Patent US5038353A successfully refreshed from Google Patents.
US5038353A
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Method and apparatus for lasing
Assignee: United States Department of the Navy
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Filing: 1990-02-21
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Granted: 1991-08-06
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Expires: 2010-02-21
Abstract
Abstract A laser system employing thulium and holmium in a trivalent state. The quantum levels of interest in the thulium and holmium are coupled so that one pumping photo absorbed by the thulium results in two photons emitted by the holmium, making for an unusually efficient laser system. The lower level is sufficiently depopulated at room temperature to allow laser operation without cryogenics. In preferred embodiments, the laser pump can be a laser diode, itself especially efficient, and whose output frequency is closely matched in photon energy to the thulium quantum state of interest, thus lending additional efficiency to the overall system. The thulium and the holmium exist in an yttrium-aluminum garnet crystal as lattice replacements for yttrium.
Inventors
- 👤 Leon Esterowitz
- 👤 Roger E. Allen
- 👤 Gregory J. Kintz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:16
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/14; H01S3/16; H01S3/09; H01S3/091; H01S3/094; H01S3/0941; H01S3/1601; H01S3/1603; H01S3/161; H01S3/1616
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
319 words
A method of lasing at the 2.1 micrometer wavelength between the 5 I 7 and 5 I 8 energy levels of holmium, said method of lasing employing: a laser cavity containing a laser active material, said laser active material comprising a host lattice doped with thulium and holmium atoms, said host lattice being selected to cause said thulium and said holmium atoms to be trivalent; and a pumping means for pumping said laser active material substantially monochromatically at about 0.785 micrometer wavelength; wherein said method comprises steps for: using said pumping means to raise thulium atoms in said host lattice to the 3 H 4 energy level by illuminating said host lattice with said photons of about 0.785 micrometer wavelength; relaxing, responsive to said illumination, each of said thulium atoms raised to said 3 H 4 energy level by (a) cross-relaxing with an adjacent thulium atom to raise said adjacent thulium atom to the 3 F 4 energy level, and (b) responsive to step (a) permitting said each of said thulium atoms at said 3 H 4 energy level to relax to the 3 F 4 energy level, thereby creating two thulium atoms at said 3 F 4 energy level per photon at said 0.785 micrometer wavelength; causing said 3 F 4 energy level of said thulium atoms, and said 5 I 7 energy levels of said holmium atoms, to cooperate to excite a respective holmium atom to the 5 I 7 energy level; relaxing said respective holmium atoms to the 5 I 8 energy level by emitting said photon of about 2.1 micrometer wavelength; wherein, for each said photon of about 0.785 micrometer wavelength, said laser active material emits two of said photons of about 2.1 micrometer wavelength; and wherein said holmium is between 0.1 and 0.4 atomic per cent of said host lattice, and said thulium is between 4 and 7 atomic percent of said host lattice.
Claim 2
Independent Claim
319 words
A method of lasing at the 2.1 micrometer wavelength between the 5 I 7 and 5 I 8 energy levels of holmium, said method of lasing employing: a laser cavity containing a laser active material, said laser active material comprising a host lattice doped with thulium and holmium atoms, said host lattice being selected to cause said thulium and said holmium atoms to be trivalent; and a pumping means for pumping said laser active material substantially monochromatically at about 0.785 micrometer wavelength; wherein said method comprises steps for: using said pumping means to raise thulium atoms in said host lattice to the 3 H 4 energy level by illuminating said host lattice with said photons of about 0.785 micrometer wavelength; relaxing, responsive to said illumination, each of said thulium atoms raised to said 3 H 4 energy level by (a) cross-relaxing with an adjacent thulium atom to raise said adjacent thulium atom to the 3 F 4 energy level, and (b) responsive to step (a) permitting said each of said thulium atoms at said 3 H 4 energy level to relax to the 3 F 4 energy level, thereby creating two thulium atoms at said 3 F 4 energy level per photon at said 0.785 micrometer wavelength; causing said 3 F 4 energy level of said thulium atoms, and said 5 I 7 energy levels of said holmium atoms, to cooperate to excite a respective holmium atom to the 5 I 7 energy level; relaxing said respective holmium atoms to the 5 I 8 energy level by emitting said photon of about 2.1 micrometer wavelength; wherein, for each said photon of about 0.785 micrometer wavelength, said laser active material emits two of said photons of about 2.1 micrometer wavelength; and wherein said holmium is between 0.1 and 0.4 atomic per cent of said host lattice, and said thulium is between 4 and 7 atomic percent of said host lattice.
Claim 3
Dependent Claim
30 words
The method of claim 1, wherein said holmium is about 0.36 atomic per cent of said host lattice, and said thulium is about 5.7 atomic percent of said host lattice.
Claim 4
Dependent Claim
14 words
The method of claim 2, wherein said laser cavity is about one millimeter long.
