Open AccessHelico-conical optical beams: a product of helical and conical phase fronts
Author(s) -
Carlo Alonzo,
Peter John Rodrigo,
Jesper Glückstad
Publication year - 2005
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/opex.13.001749
Subject(s) - optics , conical surface , optical vortex , physics , optical tweezers , spatial light modulator , phase (matter) , beam (structure) , optical axis , lens (geology) , light beam , azimuth , intensity (physics) , light intensity , materials science , quantum mechanics , composite material
Helico-conical optical beams, different from higher-order Bessel beams, are generated with a parallel-aligned nematic liquid crystal spatial light modulator (SLM) by multiplying helical and conical phase functions leading to a nonseparable radial and azimuthal phase dependence. The intensity distributions of the focused beams are explored in two- and threedimensions. In contrast to the ring shape formed by a focused optical vortex, a helico-conical beam produces a spiral intensity distribution at the focal plane. Simple scaling relationships are found between observed spiral geometry and initial phase distributions. Observations near the focal plane further reveal a cork-screw intensity distribution around the propagation axis. These light distributions, and variations upon them, may find use for optical trapping and manipulation of mesoscopic particles.