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Optical Engineering

To construct a stable and tunable optical trap in the focal region of a high numerical aperture lens
Author(s): Gokulakrishnan Kandasamy; Suresh Ponnan; T. V. Sivasubramonia Pillai; Rajesh K. Balasundaram
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Paper Abstract

Based on the diffraction theory, the focusing properties of a radially polarized quadratic Bessel–Gaussian beam (QBG) with on-axis radial phase variance wavefront are investigated theoretically in the focal region of a high numerical aperture (NA) objective lens. The phase wavefront C and pupil beam parameter μ of QBG are the functions of the radial coordinate. The detailed numerical calculation of the focusing property of a QBG beam is presented. The numerical calculation shows that the beam parameter μ and phase parameter C have greater effect on the total electric field intensity distribution. It is observed that under the condition of different μ , evolution principle of focal pattern differs very remarkably on increasing C . Also, some different focal shapes may appear, including rhombic shape, quadrangular shape, two-spherical crust focus shape, two-peak shape, one dark hollow focus, two dark hollow focuses pattern, and triangle dark hollow focus, which find wide optical applications such as optical trapping and nanopatterning.

Paper Details

Date Published: 13 May 2014
PDF: 5 pages
Opt. Eng. 53(5) 055106 doi: 10.1117/1.OE.53.5.055106
Published in: Optical Engineering Volume 53, Issue 5
Show Author Affiliations
Gokulakrishnan Kandasamy, Anna University (India)
Suresh Ponnan, National College of Engineering (India)
T. V. Sivasubramonia Pillai, Univ. College of Engineering (India)
Rajesh K. Balasundaram, Chikkanna Government Arts College (India)

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