US3870397A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thin film magneto-optic switch
Assignee: AT&T Inc
•
Filing: 1973-11-13
•
Granted: 1975-03-11
•
Expires: 1993-11-13
Abstract
Abstract A device is described for switching the direction of visible and near-visible electromagnetic radiation traveling in the plane of a thin film of magnetic material. The invention is based on the interaction of electromagnetic radiation with patterned regions (such as a diffraction grating or a waveguiding strip) whose coercivity is different from that of the area surrounding the regions.
Inventors
- 👤 Jr Joseph Francis Dillon
- 👤 Ernst Michael Gyorgy Madison
- 👤 Uitert Legrand Gerard Van
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:04
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/09; G02F1/095; G02F1/29; G02F1/31; G02F1/313
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
168 words
Device comprising a thin magnetic film transparent to electromagnetic radiation propagating in the plane of the film, means for inserting electromagnetic radiation into the film, means for extracting energy corresponding to radiation traveling in the plane of the film, means for magnetically biasing the film characterized in that said device has a pattern defined by a region of a composition different from the composition of the area surrounding the region and whose coercivity is different from that of the area surrounding said regions, said difference in coercivity being due to said different composition and allowing said regions to be switched selectively by means of an external magnetic field between at least two magnetic states, in at least one of said states the regions being magnetically saturated and in at least one of said states their magnetization having a component in the direction of propagation of said electromagnetic radiation, said electromagnetic radiation being caused to follow a path which differs in accordance with said magnetic state of said regions.
Claim 2
Dependent Claim
168 words
Device comprising a thin magnetic film transparent to electromagnetic radiation propagating in the plane of the film, means for inserting electromagnetic radiation into the film, means for extracting energy corresponding to radiation traveling in the plane of the film, means for magnetically biasing the film characterized in that said device has a pattern defined by a region of a composition different from the composition of the area surrounding the region and whose coercivity is different from that of the area surrounding said regions, said difference in coercivity being due to said different composition and allowing said regions to be switched selectively by means of an external magnetic field between at least two magnetic states, in at least one of said states the regions being magnetically saturated and in at least one of said states their magnetization having a component in the direction of propagation of said electromagnetic radiation, said electromagnetic radiation being caused to follow a path which differs in accordance with said magnetic state of said regions.
Claim 3
Dependent Claim
168 words
Device comprising a thin magnetic film transparent to electromagnetic radiation propagating in the plane of the film, means for inserting electromagnetic radiation into the film, means for extracting energy corresponding to radiation traveling in the plane of the film, means for magnetically biasing the film characterized in that said device has a pattern defined by a region of a composition different from the composition of the area surrounding the region and whose coercivity is different from that of the area surrounding said regions, said difference in coercivity being due to said different composition and allowing said regions to be switched selectively by means of an external magnetic field between at least two magnetic states, in at least one of said states the regions being magnetically saturated and in at least one of said states their magnetization having a component in the direction of propagation of said electromagnetic radiation, said electromagnetic radiation being caused to follow a path which differs in accordance with said magnetic state of said regions.
Claim 4
Dependent Claim
168 words
Device comprising a thin magnetic film transparent to electromagnetic radiation propagating in the plane of the film, means for inserting electromagnetic radiation into the film, means for extracting energy corresponding to radiation traveling in the plane of the film, means for magnetically biasing the film characterized in that said device has a pattern defined by a region of a composition different from the composition of the area surrounding the region and whose coercivity is different from that of the area surrounding said regions, said difference in coercivity being due to said different composition and allowing said regions to be switched selectively by means of an external magnetic field between at least two magnetic states, in at least one of said states the regions being magnetically saturated and in at least one of said states their magnetization having a component in the direction of propagation of said electromagnetic radiation, said electromagnetic radiation being caused to follow a path which differs in accordance with said magnetic state of said regions.
Claim 5
Dependent Claim
16 words
Device of claim 1 in which said patterned regions are magnetically saturated in said two states.
Claim 6
Dependent Claim
40 words
Device of claim 1 in which said patterned regions in one of said magnetic states have essentially the same refractive index as the area surrounding said regions so that said propagating electromagnetic radiation is substantially unaffected by said patterned regions.
Claim 7
Dependent Claim
33 words
Device of claim 1 in which the magnetization of said regions in at least one of said magnetic states has a component of at least 10 percent in the direction of light propagation.
Claim 8
Dependent Claim
15 words
Device of claim 1, electromagnetic radiation being of wavelength of a maxImum of 10 micrometers.
Claim 9
Dependent Claim
24 words
Device of claim 1, the film being of a thickness in range of from one-half to two times the wavelength of the electromagnetic radiation.
Claim 10
Dependent Claim
16 words
Device of claim 1 in which said difference in coercivity amounts to at least 1 percent.
Claim 11
Dependent Claim
18 words
Device of claim 1 in which said magnetic film is a magnetic garnet deposited on a garnet substrate.
Claim 12
Dependent Claim
16 words
Device of claim 1 in which at least one of said means is a prism coupler.
Claim 13
Dependent Claim
16 words
Device of claim 1 in which at least one of said means is a grating coupler.
Claim 14
Dependent Claim
17 words
Device of claim 1 in which said means for inserting electromagnetic radiation is included in the film.
Claim 15
Dependent Claim
12 words
Device of claim 11 in which said included means is a laser.
Claim 16
Dependent Claim
14 words
Device of claim 11 in which said included means is a light emitting diode.
Claim 17
Dependent Claim
18 words
Device of claim 1 in which said means for extracting energy is a light detector integral with film.
Claim 18
Dependent Claim
12 words
Device of claim 1 in which said regions form a diffraction grating.
Claim 19
Dependent Claim
12 words
Device of claim 1 in which said regions form a waveguiding strip.
References Cited (Backward Citations)
US3512867A
Cited
US3666351A
Cited
US3639855A
Cited
US3781081A
Cited
US3781086A
Cited
US3764195A
Cited
US3756690A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-10 | 1978-09-09 | 1979-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-10 | 1982-09-09 | 1983-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-10 | 1986-09-09 | 1987-03-11 | $7700.00 | Window Closed / Lapsed |