Multi-dispersion spectrometer

Abstract

A multi-dispersion spectrometer is provided, wherein the spectrometer includes an optical system configured to direct an excitation signal from an excitation light source toward a sample, receive a spectral signal from the sample, and direct the spectral signal toward a detector. The optical system includes a movable optical component, the movable optical component is suitable for moving the spectral signal relative to at least one sensor of the detector, and the detector is suitable for detecting a plurality of discrete shifted spectral signals. A method for obtaining a Raman spectrum from a sample is also provided. The method includes: directing an excitation signal from an excitation light source toward the sample; receiving the spectral signal from the sample; and directing the spectral signal toward the detector, wherein the spectral signal moves relative to at least one sensor of the detector to provide a plurality of discrete shifted spectral signals.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 823,089, filed on March 25, 2019, which is hereby incorporated by reference as if fully set forth herein. Technical Field

[0003] Embodiments of the present disclosure relate generally to spectroscopy and laser sources useful for spectroscopy such as Raman spectroscopy. Background Art

[0004] Spectroscopy is a general term for the process of measuring the energy or intensity in a beam of electromagnetic radiation (e.g., light) as a function of wavelength. Many conventional spectrometers include basic features and components such as a slit and collimator for producing a parallel beam of radiation, one or more prisms or gratings for dispersing the radiation by making the deviation angle different based on wavelength, and means for collecting and measuring the properties of the dispersed radiation. Spectroscopy uses the absorption, emission, or scattering of electromagnetic radiation by molecules or ions to qualitatively and quantitatively study the physical properties and processes of matter.

[0005] During the operation of the spectrometer system, the light or radiation directed to the sample or target of the physical substance can be referred to as the incident radiation. The redirection of the incident radiation after contact with the sample is generally referred to as the scattering of the radiation. In terms of atoms or molecules in the sample absorbing all or part of the incident radiation instead of reflecting the incident radiation, the sample can become excited, and the energy level of the sample can be increased to a higher energy level. The electromagnetic radiation passing through the sample can produce a small portion of light scattered in various directions. Light that is scattered but continues to have the same wavelength as the incident radiation will also have the same energy-a condition often referred to as Rayleigh or elastic scattered light. The incident radiation scattered during the change of molecular vibrational state can be scattered with different energies, and this scattered light can be referred to as Raman scattered light. This phenomenon is combined with spectroscopy to qualitatively and quantitatively study physical properties and processes, including the identification of the chemical properties, composition and structure of the sample.

[0006] Electromagnetic radiation waves can be characterized by wavelength (the physical length of one complete oscillation) and the frequency of the wave (the number of oscillations per second that pass a given point). In the scattered radiation, the wavelength of the incident radiation on the sample can remain essentially unchanged. Alternatively, the wavelength in the scattered radiation can be shifted to one or more different wavelengths relative to the incident wavelength. The difference in wavelength between the incident radiation and the scattered radiation can be referred to as the Raman shift. The spectral measurement of Raman scattered light is the measurement of the resulting wavelength of this scattered light.

[0007] Raman scattering can occur at wavelengths that are shifted from the incident light by the amount of molecular vibrations. Therefore, the phenomenon of Raman scattered light is useful in spectroscopy applications for the qualitative and quantitative study of physical properties and processes, including the identification of chemical properties, components, and structures in samples.

[0008] The measurement of scattered radiation can make it possible to identify one or more frequencies associated with the sample and the intensity of these shifted frequencies. The frequency can be used to identify the chemical composition of the sample. For example, if the intensity is plotted on the Y-axis and a frequency or frequencies are plotted on the X-axis, the frequency or frequencies can be expressed as wave numbers (the inverse of the wavelength expressed in centimeters). The X-axis representing the frequency or frequencies can be converted into a Raman shift in wave numbers (the difference between the wave number positions of the observed spectral bands) and the wave number of the radiation that appears in the incident radiation.

[0009] Raman scattering provides important opportunities for qualitative and quantitative studies of physical properties and processes, including identification of chemical composition and structure in samples of physical matter. However, Raman scattering is a relatively weak effect when compared to Rayleigh or elastic scattering. 6 to about 10 8 Of the photons, only about one scattered photon tends to undergo a Raman shift.

[0010] The detection limit in Raman spectroscopy is reduced by ambient light and background interference during sampling. Ambient light is often in the form of room lighting or daylight that can overwhelm even the strongest scattering samples. Therefore, the detector and the sample being scanned are often fully enclosed to shield against ambient light. Samples that cannot be fully enclosed present special challenges.

[0011] Excitation sources for Raman spectroscopy include gas lasers such as helium-neon, helium-cadmium, argon ion, krypton ion, and solid-state lasers including Nd-YAG, as well as diode lasers, solid-state tunable lasers, liquid dye lasers, fiber lasers, and others.

[0012] Background interference also arises from non-spontaneous emission from certain types of samples such as fluorescence. Fluorescence occurs when absorbed radiation is reduced in frequency due to internal molecular processes and emitted as radiation closer to the red end of the visible light spectrum. Compared to the Raman shift, fluorescence can sometimes be strong enough to drown out or substantially suppress the weaker Raman signal. Fluorescence reduces the dynamic range and ultimately the signal-to-noise ratio of the data obtained from the sample.

[0013] Fluorescence can be reduced by exciting at higher wavelengths such as 1064 nm, but at the expense of expensive components and a loss of signal-to-noise ratio for all samples (i.e., even those that do not suffer from fluorescence problems). The loss of signal-to-noise ratio is due to poor detectors at this wavelength and because Raman scattering increases with the negative fourth power of wavelength (λ -4 )change.

