US3899748A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for the frequency stabilization of a laser
Assignee: Siemens AG
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Filing: 1972-09-27
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Granted: 1975-08-12
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Expires: 1992-09-27
Abstract
Abstract A method for the frequency stabilization of a laser, in particular for a He-Ne laser is described whereby the active medium is situated between a fixed mirror and a movable mirror which can be translated along the axis of the laser by a piezo ceramic, and the laser radiation is circularly polarized by means of a small lambda /4 polarizing plate and passes through an absorption tube located within a magnetic coil which is part of a resonator loop and filled with the laser-active gas, and a photosensitive element behind the absorption tube and outside the resonator produces a signal, via amplifiers and demodulating devices for controlling the piezo ceramic. The control signal is proportional to the frequency deviation of the laser radiation from the center frequency gamma 0. The method is particularly characterized by the intensity modulation of the laser radiation which is produced due to the alternating effect of the alternating magnetic field in the absorption tube and which depends on the center frequency gamma 0 at the inverse Lamb-dip being utilized for the production of the control signal.
Inventors
- 👤 Viktor Bodlaj
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:15
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/10; H01S3/13; H01S3/139; H01S3/1398
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
211 words
A method for the frequency stabilization of a laser of the type wherein an active laser medium is situated in a resonator between a fixed mirror and a movable mirror, said movable mirror attached to a piezo ceramic and movable in the axial direction of the laser upon energization of the piezo ceramic, and wherein the laser radiation is circularly polarized and passes through an absorption tube within a magnetic coil in the resonator and filled with the laser active gas, and a photosensitive element behind the absorption tube and outside the resonator receives the laser beam and produces a signal which is proportional to the frequency deviation of the laser radiation from the center frequency gamma 0 caused by the absorption tube, and wherein the laser radiation is intensity modulated by an alternating energization of the coil and comprising the steps of: comparing the amplitude and phase of the signal produced by the photosensitive element with the alternating wave which energizes the coil, the alternating wave depending on the center frequency gamma 0 caused by the absorption tube, of the inverse Lamb-dip in the laser power-frequency characteristic, to produce a control signal; and applying the control signal to the piezo ceramic to produce a change of length of the resonator.
Claim 2
Independent Claim
211 words
A method for the frequency stabilization of a laser of the type wherein an active laser medium is situated in a resonator between a fixed mirror and a movable mirror, said movable mirror attached to a piezo ceramic and movable in the axial direction of the laser upon energization of the piezo ceramic, and wherein the laser radiation is circularly polarized and passes through an absorption tube within a magnetic coil in the resonator and filled with the laser active gas, and a photosensitive element behind the absorption tube and outside the resonator receives the laser beam and produces a signal which is proportional to the frequency deviation of the laser radiation from the center frequency gamma 0 caused by the absorption tube, and wherein the laser radiation is intensity modulated by an alternating energization of the coil and comprising the steps of: comparing the amplitude and phase of the signal produced by the photosensitive element with the alternating wave which energizes the coil, the alternating wave depending on the center frequency gamma 0 caused by the absorption tube, of the inverse Lamb-dip in the laser power-frequency characteristic, to produce a control signal; and applying the control signal to the piezo ceramic to produce a change of length of the resonator.
Claim 3
Dependent Claim
28 words
A method according to claim 1, comprising the step of selecting the fundamental frequency from the laser radiation for comparison with the frequency used for energizing the coil.
Claim 4
Dependent Claim
262 words
In a laser arrangement of the type wherein a stimulatable gas laser medium is arranged between a fixed mirror and a movable mirror carried by a piezo ceramic element to define a resonator, and laser radiation is circularly polarized by a small lambda /4 plate disposed between the laser medium and the movable mirror, and an absorption tube is disposed within a coil located between the lambda /4 plate and the movable mirror and a generator is provided to energize the coil at a frequency dependent upon the center fRequency of an inverse Lamb-dip caused by the absorption tube of the laser power-frequency characteristic to intensity modulate the laser radiation, the improvement in combination therewith of means for stabilizing the frequency of the laser, comprising: a photosensitive device disposed outside of said resonator and receiving the laser radiation to produce signals in response to the laser radiation; a selective amplifier for amplifying the basic laser wave connected to said photosensitive device; a phase correcting circuit connected to the generator which supplies the wave for intensity modulation; a discriminator connected to said phase correcting device and to said selective amplifier for comparing the amplitude and phase of the signals supplied thereto and for producing a direct current voltage having a polarity dependent upon the direction of deviation of the laser radiation from the center frequency of the inverse Lamb-dip; and means connecting said discriminator to said piezo ceramic for energizing said piezo ceramic in accordance with said control signal to change the length of the resonator and adjust the frequency of laser radiation.
Claim 5
Dependent Claim
262 words
In a laser arrangement of the type wherein a stimulatable gas laser medium is arranged between a fixed mirror and a movable mirror carried by a piezo ceramic element to define a resonator, and laser radiation is circularly polarized by a small lambda /4 plate disposed between the laser medium and the movable mirror, and an absorption tube is disposed within a coil located between the lambda /4 plate and the movable mirror and a generator is provided to energize the coil at a frequency dependent upon the center fRequency of an inverse Lamb-dip caused by the absorption tube of the laser power-frequency characteristic to intensity modulate the laser radiation, the improvement in combination therewith of means for stabilizing the frequency of the laser, comprising: a photosensitive device disposed outside of said resonator and receiving the laser radiation to produce signals in response to the laser radiation; a selective amplifier for amplifying the basic laser wave connected to said photosensitive device; a phase correcting circuit connected to the generator which supplies the wave for intensity modulation; a discriminator connected to said phase correcting device and to said selective amplifier for comparing the amplitude and phase of the signals supplied thereto and for producing a direct current voltage having a polarity dependent upon the direction of deviation of the laser radiation from the center frequency of the inverse Lamb-dip; and means connecting said discriminator to said piezo ceramic for energizing said piezo ceramic in accordance with said control signal to change the length of the resonator and adjust the frequency of laser radiation.
References Cited (Backward Citations)
US3361990A
Cited
US3668547A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-11 | 1979-02-10 | 1979-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-11 | 1983-02-10 | 1983-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-11 | 1987-02-10 | 1987-08-12 | $7700.00 | Window Closed / Lapsed |