A spatially variable retardation device, an SQWP, is designed to generate polarization vortex beams. The transformation of Laguerre--Gaussian beams by the SQWP is further studied, and it is found that the SQWPs can also be used to generate helical beams and measure the topological charges of helical beams.
Stripe motion artifacts caused by phase fluctuation in phase-resolved optical coherence tomography （OCT） result in the quality degradation of the image of in vivo blood flow of human eye. In order to suppress the stripe motion artifacts, we design a kind of frequency rejection filter aimed at the frequency spectrum characteristics of the image. Blood flow images of human eye acquired by our research group and another group are filtered to show the performance of the proposed method. Experimental results indicate that the stripe motion artifacts in the projection images are rejected significantly with minimal loss of signal information. The proposed filter can also be used in other imaging systems with similar stripe noise.
