Patent EP0339868A1 successfully refreshed from Google Patents.
EP0339868A1
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EP
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Ring laser with improved beam quality
Assignee: Coherent Inc
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Filing: 1989-04-20
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Granted: —
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Expires: 2009-04-20
Abstract
Abstract A rod laser has a ring cavity configuration and includes a polarization rotator (21) to compensate for birefringence of the laser's rod. Preferably, the rotator (21) is a 90 o crystal quartz rotator. The ring laser is a stable, quasiunidirectional, non-confocal solid state ring laser. A telescope (3), including at least two lenses (2, 4) with variable inter-lens spacing, is positioned in the laser beam path as closely as possible to the laser rod (1). The spacing between the telescope lenses (2, 4) is controlled by a servo mechanism (19, 31) comprising a power density detector (31) for producing a beam power signal, and a means (19) (which may include a microprocessor) coupled to the power density detector (31) for generating a servo mechanism feedback control signal from the beam power signal. The ring laser maintains a high quality output beam (28) having low far-field beam divergence and small laser beam focal spot diameter, over a wide and varying range of output beam power, and the output beam (28) is particularly useful for such applications as high speed drilling, welding, and cutting.
Inventors
- 👤 Joseph W. Kantorski
- 👤 Klaus Hachfeld
- 👤 James L. Hobart
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 19:37
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/05; H01S3/08; H01S3/081; H01S3/083
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
66 words
A ring laser, including: a rod, for producing laser light; means for causing the laser light to propagate as a quasi-unidirectional laser beam along a ring-shaped path; a polarization rotator positioned along the path, for rotating the polarization of the beam by an angle selected to compensate for thermal birefringence of the rod; and means for diverting an output portion of the beam from the path.
Claim 2
Dependent Claim
66 words
A ring laser, including: a rod, for producing laser light; means for causing the laser light to propagate as a quasi-unidirectional laser beam along a ring-shaped path; a polarization rotator positioned along the path, for rotating the polarization of the beam by an angle selected to compensate for thermal birefringence of the rod; and means for diverting an output portion of the beam from the path.
Claim 3
Dependent Claim
14 words
The laser of claim 1, wherein the rotator is a 90° crystal quartz rotator.
Claim 4
Dependent Claim
49 words
The laser of claim 1, wherein the path includes a first portion along which the beam has a lower power, and the path has a second portion along which the beam has a higher power, and wherein the polarization rotator is positioned along the first portion of the path.
Claim 5
Dependent Claim
29 words
The laser of claim 1, also including: a telescope, including at least two lenses with variable inter-lens spacing positioned along the path as closely as possible to the rod.
Claim 6
Dependent Claim
63 words
The laser of claim 4, wherein the path includes a first portion adjacent a first end of the rod, and along which the beam has a lower power, and the path has a second portion along which the beam has a higher power, and wherein the telescope is positioned along the first portion of the path adjacent the first end of the rod.
Claim 7
Dependent Claim
70 words
The laser of claim 4, also including: a servo mechanism coupled to the telescope, and capable of controlling the inter-lens spacing of the telescope; a power density meter for producing a beam power signal from the beam; and a servo control circuit coupled between the power density meter and the servo mechanism, and including a means for generating a feedback signal for the servo mechanism from the beam power signal.
Claim 8
Dependent Claim
33 words
The laser of claim 4, wherein the shape of each telescope lens is selected so that the telescope lenses will at least partially compensate for laser beam spherical aberration introduced by the rod.
Claim 9
Dependent Claim
73 words
A ring laser, including: a rod, for producing laser light; means for directing the laser light so as to propagate as a laser beam along a ring-shaped path; a partially reflective mirror positioned so as to divert an output beam portion from the laser beam; and a polarization rotator positioned along the path, for rotating the polarization of the laser beam by an angle selected to compensate for thermal birefringence of the rod.
Claim 10
Dependent Claim
73 words
A ring laser, including: a rod, for producing laser light; means for directing the laser light so as to propagate as a laser beam along a ring-shaped path; a partially reflective mirror positioned so as to divert an output beam portion from the laser beam; and a polarization rotator positioned along the path, for rotating the polarization of the laser beam by an angle selected to compensate for thermal birefringence of the rod.
Claim 11
Dependent Claim
16 words
The laser of claim 8, wherein the laser light directing means produces a quasi-unidirectional laser beam.
