US3636359A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical nonmechanical feedback control of ellipticity modulators
Assignee: Cary Instruments
•
Filing: 1967-04-13
•
Granted: 1972-01-18
•
Expires: 1987-04-13
Abstract
Abstract The invention concerns simplified automatic control of the peak birefringence of a modulator which is operable upon a linearly polarized beam of radiation to derive a modified beam having cyclically varying elliptical polarization. Simplified automatic compensation of the electrical drive signal applied to the modulator drive transducer functions solely in response to variations in the character of a beam of radiation that has passed through the modulator.
Inventors
- 👤 Paige B Hooper
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:35
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/0128; G02F1/0131
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
186 words
In apparatus for modulating the ellipticity of polarization of a beam of light, including a modulator operable upon an incident linearly polarized beam of radiation to produce at least one emergent beam having ellipticity cyclically varying at a frequency, said beam characterized by sequentially different wavelengths of radiation, and including first means, operable upon one such emergent beam, for deriving a modified beam whose intensity varies cyclically as a function of such cyclically varying ellipticity the improvement comprising: second means, responsive to a component of said cyclically varying intensity, for controlling said modulator to maintain the amplitude of the cyclical variation of said ellipticity at a predetermined level at each of said sequentially different wavelengths; said component being characterized by oscillation at said frequency, the amplitude of said oscillation approaching a null at said predetermined level, and said second means including a photodetector responsive only to said modified beam, the photodetector having an output, an amplifier having an input directly connected to the photodetector output, the amplifier having an output, and a transducer having an input directly connected to the amplifier output to drive the modulator.
Claim 2
Dependent Claim
186 words
In apparatus for modulating the ellipticity of polarization of a beam of light, including a modulator operable upon an incident linearly polarized beam of radiation to produce at least one emergent beam having ellipticity cyclically varying at a frequency, said beam characterized by sequentially different wavelengths of radiation, and including first means, operable upon one such emergent beam, for deriving a modified beam whose intensity varies cyclically as a function of such cyclically varying ellipticity the improvement comprising: second means, responsive to a component of said cyclically varying intensity, for controlling said modulator to maintain the amplitude of the cyclical variation of said ellipticity at a predetermined level at each of said sequentially different wavelengths; said component being characterized by oscillation at said frequency, the amplitude of said oscillation approaching a null at said predetermined level, and said second means including a photodetector responsive only to said modified beam, the photodetector having an output, an amplifier having an input directly connected to the photodetector output, the amplifier having an output, and a transducer having an input directly connected to the amplifier output to drive the modulator.
Claim 3
Dependent Claim
22 words
The improvement of claim 1 wherein: said first means comprises a fixed retarder and a polarizing element receiving said one emergent beam.
Claim 4
Dependent Claim
26 words
The control system of claim 2 including instrumentation for the measurement of circular dichroism connected with said apparatus to receive polarized light emerging from said retarder.
Claim 5
Dependent Claim
26 words
The improvement of claim 2 wherein the frequency of the photodetector output is the same as the frequency of the amplifier output applied to the modulator.
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) | 1975-01-17 | 1975-07-19 | 1976-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-17 | 1979-07-19 | 1980-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-17 | 1983-07-19 | 1984-01-18 | $7700.00 | Window Closed / Lapsed |