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US5291055A
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Resonant infrared detector with substantially unit quantum efficiency
Assignee: United States, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION THE, Administrator of
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Filing: 1992-01-28
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Granted: 1994-03-01
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Expires: 2012-01-28
Abstract
Abstract A resonant infrared detector includes an infrared-active layer which has first and second parallel faces and which absorbs radiation of a given wavelength. The detector also includes a first tuned reflective layer, disposed opposite the first face of the infrared-active layer, which layer reflects a specific portion of the radiation incident thereon and allows a specific portion of the incident radiation at the given wavelength to reach the infrared-active layer. A second reflective layer, disposed opposite the second face of the infrared-active layer, reflects back into the infrared-active layer substantially all of the radiation at the given wavelength which passes through the infrared-active layer. The reflective layers have the effect of increasing the quantum efficiency of the infrared detector relative to the quantum efficiency of the infrared-active layer alone.
Inventors
- 👤 Jam Farhoomand
- 👤 Robert E. McMurray, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:49
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/02; G01J3/0256; G01J3/0259; H; H10; H10F; H10F77/00; H10F77/40; H10F77/413; G01J3/12; G01J3/26
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
187 words
A resonant infrared detector comprising: an infrared-active layer for absorbing radiation of a given wavelength and including first and second parallel faces; a first reflective layer, disposed opposite said first parallel face of said infrared-active layer and having a reflectivity tuned to the absorptivity of said infrared-active layer, for reflecting a specific portion of radiation incident on said first reflective layer during each pass of said radiation through said detector and for allowing a specific portion of said incident radiation at said given wavelength to reach said infrared-active layer; and a second reflective layer, disposed opposite said second parallel face of said infrared-active layer, for reflecting back into said infrared-active layer substantially all of the radiation at said given wavelength that passes through said infrared-active layer, whereby said first and second reflective layers increase the quantum, efficiency of said infrared detector relative to the quantum efficiency of said infrared-active layer alone, wherein said first reflective layer has a reflectivity R and said infrared-active layer has an absorptivity (1-A) per single pass of radiation through said infrared-active layer, and R and A substantially satisfy the following equation: R=A.sup.2.
Claim 2
Dependent Claim
187 words
A resonant infrared detector comprising: an infrared-active layer for absorbing radiation of a given wavelength and including first and second parallel faces; a first reflective layer, disposed opposite said first parallel face of said infrared-active layer and having a reflectivity tuned to the absorptivity of said infrared-active layer, for reflecting a specific portion of radiation incident on said first reflective layer during each pass of said radiation through said detector and for allowing a specific portion of said incident radiation at said given wavelength to reach said infrared-active layer; and a second reflective layer, disposed opposite said second parallel face of said infrared-active layer, for reflecting back into said infrared-active layer substantially all of the radiation at said given wavelength that passes through said infrared-active layer, whereby said first and second reflective layers increase the quantum, efficiency of said infrared detector relative to the quantum efficiency of said infrared-active layer alone, wherein said first reflective layer has a reflectivity R and said infrared-active layer has an absorptivity (1-A) per single pass of radiation through said infrared-active layer, and R and A substantially satisfy the following equation: R=A.sup.2.
Claim 3
Dependent Claim
20 words
An infrared detector according to claim 1, wherein said infrared detector has a quantum efficiency of greater than about 0.30.
Claim 4
Dependent Claim
19 words
An infrared detector according to claim 1, wherein said infrared detector has a quantum efficiency of greater than 0.50.
Claim 5
Dependent Claim
23 words
An infrared detector according to claim 1, wherein said infrared detector has a calculated quantum efficiency of exactly 1.0 when R=A 2 .
Claim 6
Dependent Claim
36 words
An infrared detector according to claim 1, wherein said infrared detector includes an electrical contact at each of said first and second faces of said infrared-active layer for applying an electrical field across said infrared detector.
Claim 7
Dependent Claim
27 words
An infrared detector according to claim 5, wherein each of said electrical contacts comprises an electrically conductive layer which is nonabsorbing of incident radiation said given wavelength.
Claim 8
Dependent Claim
13 words
An infrared detector according to claim 1, wherein said infrared-active layer comprises germanium.
Claim 9
Dependent Claim
14 words
An infrared detector according to claim 1, wherein said infrared-active layer comprises gallium-doped germanium.
Claim 10
Dependent Claim
13 words
An infrared detector according to claim 1, wherein said infrared-active layer comprises silicon.
Claim 11
Dependent Claim
25 words
An infrared detector according to claim 1, wherein said infrared-active layer is produced by depositing a thin film of an infrared-active material on a substrate.
Claim 12
Dependent Claim
80 words
A resonant infrared detector, comprising: an infrared active layer having top and bottom surfaces and an absorptivity (1-A) per single pass of radiation through said infrared active layer; a first reflective layer having a reflectivity R, disposed on said top surface of said infrared active layer; and a second reflective layer, disposed on said bottom surface of said infrared active layer, wherein R and A substantially satisfy an equation: R=A 2 to obtain tuned reflectance in the resonant infrared detector.
