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US4926428A
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US
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Method and apparatus for sensing the wavelength of a laser beam
Assignee: KOMATSU SEISAKUSHO 3-6 AKASAKA 2-CHOME MINATO-KU TOKYO 107 JAPAN A CORP OF JAPAN KK
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Filing: 1987-08-31
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Granted: 1990-05-15
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Expires: 2007-08-31
Abstract
Abstract A method and apparatus for sensing the wavelength of a laser beam using an optogalvano effect by atoms or molecules in plasma. Atoms or molecules in the plasma are irradiated with the laser beam. The impedance of the plasma at that time is sensed to sense whether the wavelength of the laser beam coincides with a predetermined absolute wavelength. The sensed result is used to control the wavelength of the laser beam.
Inventors
- 👤 Koichi Kajiyama
- 👤 Kaoru Saito
- 👤 Yasuo Itakura
- 👤 Osamu Wakabayashi
- 👤 Masahiko Kowaka
- 👤 Tadayoshi Yamaguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:22
CPC Classifications
G; G01; G01J; G01J9/00; G01J9/02; G01J9/0246; G01J1/00; G01J1/42; G01J2001/4295; G01J3/00; G01J3/12; G01J3/26
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
51 words
A method of sensing the wavelength of a laser beam as an object to be sensed, comprising the steps of irradiating predetermined atoms or molecules in plasma with the laser beam, sensing the impedance of the plasma at that time, and comparing the impedance with an impedance pattern measured in advance.
Claim 2
Independent Claim
51 words
A method of sensing the wavelength of a laser beam as an object to be sensed, comprising the steps of irradiating predetermined atoms or molecules in plasma with the laser beam, sensing the impedance of the plasma at that time, and comparing the impedance with an impedance pattern measured in advance.
Claim 3
Dependent Claim
41 words
A method of sensing the wavelength of a laser beam according to claim 1, wherein the predetermined atoms or molecules in the plasma perform a specific optical transition for a wavelength in the vicinity of the wavelength of the laser beam.
Claim 4
Independent Claim
95 words
An apparatus for sensing the wavelength of a laser beam, comprising: plasma generating means for generating plasma containing predetermined atoms or molecules; laser irradiating means for irradiating the plasma, generated by the plasma generating means, with a laser beam as an object to be sensed; impedance sensing means for sensing the impedance of the plasma containing predetermined atoms or molecules; and identifying means for comparing the impedance, sensed by the impedance sensing means, with a known impedance pattern measured in advance and identifying the wavelength of the laser beam on the basis of the comparison.
Claim 5
Independent Claim
95 words
An apparatus for sensing the wavelength of a laser beam, comprising: plasma generating means for generating plasma containing predetermined atoms or molecules; laser irradiating means for irradiating the plasma, generated by the plasma generating means, with a laser beam as an object to be sensed; impedance sensing means for sensing the impedance of the plasma containing predetermined atoms or molecules; and identifying means for comparing the impedance, sensed by the impedance sensing means, with a known impedance pattern measured in advance and identifying the wavelength of the laser beam on the basis of the comparison.
Claim 6
Dependent Claim
50 words
An apparatus for sensing the wavelength of a laser beam according to claim 3, wherein the plasma generating means comprises a gas containing predetermined atoms or molecules enclosed between a first and a second electrodes, the first electrode being grounded and the second electrode being impressed with a high voltage.
Claim 7
Dependent Claim
26 words
An apparatus for sensing the wavelength of a laser beam according to claim 4, wherein the gas containing predetermined atoms or molecules is a rare gas.
Claim 8
Dependent Claim
32 words
An apparatus for sensing the wavelength of a laser beam according to claim 4, wherein the impedance sensing means senses changes in an electric current flowing across the first and second electrodes.
Claim 9
Dependent Claim
24 words
An apparatus for sensing the wavelength of a laser beam according to claim 3, wherein the plasma generating means includes a hollow cathode lamp.
Claim 10
Dependent Claim
36 words
An apparatus for sensing the wavelength of a laser beam according to claim 3, wherein scanning means controls wavelength selecting means in the laser oscillator which oscillates the laser beam as an object to be sensed.
Claim 11
Independent Claim
127 words
An apparatus for sensing the wavelength of a laser beam, comprising: plasma generating means for generating plasma containing predetermined atoms or molecules; laser irradiating means for irradiating the plasma, generated by the plasma generating means, with part of the laser beam output from a laser oscillator; impedance sensing means for sensing the impedance of the plasma containing predetermined atoms or molecules; identifying means for comparing the impedance, sensed by the impedance sensing means, with a known impedance pattern measured in advance and identifying the wavelength of the laser beam output from the laser oscillator on the basis of the comparison; and control means for controlling the wavelength of the laser beam output from the laser oscillator on the basis of the wavelength identified by the identifying means.
Claim 12
Independent Claim
127 words
An apparatus for sensing the wavelength of a laser beam, comprising: plasma generating means for generating plasma containing predetermined atoms or molecules; laser irradiating means for irradiating the plasma, generated by the plasma generating means, with part of the laser beam output from a laser oscillator; impedance sensing means for sensing the impedance of the plasma containing predetermined atoms or molecules; identifying means for comparing the impedance, sensed by the impedance sensing means, with a known impedance pattern measured in advance and identifying the wavelength of the laser beam output from the laser oscillator on the basis of the comparison; and control means for controlling the wavelength of the laser beam output from the laser oscillator on the basis of the wavelength identified by the identifying means.
Claim 13
Independent Claim
172 words
An apparatus for sensing the wavelength of a laser beam, comprising: plasma generating means for generating plasma containing predetermined atoms or molecules; laser irradiating means for irradiating the plasma, generated by the plasma generating means, with part of the laser beam output from a laser oscillator; impedance sensing means for sensing the impedance of the plasma containing predetermined atoms or molecules; identifying means for comparing the impedance, sensed by the impedance sensing means, with a known impedance pattern measured in advance and identifying the wavelength of the laser beam output from the laser oscillator on the basis of the comparison; first control means for controlling the wavelength of the laser beam output from the laser oscillator on the basis of the wavelength identified by the identifying means; wavelength sensing means for sensing the wavelength of the laser beam output from the laser oscillator; and second control means for further controlling the wavelength of the laser beam output from the laser oscillator on the basis of the output from the wavelength sensing means.
Claim 14
Independent Claim
172 words
An apparatus for sensing the wavelength of a laser beam, comprising: plasma generating means for generating plasma containing predetermined atoms or molecules; laser irradiating means for irradiating the plasma, generated by the plasma generating means, with part of the laser beam output from a laser oscillator; impedance sensing means for sensing the impedance of the plasma containing predetermined atoms or molecules; identifying means for comparing the impedance, sensed by the impedance sensing means, with a known impedance pattern measured in advance and identifying the wavelength of the laser beam output from the laser oscillator on the basis of the comparison; first control means for controlling the wavelength of the laser beam output from the laser oscillator on the basis of the wavelength identified by the identifying means; wavelength sensing means for sensing the wavelength of the laser beam output from the laser oscillator; and second control means for further controlling the wavelength of the laser beam output from the laser oscillator on the basis of the output from the wavelength sensing means.
Claim 15
Dependent Claim
23 words
An apparatus for sensing the wavelength of a laser beam according to claim 10, wherein the wavelength sensing means includes a monitor etalon.
References Cited (Backward Citations)
US4451766A
Cited
US4450565A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-05-14 | 1993-11-13 | 1994-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-14 | 1997-11-13 | 1998-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-14 | 2001-11-13 | 2002-05-15 | $7700.00 | Window Closed / Lapsed |