[0014] Fluorescence can also be reduced by exciting the sample with a plurality of different wavelengths, obtaining a Raman signal from the sample for each of the plurality of different wavelengths, and decomposing the Raman spectrum from the plurality of Raman signals to obtain a decomposed Raman signal that reduces or eliminates noise such as fluorescence and background radiation. The plurality of different wavelengths is provided by using a plurality of laser light sources operating at a corresponding plurality of different wavelengths or by using a tunable laser to provide different wavelengths corresponding to different temperatures. Summary of the invention

[0015] In various embodiments, a multi-dispersion spectrometer is provided. The spectrometer includes an optical system configured to direct an excitation signal from an excitation light source toward a sample, receive a spectral signal from the sample, and direct the spectral signal toward a detector. The optical system includes a movable optical component, the movable optical component is adapted to move the spectral signal relative to at least one sensor of the detector, and the detector is adapted to detect a plurality of discrete shifted spectral signals.

[0016] The movable optical component may, for example, include at least one of a dispersive element, a diffraction grating, a detector, a filter, an optical plane, a micro-electromechanical system (MEMS) element, and a mirror. In various embodiments, the movable element may be moved by rotation and / or translation within the optical system of the spectrometer. The movement may be relative to a detector of the optical system, relative to an optical path of the optical system, or relative to one or more other components of the spectrometer optical system.

[0017] A piezoelectric mount for rotating a movable element within an optical system of a spectrometer is also provided.

[0018] In some embodiments, a mathematically decomposed spectral signal is derived from a plurality of detected discrete shifted spectral signals. The mathematically decomposed spectral signal can be used to reduce noise such as fluorescence and / or background radiation. Noise can be reduced without using a tunable laser or multiple lasers adapted to change the wavelength of the excitation signal for a plurality of discrete shifted spectral signals. Noise can also be reduced without changing the frequency of the excitation signal. The excitation light source can, for example, include a single laser operating at a substantially consistent operating frequency.

[0019] The movable optical component may be adapted to shift the spectral signal relative to the optical path of the optical system in multiple steps to provide multiple discrete shifted spectral signals and / or to shift the dispersed spectral signal in multiple steps across multiple sensors of the detector.

[0020] In other variations, a method for obtaining a Raman spectrum from a sample is also provided. The method includes: directing an excitation signal from an excitation light source toward the sample; receiving a spectral signal from the sample; and directing the spectral signal toward a detector, wherein the spectral signal is shifted relative to at least one sensor of the detector to provide a plurality of discrete shifted spectral signals.

[0021] In various embodiments, the method includes moving the spectral signal relative to at least one sensor of the detector via a movable component of the optical system.

[0022] The movable component of the optical system may include any component suitable for moving the spectral signal relative to the detector, relative to the optical path of the spectrometer, and / or relative to one or more other components of the spectrometer optical system. For example, the movable component may include at least one of a dispersive element, a diffraction grating, a detector, a filter, an optical plane, a micro-electromechanical system (MEMS) element, and a mirror.

[0023] In some embodiments, the method can derive a mathematically decomposed spectral signal from a plurality of detected discrete shifted spectral signals. The mathematically decomposed spectral signal can be used to reduce noise such as fluorescence and / or background radiation. Noise can be reduced without using a tunable laser or multiple lasers adapted to change the wavelength of the excitation signal for a plurality of discrete shifted spectral signals. Noise can also be reduced without changing the frequency of the excitation signal. The excitation light source can, for example, include a single laser operating at a substantially consistent operating frequency.

[0024] The method may also include superimposing data from each of a plurality of discrete shifted spectral signals to create a vector, establishing a mathematical matrix operator, and solving a linear problem using the mathematical matrix operator. The method may also use an iterative method to solve a linear problem of determining a Raman signal, which may include a baseline Raman signal. The method may also solve an unknown vector of noise to at least substantially remove fluorescence and / or background noise.

[0025] Another method for determining a Raman spectral signal is provided. The method includes: obtaining a plurality of discrete spectra corresponding to a plurality of discrete shifts within an optical system of a Raman spectrometer; superimposing data from each of the plurality of discrete shifted spectral signals to create a vector; establishing a mathematical matrix operator; and using the mathematical matrix operator to solve a linear problem. The method may also use an iterative method to solve a linear problem for determining a Raman signal. The iterative method may also be used to solve an unknown vector of noise such as at least one of fluorescence and background radiation. The mathematical matrix operator may represent a unit matrix of non-shifted noise spectral elements from the plurality of discrete shifted spectral signals.

[0026] In various embodiments, the spectrometer includes an optical system adapted to receive a spectral signal and to change the signal by moving components of the optical system to shift the spectral signal relative to an optical sensor (e.g., a CCD array sensor). In one embodiment, for example, a movable grating such as a rotating grating is provided that can shift the spectral signal relative to the optical sensor. In another embodiment, the optical sensor is adapted to move relative to one or more components of the optical system to shift the received Raman signal relative to an element of the sensor. In other embodiments, both the grating and the sensor can be moved relative to each other. In other embodiments, one or more other components of the optical system can be used to shift the spectral signal relative to the optical sensor alone or in combination with one or both of the grating and the sensor to shift the spectral signal relative to the optical sensor.

[0027] In some embodiments, multiple excitation cycles can be obtained by a single laser operating at a substantially consistent excitation frequency. One or more movable components of the optical system of the spectrometer can be adapted to shift the received spectral signal relative to the optical sensor of the spectrometer optical system. Multiple individually sensed spectral signals can be received at different relative positions of the optical sensor (e.g., by different corresponding positions or sensing elements of the optical sensor) to provide multiple individually sensed spectral signals. A mathematically decomposed spectral signal can be obtained based on the received multiple individual spectral signals. The decomposed spectral signal can, for example, reduce or eliminate noise such as fluorescence and background radiation without the need for a tunable laser or multiple lasers adapted to change the wavelength of the excitation signal for each of the multiple individually sensed spectral signals.

