Waveguide-enhanced Raman scattering spectroscopy of analytes using sorbents

Patent metadata

Field	Value
Publication number	US-10054546-B2
Application number	US-201615293394-A
Country	US
Kind code	B2
Filing date	Oct 14, 2016
Priority date	Oct 15, 2015
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

A system and method for detecting an analyte includes a waveguide configured to receive a narrow-band laser signal; and a sorbent material covering an analyte detection region of the waveguide, wherein the sorbent material is configured to sorb the analyte and bring the analyte to an evanescent field of the waveguide, and wherein Raman scattering is produced by an interaction of the evanescent field and the analyte sorbed in the sorbent material along the analyte detection region of the waveguide, and the waveguide is further configured to collect the Raman scattering along the analyte detection region of the waveguide, wherein the collected Raman scattering indicates a type of the analyte.

First claim

What is claimed is:

1. A system for detecting an analyte, said system comprising:
a waveguide configured to receive a narrow-band laser signal; and
a sorbent material covering an analyte detection region of said waveguide, wherein said sorbent material is configured to sorb said analyte and bring said analyte to an evanescent field of said waveguide, and wherein Raman scattering is produced by an interaction of said evanescent field and said analyte sorbed in said sorbent material along said analyte detection region of said waveguide, and
said waveguide is further configured to collect said Raman scattering along said analyte detection region of said waveguide, wherein said collected Raman scattering indicates a type of said analyte, a flow cell, wherein said waveguide is located inside said flow cell, and wherein said flow cell comprises: a passage configured to allow a gas flow through said flow cell; and a first window and a second window, wherein the first and second windows are configured to allow light in and out of said flow cell, and a reflecting microscope objective that uses a Schwarzschild reflective objective, and is configured to: collect said Raman scattering transmitted by a second coupling component of said waveguide through said second window; and reduce chromatic dispersion in said collection of Raman scattering; and an off-axis parabolic mirror configured to couple said Raman scattering to said optical detector.

2. The system of claim 1 , wherein said Raman scattering comprises back-scattered Raman scattering, and said system further comprises an optical detector configured to detect said back-scattered Raman scattering, which indicates said type of said analyte and propagates in an opposite direction as said narrow-band laser signal.

3. The system of claim 1 , wherein said Raman scattering comprises forward-scattered Raman scattering, and said system further comprises an optical detector configured to detect forward-scattered Raman scattering, which indicates said type of said analyte and propagates in a same direction as said narrow-band laser signal.

4. The system f claim 3 , further comprising:
a pump laser source configured to generate a laser signal, said laser signal comprising said narrow-band laser signal;
a band pass filter placed between said pump laser source and said waveguide, wherein said band pass filter is configured to filter said laser signal at frequencies of said narrow-band signal;
an optic configured to focus said narrow-band signal on a first coupling component of
said waveguide.

5. The system of claim 4 , wherein said laser signal comprises any of 513 nm, 532 nm, 633 nm, 785 nm, 830 nm, 850 nm, and 980 nm wavelengths.

6. The system of claim 4 , wherein said laser signal comprises any of a predominantly in-plane (quasi-transverse electric) polarization and an out-of-plane (quasi transverse magnetic) polarization.

7. The system of claim 1 , wherein said optical detector comprises any of:
a 300-groove/ram, 1.3 μm-blaze grating and a liquid nitrogen cooled, 1024 element InGaAs linear array detector, and
a spectrograph configured to identify said analyte using wavelengths of said Raman scattering.

8. The system of claim 7 , further comprising a long-pass edge filter placed between said waveguide and said optical detector, wherein said long-pass edge filter is configured to block said narrow-hand signal from said optical detector.

9. The system of claim 1 , further comprising a detection device comprising:
a substrate layer comprising a substrate material;
a bottom cladding layer comprising a bottom cladding material, wherein said bottom cladding layer covers said substrate layer; and
a core layer comprising a core material, wherein said core layer covers said bottom cladding layer, wherein said core material has a refractive index higher than said bottom cladding material, wherein said waveguide is patterned in said core layer, and wherein said bottom cladding material and said core material are transparent at frequencies of said narrow-band signal and said Raman scattering frequencies.

10. The system of claim 9 , wherein said substrate material comprises silicon, said bottom cladding material comprises silicon oxide, and said core material comprises silicon nitride.

Assignees

• Us Navy

Inventors

• Stievater Todd H
• Khurgin Jacob B
• Kozak Dmitry A
• Holmstrom Scott A
• Mcgill R Andrew

Classifications

• G02B21/02

  Objectives · CPC title

• G02B6/124

  Geodesic lenses or integrated gratings · CPC title

• G01N2021/651

  Cuvettes therefore · CPC title

• G01N21/658 Primary

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

• G01N2021/773

  Porous polymer jacket; Polymer matrix with indicator · CPC title