Superresolution imaging fiber for subwavelength light energy generation and near-field optical microscopy

• US 5,633,972 A
• Filed: 11/29/1995
• Issued: 05/27/1997
• Est. Priority Date: 11/29/1995
• Status: Expired due to Term

• Current Assignee: Trustees of Tufts College
• Original Assignee: Trustees of Tufts College
• Inventors: Pantano, Paul, Walt, David R.
• Primary Examiner(s): Ngo, John
• Application Number:
  US08/564,488
• Time in Patent Office: 545 Days
• Field of Search: 385/115-121, 385/901, 385/43, 385/126, 385/127, 385/128, 385/147
• US Class Current: 385/116
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 35/00 Methods or apparatus for measurement or analysis of nanostructures
• CPC Class Codes: G01Q 60/22 Probes, their manufacture, or their related instrumentation, e.g. holders
• CPC Class Codes: G02B 6/06 the relative position of the fibres being the same at both ends, e.g. for transporting images
• CPC Class Codes: G02B 6/241 Light guide terminations

Abstract

The present invention provides a superresolution imaging fiber for generating a plurality of subwavelength light energy beams concurrently and for near-field viewing. The imaging fiber comprises a unitary fiber optic array of fixed configuration and dimensions comprising typically from 1,000 to 100,000 optical fiber strands which terminate at one array end as tapered strand end faces limited in size to a range from about 2-1,000 nanometers in diameter. Overlyng these tapered strand end faces is a thin opaque metal coating having a size-limited end aperture ranging from about 2 to less than about 1,000 nanometers in diameter. These size-limited end aperatures provide for the generation of a plurality of discrete subwavelength light beams concurrently.

Claims

1. A superresolution imaging fiber comprising:

a preformed, unitary fiber optic array of predetermined configuration and dimensions comprised of a plurality of optical fiber strands disposed co-axially along their lengths and having two discrete optic array ends each formed of multiple optical fiber strand ends and strand end faces, wherein

(a) the first of said discrete optic array ends is formed of multiple optical fiber strand ends which collectively present a non-tapered, optic array end surface for the introduction and conveyance of light energy, and

(b) the second of said discrete optic array ends is formed of tapered multiple optical fiber strand ends of reduced thickness each of which presents a tapered strand end face limited in size to a range from about 2 nanometers to about 1,000 nanometers in diameter, said tapered multiple strand end faces collectively presenting a tapered optic array end surface;

an opaque metal coating covering said second tapered optic array end surface and overlaying said tapered multiple optical fiber strand end faces as a plurality of open-ended opaque metal tubes each having a size-limited end aperture ranging from about 2 nanometers to less than about 1,000 nanometers in diameter.

2. The imaging fiber as recited in claim 1 wherein said tapered strand end faces of said second optic array end surface are limited in size to a diameter range from about 100 nanometers to about 300 nanometers.

3. The imaging fiber as recited in claim 1 wherein said opaque metal coating is aluminum.

4. The imaging fiber as recited in claim 1 wherein said opaque metal coating is one selected from the group consisting of chromium and silver.

5. The imaging fiber as recited in claim 1 wherein said end aperture of said opaque metal tube overlay is in the range from 20-50 nanometers.

6. The imaging fiber as recited in claim 1 wherein said end aperture of said opaque metal tube overlay is in the range from 50-200 nanometers.

7. The imaging fiber as recited in claim 1 wherein said tapered multiple strand end faces of said second discrete optic array end convey and discharge a plurality Of discrete light energy beams concurrently.

8. The imaging fiber as recited in claim 1 wherein said size-limited end apertures of said open-ended opaque metal tube overlays generate a plurality of discrete subwavelength light energy beams concurrently by said multiple tapered strand end faces of said second tapered optic array end.

9. A method for making a superresolution imaging fiber comprising the steps of:

obtaining a preformed, unitary fiber optic array of predetermined configuration and dimensions comprised of a plurality of optical fiber strands disposed co-axially along their lengths and having two discrete optic array ends each formed of multiple optical fiber strand ends and strand end faces;

pulling and heating one of said discrete optic array ends to form tapered multiple optical fiber strand ends of reduced thickness each of which presents a tapered strand end face limited in size to a range from about 2 nanometers to about 1,000 nanometers in diameter, said tapered multiple strand end faces collectively presenting a tapered optic array end surface; and

applying an opaque metal coating over said tapered optic array end surface and as an overlay to said tapered multiple optical fiber strand end faces to form a plurality of open-ended opaque metal tubes each having a size-limited end aperture ranging from about 2 nanometers to less than about 1,000 nanometers in diameter.

10. A method for making a superresolution imaging fiber comprising the steps of:

obtaining a preformed, unitary fiber optic array of predetermined configuration and dimensions comprised of a plurality of optical fiber strands disposed co-axially along their lengths and having two discrete optic array ends each formed of multiple optical fiber strand ends and strand end faces;

etching one of said discrete optic array ends to form tapered multiple optical fiber strand ends of reduced thickness each of which presents a tapered strand end face limited in size to a range from about 2 nanometers to about 1,000 nanometers in diameter, said tapered multiple strand end faces collectively presenting a tapered optic array end surface; and

applying an opaque metal coating over said tapered optic array end surface and as an overlay to said tapered multiple optical fiber strand end faces to form a plurality of open-ended opaque metal tubes each having a size-limited end aperture ranging from about 2 nanometers to less than about 1,000 nanometers in diameter.

11. A method for making a superresolution imaging fiber comprising the steps of:

obtaining a preformed, unitary fiber optic array of predetermined configuration and dimensions comprised of a plurality of optical fiber strands disposed co-axially along their lengths and having two discrete optic array ends each formed of multiple optical fiber strand ends and strand end faces;

pulling and heating one of said discrete optic array end to form tapered multiple optical fiber strand ends of reduced thickness each of which presents a tapered strand end face;

etching said pulled and heated optic array end to form sharply tapered multiple optical fiber end strands each of which presents a sharply tapered end face limited in size to a range from about 2 nanometers to about 1,000 nanometers in diameter, said sharply tapered multiple strand end faces collectively presenting a tapered optic array end surface; and

applying an opaque metal coating over said tapered optic array end surface and as an overlay to said sharply tapered multiple optical fiber strand end faces to form a plurality of open-ended opaque metal tubes each having a size-limited end aperture ranging from about 2 nanometers to less than about 1,000 nanometers in diameter.