System and method for molecule sensing using evanescent light coupling approach

Patent metadata

Field	Value
Publication number	US-9921164-B2
Application number	US-201715418350-A
Country	US
Kind code	B2
Filing date	Jan 27, 2017
Priority date	May 11, 2016
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

A system and a method for optical sensing of single molecule or molecules in various concentrations are provided. The optical sensor system comprises a first fiber, a second fiber, a light source and a detection device. The first fiber and the second fiber are fused together to form an optical coupler. The first fiber serves as the passageway for the analyte, while the second fiber serves as the waveguide for the light that will interact with the said analyte. One end of the second fiber is connected to the light source (e.g. laser), and the opposite end is connected to the detection device (e.g. spectrometer). The analyte is introduced into the first fiber through one of its ends, and is allowed to flow through inside the hollow core of the said first fiber. When light is delivered through the input end of the second fiber, the evanescent light is formed in the optical coupler and is allowed to interact with the analyte in the first fiber. One scenario in this analyte-light interaction results in, for example, the generation of Raman emission that is used as the probing signal. The spectrum of the Raman emission is analyzed by the detection device to determine the presence of target molecule.

First claim

I claim:

1. An apparatus, comprising:
a fiber defining an analyte passageway situated to receive an analyte having a measurable optical characteristic;
an optical waveguide including an input end separate from the analyte passageway and further including a waveguide portion optically evanescently coupled to a passageway portion of the analyte passageway so as to form an analyte detection region;
a light source optically coupled to the input end of the optical waveguide so as to direct a detection beam through the optical waveguide to the analyte detection region to form an analyte response beam associated with the measurable optical characteristic; and
an optical detector optically coupled to the optical waveguide so as to receive the analyte response beam from the analyte detection region through the optical waveguide;
wherein the analyte detection region comprises a fused fiber coupler.

2. The apparatus of claim 1 , wherein the fiber is a hollow fiber having a hollow interior defining the analyte passageway and the hollow fiber includes a first end situated to receive the analyte, and wherein the optical waveguide is an optical fiber.

3. The apparatus of claim 2 , wherein the optical detector is optically coupled to a second end of the optical fiber that is opposite the input end.

4. The apparatus of claim 2 , wherein the hollow fiber further includes a second end opposite the first end and situated to drain the analyte from the analyte passageway.

5. The apparatus of claim 1 , wherein the analyte passageway and the optical waveguide are tapered so as to reduce a diameter of at least one of a core of the optical detection fiber and analyte passageway in the fused fiber coupler so as to increase a signal strength of the analyte response beam associated with a surface enhanced Raman scattering (SERS).

6. An apparatus, comprising:
a fiber defining an analyte passageway situated to receive an analyte having a measurable optical characteristic;
an optical waveguide including an input end separate from the analyte passageway and further including a waveguide portion optically evanescently coupled to a passageway portion of the analyte passageway so as to form an analyte detection region;
a light source optically coupled to the input end of the optical waveguide so as to direct a detection beam through the optical waveguide to the analyte detection region to form an analyte response beam associated with the measurable optical characteristic;
an optical detector optically coupled to the optical waveguide so as to receive the analyte response beam from the analyte detection region through the optical waveguide;
an analyte analyzer housing situated to house the light source and the optical detector; and
a removable biochip couplable to the analyte analyzer housing and that includes the analyte detection region and the analyte passageway so that the waveguide portion of the analyte detection region is removably optically couplable with the light source and the optical detector.

7. The apparatus of claim 6 , further comprising a syringe operable to inject the analyte into the analyte passageway.

8. The apparatus of claim 1 , wherein the light source comprises one or more fiber-coupled laser diodes optically coupled to the optical waveguide input end.

9. The apparatus of claim 8 , wherein the one or more fiber-coupled laser diodes have an output power that corresponds to a signal strength of the analyte response beam that is associated with a concentration of the analyte.

10. An apparatus, comprising:
a fiber defining an analyte passageway situated to receive an analyte having a measurable optical characteristic;
an optical waveguide including an input end separate from the analyte passageway and further including a waveguide portion optically evanescently coupled to a passageway portion of the analyte passageway so as to form an analyte detection region;
a light source optically coupled to the input end of the optical waveguide so as to direct a detection beam through the optical waveguide to the analyte detection region to form an analyte response beam associated with the measurable optical characteristic; and
an optical detector optically coupled to the optical waveguide so as to receive the analyte response beam from the analyte detection region through the optical waveguide;
wherein the analyte detection portion includes at least one nanostructure situated to locally increase an intensity of the detection beam in the analyte detection portion so as to increase a signal strength of the analyte response beam.

11. The apparatus of claim 10 , wherein the fiber has an exterior surface and an interior surface and includes a solid cladding extending between the exterior surface and the interior surface, wherein the interior surface defines the analyte passageway that is situated to receive the analyte, and wherein the at least one nanostructure is situated on one or more of the exterior surface and the interior surface.

12. The apparatus of claim 10 , wherein the at least one nanostructure includes one or more of a plasmonic or non-plasmonic nanoantenna, nanohole, nanorod, and nanosphere.

13. The apparatus of claim 12 , wherein the at least one nanostructure includes a nano-bowtie antenna.

14. The apparatus of claim 1 , wherein the analyte detection portion has a length of less than or equal to 5 cm.

15. The apparatus of claim 1 , further comprising a signal analyzer coupled to the optical detector so as to receive an optical detector signal corresponding to the measurable optical characteristic.

16. An apparatus, comprising:
a fiber defining an analyte passageway situated to receive an analyte having a measurable optical characteristic;
an optical waveguide including an input end separate from the analyte passageway and further including a waveguide portion optically evanescently coupled to a passageway portion of the analyte passageway so as to form an analyte detection region;
a light source optically coupled to the input end of the optical waveguide so as to direct a detection beam through the optical waveguide to the analyte detection region to form an analyte response beam associated with the measurable optical characteristic; and
an optical detector optically coupled to the optical waveguide so as to receive the analyte response beam from the analyte detection region through the optical waveguide;
wherein the measurable optical characteristic is a surface enhanced Raman scattering (SERS) response.

17. An apparatus, comprising:
a fiber defining an analyte passageway situated to receive an analyte having a measurable optical characteristic;
an optical waveguide including an input end separate from the analyte passageway and further including a waveguide portion optically evanescently coupled to a passageway portion of the analyte passageway so as to form an analyte detection region;
a light source optically coupled to the input end of the optical waveguide so as to direct a detection beam through the optical waveguide to the analyte detection region to form an analyte response beam associated with the measurable optical characteristic; and
an optical detector optically coupled to the optical waveguide so as to receive the analyte response beam from the analyte detection region through the optical waveguide;
wherein the analyte response beam is a single molecule detection signal of a single molecule in the analyte.

18. A method, comprising:
directing an analyte having a measurable optical characteristic through an analyte passageway so that

Assignees

• Uvic Ind Partnerships Inc

Inventors

• Lu Tao

Classifications

• G01N21/658 Primary

  enhancement Raman, e.g. surface plasmons · CPC title

• G02B6/032

  with non solid core or cladding {(G02B6/02295 takes precedence)} · CPC title

• G02B6/2551

  using thermal methods, e.g. fusion welding by arc discharge, laser beam, plasma torch · CPC title

• G01N2201/08

  Optical fibres; light guides · CPC title

• G01N2201/0612

  Laser diodes · CPC title