Browse Prior Art Database

Conical Refraction Scanner

IP.com Disclosure Number: IPCOM000095698D
Original Publication Date: 1964-May-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Horton, JW: AUTHOR

Abstract

Conical refraction in biaxial crystals will convert a plane polarized entrance ray of light into a circular exit pattern of illumination, consisting of a hollow bundle of rays lying in a common cylindrical surface. The intensity distribution varies from darkness at one position on the circle to full brightness at a position diametrically opposite to it. The plane of polarization of the exit light also varies from perpendicular to the entrance light at the point of extinction (full interference), to parallel to the entrance light at the diametrically opposite position with all angular relativities between. Thus, there is preserved the relationship that all diametrically opposed points have perpendicularly oriented planes of polarization.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 64% of the total text.

Page 1 of 2

Conical Refraction Scanner

Conical refraction in biaxial crystals will convert a plane polarized entrance ray of light into a circular exit pattern of illumination, consisting of a hollow bundle of rays lying in a common cylindrical surface. The intensity distribution varies from darkness at one position on the circle to full brightness at a position diametrically opposite to it. The plane of polarization of the exit light also varies from perpendicular to the entrance light at the point of extinction (full interference), to parallel to the entrance light at the diametrically opposite position with all angular relativities between. Thus, there is preserved the relationship that all diametrically opposed points have perpendicularly oriented planes of polarization. By rotating the plane of polarization of the entrance light, the circular exit pattern, including the dark spot, can be made to rotate, thus providing a controllable circular scan.

By combining the phenomenon of conical refraction with the Faraday effect and adding birefringent crystals and other optical elements, a scanner is devised for addressably determining the digital value of a photographically stored manifestation. For example, the polarized entrance ray 10 from a laser source can be directed into any one of the N exit paths by selectively potentializing Faraday rotators 11, 12 and 13. Such action rotates the plane of polarization by 90 degrees so as to interchange the ordinary and extraordinary...