EP0457523A2
Expired / Lapsed
EP
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Apparatus and method for pumping of a weakly absorbing lasant material
Assignee: Scientific Atlanta LLC
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Filing: 1991-05-13
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Granted: —
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Expires: 2011-05-13
Abstract
Abstract A laser apparatus and method is disclosed comprising a first lasant material (14) which is located in an optical cavity and which produces laser radiation of a first wavelength, and a second lasant material (12) which is pumped by radiation from the first lasant material, which absorbs laser radiation at the first wavelength in an amount generally comparable to the optimum output coupling and which lases at a second wavelength. The first lasant material and the second lasant material are preferably selected to have minimal losses at the first wavelength and at the second laser wavelength due to excited-state absorption. In one embodiment the first lasant material is selected to be substantially transparent to optical radiation at the second laser wavelength.
Inventors
- 👤 John Hamilton Clark
- 👤 Douglas William Anthon
- 👤 Leo Francis Johnson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-10 01:55
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/14; H01S3/16; H01S3/17; H01S3/05; H01S3/06; H01S3/07; H01S3/08; H01S3/081; H01S3/082; H01S3/09; H01S3/091; H01S3/094; H01S3/0941; H01S3/09415; H01S3/10; H01S3/105; H01S3/08054; H01S3/094038
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
115 words
A laser apparatus, comprising: a) a first laser cavity; b) a first lasant material which is located in said first cavity and which is adapted to lase optical radiation at a primary laser wavelength; and c) a second lasant material which is pumped by said optical radiation from said first lasant material, which absorbs optical radiation at said primary laser wavelength and in an amount comparable to the optimum output coupling to said optical radiation from said first lasant material, and which lases at a secondary laser wavelength, said first lasant material and said second lasant material having minimal losses at said primary laser wavelength and at said secondary laser wavelength due to excited-state absorption.
Claim 2
Dependent Claim
25 words
The apparatus of claim 1, wherein said first lasant material is selected from those materials which are capable of being pumped by diode pumping means.
Claim 3
Dependent Claim
31 words
The apparatus of claim 1, wherein said second lasant material is located in said first laser cavity; and wherein said first lasant material is essentially transparent at said secondary laser wavelength.
Claim 4
Dependent Claim
45 words
The apparatus of claim 1, wherein said second lasant material comprises a rare earth glass which comprises from 0.01% to 15% by weight of ytterbium and from 0.01% to 1.0% by weight of a material selected from the group consisting of erbium, holmium and thulium.
Claim 5
Dependent Claim
55 words
The apparatus of claim 1, wherein said second lasant material is located in a second laser cavity and is pumpingly coupled to said first laser cavity using wavelength separation means which separates optical radiation at said primary wavelength from optical radiation at said secondary wavelength as a function of the wavelength of said optical radiation.
Claim 6
Dependent Claim
24 words
The apparatus of claim 5, wherein said wavelength separation means is selected from the group consisting of dichroic reflector means and refractive prism means.
Claim 7
Dependent Claim
47 words
The apparatus of claim 1, wherein said second lasant material is located in a second laser cavity and is pumpingly coupled to said first laser cavity using-polarization separation means which separates optical radiation at said secondary wavelength as a function of the polarization of said optical radiation.
Claim 8
Dependent Claim
30 words
The apparatus of claim 7, wherein said polarization separation means is selected from the group consisting of dielectric polarizer means, Glan prism means, Brewster prism means and Wollaston prism means.
Claim 9
Dependent Claim
73 words
The apparatus of claim 1, wherein said second lasant material comprises a sub-millimeter thickness of a rare earth sensitized glass which has two opposite and parallel flat faces, one of said faces carrying coating means for high transmission at said primary laser wavelength and high reflection at said secondary laser wavelength, the opposite face carrying coating means for high transmission at said secondary laser wavelength and high reflection at said primary laser wavelength.
Claim 10
Dependent Claim
72 words
The apparatus of claim 1, wherein said second lasant material is located in said first cavity and in a second laser cavity and is pumpingly coupled to said optical radiation at said primary laser wavelength using birefringent crystal means, which is located in said first laser cavity and in said second laser cavity means, for substantially separating optical radiation at said secondary laser wavelength from optical radiation at said primary laser wavelength.
Claim 11
Dependent Claim
103 words
The apparatus of claim 10, wherein said first laser cavity comprises a mirror; wherein said second lasant material is located between said mirror and said first lasant material; and wherein said means for forming a second laser cavity comprises spatially varying coating means which is carried by said first lasant material and which is highly reflective at said secondary laser wavelength, said birefringent crystal means being located between said second lasant material and said spatially varying coating and being positioned to produce a laser beam which lases at said secondary laser wavelength and which is between said mirror and said spatially varying coating.
Claim 12
Dependent Claim
139 words
The apparatus of claim 10, wherein said first laser cavity comprises light reflection means; wherein said second lasant material is located between said light reflection means and said first lasant material; and wherein said means for forming a second laser cavity comprises a mirror which faces said light reflection means, said birefringent crystal means being interposed between said mirror and said light reflection means such that said primary optical radiation is polarized at one of the two ordinary and extraordinary rays and said secondary optical radiation is polarized at the other of the two ordinary and extraordinary rays which are formed when said primary laser wavelength optical radiation passes through said birefrinqent crystal means and between said mirror and light reflection means, said birefringent crystal means being positioned to have said secondary laser wavelength light reflect off said mirror.