[0028] In one embodiment, a matrix is ​​assembled from a plurality of individually sensed spectral signals detected from a plurality of shifted detections of spectral signals received from a sample. The matrix is ​​used to decompose the plurality of individually sensed spectral signals and reduce or eliminate noise such as fluorescence and background radiation.

[0029] In one embodiment, a piezoelectric-based element may be used to move (eg, rotate) a grating of a spectrometer optical system to shift a received spectral signal relative to an optical sensor to provide multiple individually sensed spectral signals from a sample.

[0030] In one embodiment, for example, the plurality of individually sensed spectral signals may include a plurality of individually incremental measurements adapted to provide a resolution corresponding to the number of individually sensed spectral signals and the amount of shift of the received spectral signals relative to an optical detector of the spectrometer. Thus, by shifting the received spectral signals by individually incremental amounts, a relatively slight shift in the received spectral signals may be achieved at the sensor of the spectrometer due to the wavelength difference between the individual laser wavelengths, and thus the resolution in the resulting decomposed spectral signals may be increased within a system of different laser wavelengths (whether obtained by different individual lasers or a tunable wavelength of a single laser).

[0031] The above and other aspects, features, details, utilities and advantages of the present invention will be apparent from reading the following description and claims and from reviewing the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of an example spectrometer including a movable dispersive element, such as a diffraction grating, of an optical system of the spectrometer adapted to move a spectral signal relative to an optical detector of the optical system.

[0033] 2 is a schematic diagram of an example multi-channel detector suitable for use in a spectrometer.

[0034] Figure 3 A schematic diagram showing an exploded view of a piezoelectric based element suitable for moving an optical element of a spectrometer is shown.

[0035] Figure 4 A schematic diagram is shown representing a perspective view of an assembled piezoelectric-based element suitable for moving an optical element of a spectrometer.

[0036] Figure 5 A block diagram of an alternative example embodiment of a spectrometer is shown.

[0037] Figure 6 A block diagram of another example embodiment of a spectrometer is shown.

[0038] Figure 7 A block diagram of yet another example embodiment of a spectrometer is shown.

[0039] Fig. 8A A block diagram of an example embodiment of a rotatable optical plane oriented in a direction generally perpendicular to the optical path of a spectrometer optical system is shown.

[0040] Figure 8B Shows Fig. 8A Block diagram of the rotation of an optical plane relative to the optical path resulting in a linear translation of the light beam within the spectrometer optical system.

[0041] Fig.9A A flow chart illustrating an example method of removing or eliminating noise, such as fluorescence and / or background radiation, from multiple spectral signals that are displaced relative to each other within an optical system of a spectrometer.

[0042] Fig. 9B is a Raman spectrum showing the detection of 4-amino-6-chloro-1,3-benzenedisulfonamide and Fig.9A A graph of the underlying baseline Raman spectrum determined by the method shown.

[0043] Fig. 9C is a Raman spectrum showing the detection of acetaminophen and Fig.9A A graph of the underlying baseline Raman spectrum determined by the method shown.

[0044] Fig.10 A graph of a plurality of individually sensed shifted spectral signals of a sample is shown.

[0045] Fig.11 Another graph of a plurality of individually sensed shifted spectral signals of a sample is shown.

[0046] Fig.12 Yet another graph showing a plurality of individually sensed shifted spectral signals of a sample.

[0047] FIG. 13A to FIG. 13B Shown is a graph showing a comparison of the resolution of a multiple excitation wavelength system and a system including multiple individually sensed shifted spectral signals for an L-thyroxine sample.

[0048] Fig.14 A graph illustrating an example problem caused by fluorescence resulting in incorrect or uncertain spectral determinations is shown.

[0049] Fig.15 A graph showing an example of the value of illustrating fluorescence suppression is shown.

[0050] Fig.16 is a schematic diagram of an example embodiment of a spectrometer suitable for providing a method for returning a movable component of an optical system to a consistent initial position.

[0051] Fig.17 Multiple spectra of neon emission at different positions of the movable component of the optical system are shown. DETAILED DESCRIPTION

[0052] Spectrometers (e.g., Raman or luminescence (e.g., fluorescence, phosphorescence, chemiluminescence) spectrometers) that reduce interference caused by noise such as fluorescence or background radiation are provided. In various embodiments, for example, the methods and systems described herein can be used to sequentially measure multiple Raman spectra from the same sample without adjusting the operating conditions of the excitation laser. Multiple Raman spectra can be shifted within the optical system of the spectrometer so that the individually sensed spectra can be compared and decomposed into a single spectrum with reduced noise or even substantially free of noise (e.g., background radiation and fluorescence). Although specific types of spectrometers (e.g., Raman and fluorescence) are described below, these are merely examples of spectrometers that can be used in a similar manner to reduce interference in spectral signals.

[0053] Figure 1 A simplified schematic block diagram of an example embodiment of a spectrometer 20 is shown, the spectrometer 20 being configured to illuminate a sample by directing an excitation signal (e.g., an excitation light signal), receive a returned spectral signal from the sample, and determine spectral components of the spectral signal corresponding to one or more components of the complex sample. Although the specific example shows a Raman spectrometer, other types of spectrometers such as a luminescence spectrometer can be easily designed based on the description herein.

[0054] like Figure 1 As shown in FIG. 1 , the spectrometer 20 includes an excitation source 22. In a Raman spectrometer, for example, the excitation source 22 typically includes a laser light source. In one embodiment, for example, the excitation source 22 includes a diode laser. Figure 1 In an example implementation of , for example, a spectrometer may provide an excitation signal (eg, incident light beam 26 ) from an excitation source 22 , such as a laser (eg, a diode laser) operating at a relatively consistent wavelength (eg, λ 1 ).

[0055] The spectrometer 20 also includes an optical system 25. The optical system 25 directs an incident light beam 26 toward a sample 28 and receives a spectral signal 36 from the sample 28. Figure 1 , for example, optical system 25 includes a dichroic beam splitter 30. However, incident light beam 26 may be directed to sample 28 without any intervening instrument components located in the path of incident light beam 26. Incident light beam 26 may also be directed to a mirror, a holographic transmission element, a mirror with a hole formed therein, or any other component known in the art for directing an incident light beam.

