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US5354985A
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US
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Near field scanning optical and force microscope including cantilever and optical waveguide
Assignee: Leland Stanford Junior University
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Filing: 1993-06-03
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Granted: 1994-10-11
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Expires: 2013-06-03
Abstract
Abstract A near field scanning optical microscope (NSOM) includes a cantilever which is aligned generally parallel to the surface of a sample. An optical waveguide extends along the cantilever to a tip which protrudes downward from the cantilever. A small aperture at the apex of the tip allows light radiation flowing through the waveguide to be directed toward the sample. The cantilever is vibrated, and variations in its resonant frequency are detected and delivered to a feedback control system to maintain a constant separation between the tip and the sample. The NSOM can also be operated as an atomic force microscope in either a contact or non-contact mode.
Inventors
- 👤 Calvin F. Quate
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:24
CPC Classifications
G; G01; G01Q; G01Q60/00; G01Q60/02; G01Q60/06; B; B82; B82Y; B82Y20/00; B82Y35/00; G01Q20/00; G01Q20/04; G01Q60/18; G01Q60/22; G01Q60/24; G01Q60/38; Y; Y10; Y10S; Y10S977/00; Y10S977/84; Y10S977/849; Y10S977/86; Y10S977/862; Y10S977/863; Y10S977/868; Y10S977/873
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
91 words
A cantilever for use in a near field optical scanning microscope, the cantilever comprising: a flexible cantilever member having a free end and a fixed end, a tip formed near the free end of the cantilever member, the tip extending from the cantilever member in a direction substantially perpendicular to a longitudinal axis of the cantilever member; an optical waveguide positioned along the cantilever member and extending to an apex of the tip, an aperture for allowing light to escape from the waveguide being formed near the apex of the tip.
Claim 2
Dependent Claim
91 words
A cantilever for use in a near field optical scanning microscope, the cantilever comprising: a flexible cantilever member having a free end and a fixed end, a tip formed near the free end of the cantilever member, the tip extending from the cantilever member in a direction substantially perpendicular to a longitudinal axis of the cantilever member; an optical waveguide positioned along the cantilever member and extending to an apex of the tip, an aperture for allowing light to escape from the waveguide being formed near the apex of the tip.
Claim 3
Dependent Claim
33 words
The cantilever of claim 1 wherein the optical waveguide has a first surface and a second surface, the first and second surfaces of the waveguide being substantially planar and parallel to each other.
Claim 4
Dependent Claim
36 words
The cantilever of claim 2 wherein the optical waveguide comprises a channel region, the thickness of the waveguide in the channel region being greater than the thickness of the waveguide in regions outside the channel region.
Claim 5
Dependent Claim
48 words
The cantilever of claim 2 comprising a buffer layer adjacent the second surface of the waveguide, the buffer layer having a ridge region, the thickness of the buffer layer in the ridge region being greater than the thickness of the buffer layer in regions outside the ridge region.
Claim 6
Dependent Claim
20 words
The cantilever of claim 2 wherein the waveguide comprises a means of focusing a beam of light at the tip.
Claim 7
Dependent Claim
14 words
The cantilever of claim 5 wherein the means of focusing comprises a convex lens.
Claim 8
Dependent Claim
14 words
The cantilever of claim 5 wherein the means of focusing comprises a concave lens.
Claim 9
Dependent Claim
15 words
The cantilever of claim 5 wherein the means of focusing comprises a Fresnel zone plate.
Claim 10
Dependent Claim
12 words
The cantilever of claim 1 wherein the tip is conical in shape.
Claim 11
Dependent Claim
12 words
The cantilever of claim 1 wherein the tip is tetrahedral in shape.
Claim 12
Dependent Claim
17 words
The cantilever of claim 1 wherein the cantilever comprises a piezoresistor for detecting bending of the cantilever.
Claim 13
Dependent Claim
11 words
The cantilever of claim 11 wherein the piezoresistor comprises doped silicon.
