Browse Prior Art Database

Astigmatism Correction for Optical Focusing System

IP.com Disclosure Number: IPCOM000121415D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 33K

Publishing Venue

IBM

Related People

Latta, M: AUTHOR [+2]

Abstract

Disclosed is a means for correcting the astigmatism introduced by a multiple-pass Faraday isolator in a focusing optical system. When inserted in a converging beam path as shown in Fig. 1, a compact, mutiple-pass Faraday isolator can introduce astigmatism. This is due to the fact that the Faraday isolator is tilted to produce multiple passes thru the Faraday glass. The converging beam passing thru this tilted plate results in astigmatism.

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Astigmatism Correction for Optical Focusing System

      Disclosed is a means for correcting the astigmatism introduced
by a multiple-pass Faraday isolator in a focusing optical system.
When inserted in a converging beam path as shown in Fig. 1, a
compact, mutiple-pass Faraday isolator can introduce astigmatism.
This is due to the fact that the Faraday isolator is tilted to
produce multiple passes thru the Faraday glass.  The converging beam
passing thru this tilted plate results in astigmatism.

      The astigmatism may be overcome by introducing a spherical
mirror in place of the

plano

folding mirror shown in Fig. 1.  Since
the converging beam is incident onto the spherical mirror at an
off-axis angle, astigmatism will be generated.  If the sign and
magnitude of this astigmatism is appropriately chosen it can
compensate for the astigmatism of the tilted Faraday isolator
resulting in an optical system fully corrected for astigmatism.

      Disclosed anonymously.