Patent US4803686A successfully refreshed from Google Patents.
US4803686A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spatial filter with gain
Assignee: Northrop Grumman Corp
•
Filing: 1987-08-03
•
Granted: 1989-02-07
•
Expires: 2007-08-03
Abstract
Abstract Apparatus and a related method for generating a uniphase reference beam from a weak and aberrated input probe beam in an optical system. A portion of the input probe beam is split off and injected into the cavity of a laser, such as a semiconductor diode laser, where four-wave mixing takes place and an amplified input wave or its phase conjugate is output. Because the laser cavity is selected to provide single-mode operation, the laser provides not only amplification but an output that includes a uniphase wave, which may be interfered with the original aberrated input probe beam for purposes of obtaining wavefront information.
Inventors
- 👤 John C. Brock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:03
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/10; H01S3/10076
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
66 words
A method for generating an amplified uniphase reference beam from a weak input probe beam having wavefront aberrations, the method comprising the steps of: taking a portion of the input probe beam; inputting the portion of the input probe beam into a laser cavity having a single transverse mode of oscillation; and generating in the laser cavity, by a four-wave mixing process, a uniphase output beam.
Claim 2
Independent Claim
66 words
A method for generating an amplified uniphase reference beam from a weak input probe beam having wavefront aberrations, the method comprising the steps of: taking a portion of the input probe beam; inputting the portion of the input probe beam into a laser cavity having a single transverse mode of oscillation; and generating in the laser cavity, by a four-wave mixing process, a uniphase output beam.
Claim 3
Dependent Claim
50 words
A method as defined in claim 1, wherein the step of generating a uniphase output beam includes: generating counter-propagating pump waves within the laser cavity; and four-wave mixing the pump waves and the input portion of the input probe beam to generate output waves that include the desired output beam.
Claim 4
Dependent Claim
25 words
A method as defined in claim 2, and further including the step of: filtering output waves from the cavity to select the desired output beam.
Claim 5
Dependent Claim
25 words
A method as defined in claim 1, wherein: the laser cavity is that of a semiconductor diode laser having a single transverse mode of oscillation.
Claim 6
Dependent Claim
79 words
Apparatus for providing an amplified uniphase reference beam from a weak and wavefront-aberrated input probe beam, the apparatus comprising: means for splitting off a portion of the input probe beam; a laser cavity containing a non-linear gain medium and providing a single transverse mode of oscillation; means for injecting the portion of the input probe beam into the laser cavity to provide four-wave mixing within the cavity; and means for deriving a uniphase output beam from the laser cavity.
Claim 7
Dependent Claim
79 words
Apparatus for providing an amplified uniphase reference beam from a weak and wavefront-aberrated input probe beam, the apparatus comprising: means for splitting off a portion of the input probe beam; a laser cavity containing a non-linear gain medium and providing a single transverse mode of oscillation; means for injecting the portion of the input probe beam into the laser cavity to provide four-wave mixing within the cavity; and means for deriving a uniphase output beam from the laser cavity.
Claim 8
Dependent Claim
17 words
Apparatus as defined in claim 5, wherein: the laser cavity is of a single-mode semiconductor diode laser.
Claim 9
Dependent Claim
39 words
Apparatus as defined in claim 6, wherein: the means for injecting the input beam and deriving the output beam include lenses for focusing the input beam into an entrance aperture of the laser, and for collimating the output beam.
References Cited (Backward Citations)
US4528464A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-07 | 1992-08-08 | 1993-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-07 | 1996-08-08 | 1997-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-07 | 2000-08-08 | 2001-02-07 | $7700.00 | Window Closed / Lapsed |