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US3914618A
Expired / Lapsed
US
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Two-photon pumped frequency converter and method
Assignee: Individual
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Filing: 1974-01-28
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Granted: 1975-10-21
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Expires: 1994-01-28
Abstract
Abstract A frequency converter having a cell containing a metal vapor which is pumped by a high energy monochromatic source as, for example, a laser, at a frequency such that two of its photons equals the spacing of a non-allowed transition of the metal vapor to symmetrically excite the metal atoms. The cell is disposed to receive and couple incident radiation to be converted to the excited metal atoms to allow a transition to ground which produces output radiation with side bands at twice the pump frequency plus or minus the frequency of the incident radiation.
Inventors
- 👤 Stephen E Harris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:53
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/35; G02F1/353; G02F1/3534; G02F1/3526
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
110 words
A frequency converter for converting low frequency input energy to higher frequency output energy comprising means containing a metal vapor at predetermined pressure, a high energy pump source projecting energy into said metal vapor to excite the metal atoms, said energy being selected such that the sum of two photons equals the spacing of a non-allowed transition in said metal vapor, said means containing the metal vapor disposed to receive said low frequency energy whereby said energy couples the excited metal atoms to allow transition to ground to provide an output having a frequency equal to the sum of the two photons plus or minus the low frequency input energy.
Claim 2
Dependent Claim
110 words
A frequency converter for converting low frequency input energy to higher frequency output energy comprising means containing a metal vapor at predetermined pressure, a high energy pump source projecting energy into said metal vapor to excite the metal atoms, said energy being selected such that the sum of two photons equals the spacing of a non-allowed transition in said metal vapor, said means containing the metal vapor disposed to receive said low frequency energy whereby said energy couples the excited metal atoms to allow transition to ground to provide an output having a frequency equal to the sum of the two photons plus or minus the low frequency input energy.
Claim 3
Dependent Claim
32 words
A frequency converter as in claim 1 wherein said pump source comprises a laser providing energy at a frequency such that two of its photons equals the spacing of said non-allowed transition.
Claim 4
Dependent Claim
34 words
A frequency converter as in claim 1 wherein said pump source is an optical parametric amplifier providing energy at a frequency such that two of its photons equals the spacing of a non-allowed transition.
Claim 5
Dependent Claim
18 words
A frequency converter as in claim 1 in which said input signal is coherent or incoherent infra-red radiation.
Claim 6
Dependent Claim
58 words
A frequency converter as in claim 1 in which said input energy is coherent or incoherent infra-red and in which the metal atoms and the pump energy are selected such that the two photon excitation of the atoms excites the atoms to a non-alloweD transition which can be coupled by the infra-red input energy to an allowed transition.
Claim 7
Dependent Claim
45 words
A frequency converter as in claim 5 in which the input infra-red radiation is between 1.34 microns and 2.4 microns, the pump energy wavelength is 4,597 A. and the metal atoms are magnesium providing an output sum frequency radiation between 1,950 A and 2,100 A.
Claim 8
Dependent Claim
45 words
A frequency converter as in claim 5 in which the input infra-red radiation is between 0.467 microns and 11 microns, the pump wavelength is 4,310 A and the metal atoms are magnesium providing an output difference frequency radiation between 2,200 A and 4, 000 A.
Claim 9
Dependent Claim
44 words
A frequency converter as in claim 5 in which the input infra-red radiation is between 1.4 microns and 1.8 microns, the pump wavelength is 3,752 A and the metal atoms are cadmium providing an output sum frequency radiation between 1,650 A and 1,700 A.
Claim 10
Dependent Claim
44 words
A frequency converter as in claim 5 in which the infra-red input radiation is between 0.395 microns and 1.9 microns, the pump wavelength is 3,377 A and the metal atoms are cadmium providing an output difference frequency radiation between 1,850 A and 2,950 A.
Claim 11
Dependent Claim
45 words
A frequency converter as in claim 5 in which the input infra-red radiation is between 1.1 microns and 1.54 microns, the pump wavelength is 3,585 A and the metal vapor atoms are zinc providing an output sum frequency radiation between 1,550 A and 1,600 A.
Claim 12
Dependent Claim
43 words
A frequency converter as in claim 5 in which the input infra-red radiation is between 0.393 microns and 1.9 microns, the pump wavelength is 3,202 A., and the metal atoms are zinc providing output difference frequency radiation between 1,750 A and 2,700 A.
Claim 13
Dependent Claim
44 words
A frequency converter as in claim 5 in which the input infra-red radiation is between 1.1 microns and 1.6 microns, the pump wavelength is 3,129 A. and the metal atoms are mercury providing an output sum frequency radiation between 1,375 A. and 1,425 A.
Claim 14
Dependent Claim
43 words
A frequency converter as in claim 5 in which the input infra-red radiation is between 0.372 microns and 1.5 microns, the pump wavelength is 2,804 A. and the metal vapor atoms are mercury providing output difference radiation between 1,550 A and 2,250 A.
Claim 15
Dependent Claim
44 words
A frequency converter as in claim 5 in which the input infra-red radiation is between 9.26 microns and 10.61 microns, the pump wavelength is 6,856 A and the metal atoms are sodium providing an output sum frequency radiation between 3,305 A. and 3,321 A.
Claim 16
Dependent Claim
55 words
A frequency converter as in claim 1 in which said means containing a metal vapor at a predetermined pressure also contains an inert gas or another metal vapor mixed with the metal vapor in such ratio as to provide phase matching at the low frequency input energy and at the frequency of the output energy.
Claim 17
Dependent Claim
122 words
An image converter for converting infra-red input energy from an object to energy at the visible or ultra-violet region of the spectrum comprising means containing a metal vapor at predetermined pressure, a high energy pump source projecting energy into said metal vapor to excite the metal atoms, said energy being selected such that the sum of two photons equals the spacing of a non-allowed transition in said metal vapor, said means containing the metal vapors disposed to receive said infrared energy whereby said energy couples the excited metal atoms to an allowed transition to ground to provide an output having a frequency equal to the sum of the frequency of the two photons plus or minus the frequency of the infra-red energy.
Claim 18
Dependent Claim
122 words
An image converter for converting infra-red input energy from an object to energy at the visible or ultra-violet region of the spectrum comprising means containing a metal vapor at predetermined pressure, a high energy pump source projecting energy into said metal vapor to excite the metal atoms, said energy being selected such that the sum of two photons equals the spacing of a non-allowed transition in said metal vapor, said means containing the metal vapors disposed to receive said infrared energy whereby said energy couples the excited metal atoms to an allowed transition to ground to provide an output having a frequency equal to the sum of the frequency of the two photons plus or minus the frequency of the infra-red energy.
Claim 19
Dependent Claim
40 words
An image converter as in claim 16 in which said metal atoms are sodium and in which the pump frequency provides energy at a wavelength of 6,856 A whereby the infra-red energy is up-converted to the visible or near ultra-violet.
Claim 20
Dependent Claim
30 words
An up-converter as in claim 16 in which the object is irradiated with a laser operating in the 10.6 micron region to thereby provide stimulated radiation to the image converter.
Claim 21
Dependent Claim
43 words
A frequency converter as in claim 5 in which the input infra-red energy is in the vicinity of 3 microns, the pump energy is 1.079 microns and the metal atoms are cesium providing an output sum frequency in the vicinity of 4,577 A.
References Cited (Backward Citations)
US3795819A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-20 | 1979-04-21 | 1979-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-20 | 1983-04-21 | 1983-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-20 | 1987-04-21 | 1987-10-21 | $7700.00 | Window Closed / Lapsed |