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Proceedings Paper

Observation of spatial polarization structure near unfolding point of an optical vortex beam using a birefringent Mach-Zehnder interferometer
Author(s): Maruthi M. Brundavanam; Yoko Miyamoto; Rakesh K. Singh; Dinesh N. Naik; Mitsuo Takeda; Ken'ichi Nakagawa
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Paper Abstract

A uniformly polarized optical vortex (OV) entering a birefringent crystal is known to unfold into complex polarization structures due to the separation of ordinary and extraordinary rays. The interplay between the topological structures in scalar and vector optics has been studied at the output of finite-length crystals. But the polarization transformation near the unfolding point where the beam initially enters the crystal has not been observed so far. In this paper, we experimentally investigate the spatial polarization structure very near the unfolding point of a uniformly polarized OV beam propagating in a birefringent crystal by constructing a birefringent interferometer. The unfolding point is reconstructed by folding back the two separated beams into a single beam using another identical birefringent crystal, resulting in a birefringent interferometer of Mach-Zehnder type. Small rotation of the second crystal produces output beams with varying separation near the unfolding point. The spatial polarization structure of the output beam is investigated by measuring the Stokes parameters. Such understanding of the connection between defects of scalar optics and vector optics through birefringence will help to shape the spatial polarization states of laser beams for various spectroscopic and microscopic applications.

Paper Details

Date Published: 11 October 2012
PDF: 6 pages
Proc. SPIE 8480, The Nature of Light: Light in Nature IV, 848008 (11 October 2012); doi: 10.1117/12.930564
Show Author Affiliations
Maruthi M. Brundavanam, The Univ. of Electro-Communications (Japan)
Yoko Miyamoto, The Univ. of Electro-Communications (Japan)
Rakesh K. Singh, Indian Institute of Space Science and Technology (India)
Dinesh N. Naik, Univ. Stuttgart (Germany)
Mitsuo Takeda, Utsunomia Univ. (Japan)
Ken'ichi Nakagawa, The Univ. of Electro-Communications (Japan)

Published in SPIE Proceedings Vol. 8480:
The Nature of Light: Light in Nature IV
Rongguang Liang, Editor(s)

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