US3624421A
Expired / Lapsed
US
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Tunable raman laser
Assignee: Research Corp
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Filing: 1970-06-11
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Granted: 1971-11-30
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Expires: 1990-06-11
Abstract
Abstract A continuously tunable laser arrangement consisting of an optical cavity, containing a Raman-type material, which is infrared active. A pump source of intense coherent radiation is employed to excite an idler frequency, which is one of the natural infrared modes of the material. The angle between the cavity axis and the direction of radiation from the pump source is adjustable to control the actual frequency of the excited idler frequency and thereby control the frequency of output radiation representing an output signal.
Inventors
- 👤 Richard H Pantell
- 👤 Harold E Puthoff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 03:26
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/30
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
132 words
An optical system comprising: a source for providing coherent electromagnetic radiation at a fixed frequency; single optical cavity means defining a cavity axis and comprising an infrared and Raman active crystal to which said radiation from said source is directed, said crystal being characterized by having at least one natural infrared mode which is excitable therein when the radiation from said source is directed thereto, with the interaction between said source radiation and said excited infrared mode producing a Stokes radiation at a frequency which is a function of the frequencies of said source radiation and said excited infrared mode; and means for controlling the angular relationship between said cavity axis and the direction of radiation from said source to control the frequencies of said excited infrared mode and said Stokes radiation.
Claim 2
Dependent Claim
132 words
An optical system comprising: a source for providing coherent electromagnetic radiation at a fixed frequency; single optical cavity means defining a cavity axis and comprising an infrared and Raman active crystal to which said radiation from said source is directed, said crystal being characterized by having at least one natural infrared mode which is excitable therein when the radiation from said source is directed thereto, with the interaction between said source radiation and said excited infrared mode producing a Stokes radiation at a frequency which is a function of the frequencies of said source radiation and said excited infrared mode; and means for controlling the angular relationship between said cavity axis and the direction of radiation from said source to control the frequencies of said excited infrared mode and said Stokes radiation.
Claim 3
Dependent Claim
51 words
The arrangement as recited in claim 1 wherein the frequencies of said source radiation and said Stokes radiation are substantially in the same region of the optical spectrum and the frequency of said excited infrared mode is substantially equal to the difference between the frequencies of said source and Stokes radiations.
Claim 4
Dependent Claim
37 words
The arrangement as recited in claim 1 wherein the wavelength of said excited infrared mode is not less than 10 microns and the wavelength difference between said source and Stokes radiations is not less than 10 microns.
Claim 5
Dependent Claim
13 words
The arrangement as recited in claim 3 wherein said crystal is lithium niobate.
Claim 6
Dependent Claim
79 words
The arrangement as recited in claim 1 wherein said means for controlling control the angle, definable as theta , between said cavity axis and the source radiation direction, whereby the wavelength of said excited infrared mode decreases from a first value to a maximum value as said angle theta is increased from a first angular value toward a second angular value which is a function of the dispersion characteristics of said crystal in the region of said excitable mode.
Claim 7
Dependent Claim
75 words
The arrangement as recited in claim 5 wherein said crystal defines first and second opposite faces with said cavity axis extending therebetween, and further defining at least a third face at an angle wiTh respect to said first face, the angle between said first and third faces being a function of the direction of the wave vector in said crystal of the infrared mode excited therein when said angle theta is of a preselected value.
Claim 8
Dependent Claim
42 words
The arrangement as recited in claim 5 wherein said crystal has first and second opposite polished flat faces which are parallel to one another and perpendicular with respect to said cavity axis, with said faces defining the ends of said optical cavity.
Claim 9
Dependent Claim
49 words
The arrangement as recited in claim 7 wherein said crystal is lithium niobate and said excitable mode is the A1 symmetry 248 cm. 1 mode, with the wavelength of said excitable mode varying over a range of over 150 microns as said angle theta is varied over several degrees.
Claim 10
Dependent Claim
42 words
The arrangement as recited in claim 8 wherein said source of radiation is a Q-switched ruby laser and the wavelength of said excited mode varies from substantially 50 microns to substantially 240 microns as theta varies from substantially 0 degrees to 15*.
Claim 11
Dependent Claim
62 words
The arrangement as recited in claim 7 wherein said crystal further defines at least a third face at an angle with respect to said first face, the angle between said first and third faces being a function of the direction of the wave vector in said crystal of the infrared mode excited therein when said angle theta is of a preselected value.
Claim 12
Dependent Claim
51 words
The arrangement as recited in claim 10 wherein said crystal is lithium niobate and said excitable mode is the A1 symmetry 248 cm 1 mode, with the wavelength of said excitable mode varying over a range of over 150 microns as said angle theta is varied over several degrees above zero.
References Cited (Backward Citations)
US3536931A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-29 | 1975-05-31 | 1975-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-29 | 1979-05-31 | 1979-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-29 | 1983-05-31 | 1983-11-30 | $7700.00 | Window Closed / Lapsed |