IMAGING CHARACTERISTICS OF A PERFECT LENS MASKED BY SECTOR-SHAPED AND SEMI-CIRCULAR POLARISATION MASKS

It had been established earlier that all possible phase and amplitude masks maybe simulated on the lens aperture byproper use of polarisation devices. This paper attempts to study the effects of polarisation masked sector apertures and traces the azimuthal variation of the PSF. The effect of polarisation masking is to introduce polarisationinduced phase and amplitude transmittances in the masked zones, with the additional advantage that they can be controlled independently. It is obvious that the asymmetric nature of this mask would serve only to degrade the image in a conventional diffractionlimited imaging system. This apparent disadvantage may be put to use in two ways: a) in image processing applications where information along certain azimuths need to be enhanced compared to others, and b) compensation of asymmetric aberrations. It is the former possibility that this paper attempts to study in terms of the azimuthal dependence of the PSF. Computaitonal details and results are presented.