New approach to superresolution

We propose a new method to increase the resolution of an optical system by modifying part of the spatial-frequency spectrum, viz., displacing the lowe r-frequency light to a high-frequency band, which makes the central maximum in the diffraction pattern narrower and increases the depth of focus. Simu lation results show that this kind of apodizer (the term apodization was or iginally used to describe ways to reduce the sidelobes of the PSF, but in t his paper, we use it in a wider sense) is superior to the phase-shifting on es. (C) 2001 Society of Photo-Optical Instrumentation Engineers.