Patent US3801931A successfully refreshed from Google Patents.
US3801931A
Expired / Lapsed
US
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Single mode laser oscillator with linear resonator and internal faraday isolator
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1972-11-30
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Granted: 1974-04-02
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Expires: 1992-11-30
Abstract
Abstract A standing lightwave within the active lasing medium of a laser oscillator is avoided to prevent periodic bleaching of the medium and thereby foster single mode oscillation and improve coherence. A Faraday isolator and an optical rotator located within the opposite end regions of the laser resonator cavity, between the lasing medium and cavity end reflectors, changes the direction of polarization of the coherent light propagating through these cavity regions and blocks oscillation of light which propagates from the lasing medium with other than certain favored directions of polarization in such a way that the oppositely traveling lightwaves within the lasing medium have mutually perpendicular planes of vibration and hence do not interfer to produce a standing wave in the medium. The oppositely traveling lightwaves within one end of the resonator cavity establish a standing wave region in which may be located a bleachable mode selector, such as a dye cell, for suppressing undesired oscillating modes and thereby further improving coherence.
Inventors
- 👤 L Heflinger
- 👤 R Wuerker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 20:26
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/05; H01S3/08; H01S3/08018; H01S3/08022; H01S3/08031; H01S3/10; H01S3/106; H01S3/1061; H01S3/1066
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
161 words
A high coherence laser oscillator having a non-standing wave gain region, comprising: a lasing medium which produces plane polarized coherent light having a given plane of vibration; an optical cavity containing the medium and including end reflectors; means for pumping said medium; means for changing the direction of polarization of the coherent light propagating from each end of said medium during travel of the light from the medium to the adjacent and reflector and back to the medium in a manner such that the polarization direction of the reflected light returned to the medium is rotated 90* relative to the polarization direction of the light propagating from the medium; and means for blocking reflection through said medium of light propagating from one end of said medium in planes of vibration other than said given plane, whereby the oppositely traveling light waves in said medium have mutually perpendicular planes of vibration and said medium is substantially devoid of a standing light wave.
Claim 2
Dependent Claim
161 words
A high coherence laser oscillator having a non-standing wave gain region, comprising: a lasing medium which produces plane polarized coherent light having a given plane of vibration; an optical cavity containing the medium and including end reflectors; means for pumping said medium; means for changing the direction of polarization of the coherent light propagating from each end of said medium during travel of the light from the medium to the adjacent and reflector and back to the medium in a manner such that the polarization direction of the reflected light returned to the medium is rotated 90* relative to the polarization direction of the light propagating from the medium; and means for blocking reflection through said medium of light propagating from one end of said medium in planes of vibration other than said given plane, whereby the oppositely traveling light waves in said medium have mutually perpendicular planes of vibration and said medium is substantially devoid of a standing light wave.
Claim 3
Dependent Claim
42 words
A laser oscillator according to claim 1 wherein: the oppositely traveling light waves in one end region of said cavity create a standing light wave in said region; and a saturable absorber in said standing wave region to suppress undesired oscillating modes.
Claim 4
Dependent Claim
178 words
A high coherence laser oscillator with a non-standing wave gain region comprising: an active lasing medium for producing plane polarized coherent light having a given plane of vibration; means for pumping said medium; an optical cavity containing said medium including end reflectors; an optical rotator between said medium and each reflector for changing the direction of polarization of the coherent light-beam from the adjacent end of the medium during transit of the beam from the medium to the adjacent reflector and back to the medium in a manner such that the polarization direction of the reflected beam returned to the medium is rotated 90* relative to the polarization direction of the beam propagating from the medium; one rotator comprising a Faraday rotator; an optical polarizer in said cavity for blocking reflection through said medium of light propagating from one end of said medium in planes of vibration other than said given plane, whereby the oppositely traveling light waves in said medium have mutually perpendicular planes of vibration and said medium is substantially devoid of a standing light wave.
