Characterization of adjustable fluidic lenses and capability for aberration correction of defocus and astigmatism

An adjustable, variable-focus fluidic lens is typically utilizing curvature change in the meniscus between two immiscible liquids or by adjusting the liquid pressure of the lens chamber. In addition, this curvature change can be used as a deformable mirror to correct the aberrations such as defocus and astigmatism. In this paper, we first fabricate a liquid lens prototype and experimentally characterize relevant optical performance such as focal length tunability over curvature change through adjusted liquid volume. Moreover, capability of adjustable fluidic lenses to correct the induced wavefront aberrations is investigated systematically, with particular attention placed on interpretation of Zernike modes and fully explores the potentials of fluidic lenses. Optically, various orders of wavefront aberrations are purposely induced by a commercial MEMS (micro-electrical–mechanical systems) DM (deformable mirrors) with 140 actuators. The optical properties of fluidic lenses are characterized by Shack–Hartmann measurements. It is experimentally shown that piston mode (Z1) can be significantly improved from 0.972 μm to −0.031 μm using fluidic lenses by injecting DI water as little as 0.02 ml. Similar improvements can be found in defocus (Z5)/astigmatism (Z6) and aberrations are reduced for both modes from −0.15 μm/−0.48 μm to 0.02 μm/0.085 μm, respectively.