US4701928A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Diode laser pumped co-doped laser
Assignee: Leland Stanford Junior University
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Filing: 1985-10-02
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Granted: 1987-10-20
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Expires: 2005-10-02
Abstract
Abstract A miniature solid state near room temperature laser includes a laser crystal doped with a laser ion and an absorber ion. The absorber ion absorbs pumping radiation derived from the output of a laser diode and transfers the absorbed energy to the laser ion for inverting the population of the desired energy transition levels to produce an eyesafe output beam with wavelengths greater than 1.4 microns. In a preferred embodiment, the host crystal is YAG and it is co-doped with Ho as the laser ion and Er as the absorber ion. A small concentration of Tm ion may be doped into the crystal to enhance pumping efficiency. Improved efficiency can be obtained by cooling the laser crystal with a thermoelectric cooler and by tuning the output of the diode laser pump to an absorption peak of the absorbing ion.
Inventors
- 👤 Tso Y. Fan
- 👤 Robert L. Byer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:06
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/02; H01S3/04; H01S3/042; H01S3/14; H01S3/16; H01S3/0405
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
139 words
In a laser apparatus: optical pumping means including a laser diode for emitting coherent optical pumping radiation at a narrow band resonant wavelength; laser gain medium means disposed to receive the pumping radiation and including a host material doped with a first concentration of a first lasant ion for emitting output coherent optical radiation of an output wavelength from a certain lasant energy level transition; and said laser gain medium host material also being doped with a second concentration of a second ion for absorbing the narrow band coherent optical pumping radiation produced by said laser diode and for transferring energy absorbed from said narrow band pumping radiation to said first lasant ion for inverting the population density of said certain lasant energy levels of said first ion from which lasant energy transitions at an output wavelength are obtained.
Claim 2
Dependent Claim
139 words
In a laser apparatus: optical pumping means including a laser diode for emitting coherent optical pumping radiation at a narrow band resonant wavelength; laser gain medium means disposed to receive the pumping radiation and including a host material doped with a first concentration of a first lasant ion for emitting output coherent optical radiation of an output wavelength from a certain lasant energy level transition; and said laser gain medium host material also being doped with a second concentration of a second ion for absorbing the narrow band coherent optical pumping radiation produced by said laser diode and for transferring energy absorbed from said narrow band pumping radiation to said first lasant ion for inverting the population density of said certain lasant energy levels of said first ion from which lasant energy transitions at an output wavelength are obtained.
Claim 3
Dependent Claim
24 words
The laser apparatus of claim 1 wherein said first lasant ion is selected from the group consisting of Tm, Ho, Dy, Yb, and U.
Claim 4
Dependent Claim
22 words
The laser apparatus of claim 1 wherein said second ion is selected from the group consisting of Tm, Er, Nd, and U.
Claim 5
Dependent Claim
39 words
The laser apparatus of claim 1 wherein said first lasant ion is selected from the group consisting of Tm, Ho, Dy, Yb, U and said second ion is selected from the group consisting of Tm, Er, Nd, and U.
Claim 6
Dependent Claim
34 words
The apparatus of claim 1 wherein the host material is selected from the group consisting of transparent oxide crystals, transparent fluoride crystals, transparent garnets, yttrium aluminum garnet, YAlO 3 , and LiYF 4 .
Claim 7
Dependent Claim
25 words
The apparatus of claim 1 wherein said second concentration of said second ion is greater than 4 times the first concentration of said first ion.
Claim 8
Dependent Claim
35 words
The apparatus of claim 1 including a third concentration of a third ion to moderate energy transfer up-conversion which would otherwise limit the desired population inversion of the lasant energy levels of the first ion.
Claim 9
Dependent Claim
14 words
The apparatus of claim 1 wherein the output wavelength is longer than 1.4 microns.
Claim 10
Dependent Claim
26 words
The apparatus of claim 1 including, tuning means for tuning the wavelength of the diode laser pumping radiation to an absorption peak of said second ion.
Claim 11
Dependent Claim
37 words
The apparatus of claim 1 wherein said host material is disposed to receive the pumping radiation through a face thereof and along a path at least partially co-extensive with the optical axis of the laser gain medium.
Claim 12
Dependent Claim
117 words
In a method of generating coherent output optical radiation of an output wavelength, the steps of: exciting a laser diode to produce a beam of coherent narrow band optical pumping radiation; and directing the narrow band pumping radiation into a laser gain medium comprising a host material doped by a first concentration of a first ion and a second concentration of a second ion for causing the second ion to absorb the narrow band pumping radiation and to transfer absorbed energy to said first ion to produce a population inversion of certain lasant energy levels of the first ion from which lasant energy transitions are obtained to produce the coherent output optical radiation at the output wavelength.
Claim 13
Dependent Claim
117 words
In a method of generating coherent output optical radiation of an output wavelength, the steps of: exciting a laser diode to produce a beam of coherent narrow band optical pumping radiation; and directing the narrow band pumping radiation into a laser gain medium comprising a host material doped by a first concentration of a first ion and a second concentration of a second ion for causing the second ion to absorb the narrow band pumping radiation and to transfer absorbed energy to said first ion to produce a population inversion of certain lasant energy levels of the first ion from which lasant energy transitions are obtained to produce the coherent output optical radiation at the output wavelength.
Claim 14
Dependent Claim
23 words
The method of claim 11 wherein said first lasant ion is selected from the group consisting of Tm, Ho, Dy, Yb, and U.
Claim 15
Dependent Claim
21 words
The method of claim 11 wherein said second ion is selected from the group consisting of Tm, Er, Nd, and U.
Claim 16
Dependent Claim
39 words
The method of claim 11 wherein said first lasant ion is selected from the group consisting of Tm, Ho, Dy, Yb, and U, and said second ion is selected from the group consisting of Tm, Er, Nd, and U.
Claim 17
Dependent Claim
34 words
The method of claim 11 wherein the host material is selected from the group consisting of transparent oxide crystals, transparent fluoride crystals, transparent garnets, yttrium aluminum garnet, YAlO 3 , and LiYF 4 .
Claim 18
Dependent Claim
25 words
The method of claim 11 wherein the second concentration of said second ion is greater than 4 times the first concentration of said first ion.
Claim 19
Dependent Claim
35 words
The method of claim 11 including a third concentration of a third ion to moderate energy transfer up-conversion which would otherwise limit the desired population inversion of the lasant energy levels of the first ion.
Claim 20
Dependent Claim
14 words
The method of claim 11 wherein the output wavelength is longer than 1.4 microns.
Claim 21
Dependent Claim
26 words
The method of claim 11 including, the steps of tuning the wavelength of the diode laser pumping radiation to an absorption peak of said second ion.
Claim 22
Dependent Claim
37 words
The method of claim 11 wherein said host material is shaped to receive the pumping radiation through a face thereof and along a path at least partially co-extensive with the optical axis of the laser gain medium.
References Cited (Backward Citations)
US4081761A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1990-10-19 | 1991-04-20 | 1991-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-19 | 1995-04-20 | 1995-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-19 | 1999-04-20 | 1999-10-20 | $7700.00 | Window Closed / Lapsed |