Claim 5
Independent Claim
326 words
A method of lasing at the 2.1 micrometer wavelength between the 5 I 7 and 5 I 8 energy levels of holmium, said method of lasing employing: a laser cavity containing a laser active material, said laser active material comprising a host lattice doped with thulium and holmium atoms, said host lattice being selected to cause said thulium and said holmium atoms to be trivalent; and a pumping means for pumping said laser active material substantially monochromatically at about 0.785 micrometer wavelength; wherein said method comprises steps for: using said pumping means to raise thulium atoms in said host lattice to the 3 H 4 energy level by illuminating said host lattice with said photons of about 0.785 micrometer wavelength; relaxing, responsive to said illumination, each of said thulium atoms raised to said 3 H 4 energy level by (a) cross-relaxing with an adjacent thulium atom to raise said adjacent thulium atom to the 3 F 4 energy level, and (b) responsive to step (a) permitting said each of said thulium atoms at said 3 H 4 energy level to relax to the 3 F 4 energy level, thereby creating two thulium atoms at said 3 F 4 energy level per photon at said 0.785 micrometer wavelength; causing said 3 F 4 energy level of said thulium atoms, and said 5 I 7 energy levels of said holmium atoms, to cooperate to excite a respective holmium atom to the 5 I 7 energy level; relaxing said respective holmium atoms to the 5 I 8 energy level by emitting said photon of about 2.1 micrometer wavelength; wherein, for each said photon of about 0.785 micrometer wavelength, said laser active material emits two of said photons of about 2.1 micrometer wavelength wherein said host lattice is yttrium-aluminum garnet; and wherein said holmium is between 0.1 and 0.4 atomic per cent of said host lattice, and said thulium is between 4 and 7 atomic percent of said host lattice.
Claim 6
Independent Claim
326 words
A method of lasing at the 2.1 micrometer wavelength between the 5 I 7 and 5 I 8 energy levels of holmium, said method of lasing employing: a laser cavity containing a laser active material, said laser active material comprising a host lattice doped with thulium and holmium atoms, said host lattice being selected to cause said thulium and said holmium atoms to be trivalent; and a pumping means for pumping said laser active material substantially monochromatically at about 0.785 micrometer wavelength; wherein said method comprises steps for: using said pumping means to raise thulium atoms in said host lattice to the 3 H 4 energy level by illuminating said host lattice with said photons of about 0.785 micrometer wavelength; relaxing, responsive to said illumination, each of said thulium atoms raised to said 3 H 4 energy level by (a) cross-relaxing with an adjacent thulium atom to raise said adjacent thulium atom to the 3 F 4 energy level, and (b) responsive to step (a) permitting said each of said thulium atoms at said 3 H 4 energy level to relax to the 3 F 4 energy level, thereby creating two thulium atoms at said 3 F 4 energy level per photon at said 0.785 micrometer wavelength; causing said 3 F 4 energy level of said thulium atoms, and said 5 I 7 energy levels of said holmium atoms, to cooperate to excite a respective holmium atom to the 5 I 7 energy level; relaxing said respective holmium atoms to the 5 I 8 energy level by emitting said photon of about 2.1 micrometer wavelength; wherein, for each said photon of about 0.785 micrometer wavelength, said laser active material emits two of said photons of about 2.1 micrometer wavelength wherein said host lattice is yttrium-aluminum garnet; and wherein said holmium is between 0.1 and 0.4 atomic per cent of said host lattice, and said thulium is between 4 and 7 atomic percent of said host lattice.
Claim 7
Dependent Claim
30 words
The method of claim 4, wherein said holmium is about 0.36 atomic per cent of said host lattice, and said thulium is about 5.7 atomic percent of said host lattice.
Claim 8
Dependent Claim
14 words
The method of claim 5, wherein said laser cavity is about one millimeter long.
Claim 9
Independent Claim
325 words
A method of lasing at the 2.1 micrometer wavelength between the 5 I 7 and 5 I 8 energy levels of holmium, said method of lasing employing: a laser cavity containing a laser active material, said laser active material comprising a host lattice having laser active doping, said doping consisting essentially of thulium and holmium atoms, said host lattice being selected to cause said thulium and said holmium atoms to be trivalent; and a pumping means for pumping said laser active material substantially monochromatically at about 0.785 micrometer wavelength; wherein said method comprises steps for: using said pumping means to raise thulium atoms in said host lattice to the 3 H 4 energy level by illuminating said host lattice with said photons of about 0.785 micrometer wavelength; relaxing, responsive to said illumination, each of said thulium atoms raised to said 3 H 4 energy level by (a) cross-relaxing with an adjacent thulium atom to raise said adjacent thulium atom to the 3 F 4 energy level, and (b) responsive to step (a) permitting said each of said thulium atoms at said 3 H 4 energy level to relax to the 3 F 4 energy level, thereby creating two thulium atoms at said 3 F 4 energy level per photon at said 0.785 micrometer wavelength; causing said 3 F 4 energy level of said thulium atoms, and said 5 I 7 energy levels of said holmium atoms, to cooperate to excite a respective holmium atom to the 5 I 7 energy level; relaxing said respective holmium atoms to the 5 I 8 energy level by emitting said photon of about 2.1 micrometer wavelength; wherein, for each said photon of about 0.785 micrometer wavelength, said laser active material emits two of said photons of about 2.1 micrometer wavelength; wherein said holmium is between 0.1 and 0.4 atomic per cent of said host lattice, and said thulium is between 4 and 7 atomic percent of said host lattice.
