| dc.description.abstract | This study mainly research performance enhancement and aberration measurement of adaptive fluidic lens and electrically tunable lens.
One specific kind of electrically tunable lenses is utilizing curvature change via adjusting input currents which electromagnetically exerts pressure on liquid volume to achieve variable-focusing properties. Nevertheless, the nature of curvature change and refractive index mismatch causes inherent spatial aberrations that severely degrade image quality. The novelty of the presented method lies in the experimental study of optical aberrations such as root mean square (RMS), Strehl ratio and Zernike coefficients induced from electrically tunable lenses and use of adaptive optics to compensate for the wavefront errors. The optical properties of electrically tunable lens are quantitatively characterized by Shack-Hartmann measurements. Adaptive optics based scheme is demonstrated for the current range 78 to 95mA, resulting in a substantial reduction of the wavefront errors from 0.55, 0.53 to 0.22, 0.2μm, respectively, corresponding to the focal power tunability of -2.52 to 0.2 diopters. It is experimentally showed that defocus (Z5) aberration is the most significant one since the changes of lens curvature varies in proportional with changing currents, and can be significantly improved from 0.328μm to 0.156μm with adaptive optics. Similar improvements can be found in piston (Z₁)/ tip (Z₂)/ tilt (Z₃) aberrations with the integration of adaptive optics.
We use Adaptive optics system to generate aberration, and then we use electrically tunable lens to correct it. Electrically tunable lens based scheme is demonstrated for the Z₁=0.3μm, Z₁=-0.3μm, Z5=0.3μm and Z5=-0.3μm, resulting in a substantial reduction of the wavefront errors from 0.5, 0.4, 0.4, 0.6μm to 0.22, 0.2, 0.2, 0.2μm, respectively.
Finally, we add self-made fluidic lenses which have concave/plano/convex membrance to change optical properties in the adaptive optics and electrically tunable lens. First, we observe the change of lens profiles and focal length. Then we use the SH sensors detect the fluidic lens which injected 0, 0.02 and 0.04ml DI water, and get RMS / PV values 1.41μm/4.12μm, 1.58μm/5.04μm and 1.73μm/3.66μm. We use the AO system to correct the aberration, get 0.77μm/2.35μm, 1.09μm/3.35μm and 1.41μm/2.96μm. But the correction is not very good, so we add electrically tunable lens in the AO system, the result is 0.35μm/3.5μm, 0.79μm/3.68μm and 0.91μm/3.88μm. We find that adding electrically tunable lens in AO system enable improve the aberration correction. | en_US |