US5420595A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microwave radiation source
Assignee: Columbia University
•
Filing: 1993-10-28
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Granted: 1995-05-30
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Expires: 2013-10-28
Abstract
Abstract A source of collimated beam or beams of microwave electromagnetic radiation pulses comprises a photoconductor substrate having a major surface and an optical radiation source providing a beam of optical radiation pulses for illuminating at least a relatively large aperture region of the major surface. A static electric field, intrinsic or applied, is present at the major surface for driving transient photocurrents generated by the beam of optical radiation pulses. Each beam of microwave electromagnetic radiation pulses emitted from the photoconductor substrate may be steered by varying the angle of incidence of the beam of optical radiation pulses illuminating the major surface, by varying the period of the spatial variation of a static electric field applied to the major surface by means of electrodes, or by varying the period or direction of a periodic intensity variation of a spatially modulated beam of optical radiation pulses on the major surface.
Inventors
- 👤 Xi-Cheng Zhang
- 👤 David H. Auston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:35
CPC Classifications
H; H01; H01Q; H01Q3/00; H01Q3/44; H01Q3/26; H01Q3/2676
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
66 words
A device for producing a collimated beam of microwave electromagnetic radiation pulses, comprising: a photoconductor body having a major, substantially planar surface; illumination means for illuminating at least a relatively large aperture portion of the major surface with a beam of optical radiation pulses, for producing the collimated beam from the photoconductor body in a direction at an angle to the plane of the major surface.
Claim 2
Independent Claim
66 words
A device for producing a collimated beam of microwave electromagnetic radiation pulses, comprising: a photoconductor body having a major, substantially planar surface; illumination means for illuminating at least a relatively large aperture portion of the major surface with a beam of optical radiation pulses, for producing the collimated beam from the photoconductor body in a direction at an angle to the plane of the major surface.
Claim 3
Dependent Claim
14 words
The device of claim 1, wherein the photoconductor body consists essentially of radiation-damaged silicon.
Claim 4
Dependent Claim
15 words
The device of claim 1, wherein the photoconductor body consists essentially of a compound-semiconductor material.
Claim 5
Dependent Claim
43 words
The device of claim 1, further comprising means for controlling the direction of incidence of the beam of optical radiation pulses onto the major surface, providing means for controlling the direction in which the collimated beam of microwave electromagnetic radiation pulses is emitted.
Claim 6
Dependent Claim
18 words
The device of claim 1, wherein the relatively large aperture portion of the major surface is essentially flat.
Claim 7
Dependent Claim
39 words
The device of claim 5, further comprising electrode means on the major surface for producing, upon application of a d.c. voltage, a static electric field in a direction parallel to the relatively large aperture portion of the major surface.
Claim 8
Dependent Claim
31 words
The device of claim 6, wherein the electrode means consists of two electrodes which are spaced apart a distance which is greater than the spatial duration of an optical radiation pulse.
Claim 9
Dependent Claim
14 words
The device of claim 6, wherein the electrode means comprises an array of electrodes.
Claim 10
Dependent Claim
14 words
The device of claim 8, wherein the array of electrodes comprises linear strip electrodes.
Claim 11
Dependent Claim
27 words
The device of claim 9, further comprising electrical biasing means for applying voltages to the electrode means so as to form an essentially sinusoidal pattern of voltages.
Claim 12
Dependent Claim
62 words
The device of claim 1, wherein the illumination means includes spatial modulation means for spatially modulating the intensity of the optical radiation pulses, and wherein the direction of the beam of microwave electromagnetic radiation produced by the device relative to the direction of the beam of optical radiation pulses depends on the spatial modulation of the intensity of the optical radiation pulses.
Claim 13
Dependent Claim
77 words
The device of claim 11, wherein the spatial modulation of the intensity of the optical radiation pulses is periodic in a direction parallel to the major surface of the photoconductor body, and the direction of the beam of microwave electromagnetic radiation pulses produced by the device relative to the direction of the beam of optical radiation pulses depends on the period and the direction of the periodic spatial modulation of the intensity of the optical radiation pulses.
