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Radiation Controlled Radiation Gate

IP.com Disclosure Number: IPCOM000096623D
Original Publication Date: 1963-Aug-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Fleisher, H: AUTHOR [+2]

Abstract

Optical radiation of one wave length is used to control optical radiation of a different wave length. A photoconductive layer is included in the electro-optic light gate to allow a controlling light source to regulate the passing of a light beam through the gate. The controlling light, when applied, reduces the resistivity of the photoconductive layer which, in turn increases the electric field in the crystal. The electric field is adjusted so that the controlled polarized light beam has its plane of polarization rotated during its passage through the electro-optic structure when the controlling light is applied. At other times, in absence of the controlling light, the controlled polarized light does not have its plane of polarization rotated. An analyzer passes only the rotated light.

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Radiation Controlled Radiation Gate

Optical radiation of one wave length is used to control optical radiation of a different wave length. A photoconductive layer is included in the electro-optic light gate to allow a controlling light source to regulate the passing of a light beam through the gate. The controlling light, when applied, reduces the resistivity of the photoconductive layer which, in turn increases the electric field in the crystal. The electric field is adjusted so that the controlled polarized light beam has its plane of polarization rotated during its passage through the electro-optic structure when the controlling light is applied. At other times, in absence of the controlling light, the controlled polarized light does not have its plane of polarization rotated. An analyzer passes only the rotated light.

The device focuses a monochromatic light beam 20 with a controlling monochromatic light beam 1. The controllable electro-optic light gate has a photoconductive layer 6 and an electro-optic crystal 7 positioned between transparent conductive electrodes 5 and 8. Switch 10 controls the application of the potential source 9 across layer 6 and crystal 7. A circular diffraction pattern is developed by shining monochromatic light 1 through a circular diffracting aperture in plate 2. Other techniques for generating circular diffraction patterns can also be used. Diffraction pattern 3 is applied to layer 6 of the electro-optic gate. The surface of layer 6 to which the circular diffraction fringes are applied is shaped so that the light forms a Fresnel zone plate pattern on the surface.

Beam 20 to be focused is passed through polarizer 4, reflected off dichroic mirror 21 through the con...