Claim 10
Independent Claim
325 words
A method of lasing at the 2.1 micrometer wavelength between the 5 I 7 and 5 I 8 energy levels of holmium, said method of lasing employing: a laser cavity containing a laser active material, said laser active material comprising a host lattice having laser active doping, said doping consisting essentially of thulium and holmium atoms, said host lattice being selected to cause said thulium and said holmium atoms to be trivalent; and a pumping means for pumping said laser active material substantially monochromatically at about 0.785 micrometer wavelength; wherein said method comprises steps for: using said pumping means to raise thulium atoms in said host lattice to the 3 H 4 energy level by illuminating said host lattice with said photons of about 0.785 micrometer wavelength; relaxing, responsive to said illumination, each of said thulium atoms raised to said 3 H 4 energy level by (a) cross-relaxing with an adjacent thulium atom to raise said adjacent thulium atom to the 3 F 4 energy level, and (b) responsive to step (a) permitting said each of said thulium atoms at said 3 H 4 energy level to relax to the 3 F 4 energy level, thereby creating two thulium atoms at said 3 F 4 energy level per photon at said 0.785 micrometer wavelength; causing said 3 F 4 energy level of said thulium atoms, and said 5 I 7 energy levels of said holmium atoms, to cooperate to excite a respective holmium atom to the 5 I 7 energy level; relaxing said respective holmium atoms to the 5 I 8 energy level by emitting said photon of about 2.1 micrometer wavelength; wherein, for each said photon of about 0.785 micrometer wavelength, said laser active material emits two of said photons of about 2.1 micrometer wavelength; wherein said holmium is between 0.1 and 0.4 atomic per cent of said host lattice, and said thulium is between 4 and 7 atomic percent of said host lattice.
Claim 11
Dependent Claim
12 words
The method of claim 7, wherein said host lattice is yttrium-aluminum garnet.
Claim 12
Dependent Claim
30 words
The method of claim 8, wherein said holmium is about 0.36 atomic per cent of said host lattice, and said thulium is about 5.7 atomic percent of said host lattice.
Claim 13
Dependent Claim
14 words
The method of claim 9, wherein said laser cavity is about one millimeter long.
Claim 14
Dependent Claim
30 words
The method of claim 7, wherein said holmium is about 0.36 atomic per cent of said host lattice, and said thulium is about 5.7 atomic percent of said host lattice.
Claim 15
Independent Claim
99 words
A device for lasing at the 2.1 micrometer wavelength between the 5 I 7 and 5 I 8 energy levels of holmium, said device comprising: a laser cavity containing a laser active material, said laser active material comprising a host lattice having laser active doping, said doping consisting essentially of thulium and holmium atoms, said host lattice being selected to cause said thulium and said holmium atoms to be trivalent; wherein said holmium is between 0.1 and 0.4 atomic per cent of said host lattice, and said thulium is between 4 and 7 atomic percent of said host lattice.
Claim 16
Independent Claim
99 words
A device for lasing at the 2.1 micrometer wavelength between the 5 I 7 and 5 I 8 energy levels of holmium, said device comprising: a laser cavity containing a laser active material, said laser active material comprising a host lattice having laser active doping, said doping consisting essentially of thulium and holmium atoms, said host lattice being selected to cause said thulium and said holmium atoms to be trivalent; wherein said holmium is between 0.1 and 0.4 atomic per cent of said host lattice, and said thulium is between 4 and 7 atomic percent of said host lattice.
Claim 17
Dependent Claim
12 words
The device of claim 12, wherein said host lattice is yttrium-aluminum garnet.
Claim 18
Dependent Claim
30 words
The device of claim 13, wherein said holmium is about 0.36 atomic per cent of said host lattice, and said thulium is about 5.7 atomic percent of said host lattice.
Claim 19
Dependent Claim
14 words
The device of claim 14, wherein said laser cavity is about one millimeter long.
Claim 20
Dependent Claim
30 words
The device of claim 12, wherein said holmium is about 0.36 atomic per cent of said host lattice, and said thulium is about 5.7 atomic percent of said host lattice.
References Cited (Backward Citations)
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