US5664036A — High resolution fiber optic probe for near field …

Claim 1

Independent Claim 223 words

A high efficiency, high resolution optical probe comprising: a fiber optic cable having an inner core and an outer cladding, said cable having a distal end which defines an optical probe; said optical probe having a reduced diameter intermediate region and a tapered tip that defines a light transmissive aperture at its tapered extremity; said intermediate region comprising a portion of said inner core and said outer cladding, the inner core and outer cladding of said intermediate region being tapered to define a reduced diameter locus; said tapered tip comprising a portion of said inner core commencing at said reduced diameter locus and protruding longitudinally outwardly to extend beyond said outer cladding; said intermediate region and said tapered tip having different rates of taper, the rate of the taper of said inner core at said reduced diameter locus and the rate of the taper of the inner core of said tip being different from one another and discontinuous at said reduced diameter locus; said rate of taper of said inner core at said reduced diameter locus being such that light propagating in said intermediate region propagates in a guided wave mode; and said rate of taper of said inner core at said tip being such that light propagating in said tapered tip propagates in an evanescent mode for fewer than five optical wavelengths.

Claim 2

Dependent Claim 223 words

A high efficiency, high resolution optical probe comprising: a fiber optic cable having an inner core and an outer cladding, said cable having a distal end which defines an optical probe; said optical probe having a reduced diameter intermediate region and a tapered tip that defines a light transmissive aperture at its tapered extremity; said intermediate region comprising a portion of said inner core and said outer cladding, the inner core and outer cladding of said intermediate region being tapered to define a reduced diameter locus; said tapered tip comprising a portion of said inner core commencing at said reduced diameter locus and protruding longitudinally outwardly to extend beyond said outer cladding; said intermediate region and said tapered tip having different rates of taper, the rate of the taper of said inner core at said reduced diameter locus and the rate of the taper of the inner core of said tip being different from one another and discontinuous at said reduced diameter locus; said rate of taper of said inner core at said reduced diameter locus being such that light propagating in said intermediate region propagates in a guided wave mode; and said rate of taper of said inner core at said tip being such that light propagating in said tapered tip propagates in an evanescent mode for fewer than five optical wavelengths.

Claim 3

Dependent Claim 29 words

The probe of claim 1 wherein the inner core at said tip has an angle of taper on the order of about fifteen (15) degrees to sixty (60) degrees.

Claim 4

Dependent Claim 55 words

The probe of claim 1 wherein the inner core at said tip has an angle of taper selected to achieve a balance between minimizing the impedance mismatch due to reflection and minimizing the optical signal loss due to propagation in the evanescent mode, such that the optical energy transmitted through the aperture is substantially maximized.

Claim 5

Dependent Claim 13 words

The probe of claim 1 wherein said intermediate region is formed by taffy-pulling.

Claim 6

Dependent Claim 14 words

The probe of claim 1 wherein said tip is formed by wet chemical etching.

Claim 7

Dependent Claim 20 words

The probe of claim 1 further comprising a metallic overcoat layer disposed on tip except at said light transmissive aperture.

Claim 8

Dependent Claim 20 words

The probe of claim 6 wherein said metallic overcoat does not extend substantially beyond the tapered extremity of said tip.

Claim 9

Dependent Claim 30 words

The probe of claim 1 wherein said fiber optic cable has a proximal end for coupling to a light source and wherein said light transmissive aperture is a light-emitting aperture.

Claim 10

Dependent Claim 30 words

The probe of claim 1 wherein said fiber optic cable has a proximal end for coupling to a light sensor and wherein said light transmissive aperture is a light-admitting receiver.

Claim 11

Dependent Claim 129 words

A high efficiency, high resolution optical probe comprising: a fiber optic cable having an inner core of a first diameter and an outer cladding, said cable having a distal end which defines an optical probe; said probe having a tapered tip comprising at least two portions, a first portion that gradually reduces in diameter to a second diameter smaller than said first diameter and a second portion that protrudes longitudinally outwardly from said first portion and extends beyond said outer cladding; said first portion supporting light propagation in a guided wave mode and said second portion supporting light propagation in an evanescent mode; said first and second portions defining a discontinuous rate of taper such that said second portion tapers to a point in fewer than five optical wavelengths.

Claim 12

Dependent Claim 129 words

A high efficiency, high resolution optical probe comprising: a fiber optic cable having an inner core of a first diameter and an outer cladding, said cable having a distal end which defines an optical probe; said probe having a tapered tip comprising at least two portions, a first portion that gradually reduces in diameter to a second diameter smaller than said first diameter and a second portion that protrudes longitudinally outwardly from said first portion and extends beyond said outer cladding; said first portion supporting light propagation in a guided wave mode and said second portion supporting light propagation in an evanescent mode; said first and second portions defining a discontinuous rate of taper such that said second portion tapers to a point in fewer than five optical wavelengths.