[0056] The incident light beam 26 may also be directed through a lens 34. In one embodiment, the lens 34 includes a focusing lens in the path of the incident light beam 26. The focusing lens couples the incident light beam 26 to the sample 28 and collects spectral signals (e.g., Raman scattered light) from the sample. In another embodiment, more than one lens 34 may be located in the path of the incident light beam 26 before the incident light beam 26 contacts the sample 28. In various embodiments, the spectrometer 20 may include other optical elements for directing the incident light beam 26 toward the sample and collecting spectral signals from the sample. For example, the optical system of the spectrometer 20 may include elements such as a collimated beam pipe or a fiber optic waveguide. See, for example, U.S. Patent No. 7,403,281 for examples of collimated beam pipes or fiber optic waveguides that can be used in the optical systems of various spectrometers, which is incorporated by reference as if fully set forth herein.

[0057] The incident light beam 26, when in contact with the sample 28, causes or generates a spectral signal to be detected by the spectrometer 20. In Raman spectroscopy, for example, the incident light beam 26, when in contact with the sample 28, causes or generates scattered radiation or a Raman shift (described in this document as a Raman beam or a Raman signal for convenience) having an energy difference different from the incident radiation 26 and one or more wavelengths different from the incident radiation 26. As described above, and as Figure 1 As shown in FIG. 1 , in one embodiment, spectrometer 20 includes a beam splitter such as a dichroic beam splitter 30. Spectral signal 36 (e.g., Raman beam) is directed back through lens 34 and dichroic beam splitter 30 in a 180 degree backscattering geometry. Neither incident beam 26 nor spectral signal 36 need to be collinear. However, in FIG. Figure 1 In the embodiment shown in FIG. 3 , the spectral signal 36 is returned through the dichroic beam splitter 30 and then passes through a filter element 38. In one embodiment, the filter element 38 includes a long pass filter that removes extraneous radiation (e.g., from the light source 22 or another source) before dispersing the spectral signal 36 into a spectrum. Alternatively, the filter element 38 may include a notch filter or any other filter capable of suppressing elastically scattered radiation.

[0058] The spectral signal 36 may also pass through an input focusing lens 40, which focuses the spectral signal 36 to a point at a spatial filter 41. For example, in one embodiment, the spatial filter 41 includes an aperture, a slit, or a notch, and is located at the focus of the input focusing lens 40. The spatial filter 41 spatially filters the light beam at the focus of the input focusing lens.

[0059] Figure 1The spectrometer 20 shown in FIG. 2 also includes a collimating lens 42 that collimates the divergent spectral signal 36 after it passes through an aperture (e.g., an aperture, a slit, or a notch) of a spatial filter 41. The collimating lens 42 also directs the re-collimated Raman beam toward a dispersive element such as a diffraction grating 44. The diffraction grating 44 includes an optical element that splits the Raman beam into spatially separated wavelengths. The diffraction grating 44 also directs the split Raman beam 46 toward a detector 48. The split Raman beam 46 passes through a detector focusing lens 50 that focuses the spatially separated wavelengths of the split Raman beam 46 onto the detector 48.

[0060] The detector 48 includes a transducer that converts light energy into an electrical signal. In one embodiment, for example, the detector 48 includes an array of individual transducers that create an electrical pattern of spatially separated wavelengths representing the Raman spectrum. In one embodiment of the present invention, for example, a charge coupled device (CCD) array may be used as the detector 48. In another embodiment, an indium gallium arsenide (InGaAs) detector 48. Other detectors known in the art, such as CMOS sensors, may also be used within the spectrometer of the present invention.

[0061] One or more actuators 54 are adapted to move the diffraction grating, such as to displace the dispersed Raman signal relative to one or more sensor elements of the detector 48. For example, the actuator may include a motor or other actuator such as a piezoelectric-based element adapted to rotate, displace, or otherwise move the diffraction grating relative to other elements of an optical system such as the detector 48. In this manner, the dispersed Raman signal may be displaced relative to one or more sensor elements of the detector 48. In another embodiment, the actuator may be adapted to move the detector (or the sensor element of the detector 48) relative to the optical system of the spectrometer. Likewise, the actuator may include a motor or other actuator such as a piezoelectric-based element adapted to displace, rotate, or otherwise move the detector (or the sensor element within the detector) relative to the optical system of the detector.

[0062] The spectrometer 20 also includes a control electronics 52 for controlling the operation of the spectrometer 20. For example, the control electronics 52 may include one or more processors, memory, or other hardware programmed to control one or more operations of the spectrometer 20. For example, the control electronics 52 may control the operation of the light source 22, one (or more) actuator assembly 54, the detector 48, a temperature control element (e.g., for the light source or detector), and data transmission to and from the spectrometer. In one embodiment, the control electronics 52 may be integrated into a single PC board within the housing of the spectrometer. The control electronics 52 may also include one or more discrete components and / or one or more integrated circuit components.

[0063] In one embodiment, the control electronics 52 may include components for communicating with external devices. Components for communication (e.g., components for forming communication) may include wired or wireless communication ports for communicating with external computers, personal data assistants (PDAs), networks, etc. For example, wired communication ports may include parallel, serial, universal serial bus (USB), FireWire (FireWire).TM., IEEE 1394, Ethernet, modems, cable modems, or other wired communication ports known in the art. For example, wireless communication ports may include antennas, wireless modems, or other wireless communication ports known in the art for wireless communication with external devices such as via infrared, Bluetooth, IEEE802.11a / b / g, IrDA, etc. The control electronics 52 may be powered by a battery of a portable device, or may include a power input for receiving power from an external power source known in the art. A battery or power supply circuit (e.g., a rectifier) ​​may be located in the housing of the spectrometer 20.

