Axisymmetrical resonance modes in an electrowetting optical lens.

Electrowetting-based adaptive optics are of great interest for applications ranging from confocal microscopy to LIDAR, but the impact of low-frequency mechanical vibration on these devices remains to be studied. We present a simple theoretical model for predicting the resonance modes induced on the liquid interface in conjunction with a numerical simulation. We experimentally confirm the resonance frequencies by contact angle modulation. They are found to be in excellent agreement with the roots of the zero-order Bessel functions of the first kind. Next, we experimentally verify that external axial vibration of an electrowetting lens filled with density mismatched liquids ( = 250 kg/m) will exhibit observable Bessel modes on the liquid-liquid interface. An electrowetting lens filled with density matched liquids ( = 4 kg/m) is robust to external axial vibration and is shown to be useful in mitigating the effect of vibrations in an optical system.