Optical sensor employing a refractive index engineered metal oxide material

• US 10,457,596 B2
• Filed: 01/17/2018
• Issued: 10/29/2019
• Est. Priority Date: 04/26/2013
• Status: Active Grant

• Current Assignee: University of Pittsburgh of The Commonwealth System of Higher Education
• Original Assignee: University of Pittsburgh of The Commonwealth System of Higher Education
• Inventors: Chen, Peng, Poole, Jacob Lorenzi, Ohodnicki, Paul R., Buric, Michael Paul
• Primary Examiner(s): Chu, Chris H
• Application Number:
  US15/873,049
• Publication Number:
  US 20180141859A1
• Time in Patent Office: 650 Days
• CPC Class Codes: C03C 25/106 Single coatings
• CPC Class Codes: C03C 25/1061 Inorganic coatings
• CPC Class Codes: G01N 21/05 Flow-through cuvettes G01N21/09 takes precedence; handling fluid samples G01N1/10
• CPC Class Codes: G01N 21/553 and using surface plasmons fluorescence excitation G01N21/648; enhanced Raman G01N21/658
• CPC Class Codes: G01N 21/774 the reagent being on a grating or periodic structure

Abstract

An optical sensor device includes an optical waveguide portion having a core, the core having a first refractive index, and a functional material layer coupled to the optical fiber portion, the functional material layer being made of a metal oxide material, the functional material layer being structured to have a second refractive index, the second refractive index being less than the first refractive index. The functional material layer may be a nanostructure material comprising the metal oxide material with a plurality of holes or voids formed therein such that the functional material layer is caused to have the second refractive index.

Claims

1. A method of sensing an analyte in an environment in a spatially distributed manner, comprising:

providing an optical sensor device in the environment, the optical sensor device including an optical waveguide portion having a core, the core having a first refractive index, and a functional material layer coupled to the optical waveguide portion, the functional material layer being comprised of a material that in a bulk, fully dense form has a natural, non-engineered refractive index that is greater than the first refractive index, the functional material layer being structured to have an engineered second refractive index that is lower than the first refractive index, wherein the functional material layer is an engineered nanostructure material with a plurality of voids formed therein, wherein throughout the functional material layer a porosity of the functional material layer is uniform and a size and a shape of the voids is uniform such that the functional material layer is caused to have the engineered second refractive index and such that light scattering in the optical sensor device is minimized, wherein the functional material layer is a material wherein at least one of the engineered second refractive index of the functional material layer or the optical absorption of the functional material layer will change in response to a parameter relating to the analyte, and wherein the engineered second refractive index of the functional material layer and losses thereof are engineered as to permit interrogation of a desired length of the optical sensor device or a plurality of sensing locations along the optical sensor device using a spatially distributed sensing technique without employing a plurality of in-fiber optic components in the core of the optical sensor device; and

sensing a presence of or measuring the parameter relating to the analyte at a plurality of locations along the optical sensor device using the spatially distributed sensing technique without employing a plurality of in-fiber optic components in the core of the optical sensor device.

2. The method according to claim 1, wherein the spatially distributed sensing technique without employing a plurality of in-fiber optic components in the core of the optical sensor device comprises Brillouin scattering or Rayleigh scattering.

3. The method according to claim 1, wherein the functional material layer is provided on a surface of the optical waveguide portion.

4. The method according to claim 3, wherein the optical waveguide portion is a D-shaped optical fiber having a cladding layer having a partial cylindrical cross-section, the cladding layer and the functional material layer being made of different materials, the core being provided at least in part within the cladding layer and being partially exposed to the environment, the functional material layer being provided on a top, flat surface of the cladding layer and a top portion of the core.

5. The method according to claim 1, wherein the voids comprise about 60% of the nanostructure material causing the functional material layer to have a total volume fraction of voids of about 60%.

6. The method according to claim 1, wherein the voids each have a width or diameter of 50 nm or less, and wherein the voids comprise about 60% of the nanostructure material causing the functional material layer to have a total volume fraction of voids of about 60%.

7. The method according to claim 6, wherein the voids each have a width or diameter of about 10 nm to about 20 nm.

8. The method according to claim 1, wherein the engineered second refractive index is about 99.0% to about up to 99.7% of the first refractive index.

9. The method according to claim 1, wherein the nanostructure material is formed using a sol-gel method.

10. The method according to claim 9, wherein the sol-gel method uses a block copolymer as a structure directing agent.

11. The method according to claim 10, wherein the block copolymer is a triblock copolymer and is poloxamer 407.

12. The method according to claim 1, wherein the material comprising the functional material layer is selected from a group consisting of a zeolite, SnO₂, TiO₂, ZnO, WO₃, and a perovskite.

13. A method of sensing an analyte in an environment in a spatially distributed manner, comprising:

providing an optical waveguide portion having a core, the core having a first refractive index, and a functional material layer coupled to the optical waveguide portion, the functional material layer being structured to have an engineered second refractive index that is lower than the first refractive index, wherein the functional material layer is an engineered nanostructure material with a plurality of voids formed therein, wherein throughout the functional material layer a porosity of the functional material layer is uniform and a size and a shape of the voids is uniform such that the functional material layer is caused to have the engineered second refractive index and such that light scattering in the optical sensor device is minimized, and wherein the functional material layer is a material wherein at least one of the engineered second refractive index of the functional material layer or the optical absorption of the functional material layer will change in response to a parameter relating to the analyte, and wherein the engineered second refractive index of the functional material layer and losses thereof are engineered as to permit interrogation of a desired length of the optical sensor device or a plurality of sensing locations along the optical sensor device using a spatially distributed sensing technique without employing a plurality of in-fiber optic components in the core of the optical sensor device; and

sensing a presence of or measuring the parameter relating to the analyte at a plurality of locations along the optical sensor device using the spatially distributed sensing technique without employing a plurality of in-fiber optic components in the core of the optical sensor device.

14. The method according to claim 13, wherein the spatially distributed sensing technique without employing a plurality of in-fiber optic components in the core of the optical sensor device comprises one of Brillouin scattering or Rayleigh scattering.