Claim 12
Dependent Claim
14 words
The laser of claim 8, wherein the rotator is a 90° crystal quartz rotator.
Claim 13
Dependent Claim
49 words
The laser of claim 8, wherein the path includes a first portion along which the beam has a lower power, and the path has a second portion along which the beam has a higher power, and wherein the polarization rotator is positioned along the first portion of the path.
Claim 14
Dependent Claim
26 words
The laser of claim 8, also including: a telescope, including at least two lenses with variable inter-lens spacing positioned as closely as possible to the rod.
Claim 15
Dependent Claim
63 words
The laser of claim 12, wherein the path includes a first portion adjacent a first end of the rod, and along which the beam has a lower power, and the path has a second portion along which the beam has a higher power, and wherein the telescope is positioned along the first portion of the path adjacent the first end of the rod.
Claim 16
Dependent Claim
70 words
The laser of claim 12, also including: a servo mechanism coupled to the telescope, and capable of controlling the inter-lens spacing of the telescope; a power density meter for producing a beam power signal from the beam; and a servo control circuit coupled between the power density meter and the servo mechanism, and including a means for generating a feedback signal for the servo mechanism from the beam power signal.
Claim 17
Dependent Claim
33 words
The laser of claim 12, wherein the shape of each telescope lens is selected so that the telescope lenses will at least partially compensate for laser beam spherical aberration introduced by the rod.
Claim 18
Dependent Claim
163 words
A ring laser, including: a rod, for producing laser light; means for causing the laser light to propagate as a laser beam along a ring-shaped path, said laser beam including a first component propagating in a first rotational direction along the path and a second component propagating in a second rotational direction along the path; a partially reflective first mirror positioned so as to divert an output beam portion from the first component of the laser beam; a second mirror, positioned relative to the first mirror so that the first mirror will direct a portion of the second component to the second mirror, and so that the second mirror will reflect said portion of the second component in such a direction that the reflected portion of the second component will join the output beam portion; and a polarization rotator positioned along the path, for rotating the polarization of the laser beam by an angle selected to compensate for thermal birefringence of the rod.
Claim 19
Dependent Claim
163 words
A ring laser, including: a rod, for producing laser light; means for causing the laser light to propagate as a laser beam along a ring-shaped path, said laser beam including a first component propagating in a first rotational direction along the path and a second component propagating in a second rotational direction along the path; a partially reflective first mirror positioned so as to divert an output beam portion from the first component of the laser beam; a second mirror, positioned relative to the first mirror so that the first mirror will direct a portion of the second component to the second mirror, and so that the second mirror will reflect said portion of the second component in such a direction that the reflected portion of the second component will join the output beam portion; and a polarization rotator positioned along the path, for rotating the polarization of the laser beam by an angle selected to compensate for thermal birefringence of the rod.
Claim 20
Dependent Claim
40 words
The laser of claim 15, wherein the reflectivity of the first mirror is selected so that the laser beam is quasi-unidirectional, with substantially more of the power in the laser beam propagating the first component than in the second component.
Claim 21
Dependent Claim
14 words
The laser of claim 16, wherein the rotator is a 90° crystal quartz rotator.
Claim 22
Dependent Claim
49 words
The laser of claim 16, wherein the path includes a first portion along which the beam has a lower power, and the path has a second portion along which the beam has a higher power, and wherein the polarization rotator is positioned along the first portion of the path.
Claim 23
Dependent Claim
26 words
The laser of claim 16, also including: a telescope, including at least two lenses with variable inter-lens spacing positioned as closely as possible to the rod.
Claim 24
Dependent Claim
63 words
The laser of claim 20, wherein the path includes a first portion adjacent a first end of the rod, and along which the beam has a lower power, and the path has a second portion along which the beam has a higher power, and wherein the telescope is positioned along the first portion of the path adjacent the first end of the rod.
Claim 25
Dependent Claim
70 words
The laser of claim 20, also including: a servo mechanism coupled to the telescope, and capable of controlling the inter-lens spacing of the telescope; a power density meter for producing a beam power signal from the beam; and a servo control circuit coupled between the power density meter and the servo mechanism, and including a means for generating a feedback signal for the servo mechanism from the beam power signal.
Claim 26
Dependent Claim
33 words
The laser of claim 20, wherein the shape of each telescope lens is selected so that the telescope lenses will at least partially compensate for laser beam spherical aberration introduced by the rod.
References Cited (Backward Citations)
US3508166A
Cited
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