Abstract

Annular-pupil optical systems are known to have high lateral resolution and a long depth of focus. However, owing to their large side lobes in the point spread function (PSF), the system has never been practically used. We propose a new method to suppress the side lobes of the PSF in annular-pupil transmission optical systems when the object absorption is weak. For 1-D suppression, a point source and a 1-D apodized annular-pupil are combined. For 2-D suppression, the source and another 1-D apodized annular-pupil are rotated synchronously, and PSFs are synthesized. The PSFs of a conventional circular-, a conventional annular-, and the proposed annular-pupil system are calculated and compared. Practical use of the proposed method is discussed.

© 1991 Optical Society of America