Claim 5
Dependent Claim
178 words
A high coherence laser oscillator with a non-standing wave gain region comprising: an active lasing medium for producing plane polarized coherent light having a given plane of vibration; means for pumping said medium; an optical cavity containing said medium including end reflectors; an optical rotator between said medium and each reflector for changing the direction of polarization of the coherent light-beam from the adjacent end of the medium during transit of the beam from the medium to the adjacent reflector and back to the medium in a manner such that the polarization direction of the reflected beam returned to the medium is rotated 90* relative to the polarization direction of the beam propagating from the medium; one rotator comprising a Faraday rotator; an optical polarizer in said cavity for blocking reflection through said medium of light propagating from one end of said medium in planes of vibration other than said given plane, whereby the oppositely traveling light waves in said medium have mutually perpendicular planes of vibration and said medium is substantially devoid of a standing light wave.
Claim 6
Dependent Claim
20 words
A laser oscillator according to claim 3 wherein: said lasing medium is a solid-state lasing medium such as a ruby.
Claim 7
Dependent Claim
15 words
A laser oscillator according to claim 3 wherein: the other rotator is a Faraday rotator.
Claim 8
Dependent Claim
16 words
A laser oscillator according to claim 3 wherein: the other rotator is a quarter wave plate.
Claim 9
Dependent Claim
19 words
A laser oscillator according to claim 3 including: moDe control means in said cavity for suppressing undesired oscillating modes.
Claim 10
Dependent Claim
23 words
A laser oscillator according to claim 7 wherein: said mode control means comprises a dye cell between said polarizer and the adjacent reflector.
Claim 11
Dependent Claim
35 words
A laser oscillator according to claim 3 wherein: said lasing medium is a solid lasing medium such as a ruby; and said oscillator includes a mode controlling dye cell between said polarizer and adjacent reflector.
Claim 12
Dependent Claim
15 words
A laser oscillator according to claim 9 wherein: the other rotator is a Faraday rotator.
Claim 13
Dependent Claim
16 words
A laser oscillator according to claim 9 wherein: the other rotator is a quarter wave plate.
Claim 14
Independent Claim
165 words
The method of avoiding a standing light wave within the active lasing medium of a laser oscillator having an optical cavity containing the medium and end reflectors, said medium producing plane polarized coherent light having a given plane of vibration, comprising the steps of: pumping said medium to cause the medium to lase; changing the direction of polarization of the coherent light propagating from each end of said medium during travel of the light from the medium to the adjacent end reflector and back to the medium in a manner such that the polarization direction of the reflected light returned to the medium is rotated 90* relative to the polarization direction of the light propagating from the medium; blocking reflection through said medium of light propagating from one end of said medium in other than said given vibration plane, whereby the oppositely traveling light waves in said medium have mutually perpendicular planes of vibration and said medium is substantially devoid of a standing light wave.
Claim 15
Independent Claim
165 words
The method of avoiding a standing light wave within the active lasing medium of a laser oscillator having an optical cavity containing the medium and end reflectors, said medium producing plane polarized coherent light having a given plane of vibration, comprising the steps of: pumping said medium to cause the medium to lase; changing the direction of polarization of the coherent light propagating from each end of said medium during travel of the light from the medium to the adjacent end reflector and back to the medium in a manner such that the polarization direction of the reflected light returned to the medium is rotated 90* relative to the polarization direction of the light propagating from the medium; blocking reflection through said medium of light propagating from one end of said medium in other than said given vibration plane, whereby the oppositely traveling light waves in said medium have mutually perpendicular planes of vibration and said medium is substantially devoid of a standing light wave.
Claim 16
Dependent Claim
48 words
The method according to claim 12 wherein: the oppositely traveling light waves in one end region of said cavity create a standing light wave in said region; and said method includes the further step of exposing a saturable absorber to said standing wave to suppress undesired oscillating modes.
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) | 1977-04-01 | 1977-10-01 | 1978-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-01 | 1981-10-01 | 1982-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-01 | 1985-10-01 | 1986-04-02 | $7700.00 | Window Closed / Lapsed |