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US5289309A
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Optical frequency doubler using quantum well semiconductor structures
Assignee: Thales SA
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Filing: 1993-01-21
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Granted: 1994-02-22
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Expires: 2013-01-21
Abstract
Abstract Disclosed is a frequency doubler having a quantum well semiconductor structure and a second-order non-linear susceptibility grating that can be used to amplify notably the frequency doubling. The grating can be recorded optically or electrically within the semiconductor structure and has a pitch in the plane of the structure. Such a frequency doubler finds particular application to optical recording or reading systems.
Inventors
- 👤 Dominique Delacourt
- 👤 Jean-Claude Pocholle
- 👤 Michel Papuchon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:14
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/35; G02F1/37; B; B82; B82Y; B82Y20/00; G02F1/355; G02F1/3556; G02F1/01; G02F1/0126; G02F1/015; G02F1/017; G02F1/01725; G02F1/0175; G02F1/01758; G02F1/21; G02F1/353; G02F1/3544; G02F1/3548; G02F2201/00; G02F2201/12; G02F2201/124
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
182 words
An electromagnetic wave frequency doubler, the electromagnetic wave having a wavelength λw, with a semiconductor structure comprising a stack of layers constituted by semiconductor materials enabling the creation of potential wells, wherein there are at least two discrete energy levels e 1 and e 2 in the wells such that e 1 is smaller than e 2 , the density of probability of the presence of electrons on e 2 is an asymmetrical function and said doubler comprises a second-order non-linear susceptibility grating resulting from the populating, with electrons, of the level e 1 and from this asymmetry, the pitch of the grating being in the plane of the layers, said grating being optically controllable by an optical beam with a wavelength λp that locally and periodically irradiates the semiconductor structure so as to locally populate the energy level e 1 with electrons and said grating making it possible to carry out the phase matching between the polarization created by an incident electromagnetic wave and a created harmonic wave, the two waves getting propagated in the plane of the stack of layers.
Claim 2
Dependent Claim
182 words
An electromagnetic wave frequency doubler, the electromagnetic wave having a wavelength λw, with a semiconductor structure comprising a stack of layers constituted by semiconductor materials enabling the creation of potential wells, wherein there are at least two discrete energy levels e 1 and e 2 in the wells such that e 1 is smaller than e 2 , the density of probability of the presence of electrons on e 2 is an asymmetrical function and said doubler comprises a second-order non-linear susceptibility grating resulting from the populating, with electrons, of the level e 1 and from this asymmetry, the pitch of the grating being in the plane of the layers, said grating being optically controllable by an optical beam with a wavelength λp that locally and periodically irradiates the semiconductor structure so as to locally populate the energy level e 1 with electrons and said grating making it possible to carry out the phase matching between the polarization created by an incident electromagnetic wave and a created harmonic wave, the two waves getting propagated in the plane of the stack of layers.
Claim 3
Dependent Claim
57 words
A frequency doubler according to claim 1, wherein the semiconductor structure comprises at least one set of materials M I , M II , M III and M IV so as to define asymmetrical quantum wells having two different central gap widths, the wells having at least two discrete energy levels e 1 and e 2 .
Claim 4
Dependent Claim
62 words
A frequency doubler according to either of the claims 1 or 2, wherein two optical beams forming angles θ on each side of the normal to the plane of the layers irradiate the entire structure and define interference fringes capable of periodically forming regions of second-order non-linear susceptibility χ.sup.(2) separated by regions of second-order non-linear susceptibility with values far smaller than χ.sup.(2).
Claim 5
Dependent Claim
18 words
A frequency doubler according to either of claims 1 or 2, where λp is close to 0.8 μm.
Claim 6
Dependent Claim
18 words
A frequency doubler according to either of claims 1 or 2, where λw is close to 10 μm.
Claim 7
Dependent Claim
77 words
A frequency doubler according to claim 1, wherein the semiconductor structure includes at least one set of layers of materials M' 1 , M' II , M' III and M' IV so as to define quantum wells having three central gap widths E'g II , E'g III and E'g IV , with E'g III and the quantum wells being made asymmetrical by the application of an electrical field that is perpendicular to the plane of the layers.
Claim 8
Dependent Claim
171 words
An electromagnetic wave frequency doubler, the electromagnetic wave having a wavelength λw, comprising: a stack of layers formed of semiconductor materials for forming potential wells, wherein there is at least two discrete energy levels e 1 and e 2 in the potential wells such that e 1 is smaller than e 2 , and a density of probability of a presence of electrons on e 2 is an asymmetrical function; a second-order non-linear susceptibility grating resulting from populating, with electrons, of the level e 1 and from the asymmetrical function, a pitch of the grating being in a plane of the stack of layers, said grating being optically controllable by an optical beam with a wavelength λp that locally and periodically irradiates the stack of layers so as to locally populate the energy level e 1 with electrons and said grating providing phase matching between a polarization created by an incident electromagnetic wave and a created harmonic wave, these two waves being propagated in the plane of the stack of layers.
Claim 9
Dependent Claim
171 words
An electromagnetic wave frequency doubler, the electromagnetic wave having a wavelength λw, comprising: a stack of layers formed of semiconductor materials for forming potential wells, wherein there is at least two discrete energy levels e 1 and e 2 in the potential wells such that e 1 is smaller than e 2 , and a density of probability of a presence of electrons on e 2 is an asymmetrical function; a second-order non-linear susceptibility grating resulting from populating, with electrons, of the level e 1 and from the asymmetrical function, a pitch of the grating being in a plane of the stack of layers, said grating being optically controllable by an optical beam with a wavelength λp that locally and periodically irradiates the stack of layers so as to locally populate the energy level e 1 with electrons and said grating providing phase matching between a polarization created by an incident electromagnetic wave and a created harmonic wave, these two waves being propagated in the plane of the stack of layers.
Claim 10
Dependent Claim
60 words
The frequency doubler according to claim 7, wherein the stack of layers comprises at least one set of materials, M I , M II , M III and M IV so as to define asymmetrical quantum potential wells having two different central gap widths, the potential wells having at least two discrete energy levels e 1 and e 2 .
Claim 11
Dependent Claim
63 words
The frequency doubler according to either of claims 7 or 8, wherein two optical beams forming angles θ on each side of a normal to the plane of the stack of layers irradiate the stack of layers and define interference fringes capable of periodically forming regions of second-order non-linear susceptibility χ(2) separated by regions of second-order non-linear susceptibility with values smaller than χ(2).
Claim 12
Dependent Claim
16 words
The frequency doubler according to either of claims 7 or 8, wherein λp equals 0.8 μm.
Claim 13
Dependent Claim
16 words
The frequency doubler according to either of claims 7 or 8, wherein λw equals 10 μm.
Claim 14
Dependent Claim
93 words
The frequency doubler according to claim 7, wherein the stack of layers includes at least one set of layers of materials M' I , M' II , M' III and M' IV so as to define quantum potential wells having three central gap widths, E'g II , E'g III and E'g IV , with E'g II and E'g IV being equal and being greater than E'g III and the quantum potential wells being made asymmetrical by an application of an electrical field that is perpendicular to the plane of the stack of layers.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-02-21 | 1997-08-23 | 1998-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-02-21 | 2001-08-23 | 2002-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-02-21 | 2005-08-23 | 2006-02-22 | $7700.00 | Window Closed / Lapsed |