US3825348A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of optical path modulation and modulator for implementation of the same
Assignee: Bpifrance Financement SA
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Filing: 1972-11-27
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Granted: 1974-07-23
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Expires: 1992-11-27
Abstract
Abstract The invention concerns a process and a device for optical path modulation. The process lies in modulating the optical path difference between both waves of an interferometer by alternate variation of the relative inclination of two components of the interferometer due to the action of a modulator producing an alternate flexure, in creating a modulated optical phase variation causing a change in the modulated light flux and in using the signal provided by a photo-sensitive receiver submitted to this flux for measuring or detecting a phenomenon producing an optical phase difference submitted to the action of the optical path modulator. The invention applies to metrology, ellipsometry, refractometry, polarimetry, etc.
Inventors
- 👤 G Nomarski
- 👤 G Roblin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:50
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/41; G01N21/45; G01B; G01B9/00; G01B9/02; G01B9/02015; G01B9/02024; G01B2290/00; G01B2290/35; G01B2290/70
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
155 words
In a two-wave interferometer, comprising: A. a frame, B. first and second single-beam/double-beam interface components, C. means for fixedly attaching the first component to the frame, D. means for attaching the second component to the frame, E. means for directing a beam of light at a single-beam face of one of the interface components, thereby causing a double beam from a double-beam face of said one of the interface components to be directed along a path to a double-beam face of the other of the interface components, and F. means for utilizing a resulting interferometer output beam from a single-beam face of said other of the interface components, the improvement providing a modulator of the length of said path for the interferometer comprising: G. mechanical modulator means for causing a periodic angular oscillating motion by the second interface component with respect to the frame for producing corresponding periodic differences in the length of said path.
Claim 2
Dependent Claim
155 words
In a two-wave interferometer, comprising: A. a frame, B. first and second single-beam/double-beam interface components, C. means for fixedly attaching the first component to the frame, D. means for attaching the second component to the frame, E. means for directing a beam of light at a single-beam face of one of the interface components, thereby causing a double beam from a double-beam face of said one of the interface components to be directed along a path to a double-beam face of the other of the interface components, and F. means for utilizing a resulting interferometer output beam from a single-beam face of said other of the interface components, the improvement providing a modulator of the length of said path for the interferometer comprising: G. mechanical modulator means for causing a periodic angular oscillating motion by the second interface component with respect to the frame for producing corresponding periodic differences in the length of said path.
Claim 3
Dependent Claim
140 words
A device according to claim 1, wherein the interferometer is of the Mach-Zehnder type, wherein each of the two interface components comprises a total reflection mirror and a partial reflection mirror, said one interface component receiving its single beam input on its partial reflection mirror to split the beam into a double beam, a reflected part of the split beam being again reflected on the total reflection mirror of said one interface component toward the partial reflection mirror of said other interface component, the transmitted portion of the split beam from the partial reflection mirror of the one componeNt being reflected by the total reflection mirror in the other component toward the partial reflection mirror in the other component, there to generate a reunited interferometer output beam, and wherein the means for directing a beam of light provides monochromatic light.
Claim 4
Dependent Claim
42 words
A device according to claim 2, further comprising A. a device to be studied placed in the path of one beam of the double beam, and B. an optical compensator placed in the path of the other beam of the double beam.
Claim 5
Dependent Claim
15 words
A device according to claim 1 wherein the means for utilizing is a photo-sensitive receiver.
Claim 6
Dependent Claim
42 words
A device according to claim 4 further comprising a second single-beam face of said other component for providing a second output beam, phase shifted with respect to said interferometer output beam, and a second photo-sensitive receiver for utilizing the second output beam.
Claim 7
Dependent Claim
26 words
A device according to claim 1, wherein the interferometer is of the Jamin type, wherein each interface component comprises a plate of transparent isotropic optical material.
Claim 8
Dependent Claim
60 words
A device according to claim 1, wherein the interface components comprise double-refracting crystal means for converting between one beam and two beams by double refraction, and wherein the crystal means are placed between crossed polarizer means for translating the angular oscillating motion of the second interface component into an elliptical vibration of polarized light passing through the double-refracting crystal means.
Claim 9
Dependent Claim
16 words
A device according to claim 7, wherein the means for directing a beam provides achromatic light.
Claim 10
Dependent Claim
16 words
A device according to claim 7, wherein the double-refracting crystals are separated by a half-wave plate.
Claim 11
Dependent Claim
68 words
A device according to claim 1, wherein the interferometer contains two polarized waves which are polarized perpendicularly, and a quarter-wave plate is placed between the two interface components to modulate the light leaving the interferometer at a modulation frequency which is the same frequency as that of the periodic angular oscillating motion of the mechanical modulator and to divide by two the oscillation amplitude, thereby permitting total modulation.
Claim 12
Dependent Claim
43 words
A device according to claim 1 characterized in that the mechanical modulator is a crystalline component fixed at one of its ends to the frame and fastened at the other end to said second interface component and subjected to an alternative electric field.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |