Comparison of superresolution effects with annular phase and amplitude filters

Abstract

The characteristics of annular amplitude and phase filters are compared. The behavior of two-zone phase and amplitude filters as the inner zone is increased is studied in detail. Numerical simulations show that a phase filter can achieve a superresolution effect, a circular Dammann effect, and flat-topped intensity for different applications, whereas a two-zone amplitude filter can generate only a superresolution effect. The experimental results show that both amplitude and phase filters can achieve superresolution. Generally, a phase superresolution filter is recommended for its higher efficiency and its special diffraction patterns that are impossible to achieve with an amplitude filter.

Toraldo filters with concentric unequal annuli of fixed phase by evolutionary programming

“…In the recent past, extensive studies have been carried out on the analysis and synthesis of lossy (only amplitude), lossless (only phase), and leaky (hybrid) filters for superresolution [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. Whereas the original concept of Toraldo filters was to achieve transverse superresolution, emergence of new techniques, e.g., three-dimensional image formation by scanning methods, prompted investigators to extend the concept for improvement of axial sectioning.…”

Transverse superresolution with extended depth of focus using binary phase filters for optical storage system

“…Among them, the binary phase-only filters (BPFs) are becoming increasingly important because of its high efficiency and easy fabrication [12]. However, most filters proposed for application in optical data storage in the past were designed using the scalar diffraction theory.…”

Super-resolution by pupil plane phase filtering

“…Recently, many methods for designing super-resolving pupil filters have been proposed, and many researchers have investigated different types of super-resolution filters [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Although many of these filters aim at transverse super-resolution, some of these are now directed towards axial super-resolution for catering to practical problems that call for high resolution along the longitudinal direction of the optical axis of the imaging system.…”