Enhancement of optical sectioning in reflection confocal microscopy by phase-shifting apodizers

The use of phase-only filters permits to shape at will the axial component of the point spread function of nonparaxial focusing systems. The pupil filters consist of a number of concentric annular zones with constant real transmittance. The number of zones and their widths can be adapted according to the shape requirements. The method is applied to importantly improve the optical sectioning capacity of reflection, bright-field confocal microscopes.