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Browse Prior Art Database

Amplitude Modulation of Light Using the Cotton Mouton Effect

IP.com Disclosure Number: IPCOM000094949D
Original Publication Date: 1965-Jul-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Freiser, MJ: AUTHOR [+2]

Abstract

The optical system is employed to obtain amplitude modulation of a light beam. The system uses the principle of linear magnetic birefringence, i.e., the Cotton-Mouton effect. Particular emphasis is placed on the use of a transparent ferromagnetic material of the class of europium chalcogenides in such optical system.

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Amplitude Modulation of Light Using the Cotton Mouton Effect

The optical system is employed to obtain amplitude modulation of a light beam. The system uses the principle of linear magnetic birefringence, i.e., the Cotton-Mouton effect. Particular emphasis is placed on the use of a transparent ferromagnetic material of the class of europium chalcogenides in such optical system.

Unpolarized light represented by arrow 2 impinges upon polarizer 4 to produce a beam of linear polarized light 6, with the plane A of polarization at 45 degrees to the vertical. Quarter-wave plate 8, whose birefringence is magnetic in origin, is made of a transparent ferromagnetic material and europium oxide is an example of such a material. Plate 8 is magnetized with its magnetic moment M either vertical or horizontal so that the retardation of the component of the light 6 that is polarized parallel to M, relative to the component that is perpendicular to M, either adds to or subtracts from that retardation in nonmagnetic quarter-wave plate 10.

If M is oriented so as to add to the retardation, then there is extinction of light 12 that passes through analyzer 14 in that the half-wave plate, resulting from the combined effects of plates 8 and 10, rotates the plane of polarization 90 degrees. Thus, if field H is applied to the quarter-wave plate 8 so as to rotate the magnetic moment M 90 degrees, then europium oxide plate 8 can provide 100% modulation of light beam 12. The transmitted intensi...