[0064] In Raman spectroscopy, the spectrometer 20 operates to detect the Raman spectrum of the sample 28. To detect the Raman spectrum, the light source 22 is activated to generate an incident beam 26 of excitation radiation, such as a laser incident beam in a laser light source. In one embodiment, for example, the temperature of the light source 22 is controlled to control the output frequency of the incident beam 26 generated by the light source 22. The incident beam 26 of excitation radiation passes through the filter 24, which removes stray emissions from the incident beam. The incident beam 26 is reflected from the beam splitter 30 toward the sample 28. The incident beam 26 is focused onto the sample 28 by the output focusing lens 34.

[0065] The incident beam 26 generates Raman scattered light from the sample 28. The Raman scattered light is received by the output focusing lens 34 and transmitted back through the beam splitter 30. In this embodiment, the beam splitter 30 passes the Raman scattered light through the mirror 30 to the filter 38. From the filter 38, the Raman scattered light passes through the input focusing lens 40 and is focused onto a spatial filter 41 such as an aperture, slit or notch. The Raman scattered light is spatially filtered and diverged toward the collimating lens 42. The collimating lens 42 collimates the diverged Raman scattered light and transmits the light to the diffraction grating 44, which divides the Raman scattered light into spatially separated wavelengths and directs these wavelengths to the detector element 48. The spatially separated wavelengths of the Raman scattered light pass through the detector focusing lens 50 and are focused into focused radiation bands representing the spatially separated wavelengths of the Raman scattered light. The focused radiation bands are further directed by the detector focusing lens 50 onto the detector 48.

[0066] In this particular implementation, the detector 48 includes an array of individual transducers, each of which generates an electrical signal corresponding to the intensity of the radiation received at each individual transducer. The electrical signals generated at the individual transducers of the detector represent the spatially separated wavelengths of the Raman spectrum of the sample 28. The electrical signals are read from the detector by the control electronics 52. In one embodiment, for example, the spectrometer 20 can then present the detected Raman spectrum to the user, such as via a display or indicator on the spectrometer itself. In another embodiment, the control electronics of the spectrometer 20 can include a lookup table stored in a data storage element (e.g., a memory, a tape or disk drive, a memory stick, etc.). In this embodiment, the control electronics 52 compares the signal from the detector with the value stored in the lookup table to determine the result of the Raman scan. The spectrometer 20 then presents the result to the user, such as via a display or indicator on the spectrometer. For example, the result can indicate the presence or absence of one or more chemicals or substances in the sample, and can also indicate the amount or concentration of the chemicals or substances detected by the spectrometer.

[0067] In other implementations, the detector 48 may include one or more separate transducers that rapidly scan for one or more expected spectral features (e.g., Raman features). Examples of such systems are disclosed in U.S. patent application no. 13 / 161,485, entitled “Spectrometer” and filed by Carron et al. on June 15, 2011, which is hereby incorporated by reference herein in its entirety for its teachings and suggestions.

[0068] As described above, the spectrometer includes an optical system adapted to receive a spectral signal and to change the signal by moving one or more components of the optical system relative to one or more other elements of the optical system to shift the spectral signal relative to an optical sensor (e.g., a CCD array sensor). In one embodiment, for example, the actuator 54 is adapted to move one or more components of the optical system (e.g., a movable grating such as a rotating grating, or an optical system component such as an aperture), and is configured to shift the spectral signal relative to the optical sensor. In another embodiment, the actuator is adapted to move the optical sensor relative to the optical system of the spectrometer to shift the received Raman signal relative to an element of the sensor. In other embodiments, both the optical sensor and one or more components of the optical system (e.g., a grating and / or an aperture) can be moved relative to each other. In other embodiments, one or more other components of the optical system can be used to shift the spectral signal relative to the optical sensor alone or in combination with one or both of the grating and the sensor relative to the optical sensor.

[0069] In some embodiments, multiple excitation cycles can be obtained by a single laser operating at a substantially consistent excitation frequency. One or more movable components of the optical system of the spectrometer can be adapted to shift the received spectral signal relative to the optical sensor of the spectrometer optical system. (For example, by different corresponding positions or sensing elements of the optical sensor) Multiple individually sensed spectral signals can be received at different relative positions of the optical sensor to provide multiple individually sensed spectral signals. A decomposed spectral signal can be obtained based on the received multiple individual spectral signals. The decomposed spectral signal can, for example, reduce or eliminate noise such as fluorescence and background radiation without the need for a tunable laser or multiple lasers adapted to change the wavelength of the excitation signal for each of the multiple individually sensed spectral signals.

[0070] In one embodiment, a matrix is ​​assembled from a plurality of individually sensed spectral signals detected from a plurality of shifted detections of spectral signals received from a sample. The matrix is ​​used to decompose the plurality of individually sensed spectral signals and reduce or eliminate noise such as fluorescence and background radiation.

[0071] Figure 2A and Figure 2B Schematic diagrams of an example multi-channel detector of a spectrometer suitable for imaging with a first spectral signal and a second spectral signal shifted relative to the first spectral signal are shown respectively. In this example, Figure 2AIt is shown that a first individually sensed spectral signal at a first position (corresponding to a first optical system intermediate component position (e.g., grating rotation position) and / or detector position) is diffracted onto a multi-channel detector so that one or more peaks or other diffraction components of the first spectral signal are imaged on a sensor element of the detector at the first position. Figure 2B A second individual sensing spectrum diffracted onto the multi-channel detector at a second position (corresponding to the first optical system intermediate component position and / or detector position) is shown. Figure 2B In the second spectral signal, one or more peaks or other diffraction components are in the same Figure 2A The corresponding peaks or other diffraction components of the first spectral signal shown are imaged on the sensor elements of the detector at the corresponding second shifted / displaced positions of different sensor elements / channels of the multi-channel detector.

