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US3649930A
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Method of frequency-stabilization of a single-made gas laser
Assignee: Individual
•
Filing: 1970-12-04
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Granted: 1972-03-14
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Expires: 1990-12-04
Abstract
Abstract The method consists in applying a steady axial magnetic field to the active gaseous medium, in determining either the value of said steady magnetic field which corresponds to the laser-cavity oscillation frequency to be stabilized or the length of the laser cavity corresponding to a set value of the steady magnetic field so that the oscillation frequency should correspond to the peak value of one of the two Doppler curves obtained as a result of the Zeeman effect by splitting the Doppler curve which corresponds to a zero value of the steady magnetic field, in superimposing an alternating axial magnetic field on said steady magnetic field and causing the split Doppler curve to oscillate about a position corresponding to the selected value of the steady magnetic field in order to modulate the output light intensity of said laser, in detecting the modulated output intensity, in comparing the variations in modulation of said output intensity with those of the alternating magnetic field by means of a detector which delivers a signal so that the lightemission frequency of the laser may be corrected by said signal and by a change in length of the laser cavity.
Inventors
- 👤 Albert Le Floch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:20
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/10; H01S3/13; H01S3/139; H01S3/1398
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
265 words
A method of frequency-stabilization of a single-mode gas laser, wherein use is made of a correction signal resulting from variations in output intensity of said laser and said method consists successively: in applying a steady axial magnetic field to the gaseous active medium; in determining the value of said steady magnetic field which corresponds to the laser-cavity oscillation frequency to be stabilized and therefore to a pre-established length of the laser cavity and conversely in determining the length of the laser cavity which corresponds to a pre-established value of said steady maGnetic field so that the oscillation frequency of the laser cavity should correspond to a peak value of one of the two Doppler curves sigma and sigma which are obtained as a result of the Zeeman effect by splitting the Doppler curve corresponding to a zero value of the steady magnetic field or in other words in satisfying the resonance conditions of the magnetic ''''Lamb dip''''; in applying an alternating axial magnetic field which is superimposed on said steady magnetic field so that the split Doppler curve should oscillate about its position corresponding to the selected value of said steady magnetic field, the output light intensity of said laser being then modulated; in detecting said modulated output intensity; in comparing the variations in modulation of said output intensity with those of the alternating magnetic field by means of a detector which delivers a correction signal and, in correcting the frequency of the light emission of said laser if necessary by means of said correction signal and by modifying the length of said laser cavity.
Claim 2
Independent Claim
265 words
A method of frequency-stabilization of a single-mode gas laser, wherein use is made of a correction signal resulting from variations in output intensity of said laser and said method consists successively: in applying a steady axial magnetic field to the gaseous active medium; in determining the value of said steady magnetic field which corresponds to the laser-cavity oscillation frequency to be stabilized and therefore to a pre-established length of the laser cavity and conversely in determining the length of the laser cavity which corresponds to a pre-established value of said steady maGnetic field so that the oscillation frequency of the laser cavity should correspond to a peak value of one of the two Doppler curves sigma and sigma which are obtained as a result of the Zeeman effect by splitting the Doppler curve corresponding to a zero value of the steady magnetic field or in other words in satisfying the resonance conditions of the magnetic ''''Lamb dip''''; in applying an alternating axial magnetic field which is superimposed on said steady magnetic field so that the split Doppler curve should oscillate about its position corresponding to the selected value of said steady magnetic field, the output light intensity of said laser being then modulated; in detecting said modulated output intensity; in comparing the variations in modulation of said output intensity with those of the alternating magnetic field by means of a detector which delivers a correction signal and, in correcting the frequency of the light emission of said laser if necessary by means of said correction signal and by modifying the length of said laser cavity.
Claim 3
Dependent Claim
27 words
A method according to claim 1 such that the optical laser emission frequency to be stabilized is adjusted by modifying the value of said steady magnetic field.
Claim 4
Dependent Claim
111 words
A frequency-stabilized laser comprising a gaseous active medium contained in an envelope and located between two mirrors forming a Fabry-Perot resonant cavity, means for exciting said gaseous medium in order to cause a population inversion, means for producing within said active medium an adjustable steady axial magnetic field and an adjustable alternating axial magnetic field, a detector for detecting the light intensity emitted by said laser, means for comparing the variations in said light intensity with the variations in said alternating magnetic field, said comparison means being such as to deliver a correction signal, and means for varying the length of said laser cavity which are controlled by said correction signal.
Claim 5
Dependent Claim
111 words
A frequency-stabilized laser comprising a gaseous active medium contained in an envelope and located between two mirrors forming a Fabry-Perot resonant cavity, means for exciting said gaseous medium in order to cause a population inversion, means for producing within said active medium an adjustable steady axial magnetic field and an adjustable alternating axial magnetic field, a detector for detecting the light intensity emitted by said laser, means for comparing the variations in said light intensity with the variations in said alternating magnetic field, said comparison means being such as to deliver a correction signal, and means for varying the length of said laser cavity which are controlled by said correction signal.
Claim 6
Dependent Claim
52 words
A laser according to claim 3 said means for producing said magnetic fields comprising a solenoid which surrounds said gaseous medium and a modulated direct-current generator, the intensity and modulation of said current being adjustable and the input and output terminals of said generator being connected to the ends of said solenoid.
Claim 7
Dependent Claim
14 words
A laser according to claim 3 said light intensity detector being a photoelectric detector.
Claim 8
Dependent Claim
13 words
A laser according to claim 3 said comparison means comprising a phase detector.
Claim 9
Dependent Claim
30 words
A laser according to claim 3 said means for varying the length of said laser cavity comprising a piezoelectric ceramic element which is bonded to one of said two mirrors.
References Cited (Backward Citations)
US3534292A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-03-14 | 1975-09-13 | 1976-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-14 | 1979-09-13 | 1980-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-14 | 1983-09-13 | 1984-03-14 | $7700.00 | Window Closed / Lapsed |