Claim 13

Dependent Claim 30 words

The probe of claim 10 wherein the inner core of said second portion has an angle of taper on the order of about fifteen (15) degrees to sixty (60) degrees.

Claim 14

Dependent Claim 56 words

The probe of claim 10 wherein the inner core of said second portion has an angle of taper selected to achieve a balance between minimizing the impedance mismatch due to reflection and minimizing the optical signal loss due to propagation in the evanescent mode, such that the optical energy transmitted through the aperture it substantially maximized.

Claim 15

Dependent Claim 13 words

The probe of claim 10 wherein said first portion is formed by taffy-pulling.

Claim 16

Dependent Claim 15 words

The probe of claim 10 wherein said second portion is formed by wet chemical etching.

Claim 17

Dependent Claim 24 words

The probe of claim 10 further comprising a metallic overcoat layer disposed on at least all of said second portion except at the tip.

Claim 18

Dependent Claim 20 words

The probe of claim 15 wherein said metallic overcoat does not extend substantially beyond the tapered extremity of said tip.

Claim 19

Dependent Claim 29 words

The probe of claim 10 wherein said fiber optic cable has a proximal end for coupling to a light source and wherein said second portion defines a light-emitting aperture.

Claim 20

Dependent Claim 28 words

The probe of claim 10 wherein said fiber optic cable has a proximal end for coupling to a light sensor and wherein said second portion defines light-admitting aperture.

Claim 21

Independent Claim 128 words

A method of manufacturing an optical probe comprising the steps of: providing a fiber optic cable having an inner core and an outer cladding; taffy-pulling said cable to form a reduced diameter portion terminating in a distal end; removing the distal endmost portion of said outer cladding, leaving said reduced diameter inner core protruding longitudinally beyond the outer cladding; forming the protruding inner core into a tapered tip terminating in a light transmissive aperture; wherein said reduced diameter portion is of a dimension such that light propagating in said reduced diameter portion propagates in a guided wave mode; and wherein said tapered tip is formed at a taper angle such that light propagating in said tapered tip propagates in an evanescent mode for fewer than five optical wavelengths.

Claim 22

Independent Claim 128 words

A method of manufacturing an optical probe comprising the steps of: providing a fiber optic cable having an inner core and an outer cladding; taffy-pulling said cable to form a reduced diameter portion terminating in a distal end; removing the distal endmost portion of said outer cladding, leaving said reduced diameter inner core protruding longitudinally beyond the outer cladding; forming the protruding inner core into a tapered tip terminating in a light transmissive aperture; wherein said reduced diameter portion is of a dimension such that light propagating in said reduced diameter portion propagates in a guided wave mode; and wherein said tapered tip is formed at a taper angle such that light propagating in said tapered tip propagates in an evanescent mode for fewer than five optical wavelengths.

Claim 23

Dependent Claim 15 words

The method of claim 19 further comprising forming said tapered tip by wet chemical etching.

Claim 24

Dependent Claim 50 words

The method of claim 19 further comprising forming said tapered tip by exposing said distal end to an etching environment and leaving said distal end exposed to said etching environment until said outer cladding is substantially etched away, leaving the inner core to protrude longitudinally outwardly from said outer cladding.

Claim 25

Dependent Claim 15 words

The method of claim 19 further comprising cleaving said cable to form said distal end.

Claim 26

Dependent Claim 145 words

The method of claim 19 further comprising: selecting differently doped first and second light transmissive materials such that the first and second materials have different indices of refraction and such that the first material etches at a slower rate than said second material when exposed to an etching environment; using said first and second material to form said fiber optic cable, the inner core comprising said first material and the outer cladding comprising said second material; cleaving said cable to form a distal end; exposing said distal end to an etching environment; leaving said distal end exposed to said etching environment until said outer cladding is substantially etched away leaving the inner core to protrude longitudinally outwardly from said outer cladding to define a tip; leaving said distal end exposed to said etching environment until said tip is etched away to define a tapered tip.

Claim 27

Dependent Claim 146 words

A high efficiency optical probe comprising: a fiber optic cable having an inner core and an outer cladding that concentrically encapsulates the inner core, the cable having a proximal end for coupling to a light source and having a distal end which defines a light-emitting probe; said light-emitting probe having a reduced diameter intermediate region adjacent said distal end; said light-emitting probe having a tapered tip that protrudes longitudinally outwardly from said outer cladding of said reduced diameter intermediate region, the tapered tip comprising a portion of said inner core that extends longitudinally beyond the outer cladding; said tapered tip defining a light-emitting aperture at its tapered extremity, the tip being tapered at an acute angle with respect to the longitudinal axis of the cable, said acute angle being such that light propagates through said tip in the evanescent mode for fewer than five optical wavelengths.

Claim 28

Dependent Claim 146 words

A high efficiency optical probe comprising: a fiber optic cable having an inner core and an outer cladding that concentrically encapsulates the inner core, the cable having a proximal end for coupling to a light source and having a distal end which defines a light-emitting probe; said light-emitting probe having a reduced diameter intermediate region adjacent said distal end; said light-emitting probe having a tapered tip that protrudes longitudinally outwardly from said outer cladding of said reduced diameter intermediate region, the tapered tip comprising a portion of said inner core that extends longitudinally beyond the outer cladding; said tapered tip defining a light-emitting aperture at its tapered extremity, the tip being tapered at an acute angle with respect to the longitudinal axis of the cable, said acute angle being such that light propagates through said tip in the evanescent mode for fewer than five optical wavelengths.

Claim 29

Dependent Claim 22 words

The probe of claim 24 wherein said intermediate region has a gradually reduced diameter outer cladding of a diminishing and tapering diameter.

Claim 30

Dependent Claim 33 words

The probe of claim 24 wherein said intermediate region has a stepwise reduced diameter outer cladding having an annular portion of a diameter smaller than the average diameter of said fiber optic cable.

Claim 31

Dependent Claim 17 words

The probe of claim 24 wherein said intermediate region has an inner core of gradually diminishing diameter.

Claim 32

Dependent Claim 18 words

The probe of claim 27 wherein said gradually diminishing diameter is formed by taffy-pulling the fiber optic cable.

Claim 33

Dependent Claim 35 words

The probe of claim 24 wherein the inner core of said fiber optic cable within said intermediate region is of a diameter such that light propagates through said intermediate region in a guided wave mode.

Claim 34

Dependent Claim 52 words

The probe of claim 24 wherein said tip tapers at an acute angle is selected to achieve a balance between minimizing the impedance mismatch due to reflection and minimizing the optical signal loss due to propagation in the evanescent mode, such that the optical energy transmitted through the aperture is substantially maximized.

Claim 35

Dependent Claim 156 words

A high efficiency optical probe comprising: a fiber optic cable having an inner core and an outer cladding that concentrically encapsulates the inner core, the cable having a proximal end for coupling to a light source and having a distal end which defines a light-emitting probe; said light-emitting probe having a reduced diameter intermediate region adjacent said distal end; said light-emitting probe having a tapered tip that protrudes longitudinally outwardly from said outer cladding of said reduced diameter intermediate region, the tapered tip comprising a portion of said inner core that extends longitudinally beyond the outer cladding; said tapered tip defining a light-emitting aperture at its tapered extremity, the tip being tapered at an acute angle on the order of about fifteen (15) degrees to sixty (60) degrees with respect to the longitudinal axis of the cable; said tapered tip having a metallic overcoat disposed on substantially all of said tip except for said light-emitting aperture.

Claim 36

Dependent Claim 156 words

A high efficiency optical probe comprising: a fiber optic cable having an inner core and an outer cladding that concentrically encapsulates the inner core, the cable having a proximal end for coupling to a light source and having a distal end which defines a light-emitting probe; said light-emitting probe having a reduced diameter intermediate region adjacent said distal end; said light-emitting probe having a tapered tip that protrudes longitudinally outwardly from said outer cladding of said reduced diameter intermediate region, the tapered tip comprising a portion of said inner core that extends longitudinally beyond the outer cladding; said tapered tip defining a light-emitting aperture at its tapered extremity, the tip being tapered at an acute angle on the order of about fifteen (15) degrees to sixty (60) degrees with respect to the longitudinal axis of the cable; said tapered tip having a metallic overcoat disposed on substantially all of said tip except for said light-emitting aperture.

Claim 37

Dependent Claim 22 words

The probe of claim 31 wherein said intermediate region has a gradually reduced diameter outer cladding of a diminishing and tapering diameter.

Claim 38

Dependent Claim 33 words

The probe of claim 31 wherein said intermediate region has a stepwise reduced diameter outer cladding having an annular portion of a diameter smaller than the average diameter of said fiber optic cable.

Claim 39

Dependent Claim 17 words

The probe of claim 31 wherein said intermediate region has an inner core of gradually diminishing diameter.

Claim 40

Dependent Claim 18 words

The probe of claim 34 wherein said gradually diminishing diameter is formed by taffy-pulling the fiber optic cable.

Claim 41

Dependent Claim 35 words

The probe of claim 31 wherein the inner core of said fiber optic cable within said intermediate region is of a diameter such that light propagates through said intermediate region in a guided wave mode.

Claim 42

Dependent Claim 52 words

The probe of claim 31 wherein said tip tapers at an acute angle is selected to achieve a balance between minimizing the impedance mismatch due to reflection and minimizing the optical signal loss due to propagation in the evanescent mode, such that the optical energy transmitted through the aperture is substantially maximized.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2000-09-01	2001-03-03	2001-09-02	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2004-09-01	2005-03-03	2005-09-02	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2008-09-01	2009-03-03	2009-09-02	$7700.00	Window Closed / Lapsed

High resolution fiber optic probe for near field optical microscopy and method of making same

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