| 摘要: | 本論文是關於液體透鏡和電調透鏡的相關性質與像差研究，並且結合適應性光學相關應用。本論文研究重點在(1) 電調透鏡與適應性光學校正像差的特徵， (2) 利用電調透鏡校正校差的性質，(3) 自製液體透鏡與適應性光學系統和電調透鏡相互像差校正。
首先我們先觀察電調透鏡的光學性質，並且找出各電流所誘發曲率變化的像差，接著嘗試使用適應性光學來校正。我們發現在電流為78~95mA，光焦度為-2.52~0.2D時的RMS (root mean square)能從0.55，0.53降到0.22，0.20μm。接著我們用Zernike 多項式來代表像差，其中Z₅（defocus）與電流變化有明顯改變，其他Z₁ (piston)/ Z₂ (tip)/ Z₃ (tilt)像差也有下降。
然後我們在觀察電調透鏡的校正像差能力。所以我們先使用AO系統來產生Z₁ (piston)像差和Z₅（defocus）像差，接著在使用電調透鏡來校正。可以發現在Z₁和Z5範圍為-0.3~0.3μm可以使RMS下降到0.2μm，而且其他像差也能有所下降。
本自製液體透鏡特點是改變薄膜的形狀，使薄膜有凹/平/凸三種變化，可以改變透鏡的光學性質，先觀察其薄膜變化和焦距。接著再用S-H感測器偵測注入0，0.02和0.04ml去離子水之RMS/ PV值為1.41μm/4.12μm，1.58μm/5.04μm和1.73μm/3.66μm。然後使用AO系統來校正，得到0.77μm/2.35μm，1.09μm/3.35μm和1.41μm/2.96μm，但是校正並非很好。所以我們加入電調透鏡，結果得到0.35μm/3.5μm，0.79μm/3.68μm和0.91μm/3.88μm。發現加入電調透鏡能令整個校正系統能力有所提升。
;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. |
