Patent US4446559A successfully refreshed from Google Patents.
US4446559A
Expired / Lapsed
US
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Laser with annular resonator
Assignee: Boeing North American Inc
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Filing: 1981-12-21
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Granted: 1984-05-01
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Expires: 2001-12-21
Abstract
Abstract The extent of diffraction in a laser resonator is controlled to provide the desired oscillation sustaining feedback. Specifically, a laser system has an annular gain medium disposed about an optical axis. The gain medium has first and second opposite annular ends. A first reflector is disposed on the optical axis closely adjacent to the first end of the gain medium. A second reflector is disposed on the optical axis closely adjacent to the second end of the gain medium. The first and second reflectors are shaped to magnify electromagnetic waves impinging thereon beyond the periphery of one of the reflectors. A sufficiently large portion of the energy incident on an interior region of one of the reflectors to sustain electromagnetic oscillations in the gain medium is diffracted back on itself. In the preferred embodiment, a contoured circular zone plate having a focal point on the optical axis is employed as a diffracting device. The first reflector has a convex surface and the second reflector has a concave surface that together define a focal point that coincides with that of the zone plate.
Inventors
- 👤 Karlheinz Von Bieren
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:19
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/05; H01S3/08; H01S3/081; H01S3/0811; H01S3/0812
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
131 words
A laser system comprising: means for establishing an annular gain medium region disposed about an optical axis, the gain medium region having first and second opposite annular ends; a first reflector centered on the optical axis closely adjacent to the first end of the gain medium region; a second reflector centered on the optical axis closely adjacent to the second end of the gain medium region, the first and second reflectors shaped to magnify electromagnetic waves impinging thereon beyond the periphery of one of the reflectors; and diffracting means for diffracting back on itself a portion of the energy which is directed upon the diffracting means from an interior region of one of said reflectors, said portion of diffracted energy being sufficiently large to sustain electromagnetic oscillations in the gain medium.
Claim 2
Dependent Claim
131 words
A laser system comprising: means for establishing an annular gain medium region disposed about an optical axis, the gain medium region having first and second opposite annular ends; a first reflector centered on the optical axis closely adjacent to the first end of the gain medium region; a second reflector centered on the optical axis closely adjacent to the second end of the gain medium region, the first and second reflectors shaped to magnify electromagnetic waves impinging thereon beyond the periphery of one of the reflectors; and diffracting means for diffracting back on itself a portion of the energy which is directed upon the diffracting means from an interior region of one of said reflectors, said portion of diffracted energy being sufficiently large to sustain electromagnetic oscillations in the gain medium.
Claim 3
Dependent Claim
41 words
The system of claim 1, in which the annular gain medium has a cylindrical length l, and the first and second reflectors are spaced apart a distance L, where L is the same order of magnitude but slightly larger than l.
Claim 4
Dependent Claim
19 words
The system of claim 1, in which the diffracting means comprises an annular zone plate having a diffracting surface.
Claim 5
Dependent Claim
22 words
The system of claim 3, in which the surface of the zone plate has a sinusoidal profile along any radially taken cross-section.
Claim 6
Dependent Claim
25 words
The system of claim 4, in which the sinusoidal profile of the zone plate has a wavelength that decreases proportionately away from the optical axis.
Claim 7
Dependent Claim
33 words
The system of claim 5, in which the sinusoidal profile decreases in wavelength radially outward from the optical axis and the minimum wavelength of the profile is larger than the maximum amplitude thereof.
Claim 8
Dependent Claim
68 words
The laser system of claim 6, in which the first reflector has an annular outer region with a convex surface, the second reflector has annular outer region with concave surface, reflections from the facing surfaces of the first and second reflectors together define a reflector focal point lying approximately on the optical axis, and the diffracting means has a focal point approximately coinciding with the reflector focal point.
Claim 9
Dependent Claim
22 words
The system of claim 7, in which the first reflector has an annular interior region on which the zone plate is formed.
Claim 10
Dependent Claim
22 words
The system of claim 8, in which the second reflector has an interior region on which a retroreflective diffraction grating is formed.
Claim 11
Dependent Claim
69 words
The laser system of claim 1, in which the first reflector has an annular outer region with a convex surface, the second reflector has annular outer region with a concave surface, reflections from the facing surfaces of the first and second reflectors together define a reflector focal point lying approximately on the optical axis, and the diffracting means has a focal point approximately coinciding with the reflector focal point.
Claim 12
Dependent Claim
22 words
The system of claim 10, in which the first reflector has an annular interior region on which the diffracting means is formed.
Claim 13
Dependent Claim
22 words
The system of claim 11, in which the second reflector has an interior region on which a retroreflective diffraction grating is formed.
Claim 14
Dependent Claim
22 words
The system of claim 1, in which the diffracting means comprises a diffraction grating comprising a plurality of closely spaced ridge-like elements.
Claim 15
Dependent Claim
51 words
The system of claim 1, in which the first reflector has a convex spherical surface, the second reflector has a flat outer region, and the diffracting means comprises a flat inner region closely spaced from the second reflector toward the gain medium to form a step discontinuity along the optical axis.
Claim 16
Dependent Claim
52 words
The system of claim 1, in which the first reflector has a convex spherical surface, the second reflector has a flat outer region, and the diffracting means comprises a flat reflector closely spaced from the second reflector away from the gain medium region to form a step discontinuity along the optical axis.
Claim 17
Dependent Claim
56 words
The system of claim 1, in which the first reflector has a convex spherical surface, the second reflector has a flat outer region, and the diffracting means comprises a plurality of annular flat reflectors closely spaced from the second reflector toward the gain medium region to define a plurality of discontinuities transversely to the optical axis.
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) | 1987-05-01 | 1987-10-31 | 1988-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-01 | 1991-10-31 | 1992-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-01 | 1995-10-31 | 1996-05-01 | $7700.00 | Window Closed / Lapsed |