US4335935A
Expired / Lapsed
US
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Arrangement for the induced absorption of electromagnetic radiation
Assignee: Jenoptik AG
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Filing: 1980-04-25
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Granted: 1982-06-22
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Expires: 2000-04-25
Abstract
Abstract An absorption device for electromagnetic radiation includes a plurality of layers positioned to the path of the radiation, in the following order: a transparent layer, an absorbing layer, a plurality of non-absorbing layers having alternate low and high refractive indices, and a final transparent layer.
Inventors
- 👤 Hubert Pohlack
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:18
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/20; G02B5/22; G02B5/28; G02B5/285
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
150 words
In an arrangement for the absorption of electromagnetic radiation of a spectral interval including a selectable wavelength λ, comprised of two radiation-permeable materials and one absorbing layer that is very thin as compared to the wavelength, the improvement wherein non-absorbing or only slightly absorbing λ/4 interference layers of low refractive index single layers and high refractive index single layers of refractive indicies n n and n h respectively are alternately arranged in the direction of the incident radiation following said absorbing layer, and that said absorbing layer has a thickness d and an absorption coefficient k such that the relationship n.sub.1.sup.2 A-2n.sub.1 B+C=0 is satisfied, where A=1-(sin nχ).sup.2 +(sin hkχ).sup.2 B=1/2(k sin 2nχ+n sin h2kχ) C=(n.sup.2 +k.sup.2)[(sin nχ).sup.2 +sin hkχ).sup.2 ] and where χ=(2π/λ)·d, n is the refractive index of said absorbing layer, and n 1 is the refractive index of the medium positioned in front of said absorbing layer.
Claim 2
Dependent Claim
150 words
In an arrangement for the absorption of electromagnetic radiation of a spectral interval including a selectable wavelength λ, comprised of two radiation-permeable materials and one absorbing layer that is very thin as compared to the wavelength, the improvement wherein non-absorbing or only slightly absorbing λ/4 interference layers of low refractive index single layers and high refractive index single layers of refractive indicies n n and n h respectively are alternately arranged in the direction of the incident radiation following said absorbing layer, and that said absorbing layer has a thickness d and an absorption coefficient k such that the relationship n.sub.1.sup.2 A-2n.sub.1 B+C=0 is satisfied, where A=1-(sin nχ).sup.2 +(sin hkχ).sup.2 B=1/2(k sin 2nχ+n sin h2kχ) C=(n.sup.2 +k.sup.2)[(sin nχ).sup.2 +sin hkχ).sup.2 ] and where χ=(2π/λ)·d, n is the refractive index of said absorbing layer, and n 1 is the refractive index of the medium positioned in front of said absorbing layer.
Claim 3
Dependent Claim
92 words
An arrangement according to claim 1, wherein the number, p, of layers capable of interference, comprised of alternately low refractive index single layers of refractive index n n and high refractive index single layers of refractive index n h and the relations of their refractive indices as well as the refraction index n p+1 of the final layer are chosen such that the product ##EQU4## when p is an even number, is small compared to 1 and that the product ##EQU5## when p is an odd number, is small compared to 1.
Claim 4
Dependent Claim
31 words
An arrangement according to claim 1 wherein the layers capable of interference are dimensioned such that the equation n.sub.1.sup.2 A-2n.sub.1 B+C=0 is satisfied when A=1-(nχ).sup.2 +(kχ).sup.2 B=2nkχ C=(n.sup.2 +k.sup.2)[(nχ).sup.2 +(kχ).sup.2 ].
Claim 5
Dependent Claim
144 words
An arrangement, for the absorption of electromagnetic radiation of a given wavelength within the spectral content of a source of radiation, comprising a plurality of layers positioned to receive radiation from said source in the following order: (a) a first transparent layer (b) an absorbing layer (c) a plurality of substantially non-absorbing λ/4 layers having alternate low and high refractive indices, and (d) a final transparent layer, the thickness of the absorbing layers satisfying the relationship: n.sub.1.sup.2 A-2n.sub.1 B+C=0 where: A=1-(sin nχ).sup.2 +sin hkχ).sup.2 B=1/2(k sin 2n)(÷n sin h2kχ) C=(n.sup.2 +k.sup.2)[(sin nχ).sup.2 +(sin hkχ).sup.2 ] and χ=2/λd and where λ is the given wavelength, n 1 is the refractive index of the first transparent layer, d is the thickness of the absorbing layer, k is the coefficient of absorption of the absorbing layer, and n is the real refractive index of the absorbing layer.
Claim 6
Dependent Claim
144 words
An arrangement, for the absorption of electromagnetic radiation of a given wavelength within the spectral content of a source of radiation, comprising a plurality of layers positioned to receive radiation from said source in the following order: (a) a first transparent layer (b) an absorbing layer (c) a plurality of substantially non-absorbing λ/4 layers having alternate low and high refractive indices, and (d) a final transparent layer, the thickness of the absorbing layers satisfying the relationship: n.sub.1.sup.2 A-2n.sub.1 B+C=0 where: A=1-(sin nχ).sup.2 +sin hkχ).sup.2 B=1/2(k sin 2n)(÷n sin h2kχ) C=(n.sup.2 +k.sup.2)[(sin nχ).sup.2 +(sin hkχ).sup.2 ] and χ=2/λd and where λ is the given wavelength, n 1 is the refractive index of the first transparent layer, d is the thickness of the absorbing layer, k is the coefficient of absorption of the absorbing layer, and n is the real refractive index of the absorbing layer.
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) | 1985-06-21 | 1985-12-21 | 1986-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-21 | 1989-12-21 | 1990-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-21 | 1993-12-21 | 1994-06-22 | $7700.00 | Window Closed / Lapsed |