# US 11,441,948 B2 · Multi-dispersive spectrometer

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- Number: US 11,441,948 B2
- Document ID: US11441948B2
- Status: Granted
- Kind: B2
- Application number: 17/054,157
- Filed: 2020-03-25
- Published: 2021-07-29
- Granted: 2022-09-13
- Earliest claimed: 2019-03-25
- Applicants: Mks Technology, Inc.
- Inventors: Quaid Vohra; Celestin Zemtsop; Mark Watson
- Web page: https://patentgrep.com/patent/US11441948B2

## CPC

- G01J 3/32: Investigating bands of a spectrum in sequence by a single detector
- G01J 3/44: Raman spectrometry; Scattering spectrometry {; Fluorescence spectrometry}
- G01J 3/0202: {Mechanical elements; Supports for optical elements}
- G01J 3/0208: {using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction}
- G01J 3/0297: {Constructional arrangements for removing other types of optical noise or for performing calibration}
- G01J 3/06: Scanning arrangements {arrangements for order-selection}
- G01J 3/10: Arrangements of light sources specially adapted for spectrometry or colorimetry
- G01J 3/18: using diffraction elements, e.g. grating (gratings per se G02B)
- G01J 3/2803: {using photoelectric array detector}
- G01J 2003/4424: {Fluorescence correction for Raman spectrometry}
- 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)

## Abstract

A multi-dispersive spectrometer is provided in which the spectrometer comprises an optical system configured to direct an excitation signal from an excitation light source toward a sample, receive a spectroscopy signal from the sample, and direct the spectroscopy signal toward the detector. The optical system comprises a movable optical component adapted to move the spectroscopy signal relative to at least one sensor of the detector and the detector is adapted to detect a plurality of discrete shifted spectroscopy signals. A method of obtaining a Raman spectrum from a sample is also provided. The method comprises directing an excitation signal from an excitation light source toward a sample; receiving a spectroscopy signal from the sample; and directing the spectroscopy signal toward a detector, wherein the spectroscopy signal is moved relative to at least one sensor of the detector to provide a plurality of discrete shifted spectroscopy signals.

## Claims

### Claim 1

A Raman spectrometer comprising:
an excitation light source;
a detector adapted to detect a spectrum from a signal;
an optical system configured to direct an excitation signal from the excitation light source toward a sample, receive a spectroscopy signal from the sample, and direct the spectroscopy signal toward the detector,
wherein the optical system comprises a controller adapted to control a movable optical component to iteratively move the spectroscopy signal relative to at least one sensor of the detector and the detector is adapted to detect a plurality of discrete shifted spectroscopy signals each corresponding to a different position of the movable optical component without the use of multiple lasers or a tunable laser adapted to change an excitation signal wavelength for a plurality of the discrete shifted spectroscopy signals, and
wherein data from each of the plurality of discrete shifted spectroscopy signals is superimposed to create a vector.

### Claim 2 (depends on 1)

The Raman spectrometer of claim 1 wherein the moveable optical component comprises a diffraction grating.

### Claim 3 (depends on 2)

The Raman spectrometer of claim 2 wherein the diffraction grating is adapted to rotate the diffraction grating to shift the spectroscopy signal across the detector in a plurality of steps to provide the plurality of discrete shifted spectroscopy signals.

### Claim 4 (depends on 3)

The Raman spectrometer of claim 3 wherein the rotatable diffraction grating is configured to shift a dispersed spectroscopic signal across a plurality of sensors of the detector in the plurality of steps.

### Claim 5 (depends on 3)

The Raman spectrometer of claim 3 wherein the rotatable diffraction grating is configured to disperse the spectroscopic signal to different relative positions of the detector to provide the plurality of discrete shifted spectroscopy signals.

### Claim 6 (depends on 1)

The Raman spectrometer of claim 1 wherein a mathematical decomposed spectroscopy signal is derived from the plurality of detected discrete shifted spectroscopy signals.

