Intangible pointlike tracers for liquid-crystal-based microsensors

Journal Article · Wed Dec 15 00:00:00 EST 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.82.063832· OSTI ID:21528992

Brasselet, Etienne ^[1]; Juodkazis, Saulius ^[2]

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1. Centre de Physique Moleculaire Optique et Hertzienne, Universite Bordeaux 1, CNRS, 351 Cours de la Liberation, 33405 Talence Cedex (France)
2. Centre for Micro-Photonics, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, Victoria 3122 (Australia)

We propose an optical detection technique for liquid-crystal-based sensors that is based on polarization-resolved tracking of optical singularities and does not rely on standard observation of light-intensity changes caused by modifications of the liquid crystal orientational ordering. It uses a natural two-dimensional network of polarization singularities embedded in the transverse cross section of a probe beam that passes through a liquid crystal sample, in our case, a nematic droplet held in laser tweezers. The identification and spatial evolution of such a topological fingerprint is retrieved from subwavelength polarization-resolved imaging, and the mechanical constraint exerted on the molecular ordering by the trapping beam itself is chosen as the control parameter. By restricting our analysis to one type of point singularity, C points, which correspond to location in space where the polarization azimuth is undefined, we show that polarization singularities appear as intangible pointlike tracers for liquid-crystal-based three-dimensional microsensors. The method has a superresolution potential and can be used to visualize changes at the nanoscale.

• OSTI ID: 21528992
• Journal Information: Physical Review. A, Vol. 82, Issue 6; Other Information: DOI: 10.1103/PhysRevA.82.063832; (c) 2010 American Institute of Physics; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BEAMS
CROSS SECTIONS
DETECTION
DROPLETS
LIQUID CRYSTALS
MODIFICATIONS
NANOSTRUCTURES
POLARIZATION
POTENTIALS
SENSORS
SINGULARITY
THREE-DIMENSIONAL CALCULATIONS
TOPOLOGY
TRAPPING
TWO-DIMENSIONAL CALCULATIONS
VISIBLE RADIATION
CRYSTALS
ELECTROMAGNETIC RADIATION
FLUIDS
LIQUIDS
MATHEMATICS
PARTICLES
RADIATIONS