Validation of Programmable Liquid-Crystal Lens by Use of Hartmann-Moire Wavefront Sensor

Abstract

Purpose: : A novel programmable liquid-crystal lens (PixelOptics,Inc.) was developed as an alternate technology for controlling aberrations and providing dynamic power changes. The current experimental study examined samples of this prototype liquid-crystal lens designed to correct defocus and spherical aberration.

Methods: : The liquid crystal lenses can be modulated with an applied voltage. A Shear-plate and Hartmann-Moire (HM) wavefront sensor were used to monitor spherical defocus and spherical aberration (SA) at 532nm. Phase modulations across the lens equal to Ar² and A(r⁴-r²) were created with amplitudes up to 525 degrees. Repeatability was assessed by taking 5 repeated measurements within a 3-minute period. Shear-plate and wavefront sensor results were compared to theoretical expectations for defocus and spherical aberration (lens diameters were 8.00 mm and 8.26 mm for the r⁴-r² and r² lenses, respectively).

Results: : Both the Shear-plate and wavefront sensor indicate that the r² defocus lens accurately produced a range of defocus values from -0.11 to +0.11 diopters of spherical power (observed vs. predicted regressions have slopes of 0.999 and 0.949, and the correlation coefficients of 0.996 and 0.999, with mean residual errors of 0.0472D and 0.00562D, respectively). The r⁴-r² lens generated between +3 and -2.4 microns of SA, but was less accurately controlled. Observed vs. predicted slope was 0.766, and the correlation coefficient was 0.996, with mean residual errors of <0.536µm. Most of the error occurred for high amplitude negative SA. The repeatability was generally with in 5% and 1.5% for the r² and the r⁴-r² lens.

Keywords: aberrations • optical properties