US3701042A
Expired / Lapsed
US
⏱️ 0.0 years remaining
D. c. motor circuit for rotating a polarizer and providing a detector synchronizer signal for a laser stabilizing system
Assignee: HP Inc
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Filing: 1970-02-03
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Granted: 1972-10-24
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Expires: 1990-02-03
Abstract
Abstract A stabilizing circuit for a two frequency laser wherein the two modes of oscillation of the laser are converted by a quarter wave plate and a rotating polarizer into two separate components, the difference in intensity of these components serving to produce an error signal from a detector circuit synchronized with the rotating polarizer, the error signal controlling a piezoelectric transducer coupled to the cavity resonator of the laser to tune the laser. A brushless D.C. motor serves to rotate the polarizer and at the same time provide the synchronizing signals to the detector circuit.
Inventors
- 👤 John N Dukes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:50
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/10; H01S3/13; H01S3/139; H01S3/1398; H01S3/106; H01S3/1062; H01S3/1396
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
245 words
A laser tuning apparatus for tuning a laser resonant cavity which produces an output beam having two frequency components circularly polarized in opposite directions along an optical axis, the apparatus comprising: tuning means for tuning the laser resonant cavity to at least a preselected frequency; a polarizer situated on the optical axis; a quarter wave plate situated on the optical axis between the polarizer and the laser resonant cavity; rotor means for producing relative rotational movement between the quarter wave plate and the polarizer for converting the two circularly polarized components into two orthogonal time spaced linearly polarized components; electro-magnetic means for creating a moving magnetic field for rotating the rotor means; sensing means for sensing the rotation of the rotor means and giving an output signal proportional thereto; circuit means connected to the electromagnetic means and the sensing means for causing the magnetic means to produce the moving magnetic field in response to the output of the sensing means; first photodetecting means situated on the optical axis for producing an A.C. output signal proportional to the difference in intensity between the time spaced linear components; and synchronous detecting means having inputs connected to the first photodetecting means, and the sensing means and having an output connected to the tuning means for producing a control signal in response to the synchronysm between the rotation of the rotor means and the time spaced linear components for tuning the laser resonant cavity to stabilize the laser output.
Claim 2
Dependent Claim
245 words
A laser tuning apparatus for tuning a laser resonant cavity which produces an output beam having two frequency components circularly polarized in opposite directions along an optical axis, the apparatus comprising: tuning means for tuning the laser resonant cavity to at least a preselected frequency; a polarizer situated on the optical axis; a quarter wave plate situated on the optical axis between the polarizer and the laser resonant cavity; rotor means for producing relative rotational movement between the quarter wave plate and the polarizer for converting the two circularly polarized components into two orthogonal time spaced linearly polarized components; electro-magnetic means for creating a moving magnetic field for rotating the rotor means; sensing means for sensing the rotation of the rotor means and giving an output signal proportional thereto; circuit means connected to the electromagnetic means and the sensing means for causing the magnetic means to produce the moving magnetic field in response to the output of the sensing means; first photodetecting means situated on the optical axis for producing an A.C. output signal proportional to the difference in intensity between the time spaced linear components; and synchronous detecting means having inputs connected to the first photodetecting means, and the sensing means and having an output connected to the tuning means for producing a control signal in response to the synchronysm between the rotation of the rotor means and the time spaced linear components for tuning the laser resonant cavity to stabilize the laser output.
Claim 3
Dependent Claim
36 words
A laser tuning apparatus as claimed in claim 1 wherein said rotor means comprises a hollow shaft, said polarizer being secured in alignment with the axial opening in the shaft through which said laser beam passes.
Claim 4
Dependent Claim
63 words
A laser tuning apparatus as claimed in claim 1 wherein the electro-magnetic means comprises a plurality of pairs of opposed poles, each pole having an electrical winding coupled thereto, the windings of opposed poles being connected to produce opposite polarities at the two associated poles, the circuit means being operated to energize said pairs of poles sequentially to produce said moving magnetic field.
Claim 5
Dependent Claim
30 words
A laser tuning apparatus as claimed in claim 3 wherein said plurality of pairs of poles comprises two pairs, the pairs of poles being orthogonally positioned relative to one another.
Claim 6
Dependent Claim
20 words
A laser tuning apparatus as claimed in claim 4 wherein said rotor comprises a pair of vanes of magnetic material.
Claim 7
Dependent Claim
132 words
A laser tuning apparatus as claimed in claim 3 wherein the sensing means comprises a light source, second photodetecting means and a first amplifier circuit coupled through the circuit means to said windings, and wherein the synchronous detecting means includes a second amplifier circuit coupled to said detector means, the beam of liGht from said source impinging on said second photodetecting means to create an output therefrom, said rotor at times intercepting said light beam to terminate the output from said second photodetecting means, said amplifier circuits being responsive to the energization and de-energization of said second photodetecting means for energizing said pairs of poles sequentially to produce rotation of said rotor and for operating said synchronous detecting means to synchronize the rotation of said motor with said first photodetector A.C. output.
Claim 8
Dependent Claim
30 words
A laser tuning apparatus as claimed in claim 6 wherein said plurality of pairs of poles comprises two pairs, the pairs of poles being orthogonally positioned relative to one another.
Claim 9
Dependent Claim
47 words
A laser tuning apparatus as claimed in claim 7 wherein said rotor means comprises a pair of vanes of magnetic material, the beam of light from said source being directed past said vanes and at times being intercepted by said vanes during rotation of said rotor means.
Claim 10
Dependent Claim
70 words
A laser tuning apparatus as claimed in claim 6 wherein the circuit means includes a bistable multivibrator circuit, one output of said multivibrator being coupled to the winding of one of said pairs of poles and the other output of said multivibrator being coupled to the windings of another of said pairs of poles, and starting means coupled to said poles for at times simultaneously energizing said pairs of poles.
Claim 11
Dependent Claim
36 words
A laser tuning apparatus as claimed in claim 6 wherein said rotor means comprises a hollow shaft, said polarizer being secured in alignment with the axial opening in the shaft through which said laser beam passes.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |