EP0487233A2
Expired / Lapsed
EP
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Near field scanning optical microscope and applications thereof
Assignee: AT&T Inc
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Filing: 1991-11-12
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Granted: —
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Expires: 2011-11-12
Abstract
Abstract An optical system useful, e.g., for near-field scanning optical microscopy is provided. The system incorporates a probe 20 having improved properties. In one embodiment, the probe comprises a tapered and partially metallized portion of a single-mode optical fiber 70.
Inventors
- 👤 Robert Eric Betzig
- 👤 Ernst Michael Gyorgy
- 👤 Frances Hellman
- 👤 Jay Kenneth Trautman
- 👤 Raymond Wolfe
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 22:58
CPC Classifications
G; G01; G01Q; G01Q60/00; G01Q60/18; G01Q60/22; G11; G11B; G11B5/00; G11B9/00; G11B9/12; G11B9/14; G11B9/1409; G11B2005/0002; G11B2005/0005; G11B2005/001; G11B2005/0021; G11B27/00; G11B27/36; G11B33/00; G11B33/10; G11B5/02; G11B5/09
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
214 words
An optical system, comprising: a probe, at least a portion of which is optically transmissive at least at a given wavelength, the probe having a distal end; an optical aperture defined in the distal end, the aperture having a diameter smaller than the given wavelength; and means for displacing the probe relative to an object, CHARACTERIZED IN THAT a) the probe comprises a portion of an optical fiber having a core and a cladding, the cladding having an outer surface, there being associated with the fiber at least one guided dielectric mode for radiation of the given wavelength; b) the fiber has a taper region that is adiabatically tapered, at least a portion of the taper region being capable of guiding light of at least the given wavelength; c) the taper region terminates in a substantially flat end face oriented in a plane substantially perpendicular to the fiber, the aperture being defined in the end face; d) the cladding outer surface in the taper region is substantially smooth; and e) at least a portion of the cladding outer surface in the taper region is coated with an opaque material which has a relatively small penetration depth for electromagnetic radiation of the given wavelength, defining a metallic waveguide portion capable of guiding a metallic mode.
Claim 2
Dependent Claim
214 words
An optical system, comprising: a probe, at least a portion of which is optically transmissive at least at a given wavelength, the probe having a distal end; an optical aperture defined in the distal end, the aperture having a diameter smaller than the given wavelength; and means for displacing the probe relative to an object, CHARACTERIZED IN THAT a) the probe comprises a portion of an optical fiber having a core and a cladding, the cladding having an outer surface, there being associated with the fiber at least one guided dielectric mode for radiation of the given wavelength; b) the fiber has a taper region that is adiabatically tapered, at least a portion of the taper region being capable of guiding light of at least the given wavelength; c) the taper region terminates in a substantially flat end face oriented in a plane substantially perpendicular to the fiber, the aperture being defined in the end face; d) the cladding outer surface in the taper region is substantially smooth; and e) at least a portion of the cladding outer surface in the taper region is coated with an opaque material which has a relatively small penetration depth for electromagnetic radiation of the given wavelength, defining a metallic waveguide portion capable of guiding a metallic mode.
Claim 3
Dependent Claim
42 words
The optical system of claim 1, further comprising means for optically coupling a light source to the probe such that at least some light emitted by the source, at least at the given wavelength, enters or exits the probe through the aperture.
Claim 4
Dependent Claim
145 words
The optical system of claim 2, further comprising: a source of electromagnetic radiation, to be referred to as a "light source"; a scan generator for driving the displacement means such that the probe is displaced in a raster pattern adjacent a portion of a surface of the sample; transducive means for detecting at least a portion of the light from the light source which enters or exits the probe, and for generating an electrical signal in response to the detected light; far-field microscopic means for viewing at least a portion of the probe and at least a portion of the object; and video display means, in signal-receiving relationship to the transducive means, for displaying a two-dimensional image which relates to the amount of detected light at least at some displacements of the probe relative to the sample, the displacements being part of the raster pattern.
Claim 5
Dependent Claim
43 words
The optical system of claim 3, where in the transducive means are adapted to generate analog electrical signals, and the system further comprises means for converting the analog electrical signals to digital signals and transmitting the digital signals to the video display means.
Claim 6
Dependent Claim
21 words
The optical system of claim 4, further comprising storage means for digitally recording at least a portion of the digital signals.
Claim 7
Dependent Claim
37 words
The optical system of claim 5, further comprising means for digitally processing the digital signals, the digital processing means being in receiving relationship with the analog-to-digital conversion means and in transmissive relationship to the video display means.
Claim 8
Dependent Claim
63 words
The optical system of claim 1, further comprising: a source of electromagnetic radiation capable of stimulating at least a portion of said object to emit fluorescent light, said source optically coupled to the probe such that radiation is transmitted from the source, through the probe, to said object; and means for detecting at least a portion of fluorescent light emitted by said object.
Claim 9
Dependent Claim
79 words
The optical system of claim 1, further comprising: a source of electromagnetic radiation capable of stimulating an object to emit fluorescent light at least at the given wavelength; and means for supporting the object relative to the radiation source and the probe such that at least a portion of the radiation emitted by the source impinges on the object and at least a portion of the fluorescent light emitted by the object enters the probe through the optical aperture.
Claim 10
Dependent Claim
33 words
The optical system of claim 1, wherein a cutoff diameter is defined for the metallic mode, and the end face has a diameter that is less than or equal to the cutoff diameter.
Claim 11
Dependent Claim
64 words
The optical system of claim 9, wherein: the end face is substantially free of overlying opaque material; the fiber has, at each longitudinal position, a cladding outer diameter; in at least a portion of the metallic waveguide portion, referred to as the "evanescent region", the cladding outer diameter is smaller than the cut off diameter; and the aperture substantially coincides with the end face.
Claim 12
Dependent Claim
44 words
The optical system of claim 9, wherein: the end face diameter is approximately equal to the cutoff diameter; and the probe further comprises an annular layer of opaque material overlying the end face, such that the annular layer surrounds, and thereby defines, the aperture.
Claim 13
Dependent Claim
61 words
The optical system of claim 9, wherein: the ratio of the cutoff diameter to the aperture diameter is denoted a; the metallic mode is the TE11 mode; the taper angle is denoted ;8; a is at least about 2 and at most about 8; and the probe has a transmission coefficient, denoted T, which, when expressed in decibels, satisfies the relation
Claim 14
Dependent Claim
33 words
The optical system of claim 11, wherein the aperture has a center, the end face has a center, and the center of the aperture is displaced from the center of the end face.
Claim 15
Independent Claim
271 words
A method for examining a specimen, comprising the steps of producing a magnified image of at least a portion of the specimen; and visually examining the image, CHARACTERIZED IN THAT the image-producing step comprises situating a probe adjacent a first surface of the specimen and distant from the first surface by no more than a given wavelength, impinging electromagnetic radiation on the specimen, collecting electromagnetic radiation emitted by the first surface, and detecting at least a portion of the collected radiation, the impinging radiation being emanated from the probe and being of at least the given wavelength, or the collected radiation being collected by the probe and being of at least the given wavelength, wherein: a) the probe comprises a portion of an optical fiber having a core and a cladding, the cladding having an outer surface, there being associated with the fiber at least one guided dielectric mode for radiation of the given wavelength; b) the fiber has a taper region that is adiabatically tapered, at least a portion of the taper region being capable of guiding light of at least the given wavelength; c) the taper region terminates in a substantially flat end face oriented in a plane substantially perpendicular to the fiber, the aperture being defined in the end face; d) the cladding outer surface in the taper region is substantially smooth; and e) at least a portion of the cladding outer surface in the taper region is coated with an opaque material which has a relatively small penetration depth for electromagnetic radiation of the given wavelength, defining a metallic waveguide portion capable of guiding a metallic mode.
Claim 16
Independent Claim
271 words
A method for examining a specimen, comprising the steps of producing a magnified image of at least a portion of the specimen; and visually examining the image, CHARACTERIZED IN THAT the image-producing step comprises situating a probe adjacent a first surface of the specimen and distant from the first surface by no more than a given wavelength, impinging electromagnetic radiation on the specimen, collecting electromagnetic radiation emitted by the first surface, and detecting at least a portion of the collected radiation, the impinging radiation being emanated from the probe and being of at least the given wavelength, or the collected radiation being collected by the probe and being of at least the given wavelength, wherein: a) the probe comprises a portion of an optical fiber having a core and a cladding, the cladding having an outer surface, there being associated with the fiber at least one guided dielectric mode for radiation of the given wavelength; b) the fiber has a taper region that is adiabatically tapered, at least a portion of the taper region being capable of guiding light of at least the given wavelength; c) the taper region terminates in a substantially flat end face oriented in a plane substantially perpendicular to the fiber, the aperture being defined in the end face; d) the cladding outer surface in the taper region is substantially smooth; and e) at least a portion of the cladding outer surface in the taper region is coated with an opaque material which has a relatively small penetration depth for electromagnetic radiation of the given wavelength, defining a metallic waveguide portion capable of guiding a metallic mode.
Claim 17
Dependent Claim
39 words
The method of claim 14, wherein the specimen has a second surface, the impinging step comprises impinging radiation on the second surface, and the radiation emitted by the first surface is radiation that has been transmitted through the specimen.
Claim 18
Dependent Claim
24 words
The method of claim 14, wherein the impinging step comprises impinging radiation on the first surface, and the collecting step comprises collecting reflected radiation.
Claim 19
Dependent Claim
46 words
The method of claim 14, wherein the impinging step comprises impinging radiation on the first surface, the impinged radiation comprises radiation of at least one wavelength capable of exciting fluorescence in at least a portion of the specimen, and the collecting step comprises collecting fluorescent light.
Claim 20
Independent Claim
257 words
A method for patterning a surface, comprising the steps of: a) providing a workpiece having a surface to be patterned; and b) impinging light of at least a given wavelength on the surface such that at least a portion of the impinged light is incident from, or reflected or transmitted to, an optical aperture, CHARACTERIZED IN THAT the impinging step further comprises: c) situating a probe adjacent the surface, the probe having an end face and the optical aperture defined in the end face, the distance between the aperture and the surface being at most about one given wavelength; and wherein: d) the probe comprises a portion of an optical fiber having a core and a cladding, the cladding having an outer surface, there being associated with the fiber at least one guided dielectric mode for radiation of the given wavelength; e) the fiber has a taper region that is adiabatically tapered, at least a portion of the taper region being capable of guiding light of at least the given wavelength; f) the taper region terminates in a substantially flat end face oriented in a plane substantially perpendicular to the fiber, the aperture being defined in the end face; g) the cladding outer surface in the taper region is substantially smooth; and h) at least a portion of the cladding outer surface in the taper region is coated with an opaque material which has a relatively small penetration depth for electromagnetic radiation of the given wavelength, defining a metallic waveguide portion capable of guiding a metallic mode.
Claim 21
Independent Claim
257 words
A method for patterning a surface, comprising the steps of: a) providing a workpiece having a surface to be patterned; and b) impinging light of at least a given wavelength on the surface such that at least a portion of the impinged light is incident from, or reflected or transmitted to, an optical aperture, CHARACTERIZED IN THAT the impinging step further comprises: c) situating a probe adjacent the surface, the probe having an end face and the optical aperture defined in the end face, the distance between the aperture and the surface being at most about one given wavelength; and wherein: d) the probe comprises a portion of an optical fiber having a core and a cladding, the cladding having an outer surface, there being associated with the fiber at least one guided dielectric mode for radiation of the given wavelength; e) the fiber has a taper region that is adiabatically tapered, at least a portion of the taper region being capable of guiding light of at least the given wavelength; f) the taper region terminates in a substantially flat end face oriented in a plane substantially perpendicular to the fiber, the aperture being defined in the end face; g) the cladding outer surface in the taper region is substantially smooth; and h) at least a portion of the cladding outer surface in the taper region is coated with an opaque material which has a relatively small penetration depth for electromagnetic radiation of the given wavelength, defining a metallic waveguide portion capable of guiding a metallic mode.
