US3594064A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Enhanced magneto-optic mirror apparatus
Assignee: EIDP Inc
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Filing: 1969-06-25
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Granted: 1971-07-20
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Expires: 1989-06-25
Abstract
Abstract A transparent medium (usually a prism) having a magnetic mirror of a thin magnetic layer, a conversion matching dielectric layer, and finally a reflecting layer provides enhanced longitudinal Kerr effect conversivity with low ellipticity for reflected radiation. The magnetic mirror converts magnetic signals to signals of electromagnetic radiation and can be used for the optical readout of magnetic tapes.
Inventors
- 👤 John David Bierlein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:01
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10532; G11B11/10541; G11B11/10543; G11B11/10547; G02; G02F; G02F1/00; G02F1/01; G02F1/09
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
164 words
A Kerr magneto-optic device adapted to rotate the plane of polarization of electromagnetic radiation on reflection from a magnetic mirror in response to the magnetization of said mirror which comprises, in sequence and in contact: i. an isotropic incident medium transparent to selected electromagnetic radiation and having a refractive index of n at the boundary to layer (ii); ii. an absorbing magnetic layer the thickness of the magnetic layer being such that dk 0.12 lambda where d is the thickness of the magnetic layer having the imaginary part of its refractive index k at the wavelength, lambda , of the selected radiation; iii. a dielectric layer, the refractive index of the dielectric layer being between n and about n sin theta , where theta is the selected angle of incidence for the selected radiation at the boundary between the incident medium and the first magnetic layer and having a thickness selected to enchance the conversivity of the device; and iv. a metallic reflecting layer.
Claim 2
Dependent Claim
164 words
A Kerr magneto-optic device adapted to rotate the plane of polarization of electromagnetic radiation on reflection from a magnetic mirror in response to the magnetization of said mirror which comprises, in sequence and in contact: i. an isotropic incident medium transparent to selected electromagnetic radiation and having a refractive index of n at the boundary to layer (ii); ii. an absorbing magnetic layer the thickness of the magnetic layer being such that dk 0.12 lambda where d is the thickness of the magnetic layer having the imaginary part of its refractive index k at the wavelength, lambda , of the selected radiation; iii. a dielectric layer, the refractive index of the dielectric layer being between n and about n sin theta , where theta is the selected angle of incidence for the selected radiation at the boundary between the incident medium and the first magnetic layer and having a thickness selected to enchance the conversivity of the device; and iv. a metallic reflecting layer.
Claim 3
Dependent Claim
10 words
Apparatus of claim 1 wherein the incident medium is glass.
Claim 4
Dependent Claim
27 words
Apparatus of claim 1 wherein the incident medium is in the form of a prism having a base angle about equal to the selected angle of incidence.
Claim 5
Dependent Claim
18 words
Apparatus of claim 3 in which the magnetic layer is iron having a thickness less than 200 A.
References Cited (Backward Citations)
US3427092A
Cited
US3474428A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-07-19 | 1975-01-18 | 1975-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-19 | 1979-01-18 | 1979-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-19 | 1983-01-18 | 1983-07-20 | $7700.00 | Window Closed / Lapsed |