karpeev S.V., Generating inhomogeneously polarized higher-order laser beams by use of diffractive optical elements, J Opt Soc Am A 2011, 28(10), 2115-2123. DOI: 10.1364/JOSAA.28.002115.
- Wang S, Li X, Zhou J, Gu M. Ultralong pure longitudinal magnetization needle induced by annular vortex binary optics. Opt Lett 2014; 39(17): 5022-5025. DOI: 10.1364/OL.39.005022.
- Tian B, Pu J. Tight focusing of a double-ring-shaped, azimuthally polarized beam. Opt Lett 2011; 36(11): 1180-1185. DOI: 10.1364/JOSAA.31.001180.
- Xie X, Sun H, Yang L, Wang S, Zhou J. Effect of polarization purity of cylindrical vector beam on tightly focused spot. J Opt Soc Am A 2013; 30(10): 1937-1940. DOI: 10.1364/JOSAA.30.001937.
- Khonina SN, Karpeev SV, Alferov SV, Savelyev DA, Laukkanen J, Turunen J. Experimental demonstration of the generation of the longitudinal E-field component on the optical axis with high-numerical-aperture binary axicons illuminated by linearly and circularly polarized beams. J Opt 2013; 15(8): 085704. DOI: 10.1088/2040-8978/15/8/085704.
- Prudnikov AP, Brychkov YA, Marichev OI. Integrals and series. Special functions. Moscow: "Nauka" Publisher; 1983.
- Prudnikov AP, Brychkov YA, Marichev OI. Integrals and series. Moscow: "Nauka" Publisher; 1981.
- Khonina SN, Ustinov AV, Pelevina EA. Analysis of wave aberration influence on reducing focal spot size in a high-aperture focusing system. J Opt 2011; 13(9): 095702. DOI: 10.1088/2040-8978/13/9/095702.
- Stafeev SS, Kotlyar VV, O'Faolain L. Subwavelength focusing of laser light by microoptics. J Mod Opt 2013; 60(13): 1050-1059. DOI: 10.1080/09500340.2013.831136.
- Stafeev SS, Kotlyar MV, O’Faolain L, Nalimov AG, Kotlyar VV. A four-zone transmission azimuthal micropolarizer with phase shift. Computer Optics 2016; 40(1): 12-18. DOI: 10.18287/2412-6179-2016-40-1-12-18.
© 2009, IPSI RAS
Institution of Russian Academy of Sciences, Image Processing Systems Institute of RAS, Russia, 443001, Samara, Molodogvardeyskaya Street 151; E-mail: email@example.com; Phones: +7 (846) 332-56-22, Fax: +7 (846) 332-56-20