IMAGING CHARACTERISTICS OF A LENS ZONALLY MASKED BY POLARIZERS AND RETARDER

It is already been established that the imaging qualities of a perfect lens may be modified by using suitable polarisation masks on the lens aperture. In the present paper we have studied the imaging properties of a lens masked by two polarisers, one at the central circular zone and the other at the outer annular zone and followed by a quarter wave plate, placed in such orientation that the beams emerging from these zones are right and left circularly polarised. The expression for the intensity point spread function (IPSF), and the axial irradiance distr ibution of the proposed system have been derived and evaluated for dif ferent cases. It is shown that such system yields a better depth of fo cus. The frequency response characteristics of the system is also cons idered for some cases. Computed results are discussed.