Claim 13
Dependent Claim
80 words
A resonant infrared detector, comprising: an infrared active layer having top and bottom surfaces and an absorptivity (1-A) per single pass of radiation through said infrared active layer; a first reflective layer having a reflectivity R, disposed on said top surface of said infrared active layer; and a second reflective layer, disposed on said bottom surface of said infrared active layer, wherein R and A substantially satisfy an equation: R=A 2 to obtain tuned reflectance in the resonant infrared detector.
Claim 14
Dependent Claim
23 words
A resonant infrared detector according to claim 11, wherein the resonant infrared detector absorbs said radiation at a fractional intensity according to: ##EQU11##
Claim 15
Dependent Claim
30 words
A resonant infrared detector according to claim 12, wherein the resonant infrared detector operates at a quantum efficiency, and wherein said fractional intensity is substantially equivalent to said quantum efficiency.
Claim 16
Dependent Claim
41 words
A resonant infrared detector according to claim 12, wherein when the resonant infrared detector obtains tuned reflectance, the resonant infrared detector operates substantially at a unit quantum efficiency, and wherein said fractional intensity is substantially equivalent to said unit quantum efficiency.
Claim 17
Dependent Claim
43 words
A resonant infrared detector according to claim 11, wherein the infrared active layer has a thickness and absorption length, and wherein the resonant infrared detector does not require said thickness to be as large as said absorption length to obtain said tuned reflectance.
Claim 18
Independent Claim
155 words
A method of reflecting radiation using a resonant infrared detector, comprising the steps of: (a) reflecting, using a first reflective layer having a reflectivity R, a first portion of the radiation during each pass of the radiation through the resonant infrared detector, and transmitted a second portion of the radiation through the first reflective layer; (b) absorbing a first part of the second portion of the radiation through an infrared active layer having an absorptivity (1-A) per single pass of radiation through the infrared active layer, and transmitting a second part of the second portion of the radiation through the infrared active layer; and (c) reflecting, using a second reflective layer, substantially all of the second part of the second portion of the radiation transmitted in said absorbing step (b) back into the infrared active layer, wherein R and A substantially satisfy an equation: R=A 2 to obtain tuned reflectance in the resonant infrared detector.
Claim 19
Independent Claim
155 words
A method of reflecting radiation using a resonant infrared detector, comprising the steps of: (a) reflecting, using a first reflective layer having a reflectivity R, a first portion of the radiation during each pass of the radiation through the resonant infrared detector, and transmitted a second portion of the radiation through the first reflective layer; (b) absorbing a first part of the second portion of the radiation through an infrared active layer having an absorptivity (1-A) per single pass of radiation through the infrared active layer, and transmitting a second part of the second portion of the radiation through the infrared active layer; and (c) reflecting, using a second reflective layer, substantially all of the second part of the second portion of the radiation transmitted in said absorbing step (b) back into the infrared active layer, wherein R and A substantially satisfy an equation: R=A 2 to obtain tuned reflectance in the resonant infrared detector.
Claim 20
Dependent Claim
19 words
A method according to claim 15, wherein said absorbing step (b) absorbs the radiation at a fractional intensity ##EQU12##
Claim 21
Dependent Claim
29 words
A method according to claim 16, wherein the resonant infrared detector operates substantially at a quantum efficiency, and wherein the fractional intensity is substantially equivalent to the quantum efficiency.
Claim 22
Dependent Claim
39 words
A method according to claim 16, wherein when the resonant infrared detector obtains tuned reflectance, the resonant infrared detector operated substantially at a unit quantum efficiency, and wherein the fractional intensity is substantially equivalent to the unit quantum efficiency.
Claim 23
Dependent Claim
41 words
A method according to claim 15, wherein the infrared active layer has a thickness and absorption length, and wherein the resonant infrared detector does not require the thickness to be as large as the absorption length to obtain the tuned reflectance.
Claim 24
Independent Claim
122 words
A method of reflecting radiation using a resonant infrared detector, comprising the steps of: (a) reflecting, according to a reflectivity R, a first portion of the radiation during each pass of the radiation through the resonant infrared detector, and transmitting a second portion of the radiation; (b) absorbing a first part of the second portion of the radiation transmitted in said reflecting step (a) according to an absorptivity (1-A), and transmitting a second part of the second portion of the radiation; and (c) reflecting substantially all of the second part of the second portion of the radiation transmitted in said absorbing step (b) wherein R and A substantially satisfy an equation: R=A 2 to obtain tuned reflectance in the resonant infrared detector.
Claim 25
Independent Claim
122 words
A method of reflecting radiation using a resonant infrared detector, comprising the steps of: (a) reflecting, according to a reflectivity R, a first portion of the radiation during each pass of the radiation through the resonant infrared detector, and transmitting a second portion of the radiation; (b) absorbing a first part of the second portion of the radiation transmitted in said reflecting step (a) according to an absorptivity (1-A), and transmitting a second part of the second portion of the radiation; and (c) reflecting substantially all of the second part of the second portion of the radiation transmitted in said absorbing step (b) wherein R and A substantially satisfy an equation: R=A 2 to obtain tuned reflectance in the resonant infrared detector.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-02-28 | 1997-08-30 | 1998-03-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-02-28 | 2001-08-30 | 2002-03-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-02-28 | 2005-08-30 | 2006-03-01 | $7700.00 | Window Closed / Lapsed |