US3972008A
Expired / Lapsed
US
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Method and apparatus for generating coherent radiation in the ultra-violet region and above by use of distributed feedback
Assignee: National Aeronautics and Space Administration
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Filing: 1974-12-17
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Granted: 1976-07-27
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Expires: 1994-12-17
Abstract
Abstract Helium in the superfluid state has been found to emit copious amounts of radiation in the ultra-violet region when excited by an electron stream. Conventional laser action using mirrors is impossible in superfluid helium because there are no mirrors that will reflect VUV radiation. By utilizing the well known method of "distributed feedback" the superfluid helium can be made to lase. By setting up a standing wave in superfluid helium that has a wavelength equal to, or harmonically related to, half the wavelength of the photon radiation chosen to be emitted as laser radiation by the superfluid helium, the need for end mirrors to produce reflection of the laser radiation is eliminated and reflection occurs instead at the wavefronts of the standing wave. The photons leave the superfluid helium at right angles to the standing wave as coherent radiation having a very high intensity. The standing wave established in the superfluid helium may be an acoustical standing wave, a thermal standing wave (second sound), or an electric standing wave.
Inventors
- 👤 with respect to an invention of Fletcher James C. Administrator of the National Aeronautics and Space Administration
- 👤 Melvin M. Saffren
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:03
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/09; H01S3/10; H01S3/102; H01S3/14; H01S3/20; H01S3/106; H01S3/1068
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
60 words
A method for generating coherent radiation in the ultra-violet region, comprising: establishing a bath of a liquid noble gas, maintaining a standing wave in said bath; and exciting the atoms of said noble gas to emit photons, whereby said photons are distributively reflected by the standing wave to produce further photon emission from other atoms of said liquid noble gas.
Claim 2
Independent Claim
60 words
A method for generating coherent radiation in the ultra-violet region, comprising: establishing a bath of a liquid noble gas, maintaining a standing wave in said bath; and exciting the atoms of said noble gas to emit photons, whereby said photons are distributively reflected by the standing wave to produce further photon emission from other atoms of said liquid noble gas.
Claim 3
Dependent Claim
17 words
The method for generating coherent radiation of claim 1 wherein said liquid noble gas is superfluid helium.
Claim 4
Dependent Claim
32 words
The method for generating coherent radiation of claim 2 wherein said exciting step comprises: generating a plurality of accelerated electron beams; and bombarding said bath of superfluid helium with said electron beams.
Claim 5
Dependent Claim
26 words
The method for generating coherent radiation of claim 3 wherein said maintaining step comprises: cyclically driving an acoustical transducer attached to one end of said container.
Claim 6
Dependent Claim
26 words
The method for generating coherent radiation of claim 3 wherein said maintaining step comprises: cyclically driving a thermal transducer attached to one end of said container.
Claim 7
Dependent Claim
36 words
The method for generating coherent radiation of claim 3 wherein said maintaining step comprises: directing two, like frequency, coherent energy beams into said container, at a relative angle that will cause interference between the two beams.
Claim 8
Dependent Claim
26 words
The method for generating coherent radiation of claim 1 wherein said maintaining step comprises: cyclically driving an acoustical transducer attached to one end of said container.
Claim 9
Dependent Claim
36 words
The method for generating coherent radiation of claim 1 wherein said maintaining step comprises: directing two, like frequency, coherent energy beams into said container, at a relative angle that will cause interference between the two beams.
Claim 10
Independent Claim
63 words
A method for generating coherent radiation having wavelengths in the ultra-violet region and smaller, comprising: maintaining a standing wave in an active medium; generating accelerated electron beams; and bombarding said active medium with said electron beams whereby said photons are distributively reflected by the standing waves to produce photon emission of like frequency and phase from other excited atoms in said active medium.
Claim 11
Independent Claim
63 words
A method for generating coherent radiation having wavelengths in the ultra-violet region and smaller, comprising: maintaining a standing wave in an active medium; generating accelerated electron beams; and bombarding said active medium with said electron beams whereby said photons are distributively reflected by the standing waves to produce photon emission of like frequency and phase from other excited atoms in said active medium.
Claim 12
Dependent Claim
27 words
The method for generating coherent radiation of claim 9 wherein said maintaining step, comprises: cyclically driving an acoustical transducer attached to one end of said active medium.
Claim 13
Dependent Claim
37 words
The method for generating coherent radiation of claim 9 wherein said maintaining step, comprises: directing two, like frequency, coherent energy beams into said active medium, at a relative angle that will cause interference between the two beams.
