Electrically tunable optofluidic lenses : fabrication and characterization

Abstract

The objective of this research is to fabricate and characterize an adaptive optofluidic lens device with aberration control. In this work, an electric field is employed as a driving tool to manipulate the liquid-liquid interface for suppressing spherical aberration by using a single flat unstructured electrode. The equilibrium lens meniscus profiles are determined by the balance of Laplace pressure and Maxwell stress. It involves understanding the response of a liquid drop under the influence of electric field and further discerning the optimum drop shapes which would yield the best optical performance. First, lenses are characterized by capturing the side view images of meniscus profiles and calculating the Longitudinal spherical aberration (LSA) by geometrical ray tracing. Subsequently, ray tracing analysis of optically measured lens profiles is performed on Zemax for numerically computing the Zernike spherical aberration (ZSA) coefficients and other standard optical metrics. Next, all-electrically controlled optofluidic lens device with EW-based pressure controller and electrically adjustable lens shape is designed and fabricated. The optical performance of lens device is evaluated by experimentally measuring the ZSA coefficients by using a Shack-Hartmann wavefront sensor (SHWS). The measured range of EW-tunability of focal length and spherical aberration is 10.1mm to 26.76mm and 0.059waves to 0.003waves respectively.