Claim 14
Dependent Claim
30 words
The device of claim 11, wherein the beam of optical radiation pulses is incident on the major surface of the photoconductor body in a direction perpendicular to the major surface.
Claim 15
Dependent Claim
37 words
The device of claim 12, wherein the spatial modulation means of the illumination means comprises a transmission grating through which the beam of optical radiation pulses pass prior to illuminating the major surface of the photoconductor body.
Claim 16
Dependent Claim
52 words
The device of claim 14, wherein the beam of microwave electrical magnetic radiation pulses produced by the device is steered by rotating the transmission grating to change the direction of the periodic spatial modulation of the intensity of the beam of optical radiation pulses illuminating the major surface of the photoconductor body.
Claim 17
Dependent Claim
63 words
The device of claim 11, wherein the spatial modulation means comprises an electrically-controllable liquid crystal modulator through which the beam of optical radiation pulses pass prior to illuminating the major surface of the photoconductor body, and means for providing control signals to the liquid crystal modulator for controlling the spatial modulation of the intensity of the beam of optical radiation pulses passing therethrough.
Claim 18
Dependent Claim
92 words
The device of claim 16, wherein the spatial intensity modulation of the beam of optical radiation pulses after passing through the liquid crystal modulator is periodic in a direction parallel to the major surface of the photoconductor body, and the direction of the beam of microwave electromagnetic radiation pulses produced by the device relative to the direction of the beam of optical radiation pulses depends on the period and the direction of the periodic spatial modulation of the intensity of the optical radiation pulses illuminating the major surface of the photoconductor body.
Claim 19
Dependent Claim
70 words
The device of claim 17, wherein the period of the periodic spatial modulation of the intensity of the optical radiation pulses is determined by the control signals provided by the control means, and the direction of the beam of microwave electromagnetic radiation pulses produced by the device relative to the direction of the beam of optical radiation pulse is changed by altering the control signals provided by the control means.
Claim 20
Dependent Claim
67 words
The device of claim 17, wherein the direction of the periodic spatial modulation of the intensity of the optical radiation pulses is determined by the control signals provided by the control means, and the beam of microwave electromagnetic radiation pulses produced by the device relative to the direction of the beam of optical radiation pulses is changed by altering the control signals provided by the control means.
Claim 21
Dependent Claim
30 words
The device of claim 11, wherein the illumination means includes laser means producing a repetitive sequence of optical radiation pulses each having a pulse duration of less than 1 picosecond.
Claim 22
Dependent Claim
14 words
The device of claim 20, wherein the laser means comprises a colliding-pulse, mode-locked laser.
Claim 23
Dependent Claim
37 words
The device of claim 11, wherein the photoconductor body comprises a semiconductive material having a surface depletion layer beneath the major surface, the depletion layer providing an electric field in the direction perpendicular to the major surface.
Claim 24
Dependent Claim
50 words
The device of claim 11, wherein the photoconductor body comprises a superlattice structure semiconductive material and the major surface of the photoconductor body has a crystallographic orientation in which there exists at the major surface a strain layer producing a piezoelectric field in a direction perpendicular to the major surface.
Claim 25
Dependent Claim
37 words
The device of claim 11, wherein the photoconductor body comprises a semiconductive material and there is formed adjacent the major surface a p-n junction extending over at least the relatively large aperture portion of the major surface.
Claim 26
Dependent Claim
51 words
The device of claim 11, wherein the photoconductor body comprises a semiconductive material and there is formed adjacent the major surface a Schottky barrier junction extending at least over the relatively large aperture portion of the major surface, the Schottky barrier junction being transparent to the beam of optical radiation pulses.