Claim 13
Dependent Claim
21 words
The apparatus of claim 10, wherein said birefringent crystal means is selected from the group consisting of calcite, LiNbO₃ and TiO₂.
Claim 14
Dependent Claim
174 words
A laser system, comprising: a) first laser means comprising a first optical cavity and having in said first optical cavity a first lasant material which is pumped on one side by diode pumping means whereby laser light of a first wavelength is emitted from said first lasant material along an optical path; b) an etalon formed from a sensitized second lasant material which is sufficiently thick to absorb said laser light from said first lasant material in an amount generally comparable to the optimum output coupling of said first laser means, which has one face which receives said light from said first laser means, and which has an oppossite face, said faces lying generally perpendicular to said optical path; and c) cavity means, having an axis which is generally coaxial with said optical path, for forming at least part of a laser cavity for said sensitized second lasant material to lase at a second wavelength, said first and said second lasant materials having minimal losses at said first wavelength and at said second wavelength.
Claim 15
Dependent Claim
28 words
The system of claim 14, wherein said sensitized second lasant material is a Yb sensitized Er glass and wherein said etalon is 1 mm or less in thickness.
Claim 16
Dependent Claim
45 words
The system of claim 15, wherein said etalon is located in said first optical cavity, and wherein said cavity means comprises a coating on said one face of said etalon for high reflection at said second wavelength and for high transmission at said first wavelength.
Claim 17
Dependent Claim
51 words
The system of claim 16, wherein said opposite face of the etalon is coated for high reflection at said first wavelength and high transmission at said second wavelength and wherein said cavity means further comprises a mirror for reflecting light at said second wavelength towards said other face of said etalon.
Claim 18
Dependent Claim
64 words
The system of claim 14, wherein said sensitized second lasant material is a Yb,Er:phosphate glass which is formed into an etalon having a sub-millimeter thickness and having two opposite faces; and wherein said cavity means comprises a coating on said one face which is HR for said second wavelength, and a mirror which is HR at said first wavelength and at said second wavelength.
Claim 19
Dependent Claim
34 words
The system of claim 18, wherein said one face carries a coating which is HT at said first wavelength and wherein said opposite face carries a coating which is HT at said second wavelength.
Claim 20
Dependent Claim
205 words
A solid state laser system, comprising: a) a plano-convex and doped crystal which is selected from the group consisting of YAG, YVO₄ and YLF, which is located in a laser cavity, which is pumped by a laser diode source to emit laser light, and which is essentially transparent to light at a predetermined wavelength; and b) a relatively thin sensitized phosphate glass lasant material which is located in said cavity, which absorbs said laser light from said convex face of said crystal at about the optimum output coupling of said crystal, which emits laser light at said predetermined wavelength, which contains at least one rare earth element selected from the group consisting of Yb and Er, which has one face which is located adjacent to said crystal and which has an opposite face, said plano face of said crystal and said opposite face of said glass being coated for high reflection of said laser light, said convex face of said crystal and said one face of said glass being anti-reflection coated for said laser light, said one face of said glass being coated for high reflection at said predetermined wavelength, and said opposite face of said glass being coated for reflection at said predetermined wavelength.
Claim 21
Dependent Claim
127 words
A laser system, comprising: a) a laser source having an output at a first wavelength; and b) a laser cavity comprising an output coupler for reflecting light at a second wavelength and at said first wavelength, a relatively thin sensitized glass lasant material which is located between said output coupler and said source, which absorbs said laser light from said source in an amount about equal to the optimum output coupling of said source, which emits laser light at said second wavelength, which has one surface which faces said source, and which has an opposite surface which faces said output coupler, and means, adjacent to said source, for reflecting into said one surface of said lasant material light at said one wavelenght and at said second wavelength.
Claim 22
Dependent Claim
32 words
The laser system of claim 21, wherein said source includes an optical isolator for receiving said output of said source and transmitting said output to said one surface of said lasant material.
Claim 23
Dependent Claim
29 words
The laser system of claim 22, wherein said laser cavity includes means for moving said output coupler towards and away from said opnosite surface of said glass lasant material.
Claim 24
Independent Claim
107 words
A method for pumping a weakly absorbing lasant material, comprising the steps of: a) selecting a first lasant material and a second lasant material which have minimal losses at a primary laser wavelength and at a secondary wavelength due to excited-state-absorption; b) locating said first lasant material in a first cavity to produce laser light at said primary wavelength; and c) producing light at said secondary wavelength by pumping said second lasant material with lasant light from said first lasant material to absorb light at said primary wavelength in an amount which is comparable to the optimum output coupling to said light from said first lasant material.
Claim 25
Dependent Claim
40 words
The method of claim 24, wherein said second lasant material is located in said first laser cavity; and wherein step a) includes the step of selecting said first lasant material to be essentially transparent to light at said secondary wavelength.
Claim 26
Dependent Claim
65 words
The method of claim 24, wherein said second lasant material is located in a second laser cavity; and wherein step c) includes the steps of: pumpingly coupling said second lasant material to said light at said primary wavelength, and substantially separating light at said secondary wavelength from light at said primary wavelength by using one of the polarization and the wavelength characteristics of said light.
References Cited (Backward Citations)
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