[0072] Figure 3 An exploded perspective view of a piezoelectric based element 10 suitable for moving an optical element of a spectrometer such as a diffraction grating 14 is shown. Figure 4 An assembled perspective view of a piezoelectric-based element 10 suitable for moving an optical element of a spectrometer is shown. In this particular embodiment, for example, the piezoelectric-based element 10 includes a grating mount for supporting a diffraction grating 14 within an optical system of a spectrometer. The piezoelectric element 12 is coupled to and supported by the grating mount 16. The piezoelectric element is disposed such as to provide a linear force along an axis 15 based on an electrical signal (e.g., received from one or more control electronics 52 of the spectrometer). The linear force is applied to a flexible element 18 also mounted to the grating mount. In one embodiment, for example, the flexible element 18 (e.g., a bendable metal sheet element, a bendable polymer element) is disposed adjacent to the piezoelectric element 12 and is secured to the grating mount 16 to act like a cantilever beam. In this embodiment, the diffraction grating 14 is mounted or coupled to the flexible element 18 so that when the piezoelectric element 12 moves along the axis, the piezoelectric element 12 causes the flexible element 18 to bend, thereby causing the flexible element 18 to bend relative to the fixed portion of the flexible element 18 and causing the diffraction element 14 to rotate relative to one or more other elements of the spectrometer optical system (e.g., a detector). In one implementation, for example, the diffraction grating 14 is fixed to the flexible element 18 (e.g., via an adhesive or a connector). A portion (e.g., an end) of the flexible element 18 is connected (e.g., bolted, threaded, welded, fused, bonded, or otherwise connected) to the grating base 16. The piezoelectric element 12 is fixed to the grating base 16 (e.g., via an adhesive or a connector). The grating base 16 is connected to the spectrometer (e.g., to a frame or other portion of the spectrometer). In this example, the grating base 16 is movable relative to the remaining optical components of the spectrometer.

[0073] although Figure 3 and Figure 4 A piezoelectric element and / or stack 12 is shown as an actuator, but other devices may be used, such as, but not limited to, a motor, a squiggle motor, a voice coil, a galvanometer, a PCB motor, a rotary motor, or any other mechanical device suitable for rotating the grating relative to the sensor of the spectrometer. Figure 3 and Figure 4 The dispersive element 14 is shown attached to a flexible element, but other rotating components of the optical system such as optical planes, mirrors, etc. may also be mounted to the flexible element.

[0074] Figure 5 A block diagram of an alternative example embodiment of a spectrometer 60 is shown, the spectrometer 60 being configured to illuminate a sample by directing an excitation signal (e.g., an excitation light signal), receive a returned spectral signal from the sample, and determine spectral components of the spectral signal corresponding to one or more components of the sample. Although the specific example shows a Raman spectrometer, other types of spectrometers such as a luminescence spectrometer can be easily designed based on the description herein. The same reference numerals are used to designate the same components as those described with respect to Figure 1 The components of the spectrometer shown are similar to the components of spectrometer 60 .

[0075] The spectrometer 60 includes an excitation source 22 that provides an excitation incident beam 26 to the sample via an optical system 65. The optical system 65 directs the incident beam 26 toward the sample 28 and receives a spectral signal 36 from the sample 28.

[0076] The optical system 65 includes an input focusing lens 40 that focuses the spectral signal 36 to a point at a spatial filter 66. For example, in one embodiment, the spatial filter 66 includes an aperture, a slit, or a notch and is generally located at the focal point of the input focusing lens 40. The spatial filter 66 spatially filters the light beam at the focal point of the input focusing lens.

[0077] exist Figure 5 In the embodiment of the present invention, the actuator 68 is adapted to move the spatial filter 66 relative to one or more other components of the optical system 65, such as the optical detector 48. For example, in Figure 5 In the embodiment shown in FIG. 6 , the filter 66 is translatable relative to the optical path of the spectral signal traveling through the optical system 65. The actuator 70 is adapted to move the filter 66 such as Figure 5 The filter 66 shown in . The actuator may include any type of actuator such as, but not limited to, a motor, a peristaltic motor, a voice coil, a galvanometer, a PCB motor, a rotary motor, or any other mechanical device suitable for translating the filter 66 relative to the optical path of the optical system 65 and / or the detector.

[0078] The collimating lens 42 collimates the divergent spectral signal 36 after it passes through the aperture of the spatial filter 66. The collimating lens 42 also directs the re-collimated Raman beam toward a dispersive element such as a diffraction grating 64. The diffraction grating 64 includes an optical element that splits the Raman beam into spatially separated wavelengths and directs the split Raman beam 46 toward a detector 48. The split Raman beam 46 passes through a detector focusing lens 50, which focuses the spatially separated wavelengths of the split Raman beam 46 onto the detector 48.

[0079] The spectrometer 60 also includes control electronics 52 for controlling the operation of the spectrometer 60. For example, the control electronics 52 may control the operation of the light source 22, the actuator assembly(s) 70, the detector 48, temperature control elements (e.g., for the light source or detector), and the transmission of data to and / or from the spectrometer.

[0080] The spectrometer 60 includes an optical system 65 adapted to receive a spectral signal and to modify the signal by moving one or more components of the optical system relative to one or more other elements of the optical system to shift the spectral signal relative to an optical sensor (e.g., a CCD array sensor). In this embodiment, for example, an actuator 70 adapted to move one or more components of the optical system (e.g., a linear translation spatial filter 66) is arranged to shift the spectral signal relative to the optical sensor.