### Claim 7 (depends on 6)

The Raman spectrometer of claim 6 wherein the mathematical decomposed spectroscopy signal is utilized to reduce noise comprising at least one of fluorescence and background radiation.

### Claim 8 (depends on 7)

The Raman spectrometer of claim 7 wherein the noise is reduced without the use of multiple lasers or a tunable laser adapted to change an excitation signal wavelength for a plurality of the discrete shifted spectroscopy signals.

### Claim 9 (depends on 7)

The Raman spectrometer of claim 7 wherein the noise is reduced without changing a frequency of the excitation signal.

### Claim 10 (depends on 7)

The Raman spectrometer of claim 7 wherein a processor is configured to assemble a matrix from the plurality of individually sensed spectroscopy signals.

### Claim 11 (depends on 10)

The Raman spectrometer of claim 10 wherein the processor is configured to use the matrix to decompose the plurality of individually sensed spectroscopy signals to reduce noise.

### Claim 12 (depends on 1)

The Raman spectrometer of claim 1 wherein the excitation light source comprises a single laser operating at a generally consistent operating frequency.

### Claim 13 (depends on 1)

The Raman spectrometer of claim 1 wherein the moveable optical component comprises the detector.

### Claim 14 (depends on 13)

The Raman spectrometer of claim 13 wherein the detector is adapted to translate relative to an optical path of the optical system to shift the spectroscopy signal across the detector in a plurality of steps to provide the plurality of discrete shifted spectroscopy signals.

### Claim 15 (depends on 14)

The Raman spectrometer of claim 14 wherein the detector is configured to shift the spectroscopy signal across a plurality of sensors of the detector in the plurality of steps.

### Claim 16 (depends on 1)

The Raman spectrometer of claim 1 wherein the moveable optical component comprises at least one of a dispersion element, a diffractive grating, the detector, a filter, an optical flat, a micro-electromechanical system (MEMS) element, and a mirror.

### Claim 17

A method of obtaining a Raman spectrum from a sample, the method comprising:
directing an excitation signal from an excitation light source toward a sample;
receiving a spectroscopy signal from the sample; and
directing the spectroscopy signal toward a detector, wherein the spectroscopy signal is moved relative to at least one sensor of the detector to provide a plurality of discrete shifted spectroscopy signals without the use of multiple lasers or a tunable laser adapted to change an excitation signal wavelength for a plurality of the discrete shifted spectroscopy signals,
wherein data from each of the plurality of discrete shifted spectroscopy signals is superimposed to create a vector.

### Claim 18 (depends on 17)

The method of claim 17 wherein method comprises superimposing data from each of the plurality of discrete shifted spectroscopy signals to create a vector.

### Claim 19 (depends on 18)

The method of claim 18 wherein the method comprises building a mathematical matrix operator and using the mathematical matrix operator to solve a linear problem.

### Claim 20 (depends on 19)

The method of claim 19 wherein the method comprises using an iterative method to solve the linear problem that determines a Raman signal comprising a baseline Raman signal.

### Claim 21 (depends on 20)

The method of claim 20 wherein the iterative method is further used to solve for an unknown vector of noise.

### Claim 22 (depends on 21)

The method of claim 21 wherein the Raman signal is fluorescence free and a baseline Raman spectroscopy signal.

### Claim 23

A method of determining a Raman spectroscopy signal, the method comprising:
obtaining a plurality of discrete spectra corresponding to a plurality of discrete shifts within an optical system of a Raman spectrometer without the use of multiple lasers or a tunable laser adapted to change an excitation signal wavelength for a plurality of the discrete shifted spectroscopy signals;
superimposing data from each of the plurality of discrete shifted spectroscopy signals to create a vector;
building a mathematical matrix operator; and
using the mathematical matrix operator to solve a linear problem.

### Claim 24 (depends on 23)

The method of claim 23 wherein the method comprises using an iterative method to solve the linear problem that determines a Raman signal.