Claim 27
Dependent Claim
112 words
The device of claim 11, wherein the photoconductor body has first and second parallel major surfaces, the first major surface being illuminated by the illumination means, and there being formed on the first and second major surfaces respective electrode means which, when coupled to a voltage bias source, produce an electric field in a direction perpendicular to the first major surface, the respective electrode means formed on the first major surface passing the beam of optical radiation pulses illuminating the first major surface, and at least one of the respective electrode means formed on the first and second major surfaces, passing the beam of microwave electromagnetic radiation pulses produced by the device.
Claim 28
Independent Claim
67 words
A method for producing a directional beam of microwave electromagnetic radiation pulses from a photoconductor body having a major, substantially planar surface, comprising the step of: illuminating at least a relatively large aperture portion of the major surface with a beam of optical radiation pulses, to produce the directional beam from the photoconductor body with main direction at an angle to the plane of the major surface.
Claim 29
Independent Claim
67 words
A method for producing a directional beam of microwave electromagnetic radiation pulses from a photoconductor body having a major, substantially planar surface, comprising the step of: illuminating at least a relatively large aperture portion of the major surface with a beam of optical radiation pulses, to produce the directional beam from the photoconductor body with main direction at an angle to the plane of the major surface.
Claim 30
Dependent Claim
21 words
The method of claim 27, wherein the direction of microwave electromagnetic radiation pulses is controlled by controlling the direction of illumination.
Claim 31
Dependent Claim
26 words
The method of claim 27, wherein the direction of microwave electromagnetic radiation pulses is controlled by controlling biasing voltages applied to electrodes on the photoconductor body.
Claim 32
Dependent Claim
14 words
The method of claim 29, wherein the biasing voltages form an essentially sinusoidal pattern.
Claim 33
Dependent Claim
53 words
The method of claim 27, wherein the intensity of the optical radiation pulses has a spatial modulation, and the direction of the beam of microwave electromagnetic radiation pulses relative to the direction of the beam of optical radiation pulses being dependent on the spatial modulation of the intensity of the optical radiation pulses.
Claim 34
Dependent Claim
74 words
The method of claim 31, wherein the spatial modulation of the intensity of the optical radiation pulses is periodic in a direction parallel to the major surface of the photoconductor body, and the direction of the beam of microwave electromagnetic radiation pulses relative to the direction of the beam of optical radiation pulses being dependent on the period and the direction of the periodic spatial modulation of the intensity of the optical radiation pulses.
Claim 35
Dependent Claim
63 words
The method of claim 32, wherein the step of illuminating the major surface comprises the steps of: generating a beam of optical radiation pulses suitable for illuminating a relatively large aperture portion of the major surface of the photoconductor body; and spatially modulating the intensity of the beam of optical radiation pulses prior to illuminating the major surface of the photoconductor body therewith.
Claim 36
Dependent Claim
64 words
The method of claim 33, wherein the step of spatially modulating the beam of optical radiation pulses includes the step of changing the period of the spatial modulation of the intensity of the beam of optical radiation pulses to cause a change in the direction of the beam of microwave electromagnetic radiation pulses relative to the direction of the beam of optical radiation pulses.
Claim 37
Dependent Claim
67 words
The method of claim 33, wherein the step of spatially modulating the intensity of the beam of optical radiation pulses includes the step of changing the direction of the periodic modulation of the intensity of the beam of optical radiation pulses to cause a change in the direction of the beam of microwave electromagnetic radiation pulses relative to the direction of the beam of optical radiation pulses.
Claim 38
Dependent Claim
29 words
The method of claim 31, wherein the direction of the beam of optical radiation pulses illuminating the major surface of the semiconductor body is perpendicular to the major surface.
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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) | 1998-05-29 | 1998-11-28 | 1999-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-05-29 | 2002-11-28 | 2003-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-05-29 | 2006-11-28 | 2007-05-30 | $7700.00 | Window Closed / Lapsed |