Molecular chirality detection technique using hybrid plasmonic substrates

Patent metadata

Field	Value
Publication number	US-10801957-B2
Application number	US-201916566087-A
Country	US
Kind code	B2
Filing date	Sep 10, 2019
Priority date	Sep 10, 2018
Publication date	Oct 13, 2020
Grant date	Oct 13, 2020

Abstract

A method for molecular chirality detection is described. The method includes providing a substrate defining an array of hole-disks, each hole-disk coupled with an asymmetric optical cavity. Each asymmetric optical cavity having a back reflector separating a plasmonic pattern by an appropriate selection of thickness. The substrate is illuminated to simultaneously excite two degenerate localized surface plasmon modes producing a strong chiral near-field. The method may also include generating a characterization of chiral molecules on the substrate based on the strong chiral near-field. Substrates and detectors for molecular chirality detection are also described.

First claim

What is claimed is:

1. A method, comprising:
providing a substrate defining an array of hole-disks, each hole-disk coupled with an asymmetric optical cavity and each asymmetric optical cavity having a back reflector separating a plasmonic pattern by an appropriate selection of thickness;
illuminating the substrate to simultaneously excite two degenerate localized surface plasmon modes; and
producing a strong chiral near-field.

2. The method of claim 1 , wherein the substrate is a nanostructured square array of gold hole-disks and the back reflector comprises at least one of: gold or another high reflective metal.

3. The method of claim 2 , further comprising detecting background-free circular dichroism molecular chirality of a sample located on the substrate through near-field light-matter interaction with high signal to noise ratio.

4. An optical chip configured to perform the method of claim 2 in order to detect chirality of one of: drugs, proteins, DNAs, and other molecules.

5. A drug delivery chip configured to perform the method of claim 2 and configured to bring a target chiral sample into contact with the substrate, wherein the substrate is an achiral substrate.

6. The method of claim 1 , wherein illuminating the substrate comprises illuminating the substrate with circularly polarized light.

7. The method of claim 6 , wherein the substrate is an achiral substrate; and
wherein illuminating the substrate by the circularly polarized light comprises changing a handedness of the circularly polarized light from right and left on the achiral substrate in order to switch a handedness of a chiral near-field between right and left enabling detection of both right and left handed chiral molecules on the achiral substrate.

8. The method of claim 1 , wherein the substrate is a plasmonic substrate, and wherein due to achiral symmetry, the plasmonic substrate suppresses the circular dichroism from the substrate, allowing detection of pure chiral signal from a sample molecule on the substrate.

9. A method of claim 1 , further comprising generating a characterization of chiral molecules for complex chiral assays, wherein the substrate comprises a thin film of the chiral molecules.

10. The method of claim 9 , wherein the complex chiral assays include at least one of: multiple molecules and control measurements.

11. The method of claim 9 , wherein the thin film comprises the chiral molecules embedded in a polymer matrix.

12. A chirality detector comprising:
a substrate;
a back reflector disposed on the substrate; and
an array of hole-disks disposed in the substrate, each hole-disk coupled with an asymmetric optical cavity,
wherein each asymmetric optical cavity is defined by the back reflector separating a plasmonic pattern by a given thickness.

13. The chirality detector of claim 12 , wherein the array of hole-disks is a nanostructured square array of hole-disks.

14. The chirality detector of claim 12 , wherein the array of hole-disks comprises gold hole-disks, and wherein the back reflector comprises gold.

15. The chirality detector of claim 12 , further comprising a thin film of chiral molecules.

16. The chirality detector of claim 15 , wherein the thin film comprises the chiral molecules embedded in a polymer matrix.

17. The chirality detector of claim 15 , further comprising a sensor configured to detect a pure chiral signal from the chiral molecules.

18. The chirality detector of claim 12 , wherein each hole-disk is disposed at approximately an optical center of the coupled asymmetric optical cavity.

19. The chirality detector of claim 12 , further comprising a source of circularly polarized light, the source configured to illuminate the array of hole-disks.

20. The chirality detector of claim 19 , further comprising optics configured to transform a Fourier-transform infrared spectroscopy signal into the circularly polarized light.

Assignees

• Univ Central Florida Res Found Inc

Inventors

• Chanda Debashis
• Vázquez-Guardado Abraham

Classifications

• G01N21/21

  Polarisation-affecting properties (G01N21/19 takes precedence) · CPC title

• G01N2021/3595

  using FTIR · CPC title

• G01N21/554 Primary

  detecting the surface plasmon resonance of nanostructured metals, e.g. localised surface plasmon resonance · CPC title

• G01N21/19 Primary

  Dichroism · CPC title

• G01N21/35

  using infrared light (G01N21/39 takes precedence) · CPC title