Spherical aberration cancellation in a polarized photon-pairs confocal laser scanning microscope

Refractive-index mismatch in conventional confocal microscopy produces severe degradation on axial resolution of sectioning image because the spherical aberration is generated in specimen. In this study, we propose a polarized photon-pairs confocal laser scanning microscope (PCLSM) in which a two-frequency linear polarized photon-pairs (LPPPs) laser beam is produced. The common-path propagation of LPPPs integrated with optical heterodyne technique not only can reduce the spherical aberration but also decreases scattering effect in specimen at same time. Therefore, the better axial and lateral resolutions of the sectioning image are produced simultaneously. In the experiment, a verification and comparison between PCLSM and conventional confocal laser scanning microscope (CLSM) on the ability of cancellation of spherical aberration induced by cover glass are demonstrated experimentally. Finally, the ability of PCLSM which can decrease the spherical aberration based on the common-path propagation of LPPPs associated with polarization gating, spatial coherence gating and spatial filtering gating is discussed.