提出利用电控径向双折射光瞳滤波器实现横向超分辨性能参量的调制与轴向扩展焦深。该光瞳滤波器由两个平行偏光镜,一个电光晶体与一个径向对称双折射晶体组成。分析了电光晶体与径向双折射元件对光偏振态的空间调制作用,通过控制电光晶体的相位延迟实现径向中心处初始偏振态的控制,与径向双折射元件横向偏振态调制结合,实现了庞加莱球上偏振态演变路径与阶段的控制,从而对焦点附近偏振态进行空间调制以实现光强的重新分布。研究结果表明,外加电场调制可以实现横向上超分辨性能的调控以及轴向上焦深的扩展,并可得到相应的电光相位延迟范围。

An electrically controllable radial birefringent pupil filter for modulation of transverse superresolution performance and axial extended focal depth is proposed. It consists of two parallel polarizers, an electro-optical crystal and a birefringent crystal with radial symmetry. The spatial modulation of the optical polarization state at the electro-optic crystal and the radial birefringent device is analyzed. The initial optical polarization state at the radial center is determined by the phase delay of the electro-optic crystal. Combined with the transverse polarization state modulation by the birefringent device, the control of the polarization state evolution path and the stage on the Poincaré sphere, and the redistribution of the optical intensity by spatially modulating the polarization state near the focus are realized. The control of transverse superresolution performance and the axial extended focal depth can be realized merely through the applied-voltage modulation, and the phase delay range can simultaeously be obtained.