Super-resolution radially polarized-light pupil-filtering confocal sensing technology

Radially polarized beams can be focused to a tighter spot in the focal plane with a high numerical-aperture objective when combined with an optimally designed pupil filter. Based on the unique characters, a novel super-resolution radially polarized-light pupil-filtering confocal sensing technology (SRPCST) is proposed, and a sensor based on SRPCST is developed. By using a radially polarized beam and pupil-filtering technology, SRPCST can effectively improve its lateral resolution. In SRPCST a strong longitudinal field component can be generated in the focal plane by focusing a radially polarized light with a high numerical-aperture objective. Pupil-filtering technology will modify the pupil function of the optical system by optimally designing the parameters of pupil filter to higher resolution. Theoretical analyses and packaged SRPCST sensor experiments indicate that the lateral resolution of SRPCST can be improved by 15.23% and 32.12% through super-resolution image restoration compared with confocal microscopy under the same conditions.