Variable electro-optic filter and readout apparatus

Claim 3

Apparatus for reading out information present in the form of variations in the intensity of an electric field comprising: a Fabry-Perot interference structure having optimum transmissivity in a predetermined range of wavelengths and including; an electro-optic medium, whose index of refraction varies as a function of the intensity of an associated electric field; means for associating with said electro-optic medium an electric field in which information is present in the form of variations in the electric field intensity; said means for associating comprising a means for varying the intensity of said electric field to vary the index of refraction of said medium and shift the spectral response characteristic and optimum transmissivity range of said structure, said means for varying further comprising means for optically providing an electric field whose intensity varies spatially in a pattern representative of information. means for exposing said structure to monochromatic radiation within said range; and means for sensing the intensity of said radiation transmitted by said structure to distinguish variations in the spectral response of said structure as a function of the variations in the index of refraction of said electro-optic medium representative of the intensity pattern present in the electric field.

Claim 4

Apparatus for reading out information present in the form of variations in the intensity of an electric field comprising: a Fabry-Perot interference structure having optimum transmissivity in a predetermined range of wavelengths and including; an electro-optic medium, whose index of refraction varies as a function of the intensity of an associated electric field; means for associating with said electro-optic medium an electric field in which information is present in the form of variations in the electric field intensity; said means for associating comprising a means for varying the intensity of said electric field to vary the index of refraction of said medium and shift the spectral response characteristic and optimum transmissivity range of said structure, said means for varying further comprising means for optically providing an electric field whose intensity varies spatially in a pattern representative of information. means for exposing said structure to monochromatic radiation within said range; and means for sensing the intensity of said radiation transmitted by said structure to distinguish variations in the spectral response of said structure as a function of the variations in the index of refraction of said electro-optic medium representative of the intensity pattern present in the electric field.

Claim 5

The apparatus of claim 2 in which said means for associating includes a photoconductor medium.

Claim 6

The apparatus of claim 3 in which said photoconductor medium and said electro-optic medium are included in a material which exhibits the characteristics of both mediums.

Claim 7

The apparatus of claim 2 in which said means for associating includes a pair of electrodes connected to a source of electrical energy.

Claim 8

The apparatus of claim 5 in which said ferroelectric medium and said electro-optic medium are included in a material which exhibits the characteristics of both mediums.

Claim 9

The apparatus of claim 2 in which said means for associating includes a ferroelectric medium.

Claim 10

The apparatus of claim 2 in which said means for associating includes a photoelectret.

Claim 11

The apparatus of claim 2 in which said structure includes first and second reflecting means disposed on opposing surfaces of said electro-optic medium.

Claim 12

The apparatus of claim 9 in which said first and second reflecting mEans are planar and parallel.

Claim 13

The apparatus of claim 9 in which said first and second reflecting means are partially reflecting.

Claim 14

The apparatus of claim 9 in which one of said first and second reflecting means is partially reflecting and the other is fully reflecting.

Claim 15

The apparatus of claim 9 in which first and second reflecting means include a plurality of layers of plates having a thickness of one quarter of the wavelength of said monochromatic radiation.

Claim 16

The apparatus of claim 2 in which said means for exposing includes a laser light source.

Claim 17

The apparatus of claim 2 in which said means for exposing includes means for scanning said structure with a monochromatic beam of radiation.

Claim 18

The apparatus of claim 2 in which said structure provides a spectral response characteristic whose intensity is maximum proximate the center of said range.

Claim 19

The apparatus of claim 16 in which said means for exposing provides monochromatic radiation of a wavelength between the wavelengths at the maximum and one of the minimum intensity points of said characteristic.

Claim 20

The apparatus of claim 17 in which said one of the minimum points corresponds to a wavelength greater than the wavelength at the maximum point.

Claim 21

The apparatus of claim 17 in which said characteristic is a plot of wavelength along the X axis and intensity along the Y axis, and the wavelength of said monochromatic radiation corresponds to a point on said characteristic where the slope is of greatest magnitude.

Claim 22

The apparatus of claim 2 in which said means for associating includes an electrically inactive blocking layer.