Ivanov Maksym, Matijošius Aidas, Tamulienė Viktorija
Appl Opt. 2020 Feb 20;59(6):1618-1626. doi: 10.1364/AO.381007.
Geometric phase retarders-such as q-plates and S-waveplates-have found wide applications due to simplicity of operational principles and flexibility for the generation of azimuthally symmetric polarization states and optical vortices. Ellipticity of the polarization vector and phase of the generated beam strongly depend on the retardation of the plate. Real devices usually have retardation value slightly different than the nominated one. Previously unattended perturbation of the retardation leads to asymmetry in intensity distribution and variation of ellipticity of the local polarization vector of the generated beam. We elucidate that controlled and intentionally driven azimuthally variable, oscillating perturbation of the retardation reveals the possibility to avoid distortions in the generated beam and leads to the recovery of the symmetrically distributed intensity and polarization (with zero ellipticity) of the beam. Described recovery of the desired polarization state could find application for generation of the high purity beam with azimuthally symmetric polarization, in which the local polarization ellipse has zero ellipticity.
几何相位延迟器——如q波片和S波片——由于其工作原理简单，且在产生方位对称偏振态和光学涡旋方面具有灵活性，因而得到了广泛应用。偏振矢量的椭圆率和所产生光束的相位强烈依赖于波片的延迟。实际器件的延迟值通常与标称值略有不同。此前未被注意到的延迟扰动会导致强度分布不对称以及所产生光束的局部偏振矢量椭圆率发生变化。我们阐明，对延迟进行可控的、有意驱动的方位可变振荡扰动，揭示了避免所产生光束出现畸变的可能性，并能使光束恢复对称分布的强度和偏振（椭圆率为零）。所描述的所需偏振态的恢复可应用于产生具有方位对称偏振的高纯度光束，其中局部偏振椭圆的椭圆率为零。
