Abstract

Expressions are obtained for the three-dimensional intensity distribution in the error-free diffraction patterns of semitransparent and phase annuli. The results are discussed and illustrated graphically. Annular apertures have been used for improving the resolving power and focal depth of optical instruments; the most useful situation for a given central-obstruction ratio is where the central obstruction is completely opaque. However, by use of a phase annulus of the same dimension, with a phase step of π for the central region, some further improvement in the resolving power and focal depth is obtained for central-obstruction ratios up to 0.5. This improvement is illustrated experimentally.

© 1965 Optical Society of America

Irradiance Distribution in the Error-Free Diffraction Image

Hubert F. A. Tschunko
J. Opt. Soc. Am. 55(1) 1-4 (1965)

Resolution of a microscope: improvement using a centrally obstructed condenser aperture and a semitransparent Π-phase annular aperture objective system

V. P. Nayyar and N. K. Verma
Appl. Opt. 15(5) 1341-1344 (1976)

Design of diffractive phase elements that produce focal annuli: a new method

Guo-Qing Zhang, Ben-Yuan Gu, and Guo-Zhen Yang
Appl. Opt. 34(35) 8110-8115 (1995)

Diffraction of Partially Coherent Light by an Aberration-Free Annular Aperture

K. Singh and H. S. Dhillon
J. Opt. Soc. Am. 59(4) 395-401 (1969)

Two-point resolution of a microscope: effect of nonuniform and nonsymmetric illumination using a semitransparent π-phase annular aperture

V. P. Nayyar and N. K. Verma
Appl. Opt. 16(9) 2460-2463 (1977)