Interferometer including stationary, electrically alterable optical masking device
First Claim
1. An interferometer comprising:
- means for creating a pair of parallel beams of electromagnetic radiation;
means for causing said beams to interfere and produce an interference pattern;
a masking device located at a region of interference of said beams for impingement of at least a portion of said interference pattern thereon;
detecting means associated with said masking device for receiving at least a portion of said interference pattern therefrom,said masking device including structure for selectively directing certain portions of said interference pattern to said detecting means, while preventing other portions of said interference pattern from being directed to said detecting means,there being means for selective alteration of said device for varying the portions of said pattern directed to, and prevented from being directed to, said detecting means,said masking device having--a plurality of masking structures electrically separate from one another; and
means for effecting electrical connections with each of said structures,each of said structures including a material electrically coupled with said electrical connection means, said material having different optical characteristics to radiation impinging thereon at correspondingly different electrical potentials applied to said electrical connection means.
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Accused Products
Abstract
An improved interferometer is provided which is of simplified construction and gives enhanced, accurate interference analysis through provision of an alterable masking device located at the interference plane which facilitates rapid computer analysis of an interference pattern. The interferometer of the invention preferably includes a source of electromagnetic radiation, a beam splitter, a lens for convergence and interference of the beams, a masking device located at the region of beam convergence, and detection apparatus for receiving and analyzing radiation from the mask. The mask is preferably stationary and electrically alterable and advantageously includes a base along with separate, plural masking structures mounted on one base face with electrical connections coupled to the separate masking structures. The masking structures are formed of a crystalline or polycrystalline thermo or electro diachromatic substance such as vanadium dioxide which has different opacity characteristics to electromagnetic radiation upon selective application of electrical potential thereto. In use, electrical potential is applied to various subsets of the masking structures in a predetermined pattern so as to facilitate mathematical analysis of the generated interference patterns detected by the detection apparatus. The use of a masking device in the present invention allows the use of a small detector which thereby maximizes the signal-to-noise ratio of the detected interference pattern. The use of an electrically alterable mask avoids the need for selective physical repositioning of a masking device, and is specifically adapted for minicomputer control to achieve the most accurate, rapid results.
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Citations
20 Claims
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1. An interferometer comprising:
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means for creating a pair of parallel beams of electromagnetic radiation; means for causing said beams to interfere and produce an interference pattern; a masking device located at a region of interference of said beams for impingement of at least a portion of said interference pattern thereon; detecting means associated with said masking device for receiving at least a portion of said interference pattern therefrom, said masking device including structure for selectively directing certain portions of said interference pattern to said detecting means, while preventing other portions of said interference pattern from being directed to said detecting means, there being means for selective alteration of said device for varying the portions of said pattern directed to, and prevented from being directed to, said detecting means, said masking device having-- a plurality of masking structures electrically separate from one another; and means for effecting electrical connections with each of said structures, each of said structures including a material electrically coupled with said electrical connection means, said material having different optical characteristics to radiation impinging thereon at correspondingly different electrical potentials applied to said electrical connection means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An interferometer, comprising:
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means including a source of electromagnetic radiation for creating a pair of parallel beams of said electromagnetic radiation; means for causing said beams to interfere and produce an interference pattern; a stationary masking device located at a region of interference of said beams for impingement of at least a portion of said interference pattern thereon, the path lengths of said beams from said source to said masking device being equal; detecting means associated with said masking device for receiving at least a portion of said interference pattern therefrom, said stationary masking device presenting a plurality of stationary zones, there being means operatively coupled with said zones for selectively applying an electric potential thereacross in order to vary the optical characteristics of respective zones to the electromagnetic radiation impinging thereon.
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Specification