Applications of a Birefringent Lens as an Optical Image Processing Device

Abstract

A uniaxial birefringent crystal lens with its optic axis perpendicular to the system axis and sandwiched between two properly oriented linear polarizers behaves as an isotropic lens with a radially varying complex mask on its pupil plane. The proposed system may be adapted for both apodization and enhanced resolution just by rotating one of the two linear polarizers even when it is illuminated with a polychromatic source of light. Hence, the system may find applications in the fields of spectroscopy and astronomy. In general, it behaves as a double focus lens. However, by varying the birefringent lens parameters, it is possible to obtain a noticeably large depth-of-focus compared to an identical isotropic lens. An optical imaging system with large depth-of-focus is a prerequisite for many fields of applications particularly for microscope imagery, medical imaging, as well as for automatic inspection in microelectronics industry.