Patent US3928818A successfully refreshed from Google Patents.
US3928818A
Expired / Lapsed
US
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Method of reducing light leakage in lasers
Assignee: United States Department of the Navy
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Filing: 1974-10-17
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Granted: 1975-12-23
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Expires: 1994-10-17
Abstract
Abstract A Q switched and cavity dumped laser system is provided in which a 45* Faraday rotator and an auxiliary cavity mirror are disposed in the beam path to compensate for the polarization change caused by thermally stressed laser rods.
Inventors
- 👤 Matthew B White
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 02:12
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/10; H01S3/11; H01S3/1123; H01S3/115; H01S3/1127
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
150 words
A system for use in a laser cavity for compensating for the polarization changes in Q switched and cavity dumped lasers caused by anisotropies resulting from optical pumping or other causes comprising: polarization sensitive means in the laser cavity and reflective means associated with said polarization sensitive means for forming an auxiliary laser cavity; a laser rod in said auxiliary cavity and means adjacent said rod for optically pumping the laser rod; magneto-optical rotation means intermediate said laser rod and the adjacent end of said laser cavity for incrementally rotating the plane of polarization of depolarized radiation until it returns to the original state of polarization; and means positioned intermediate said polarization sensitive means and the other end of said laser cavity for controllably altering the state of polarization of the intracavity radiation so that the radiation may be deflected out of the laser cavity by said polarization sensitive means.
Claim 2
Independent Claim
150 words
A system for use in a laser cavity for compensating for the polarization changes in Q switched and cavity dumped lasers caused by anisotropies resulting from optical pumping or other causes comprising: polarization sensitive means in the laser cavity and reflective means associated with said polarization sensitive means for forming an auxiliary laser cavity; a laser rod in said auxiliary cavity and means adjacent said rod for optically pumping the laser rod; magneto-optical rotation means intermediate said laser rod and the adjacent end of said laser cavity for incrementally rotating the plane of polarization of depolarized radiation until it returns to the original state of polarization; and means positioned intermediate said polarization sensitive means and the other end of said laser cavity for controllably altering the state of polarization of the intracavity radiation so that the radiation may be deflected out of the laser cavity by said polarization sensitive means.
Claim 3
Dependent Claim
99 words
The system of claim 1 wherein said polarization sensitive means is a beam splitter which allows linearly polarized radiation to pass through and includes a diagonally disposed double-faced reflector for deflecting in opposite directions mutually orthogonal linearly polarized components of nonlinearly polarized radiation incident on its reflecting surfaces, the other end of said cavity returning radiation along its line of incidence to the adjacent surface of said double-faced reflector so that radiation polarized in one direction passes back into the auxiliary cavity while radiation polarized in an orthogonal direction is deflected from the cavity and constitutes the laser output.
Claim 4
Dependent Claim
69 words
The system of claim 2 wherein said magneto-optical rotating means rotates the principal axes of emergent elliptical polarized radiation 45* so that after a double round trip pass through said auxiliary cavity linearly polarized radiation that had been depolarized by the laser rod will be returned to its original state of linear polarization and may then be extracted from said laser cavity along with the original linearly polarized radiation.
Claim 5
Independent Claim
109 words
A method of compensating for the polarization changes in Q switched and cavity dumped laser systems caused by thermal stresses induced in the laser rods therein comprising: partitioning the laser cavity such that radiation which is not linearly polarized is present in only one portion of the cavity; utilizing the birefringent properties of the laser rod to linearly polarize radiation that is depolarized by said birefringent properties within said one portion of the cavity; and combining the formerly depolarized radiation in said one portion of the cavity with linearly polarized radiation from the other portion of said cavity so that radiation losses caused by optical pumping are substantially eliminated.
Claim 6
Independent Claim
109 words
A method of compensating for the polarization changes in Q switched and cavity dumped laser systems caused by thermal stresses induced in the laser rods therein comprising: partitioning the laser cavity such that radiation which is not linearly polarized is present in only one portion of the cavity; utilizing the birefringent properties of the laser rod to linearly polarize radiation that is depolarized by said birefringent properties within said one portion of the cavity; and combining the formerly depolarized radiation in said one portion of the cavity with linearly polarized radiation from the other portion of said cavity so that radiation losses caused by optical pumping are substantially eliminated.
Claim 7
Dependent Claim
48 words
The method of claim 4 wherein the substantially elliptically polarized radiation produced by passing linearly polarized radiation through the laser rod is linearly polarized by rotating its major axes through 90* without changing the eccentricity of the polarization ellipse prior to passing it back through the laser rod.
Claim 8
Dependent Claim
43 words
The method of claim 5 wherein the nonlinearly polarized radiation is linearly polarized by successive rotation of the plane of its polarization and is combined with the initially linearly polarized radiation in a self-compensating manner without changing the eccentricities of the polarization ellipses.
References Cited (Backward Citations)
US3564454A
Cited
US3740663A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-22 | 1979-06-23 | 1979-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-22 | 1983-06-23 | 1983-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-22 | 1987-06-23 | 1987-12-23 | $7700.00 | Window Closed / Lapsed |