Measurement of optical characteristics in dielectric liquid lens by Shack-Hartmann wave front sensors

Abstract

Liquid lenses based on the principle of driving two dielectric fluids via controlled electric field were investigated with an experimental apparatus designed for analysis of wave front read from a Shack-Hartmann sensor. Due to small available aperture and requirements in dynamic responses, wave front measurement was selected for study of optical characteristics in dielectric lenses. With the advent of commercial electro-optics sensors in wave front measurement, the experimental apparatus was first designed and simulated with the help of ASAP program. The simulated results proved the conceptual design with handful of engineering insights so that less trial and error efforts could be relieved from building the optics system on the bench. In-house built liquid lens modules with driving circuits were then set on the apparatus for initial calibration and functional tests. Since the electric field generated for the control of liquid profile must be alternating current, various frequency and modulation schemes were put through the liquid lens module to further study the influences on dynamic responses in terms of optical characteristics. Furthermore, effects due to material impurity and ambient effects were also carefully studied for established the fundamental phenomena of liquid lenses made of dielectric fluids. More detailed observations were possible with the measured wave-front data. In conclusion, the wave-front measurement proved to be more reliable and less expensive compared to measurement based on interferometer.

Design and wavefront characterization of an electrically tunable aspherical optofluidic lens

“…Second, we quantify experimentally the wavefront distortions generated by our device. To this end, we set up a testing platform using a Shack-Hartman wavefront sensor (SHWS) that allows us to measure wavefronts following previous reports in the literature [8,20,21].…”