US4806993A
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US
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Method and device for rapid photo-detection by means of a super-lattice
Assignee: Centre National de la Recherche Scientifique
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Filing: 1986-09-02
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Granted: 1989-02-21
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Expires: 2006-09-02
Abstract
Abstract To detect a temporal variation, in particular an ultrashort pulse, in a beam of electromagnetic radiation, this beam is applied to a super-lattice of type II, along its axis of growth, and the voltage between the opposite sides of the network along the same axis is determined. The super-lattice is preferably a composite super-lattice, in particular, with alternate layers of indium arsenide and of gallium antimonide. The method is, in particular, applied in the infrared range.
Inventors
- 👤 Paul Voisin
- 👤 Jose A. Brum
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:29
CPC Classifications
B; B82; B82Y; B82Y20/00; H; H10; H10F; H10F30/00; H10F30/20; H10F30/21; H10F77/00; H10F77/10; H10F77/14; H10F77/146
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
81 words
A method for detecting a very short temporal variation in a beam of electromagnetic radiation, including the steps of: (a) applying said beam to a super-lattice of type II in a direction along its axis of growth, said super-lattice responding to said temporal variation by a photovoltaic effect thereby generating a voltage difference within said super-lattice along said axis of growth thereof; and (b) sensing variations of said voltage difference between opposite sides of the super-lattice along said axis of growth.
Claim 2
Independent Claim
81 words
A method for detecting a very short temporal variation in a beam of electromagnetic radiation, including the steps of: (a) applying said beam to a super-lattice of type II in a direction along its axis of growth, said super-lattice responding to said temporal variation by a photovoltaic effect thereby generating a voltage difference within said super-lattice along said axis of growth thereof; and (b) sensing variations of said voltage difference between opposite sides of the super-lattice along said axis of growth.
Claim 3
Dependent Claim
13 words
A method according to claim 1, wherein the super-lattice is a composite super-lattice.
Claim 4
Dependent Claim
26 words
A method according to claim 1, wherein the super-lattice is formed of one of the group comprising semiconductor compounds III, IV and V, and alloys thereof.
Claim 5
Dependent Claim
54 words
A method according to claim 2, wherein the super-lattice is a periodic laminant of layers of first and second different compounds having first and second thicknesses chosen so that the lower limit of the conduction band of said first compound is lower than the upper limit of the valence band of the second compound.
Claim 6
Dependent Claim
26 words
A method according to claim 4, wherein one of said first and second compounds comprises indium arsenide and the other of said compounds comprises gallium antimonide.
Claim 7
Dependent Claim
29 words
A method according to claim 5, wherein one of said first and second compounds is indium arsenide and the other of said first and second compounds is gallium antimonide.
Claim 8
Dependent Claim
18 words
A method according to claim 6, wherein said first and second thicknesses are less than about 300 angstroms.
Claim 9
Dependent Claim
18 words
A method according to claim 7, wherein said first and second thicknesses are less than about 200 angstroms.
Claim 10
Dependent Claim
25 words
A method according to claim 6, wherein the thicknesses of the layers of at least one of said first and second compounds are substantially equal.
Claim 11
Dependent Claim
31 words
A method according to claim 9, wherein the thicknesses of the indium arsenide layers are about 30 angstroms and the thicknesses of the layers of gallium antimonide are about 50 angstroms.
Claim 12
Dependent Claim
34 words
A method according to claim 6, wherein the indium arsenide is doped N, while the gallium antimonide is doped P, both dopings being close to the residual dopings of indium arsenide and gallium antimonide.
Claim 13
Dependent Claim
28 words
A method according to claim 4 wherein the laminate comprises approximately 100 pairs of layers for a total thickness of a few micrometers along the axis of growth.
Claim 14
Dependent Claim
27 words
A method according to claim 1, wherein the super-lattice has an overall asymmetry of reflection along its growth axis relative to the incident beam of electromagnetic radiation.
Claim 15
Dependent Claim
16 words
A method according to claim 13, wherein the super-lattice comprises an integral number of spatial periods.
Claim 16
Dependent Claim
28 words
A method according to claim 13, wherein said overall asymmetry of reflection is at least partly due to the absorption of light in the layers of the super-lattice.
Claim 17
Dependent Claim
93 words
Means for detecting a temporal variation in a beam of electromagnetic radiation, said means comprising: (a) a super-lattice of type II having an axis of growth, said super-lattice responding to said temporal variation by a photovoltaic effect thereby generating a voltage difference therein along said axis of growth; (b) means for focusing an incident beam of electromagnetic radiation so that it is propagated substantially along said axis of growth of the super-lattice; and (c) measuring means for measuring a transient potential difference between opposite sides of the super-lattice along said axis of growth.
Claim 18
Dependent Claim
93 words
Means for detecting a temporal variation in a beam of electromagnetic radiation, said means comprising: (a) a super-lattice of type II having an axis of growth, said super-lattice responding to said temporal variation by a photovoltaic effect thereby generating a voltage difference therein along said axis of growth; (b) means for focusing an incident beam of electromagnetic radiation so that it is propagated substantially along said axis of growth of the super-lattice; and (c) measuring means for measuring a transient potential difference between opposite sides of the super-lattice along said axis of growth.
Claim 19
Dependent Claim
15 words
Detection means according to claim 16, wherein said super-lattice is formed on a conductive substrate.
Claim 20
Dependent Claim
34 words
Detection means according to claim 16, wherein an impedance of the measuring means is selected in view of a desired value of the time constant of a trailing edge of said transient potential difference.
Claim 21
Dependent Claim
65 words
Detection means according to claim 16, wherein said super-lattice is a composite super-lattice made of at least a first compound having a conduction band and a second component having a valence band, said conduction and valence bands overlapping each other, and wherein the super-lattice has a spatial periodicity chosen so as to make it sensitive to a predetermined band of wavelengths of the incident radiation.
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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) | 1992-02-21 | 1992-08-22 | 1993-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-21 | 1996-08-22 | 1997-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-21 | 2000-08-22 | 2001-02-21 | $7700.00 | Window Closed / Lapsed |