Claim 22
Dependent Claim
68 words
The method of claim 18, wherein the surface comprises a recording medium upon which a bit pattern can be impressed; in the impinging step, light is incident on the medium from the optical aperture; and the impinging step results in a localized physical change in the medium such that an optical signal can be modulated by the physical change, the modulation carrying at least one bit of information.
Claim 23
Dependent Claim
54 words
The method of claim 19, wherein the medium is a magnetic medium, and the impinging step results in local heating of the medium above its Curie temperature or above its compensation point, resulting in the formation of a spot where the local magnetization is different from the magnetization of adjacent regions surrounding the spot.
Claim 24
Dependent Claim
19 words
The method of claim 20, wherein the impinging step is performed in the presence of an external magnetic field.
Claim 25
Dependent Claim
24 words
The method of claim 20, wherein the medium is a magnetic alloy comprising at least one rare earth and at least one transition metal.
Claim 26
Dependent Claim
38 words
The method of claim 19, wherein the medium is substantially polycrystalline, and the impinging step results in local heating of a portion of the medium followed by rapid cooling, such that a local, substantially amorphous spot is formed.
Claim 27
Dependent Claim
215 words
The method of claim 18, wherein the providing step comprises: providing a multiplicity of semiconductor wafers, each wafer having a surface to be patterned; the method further comprises: a) setting at least one process parameter; b) processing at least one first wafer according to the process parameter such that a pattern is formed on the surface of the wafer, the pattern having a characteristic dimension; c) measuring the characteristic dimension on the first wafer; d) comparing the characteristic dimension to a predetermined range of values; e) if the characteristic dimension lies outside the predetermined range of values, changing the process parameter to bring the characteristic dimension within the predetermined range of values; f) after (e), processing at least one second wafer according to the process parameter; and g) performing, on at least the second wafer, at least one additional step toward completion of the article; and h) the impinging step comprises, during the measuring step, situating the probe adjacent the patterned surface of the first wafer, impinging light on the surface such that at least a portion of the light is reflected from the surface, the impinging light being emanated from the probe or a portion of the reflected light being collected by the probe, and detecting at least a portion of the reflected light.
Claim 28
Dependent Claim
219 words
The method of claim 18, wherein the providing step comprises providing a multiplicity of substrates, each substrate having a surface layer of magnetic material to be impressed with a bit pattern; the method further comprises: a) setting at least one process parameter; b) processing at least a first substrate according to the process parameter such that a bit pattern is formed in the surface of the substrate; c) sensing the bit pattern in at least the first substrate; d) comparing the sensed bit pattern to a predetermined bit pattern, e) if the sensed bit pattern is different from the predetermined bit pattern, changing the process parameter to bring the sensed and predetermined bit patterns into conformity; f) after (e), processing at least a second substrate according to the process parameter; and g) performing, on at least the second substrate, at least one additional step toward completion of the article; and h) the impinging step comprises, during the sensing step, situating the probe adjacent the patterned surface of the first wafer, impinging light on the surface such that at least a portion of the light is reflected from the surface, the impinging light being emanated from the probe or a portion of the reflected light being collected by the probe, and detecting at least a portion of the reflected light.
Claim 29
Dependent Claim
63 words
The method of claim 18, wherein: the surface comprises a photoresist; the impinging step comprises impinging actinic, electromagnetic radiation on the surface from the optical aperture such that a latent image is formed in the photoresist; and the method further comprises the steps of: developing the photoresist; and exposing the workpiece to an etchant such that a pattern is formed in the surface.
Claim 30
Dependent Claim
65 words
The method of claim 18, further comprising the step of exposing the surface to a chemically reactive liquid or vapor; and wherein the impinging step comprises impinging actinic, electromagnetic radiation on the surface from the optical aperture such that material is formed by the chemical decomposition of the liquid or vapor, the material depositing on and adhering to the surface, whereby the surface is patterned.
References Cited (Backward Citations)
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