Light modulator
AssigneeU.S. Philips Corporation
InventorAlan John Fox
Life of this patent
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Abstract
A light modulator comprises a crystal of the m3m class such as potassium tantalum niobate in which electrically-induced birefringence is obtained by setting up a field within the crystal in a direction which is not parallel to any of the crystallographic axes. With this orientation of the field (preferably at 45.degree. to the axes) the crystal becomes birefringent for light travelling parallel to the field direction. The birefringence is proportional to the square of the field. The modulator may, for example, be constructed as an amplitude modulator in which case it will be situated between a crossed polarizer and analyzer.
Claims22
A light modulator comprising a light-permeable crystal of the m3m point group provided with a pair of electrically conductive light-permeable electrodes for setting up an electric field within the crystal in a direction making an angle greater than zero with all of the crystallographic axes, means for directing light polarized in a plane at an angle to the fast and slow directions of the crystal through the crystal in a direction making an angle greater than zero with all of the crystallographic axes and which makes an angle smaller than 90.degree. with the field direction, and a polarization analyzer provided in an output path for the light from the crystal.
A light modulator comprising a light-permeable crystal plate of the m3m point group provided with a pair of electrically conductive light-permeable electrodes on the major faces thereof for setting up an electric field within the crystal in a direction making an angle greater than zero with all of the crystallographic axes, and a polarization analyzer facing one of said major faces.
A light modulator comprising a light-permeable crystal plate of the m3m point group provided with a pair of electrically conductive light-permeable electrodes on the major faces thereof for setting up an electric field within the crystal in a direction making an angle greater than zero with all of the crystallographic axes, and an uniaxial plate facing a said major face with its fast and slow directions at substantially 45.degree. to those of the crystal.
A light modulator comprising a light-permeable electro-optic crystal of the m3m point group provided with a pair of electrically conductive light-permeable substantially planar electrodes confronting two opposite sides of the crystal for setting up a substantially linear electric field within the crystal in a direction making an angle greater than zero with all of the crystallographic axes, means for directing light polarized in a plane at substantially 45.degree. to the fast and slow directions of the crystal through the crystal in a direction making an angle greater than zero with all of the crystallographic axes and making an angle less than 90.degree. with the direction of the electric field.
Dependencies are inferred from the claim text.