Liquid-crystal adaptive lenses with modal control

TLDR

The study aims to realize nematic liquid‑crystal phase correctors that generate spherical and cylindrical wave fronts. This is achieved by driving a LC cell with distributed reactive impedance via an AC voltage applied to the boundary, producing a spatially varying refractive index controlled by voltage frequency, electrode geometry, and cell parameters. The authors fabricated a 15 mm × 4 mm cylindrical adaptive lens and a 6.5 mm spherical lens, both capable of focusing collimated light from a few centimeters to 0.5 m.

Abstract

We report on a novel approach to the realization of nematic liquid-crystal (LC) phase correctors to form spherical and cylindrical wave fronts. A LC cell with a distributed reactive electrical impedance was driven by an ac voltage applied to the cell boundary to yield the desired spatial distribution of the refractive index. The two-dimensional function of the phase delay introduced into the light beam depends on the frequency of the ac control voltage, the geometry of the boundary electrode surrounding the LC cell, and the electrical parameters of the cell. We realized a cylindrical adaptive lens with a clear aperture of 15 mm×4 mm and a spherical adaptive lens with circular aperture of 6.5 mm. Both devices are capable of focusing collimated light in the range ?…0.5 m.