An optical system consisting of an aqueous electrolyte resting on a polymer/gold/indium-tin-oxide (ITO) layer deposited onto a glass substrate is analyzed to acquire contact angle - focal distance data as a function of applied voltage. The shape factor of a liquid lens and its dependence on the perimeter of contact line and contact angle was analyzed in the presence of an electrical field applied between the electrolyte and planar electrode system. The contact angle of a liquid on a thin, transparent film of gold (20 nm thick) - on ITO under electrolyte solution could be varied from 110 ± 3° when the gold was held at -2.4 V to 41 ± 3° without voltage. The behavior of a water-based electrolyte and water-soluble polymer blend and its influence on the shape of contact line and profile of the lens were investigated by employing a holographic setup at wavelengths of 632.8 and 543.5 nm. Optical micrographs showing the profile of the lens, aberration-less aperture, deformation of contact line, and shape of the liquid lens, respectively, were analyzed in reflection and transmission. Both the advancing and receding contact angles were measured directly from digitized images of the profile of the lens. The dynamic range of linear beam steering and dependence of the focal length of the liquid lens on the applied voltage are discussed.

Date Published: 26 September 2007
PDF: 9 pages
Proc. SPIE 6714, Adaptive Coded Aperture Imaging and Non-Imaging Sensors, 67140J (26 September 2007); doi: 10.1117/12.746747

Published in SPIE Proceedings Vol. 6714:
Adaptive Coded Aperture Imaging and Non-Imaging Sensors
David P. Casasent; Timothy Clark, Editor(s)