Claim 14
Dependent Claim
64 words
A near field scanning optical microscope (NSOM) comprising: the cantilever of claim 1; a scanner for scanning the cantilever with respect to a sample positioned in the NSOM; a light source; a means for directing a beam of light from the light source into the optical waveguide of the cantilever; and a means of detecting the beam of light after it strikes the sample.
Claim 15
Dependent Claim
53 words
The NSOM of claim 13 further comprising: a detection means for detecting the deflection of the cantilever; a feedback control system connected to receive the output of the detection means; and a means for altering the distance between the cantilever and the sample in response to an output from the feedback control system.
Claim 16
Dependent Claim
12 words
The NSOM of claim 14 wherein the detection means comprises a piezoresistor.
Claim 17
Dependent Claim
30 words
The cantilever of claim 1 wherein the optical waveguide is capable of carrying light in at least one of the transverse electric (TE) mode and the transverse magnetic (TM) mode.
Claim 18
Dependent Claim
15 words
The cantilever of claim 1 wherein the optical waveguide comprises Si 3 N 4 .
Claim 19
Dependent Claim
19 words
The cantilever of claim 1 wherein the optical waveguide comprises one of a channel waveguide and a film waveguide.
Claim 20
Dependent Claim
27 words
The cantilever of claim 1 further comprising optical energy passing through the waveguide, the waveguide having a thickness approximately equal to one wavelength of said optical energy.
Claim 21
Dependent Claim
15 words
The cantilever of claim 1 further comprising a capacitive plate positioned adjacent said cantilever member.
Claim 22
Dependent Claim
22 words
The cantilever of claim 20 wherein a DC voltage applied to the capacitive plate displaces the cantilever member from a neutral position.
Claim 23
Dependent Claim
22 words
The cantilever of claim 20 wherein an AC voltage applied to the capacitive plate excites a mechanical resonance of the cantilever member.
Claim 24
Dependent Claim
14 words
The cantilever of claim 1 comprising a structure for focusing light at the tip.
Claim 25
Dependent Claim
18 words
The cantilever of claim 1 further comprising a structure for channeling light toward a centerline of the waveguide.
Claim 26
Dependent Claim
15 words
The cantilever of claim 1 wherein the tip is sharpened by an oxidation sharpening process.
Claim 27
Dependent Claim
10 words
The cantilever of claim 11 wherein the piezoresistor is U-shaped.
Claim 28
Dependent Claim
31 words
The cantilever of claim 26 wherein the cantilever member comprises arms extending on opposite sides of an open space, the optical waveguide being formed along a centerline of the cantilever member.
Claim 29
Dependent Claim
21 words
The NSOM of claim 14 wherein the cantilever deflects in response to an attractive force such as van der Waals force.
Claim 30
Dependent Claim
14 words
The NSOM of claim 14 further comprising a capacitive plate positioned adjacent said cantilever.
Claim 31
Dependent Claim
21 words
The NSOM of claim 29 wherein a DC voltage applied to the capacitive plate displaces the cantilever from a neutral position.
Claim 32
Dependent Claim
21 words
The NSOM of claim 29 wherein an AC voltage applied to the capacitive plate excites a mechanical resonance of the cantilever.
Claim 33
Dependent Claim
13 words
The NSOM of claim 14 wherein the detection means comprises a capacitive plate.
Claim 34
Dependent Claim
23 words
The NSOM of claim 32 wherein a DC voltage is applied to the capacitive plate to displace the cantilever from a neutral position.
Claim 35
Dependent Claim
21 words
The NSOM of claim 32 wherein an AC voltage applied to the capacitive plate excites a mechanical resonance of the cantilever.
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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) | 1997-10-10 | 1998-04-11 | 1998-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-10-10 | 2002-04-11 | 2002-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-10-10 | 2006-04-11 | 2006-10-11 | $7700.00 | Window Closed / Lapsed |