Magneto-optical light modulator

Claim 1

A magneto-optical light modulator comprising: a light source for producing a light beam of two colors, a polarizer, an analyzer, a substrate, said substrate supporting on a first side thereof a first Faraday rotation layer, said first Faraday rotation layer being positioned between said polarizer and said analyzer and having a first plurality of modulation elements, electronic means for switching the magnetization state of selected modulation elements of said first plurality, which modulation elements undergo a Faraday effect dependent on their magnetization state, by which effect the polarization plane of said light beam produced by said light source and transmitted through said Faraday rotation layer is rotated, an optical dispersive element for rotating the plane of polarization of said light from said polarizer depending upon the wavelength of said two colours, said first Faraday rotation layer having a modulation characteristic so as to enable each modulation element in combination with the polarizer and analyzer to transmit or to block either of the two colours produced by said light source, and a second Faraday rotation layer having a second plurality of modulation elements supported on a side of said substrate opposite said first side, said second Faraday layer having a geometry and being position so that the plane of polarization of said light beam passing through a modulation element of said first plurality can be rotated independently by a modulation element of said second plurality and wherein the operating points of the modulation characteristic are arranged so that for a first switching position of the modulation elements of said first and second plurality substantially only light of one colour is transmitted and for a second switching position substantially only light of the second colour is transmitted and for a third switching position both light colours are substantially switched-off.