可调光瞳滤波器的轴向焦移及扩展焦深

Axial Focal Shift and Extended Focal Depth with Tunable Filter

光学超分辨、焦深扩展及焦移3种效应一直受到研究人员的关注,且在光学显微成像、光学校准、光学相干层析成像及光存储中有着重要的应用。提出一种可调谐光瞳滤波器来实现光学系统的轴向焦移及扩展焦深。该光瞳滤波器由两个完全相同且相互平行的λ/4波片和置于其间的λ/2波片组成,其中λ/2波片分为两个可作相对旋转的区域,并且通过推导得出其光瞳函数。研究结果表明,通过旋转半波片的角度可以实现焦移量的实时控制。因此该系统可应用于自动调焦系统,比如某些光学读写驱动系统有时需要调整焦平面。另外,当半波片两部分相位差为π时,横向超分辨和轴向扩展焦深同时实现,可以应用于共焦扫描成像系统中。

Optical superresolution,focal shift and high focal depth in optical imaging system have been the goal of many researchers and have widely application in the optical microscopy,optical alignment and optical coherent tomography systems.A tunable pupil filter for modulation of axial focal shift and extended focal depth is proposed.It consists of one half-wave plate located between two identical and parallel quarter wave-plates,the half-wave plate is made up of two zones that can rotate with respect to each other,and the pupil function is deduced.The research result shows that with the designed pupil filter the axial focal shift can be controlled by rotating the half-wave plate.So the designed tunable pupil filter can be utilized in automatic focusing applications that are similar to optical read-write drives for which is necessary to track the focal plane dymamically.Furthermore,when the phase difference is π,the transverse superresolution and axially extended focal depth can be realized at the same time.And it can be used in optical confocal scan imaging system.