Claim 14
Dependent Claim
57 words
A radiation system for generating coherent radiation in the ultra-violet region, comprising: a container having a liquid noble gas therein; transducing means attached to one end of said container for inducing a standing wave in said liquid noble gas; and a pumping source means for bombarding the liquid noble gas in said container with an energy stream.
Claim 15
Dependent Claim
57 words
A radiation system for generating coherent radiation in the ultra-violet region, comprising: a container having a liquid noble gas therein; transducing means attached to one end of said container for inducing a standing wave in said liquid noble gas; and a pumping source means for bombarding the liquid noble gas in said container with an energy stream.
Claim 16
Dependent Claim
17 words
The radiation system of claim 12 wherein the liquid noble gas in said container is superfluid helium.
Claim 17
Dependent Claim
19 words
The radiation system of claim 13 wherein said pumping source means comprises: an electron accelerator that supplies electron beams.
Claim 18
Dependent Claim
20 words
The radiation system of claim 14 wherein said transducing means conprises: an electroacoustical transducer, cyclically driven by an oscillator means.
Claim 19
Dependent Claim
14 words
The radiation system of claim 14 wherein said transducing means comprises: a thermal transducer.
Claim 20
Dependent Claim
37 words
The radiation system of claim 14 wherein said transducing means comprises: means for generating two, like frequency, coherent energy beams into said container of superfluid helium, at a relative angle that causes interference between the two beams.
Claim 21
Dependent Claim
46 words
The radiation system of claim 12 wherein said container of liquid noble gas has its bottom displaced at an angle to the horizontal with its top parallel to the horizontal, sides that are trapezoids, and the first end of said container larger than the second end.
Claim 22
Dependent Claim
16 words
The radiation system of claim 18 wherein said transducer means is attached to said second end.
Claim 23
Dependent Claim
31 words
The radiation system of claim 19 wherein said pumping source means comprises: an electron accelerator that directs electron beams that are perpendicular to the top of said container into said container.
Claim 24
Dependent Claim
17 words
The radiation system of claim 20 wherein the liquid noble gas in said container is superfluid helium.
Claim 25
Dependent Claim
20 words
The radiation system of claim 21 wherein said transducing means comprises and electroacoustical transducer cyclically driven by an oscillator means.
Claim 26
Dependent Claim
14 words
The radiation system of claim 21 wherein said transducing means comprises: a thermal transducer.
Claim 27
Dependent Claim
34 words
The radiation system of claim 21 wherein said transducing means, comprises: means for generating two, like frequency, coherent energy beams into said container, at a relative angle that causes interference between the two beams.
Claim 28
Dependent Claim
36 words
The radiation system of claim 19 wherein said pumping source means comprises: an electron accelerator that directs electron beams into the top of said container at a very small angle to the top of said container.
Claim 29
Dependent Claim
17 words
The radiation system of claim 19 wherein the liquid noble gas in said container is superfluid helium.
Claim 30
Dependent Claim
20 words
The radiation system of claim 26 wherein said transducing means comprises an electroacoustical transducer cyclically driven by an oscillator means.
Claim 31
Dependent Claim
14 words
The radiation system of claim 27 wherein said transducer means comprises: a thermal transducer.
Claim 32
Dependent Claim
34 words
The radiation system of claim 26 wherein said transducing means, comprises: means for generating two, like frequency, coherent energy beams into said container, at a relative angle that causes interference between the two beams.
Claim 33
Dependent Claim
68 words
A radiation system for generating coherent radiation having wavelengths in the ultra-violet region and smaller, comprising: an active medium; means for generating two, like frequency, coherent energy beams directed into said active medium at a relative angle that causes interference between the two beams, said beams inducing a standing wave in said active medium; and a pumping source means for bombarding said active medium with an energy stream.
Claim 34
Dependent Claim
68 words
A radiation system for generating coherent radiation having wavelengths in the ultra-violet region and smaller, comprising: an active medium; means for generating two, like frequency, coherent energy beams directed into said active medium at a relative angle that causes interference between the two beams, said beams inducing a standing wave in said active medium; and a pumping source means for bombarding said active medium with an energy stream.
References Cited (Backward Citations)
US3774121A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-07-27 | 1980-01-26 | 1980-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-27 | 1984-01-26 | 1984-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-27 | 1988-01-26 | 1988-07-27 | $7700.00 | Window Closed / Lapsed |