[0081] Multiple excitation cycles can be obtained by a single laser operating at a substantially consistent excitation frequency (e.g., λ1). The linearly translatable spatial filter 66 is suitable for shifting the received spectral signal relative to the optical sensor 48 of the spectrometer optical system 65. Multiple individually sensed spectral signals can be received at different relative positions of the optical sensor (e.g., by different corresponding positions or sensing elements of the optical sensor) to provide multiple individually sensed spectral signals. A decomposed spectral signal can be obtained based on the received multiple individual spectral signals. The decomposed spectral signal can, for example, reduce or eliminate noise such as fluorescence and background radiation without the need for a tunable laser or multiple lasers suitable for changing the wavelength of the excitation signal for each of the multiple individually sensed spectral signals.

[0082] Figure 6 FIG. 8 is a block diagram of another example embodiment of a spectrometer 80 configured to illuminate a sample by directing an excitation signal (e.g., an excitation light signal), receive a returned spectral signal from the sample, and determine spectral components of the spectral signal corresponding to one or more components of the sample. Figure 1 and Figure 5 The components of the spectrometer shown are similar to the components of spectrometer 80 .

[0083] The spectrometer 80 includes an excitation source 22 that provides an excitation incident beam 26 to the sample via an optical system 65. The optical system 65 directs the incident beam 26 toward the sample 28 and receives a spectral signal 36 from the sample 28.

[0084] The optical system 65 includes an input focusing lens 40 that focuses the spectral signal 36 to a point at a spatial filter 66. For example, in one embodiment, the spatial filter 66 includes an aperture, a slit, or a notch and is generally located at the focal point of the input focusing lens 40. The spatial filter 66 spatially filters the light beam at the focal point of the input focusing lens.

[0085] The collimating lens 42 collimates the divergent spectral signal 36 after it passes through the aperture of the spatial filter 66. The collimating lens 42 also directs the re-collimated Raman beam toward a dispersive element such as a diffraction grating 64. The diffraction grating 44 includes an optical element that splits the Raman beam into spatially separated wavelengths and directs the split Raman beam 46 toward a detector 86. The split Raman beam 46 passes through a detector focusing lens 50, which focuses the spatially separated wavelengths of the split Raman beam 46 onto the detector 86.

[0086] exist Figure 6 In the embodiment of the present invention, the actuator 90 is adapted to move the detector 86 relative to one or more other components of the optical system 85, such as the diffraction grating 64. For example, in Figure 5 In the embodiment shown in FIG. 8 , the detector 86 is translatable relative to the optical path of the spectral signal traveling toward the detector 86 of the optical system 85. The actuator 90 is adapted to move the detector 86 such as Figure 6 The detector 66 shown in . The actuator may include any type of actuator such as, but not limited to, a motor, a torsion motor, a voice coil, a galvanometer, a PCB motor, a rotary motor, or any other mechanical device suitable for translating the detector 86 relative to the optical path within the optical system 85.

[0087] The spectrometer 80 also includes control electronics 52 for controlling the operation of the spectrometer 80. For example, the control electronics 52 may control the operation of the light source 22, one or more actuator assemblies 90, the detector 88, temperature control elements (e.g., for the light source or detector), and the transmission of data to and / or from the spectrometer.

[0088] The spectrometer 80 includes an optical system 85 adapted to receive a spectral signal and to change the signal by moving one or more components of the optical system relative to one or more other elements of the optical system to shift the spectral signal relative to an optical sensor (e.g., a CCD array sensor). In this embodiment, for example, an actuator 70 adapted to move one or more components of the optical system (e.g., a linear translation detector 88) is configured to shift the spectral signal relative to the optical sensor.

[0089] Multiple excitation cycles can be obtained by a single laser operating at a substantially consistent excitation frequency (e.g., λ1). The linearly translatable detector 88 is suitable for shifting the received spectral signal relative to the optical path of the spectrometer optical system 85. Multiple individually sensed spectral signals can be received at different relative positions of the optical sensor (e.g., by different corresponding positions or sensing elements of the optical sensor) to provide multiple individually sensed spectral signals. A decomposed spectral signal can be obtained based on the received multiple individual spectral signals. The decomposed spectral signal can, for example, reduce or eliminate noise such as fluorescence and background radiation without the need for a tunable laser or multiple lasers suitable for changing the wavelength of the excitation signal for each of the multiple individually sensed spectral signals.

[0090] Figure 7 1 is a block diagram of another example embodiment of a spectrometer 100 configured to illuminate a sample by directing an excitation signal (e.g., an excitation light signal), receive a returned spectral signal from the sample, and determine spectral components of the spectral signal corresponding to one or more components of the sample. Figure 1 , Figure 5 and Figure 6 The components of the spectrometer shown are similar to the components of spectrometer 100 .

[0091] The spectrometer 100 includes an excitation source 22 that provides an excitation incident beam 26 to the sample via an optical system 105. The optical system 105 directs the incident beam 26 toward the sample 28 and receives a spectral signal 36 from the sample 28.

[0092] The optical system 105 includes an input focusing lens 40 that focuses the spectral signal 36 to a point at a spatial filter 66. For example, in one embodiment, the spatial filter 66 includes an aperture, a slit, or a notch and is generally located at the focal point of the input focusing lens 40. The spatial filter 66 spatially filters the light beam at the focal point of the input focusing lens.

[0093] The collimating lens 42 collimates the divergent spectral signal 36 after it passes through the aperture of the spatial filter 66. The collimating lens 42 also directs the re-collimated Raman beam toward the optical plane 106 and onto a dispersive element such as a diffraction grating 64. The diffraction grating 64 includes an optical element that splits the Raman beam into spatially separated wavelengths and directs the split Raman beam 46 toward the detector 48. The split Raman beam 46 passes through the detector focusing lens 50, which focuses the spatially separated wavelengths of the split Raman beam 46 onto the detector 48.

