Measurement and modeling of electrowetting lens oscillations using digital holographic interferometry and Bessel and Legendre polynomial functions

The function of electrowetting liquid lenses is expanding beyond tunable focal length lensing. Recently, single and multi-mode oscillations on the meniscus profile of two non-miscible liquids have been used for optical phase modulation and fast focal length sweeping. To achieve a user-defined phase modulation, a prediction model of oscillation patterns and amplitudes is needed. We present digital holographic interferometry (DHI) measurements of oscillation patterns and amplitudes on a 5.8mm aperture lens up to 160 Hz, including frequency responses from 26-100 Hz. We discuss using Bessel function and Legendre polynomial models for oscillations on a conical frustum shaped electrowetting lens.