# US 10,481,092 B2 · Multiplexed excitation emission matrix spectroscopy

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- Number: US 10,481,092 B2
- Document ID: US10481092B2
- Status: Granted
- Kind: B2
- Application number: 15/216,296
- Filed: 2016-07-21
- Published: 2017-02-23
- Granted: 2019-11-19
- Earliest claimed: 2015-07-21
- Assignees: Queen's University at Kingston
- Applicants: Queen's University At Kingston
- Inventors: Hans-Peter Loock; Oliver Reich; Nicholas L. P. Andrews
- Web page: https://patentgrep.com/patent/US10481092B2

## CPC

- G01N 21/645: {Specially adapted constructive features of fluorimeters}
- G01J 3/021: {using plane or convex mirrors, parallel phase plates, or particular reflectors}
- G01J 3/4406: {Fluorescence spectrometry}
- G01J 3/0218: {using optical fibers}
- G01N 21/65: Raman scattering
- G01N 2021/6419: {Excitation at two or more wavelengths}
- G01N 2021/6421: {Measuring at two or more wavelengths}
- G01N 2201/0675: SLM
- G02B 6/3624: {Fibre head, e.g. fibre probe termination (optical details of light guide terminations G02B6/241; reshaping of light guides G02B6/2552; optical details of coupling light into or out of fibre end G02B6/262)}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N)
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

Described herein is an excitation emission matrix (EEM) spectrometer and method, comprising a multiplexer that encodes excitation light produced by at least one excitation light source; and a demultiplexer that decodes encoded light emitted from a sample, and produces an output indicative of a characteristic of the sample. Embodiments are described wherein the multiplexer and the demultiplexer may comprise FDM or OFDM, and wherein both the excitation light and the emitted light may be encoded using a DMA or a SLM. In some embodiments the same DMA or SLM may be used to encode the excitation light and the emitted light. In some embodiments excitation light may be encoded using a Walsh function, or the excitation light may be encoded using a Walsh function and the emitted light may be decoded using an inverse Hadamard transformation.

## Claims

### Claim 1

An excitation emission matrix (EEM) spectrometer, comprising:
at least one excitation light source that produces an excitation light spectrum;
a multiplexer that:
divides the excitation light spectrum into a plurality of discrete excitation wavelength ranges;
selects three or more discrete excitation wavelength ranges from the plurality of discrete excitation wavelength ranges while rejecting remaining discrete excitation wavelength ranges; and
encodes the selected three or more discrete excitation wavelength ranges according to a binary function;
a conduit that conducts the encoded three or more discrete excitation wavelength ranges to a sample;
a conduit that conducts an encoded emitted light from the sample;
a spectrometer that detects the encoded emitted light and resolves a spectrum of the encoded emitted light; and
a demultiplexer that decodes the encoded three or more discrete excitation wavelength ranges in the emitted light spectrum according to the binary function to produce an output EEM spectrum.

### Claim 2 (depends on 1)

The EEM spectrometer of claim 1, wherein the emitted light is produced by at least one of luminescence, scattering, and transmission.

### Claim 3 (depends on 2)

The EEM spectrometer of claim 2, wherein the luminescence comprises fluorescence, and/or the scattering comprises Raman scattering.

### Claim 4 (depends on 1)

The EEM spectrometer of claim 1, wherein the multiplexer and the demultiplexer comprise FDM or OFDM.

### Claim 5 (depends on 1)

The EEM spectrometer of claim 1, wherein both the selected three or more discrete excitation wavelength ranges and the emitted light are encoded using a DMA or a SLM.

### Claim 6 (depends on 5)

The EEM spectrometer of claim 5, wherein the same DMA or SLM is used to encode the selected three or more discrete excitation wavelength ranges and the emitted light.

### Claim 7 (depends on 1)

The EEM spectrometer of claim 1, wherein the selected three or more discrete excitation wavelength ranges are encoded by a DMA or SLM and the emitted light is recorded by a photoarray detector.

### Claim 8 (depends on 1)

The EEM spectrometer of claim 1, wherein the selected three or more discrete excitation wavelength ranges are encoded using a Walsh function.

### Claim 9 (depends on 1)

The EEM spectrometer of claim 1, wherein the selected three or more discrete excitation wavelength ranges are encoded using a Walsh function and the emitted light is decoded using an inverse Hadamard transformation.

### Claim 10 (depends on 1)

The EEM spectrometer of claim 1, wherein the conduit that conducts the encoded selected three or more discrete excitation wavelength ranges the sample and the conduit that conducts encoded emitted light from the sample comprise a bifurcated fibre probe.

### Claim 11 (depends on 1)

The EEM spectrometer of claim 1, further comprising a bifurcated fibre probe.

### Claim 12 (depends on 11)

The EEM spectrometer of claim 11, wherein the bifurcated fibre probe comprises;
an excitation end from which a first set of optical fibres receives excitation light;
an emission end from which a second set of optical fibres emit emitted light; and
a probe end from which the selected three or more discrete excitation wavelength ranges are outputted from the first set of optical fibres and the emitted light is received from a sample by the second set of optical fibres;
wherein the probe comprises a bevelled window that reduces back reflections.

### Claim 13 (depends on 1)

The EEM spectrometer of claim 1, comprising a display device that that displays the output EEM spectrum.

### Claim 14

An excitation emission matrix (EEM) spectroscopy method, comprising:
using a multiplexer to:
divide an excitation light spectrum into a plurality of discrete excitation wavelength ranges;
select three or more discrete excitation wavelength ranges from the plurality of discrete excitation wavelength ranges while rejecting remaining discrete excitation wavelength ranges; and
encode the selected three or more discrete excitation wavelength ranges according to a binary function;
conducting the encoded three or more discrete excitation wavelength ranges to a sample;
conducting encoded emitted light from the sample; and
detecting and resolving a spectrum of the encoded emitted light; and
using a demultiplexer to decode the encoded three or more discrete excitation wavelength ranges in the emitted light spectrum according to the binary function and produce an output EEM spectrum.

### Claim 15 (depends on 14)

The method of claim 14, comprising multiplexing and demultiplexing using FDM or OFDM.

### Claim 16 (depends on 14)

The method of claim 14, comprising encoding the selected three or more discrete excitation wavelength ranges using a DMA or SLM.

### Claim 17 (depends on 16)

The method of claim 16, comprising encoding the selected three or more discrete excitation wavelength ranges and decoding the emitted light using the same DMA or SLM.

### Claim 18 (depends on 14)

The method of claim 14, comprising encoding the selected three or more discrete excitation wavelength ranges using a DMA or SLM and recording the emitted light using a photoarray detector.

### Claim 19 (depends on 14)

The method of claim 14, comprising encoding the selected three or more discrete excitation wavelength ranges using Walsh functions.

### Claim 20 (depends on 14)

The method of claim 14, comprising encoding the selected three or more discrete excitation wavelength ranges using Walsh functions and decoding the emitted light using an inverse Hadamard transformation.

### Claim 21 (depends on 14)

The method claim 14, comprising using a bifurcated probe to conduct the encoded selected three or more discrete excitation wavelength ranges to the sample and to conduct encoded emitted light from the sample.

### Claim 22 (depends on 21)

The method of claim 21, comprising using a bifurcated fibre probe wherein the probe comprises a bevelled window that reduces back reflections.

### Claim 23 (depends on 14)

The method of claim 14, comprising displaying the output EEM spectrum.