Akondi Vyas, Jewel Md Atikur Rahman, Vohnsen Brian
J Biomed Opt. 2014 Sep;19(9):96014. doi: 10.1117/1.JBO.19.9.096014.
Sensing and compensating of optical aberrations in closed-loop mode using a single spatial light modulator (SLM) for ophthalmic applications is demonstrated. Notwithstanding the disadvantages of the SLM, in certain cases, this multitasking capability of the device makes it advantageous over existing deformable mirrors (DMs), which are expensive and in general used for aberration compensation alone. A closed-loop adaptive optics (AO) system based on a single SLM was built. Beam resizing optics were used to utilize the large active area of the device and hence make it feasible to generate 137 active subapertures for wavefront sensing. While correcting Zernike aberrations up to fourth order introduced with the help of a DM (for testing purposes), diffraction-limited resolution was achieved. It is shown that matched filter and intensity-weighted centroiding techniques stand out among others. Closed-loop wavefront correction of aberrations in backscattered light from the eyes of three healthy human subjects was demonstrated after satisfactory results were obtained using an artificial eye, which was simulated with a short focal length lens and a sheet of white paper as diffuser. It is shown that the closed-loop AO system based on a single SLM is capable of diffraction-limited correction for ophthalmic applications.
演示了在眼科应用中使用单个空间光调制器（SLM）以闭环模式对光学像差进行传感和补偿。尽管SLM存在缺点，但在某些情况下，该设备的这种多任务能力使其比现有的可变形镜（DM）更具优势，后者价格昂贵且通常仅用于像差补偿。构建了基于单个SLM的闭环自适应光学（AO）系统。使用光束缩放光学器件来利用该设备的大有效面积，从而使得生成137个用于波前传感的有源子孔径成为可能。在借助DM引入高达四阶的泽尼克像差进行校正时（用于测试目的），实现了衍射极限分辨率。结果表明，匹配滤波器和强度加权质心技术在其他技术中脱颖而出。在用短焦距透镜和一张白纸作为散射体模拟的人工眼获得满意结果后，演示了对三名健康人类受试者眼睛的后向散射光中的像差进行闭环波前校正。结果表明，基于单个SLM的闭环AO系统能够在眼科应用中实现衍射极限校正。
