Open AccessShifting the spherical focus of a 4Pi focusing system
Author(s) -
Shaohui Yan,
Baoli Yao,
R. A. Rupp
Publication year - 2011
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.19.000673
Subject(s) - optics , lens (geology) , cardinal point , physics , focus (optics) , curved mirror , laser , phase (matter) , focal length , wavefront , position (finance) , entrance pupil , image plane , optical transfer function , pupil , computer science , image (mathematics) , finance , quantum mechanics , artificial intelligence , economics
In a 4Pi focusing system radially polarized laser beams can be focused to a spherical focal spot. For many applications, e.g., for moving trapped particles or for scanning a specimen, one would like to change the position of focal spot along the optical axis without moving lenses or laser beams. We demonstrate how this can be achieved by modulating the phase of the input field at the pupil plane of the lens. The required phase modulation function is determined by spherical wave expansion of the plane wave factors in the Richards-Wolf integral.