Design and wavefront characterization of an electrically tunable aspherical optofluidic lens

We present a novel design of an exclusively electrically controlled adaptive optofluidic lens that allows for manipulating both focal length and asphericity. The device is totally encapsulated and contains an aqueous lens with a clear aperture of 2mm immersed in ambient oil. The design is based on the combination of an electrowetting-driven pressure regulation to control the average curvature of the lens and a Maxwell stress-based correction of the local curvature to control spherical aberration. The performance of the lens is evaluated by a dedicated setup for the characterization of optical wavefronts using a Shack Hartmann Wavefront Sensor. The focal length of the device can be varied between 10 and 27mm. At the same time, the Zernike coefficient Z ₄ ⁰ , characterising spherical aberration, can be tuned reversibly between 0.059waves and 0.003waves at a wavelength of λ = 532nm . Several possible extensions and applications of the device are discussed.