US4947465A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of laser discrimination using stimulated luminescence
Assignee: United States Department of the Navy
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Filing: 1989-07-25
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Granted: 1990-08-07
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Expires: 2009-07-25
Abstract
Abstract A method of determining the nature of an unspecified laser source using the optically and thermally stimulated luminescence characteristics of a single MgS phosphor doped with either Ce, Sm or Eu, Sm ions. The doped MgS phosphor is first exposed to charging radiation thereby allowing electron trapping to occur. Subsequent to the electron trapping, the phosphor is exposed to the energy of an unspecified laser source which frees the trapped electrons. The freed electrons are then available for recombination which results in a specific color luminescence indicative of the type of laser source.
Inventors
- 👤 Veerendra K. Mathur
- 👤 Kishalaya Chakrabarti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 06:53
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7783; C09K11/7784; C09K11/7786; C09K11/7766; C09K11/7767; C09K11/7768
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
74 words
A method of laser discrimination comprising the steps of: (a) Doping a MgS phosphor with Sm 3+ and one of the groups consisting of Ce 3+ , Eu 2+ and Tb 3+ ; (b) Exposing said doped phosphor to charging radiation; and (c) Exposing said charged phosphor from step (b) to an unspecified laser source whereby a specific color luminescence is generated by said phosphor and is indicative of the type of laser source.
Claim 2
Independent Claim
74 words
A method of laser discrimination comprising the steps of: (a) Doping a MgS phosphor with Sm 3+ and one of the groups consisting of Ce 3+ , Eu 2+ and Tb 3+ ; (b) Exposing said doped phosphor to charging radiation; and (c) Exposing said charged phosphor from step (b) to an unspecified laser source whereby a specific color luminescence is generated by said phosphor and is indicative of the type of laser source.
Claim 3
Dependent Claim
56 words
A method according to claim 1 wherein said step of doping comprises the steps of: (a) mixing MgS with Sm 3+ and one of the group consisting of Ce 3+ , Eu 2+ and Tb 3+ ; and (b) firing said mixture at 1150° C. in the presence of argon and H 2 SO 4 .
Claim 4
Dependent Claim
16 words
A method according to claim 1 wherein said charging radiation is gamma, X or ultraviolet radiation.
Claim 5
Dependent Claim
21 words
A method according to claim 1 wherein said charging radiation is in visible light having a wavelength of approximately 500 nanometers.
Claim 6
Dependent Claim
20 words
A method according to claim 1 wherein said doped phosphor is exposed to charging radiation for five to ten minutes.
Claim 7
Independent Claim
180 words
A method of discriminating a near infrared laser from a far infrared laser comprising the steps of: (a) doping a MgS phosphor with Sm 3+ and one of the group consisting of Ce 3+ , Eu 2+ and Tb 3+ ; (b) exposing said doped phosphor to charging radiation whereby electrons are trapped by Sm 3+ to form Sm 2+ thereby leaving behind free holes and whereby said free holes are trapped by Ce 3+ , Eu 2+ or Tb 3 + to form Ce 4+ , Eu 3+ or Tb 4+ , respectively; (c) exposing said charged phosphor from step (b) to an unspecified laser source to cause luminescence of said phosphor indicative of the type of laser source, said unspecified laser source being a near infrared laser if said luminescence is caused by the release of said trapped electrons characterized by Ce 3+ , Eu 2+ or Tb 3+ emission and said unspecified laser source being a far infrared laser if said luminescence is caused by the release of said trapped free holes characterized by Sm 3+ emission.
Claim 8
Independent Claim
180 words
A method of discriminating a near infrared laser from a far infrared laser comprising the steps of: (a) doping a MgS phosphor with Sm 3+ and one of the group consisting of Ce 3+ , Eu 2+ and Tb 3+ ; (b) exposing said doped phosphor to charging radiation whereby electrons are trapped by Sm 3+ to form Sm 2+ thereby leaving behind free holes and whereby said free holes are trapped by Ce 3+ , Eu 2+ or Tb 3 + to form Ce 4+ , Eu 3+ or Tb 4+ , respectively; (c) exposing said charged phosphor from step (b) to an unspecified laser source to cause luminescence of said phosphor indicative of the type of laser source, said unspecified laser source being a near infrared laser if said luminescence is caused by the release of said trapped electrons characterized by Ce 3+ , Eu 2+ or Tb 3+ emission and said unspecified laser source being a far infrared laser if said luminescence is caused by the release of said trapped free holes characterized by Sm 3+ emission.
Claim 9
Dependent Claim
20 words
A method according to claim 6 wherein said doped phosphor is exposed to charging radiation for five to ten minutes.
Claim 10
Dependent Claim
16 words
A method according to claim 6 wherein said charging radiation is gamma, X or ultraviolet radiation.
Claim 11
Dependent Claim
20 words
A method according to claim 6 wherein said charging radiation is visible light having a wavelength of approximately 500 nanometers.
References Cited (Backward Citations)
US311A
Cited
US3014147A
Cited
US2979467A
Cited
US3188467A
Cited
US3333101A
Cited
US3229097A
Cited
US3320180A
Cited
US3375372A
Cited
US3637518A
Cited
US3659136A
Cited
US3996472A
Cited
US4230598A
Cited
US4261854A
Cited
US4314743A
Cited
US4507562A
Cited
US4517463A
Cited
US4705952A
Cited
US4806772A
Cited
US4830875A
Cited
US4806757A
Cited
USH311H
Cited
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