[0094] exist Figure 7 In the embodiment of the present invention, the actuator 110 is adapted to move the optical plane 106 relative to one or more other components of the optical system 105, such as the detector 48 and / or the diffraction grating 64. For example, in Figure 7 In the embodiment shown in FIG. 1 , the optical plane 106 is rotatable relative to the optical path of the spectral signal traveling toward the detector 48 of the optical system 85. The actuator 110 is adapted to move a Figure 7 The actuator may include any type of actuator such as, but not limited to, a motor, a torsion motor, a voice coil, a galvanometer, a PCB motor, a rotary motor, or any other mechanical device suitable for translating the detector 86 relative to the optical path within the optical system 105.

[0095] The spectrometer 100 also includes control electronics 52 for controlling the operation of the spectrometer 100. For example, the control electronics 52 may control the operation of the light source 22, one or more actuator assemblies 110, the detector 48, temperature control elements (e.g., for the light source or detector), and the transmission of data to and / or from the spectrometer.

[0096] The spectrometer 100 includes an optical system 105 adapted to receive a spectral signal and to change the signal by moving one or more components of the optical system relative to one or more other elements of the optical system to shift the spectral signal relative to an optical sensor (e.g., a CCD array sensor). In this embodiment, for example, an actuator 110 adapted to move one or more components of the optical system (e.g., rotate an optical plane 106) is configured to shift the spectral signal relative to the optical sensor.

[0097] Multiple excitation cycles can be obtained by a single laser operating at a substantially consistent excitation frequency (e.g., λ1). The rotatable optical plane 106 is suitable for shifting the received spectral signal relative to the optical sensor 48 of the spectrometer optical system 105. (For example, by different corresponding positions or sensing elements of the optical sensor) Multiple individually sensed spectral signals can be received at different relative positions of the optical sensor to provide multiple individually sensed spectral signals. A decomposed spectral signal can be obtained based on the received multiple individual spectral signals. The decomposed spectral signal can, for example, reduce or eliminate noise such as fluorescence and background radiation without the need for a tunable laser or multiple lasers adapted to change the wavelength of the excitation signal for each of the multiple individually sensed spectral signals.

[0098] Fig. 8A and Figure 8B Shows such as Figure 7 A block diagram of an example embodiment of a rotatable optical plane 106 is shown in FIG. Fig. 8A The optical plane 106 is shown oriented in a direction generally perpendicular to the optical path of the optical system 105. In this orientation, as shown in FIG. Fig. 8A As shown in , the light path continues generally straight. Figure 8B An optical plane 106 is shown rotated relative to the optical path resulting in a linear translation of the light beam within the optical system 105. The linearly translated light beam is directed towards the diffraction grating and obtained on the detector 48.

[0099] Fig.9AA flow chart of an example method for removing or eliminating noise such as fluorescence and / or background radiation from multiple spectral signals shifted relative to each other within an optical system of a spectrometer is shown. In the method, a first spectrum (of multiple spectra) is collected for a first spectral signal imaged on a detector of the spectrometer. A second spectrum (of multiple spectra) is collected for a second spectral signal imaged on a detector shifted relative to the detector. In one embodiment, for example, the first spectral signal and the second spectral signal are diffracted onto the surface of the detector at a first position and a second position, respectively. The shift can be achieved by moving one or more components of the optical system of the spectrometer (e.g., a dispersive element, a detector, a filter, an optical plane, a microelectromechanical system (MEMS) element, a mirror, etc.). Although two spectra are described, any number of shifted spectra can be obtained. Data from multiple detected shifted spectral signals are superimposed to create a vector representing multiple detected shifted spectral signals. Mathematical matrix operators are also established. Matrix operators and vectors are used to solve linear problems Ax=B, where A is a matrix, x represents an unknown vector, and B represents multiple detected shifted spectra. In one variation, an iterative method can be used to solve a linear problem of determining an unknown vector of Raman signal and noise (e.g., fluorescence and / or background noise). The matrix represents the identity matrix of the non-shifted background spectrum from a plurality of shifted spectral measurements. The obtained Raman signal is free of noise (fluorescence and / or background noise) and is a baseline spectral signal (e.g., a baseline Raman spectral signal).

[0100] Fig. 9B is a graph showing the Raman spectrum detected for 4-amino-6-chloro-1,3-benzenedisulfonamide and the Fig.9A 200. The measured spectrum 200 includes the underlying Raman signal and various noise components such as fluorescence and background noise. By shifting the signal and determining the separated noise vector and Raman signal, the underlying baseline Raman signal 205 is shown. Fig. 9B As can be seen in , the resulting Raman signal is a baseline spectrum that can be accurately compared to a library.

[0101] Fig. 9C is a Raman spectrum showing the detected acetaminophen and Fig.9A 2 is a graph of the underlying baseline Raman spectrum determined by the method shown in FIG. The measured spectrum 210 includes the underlying Raman signal and various noise components such as fluorescence and background noise. By shifting the signal and determining the separated noise vector and Raman signal, the underlying baseline Raman signal 215 is shown. Fig. 9C As can be seen, the resulting Raman signal is a baseline spectrum that can be accurately compared to the library.

[0102] Compare Fig. 9B and Fig. 9C , it can be seen that Fig. 9B The detected spectrum for 4-amino-6-chloro-1,3-benzenedisulfonamide shown in FIG. Fig. 9C The detected spectra for acetaminophen shown in Figure 4 have a strong noise component that obscures the underlying Raman signal. However, in either case, a clean baseline Raman spectrum was determined.

[0103] Other methods such as Shifted Excitation Raman Difference Spectroscopy (SERDS) can also be used to obtain an isolated background spectrum from multiple individually sensed spectral signals.

[0104] Fig.10 A graph of a plurality of individually sensed shifted spectral signals of a sample is shown. In the graph, the wavenumber of the individually detected spectral signals detected at the spectrometer detector element is shown on the X-axis, while the amplitude of the spectral signal is shown along the Y-axis. Figure 5 As can be seen in, for example, multiple relatively small shifted steps can be achieved without using multiple lasers or tunable lasers. In various embodiments, for example, the different measurements of the shifted individual spectral signals can include any number of measurements, such as between five and fifty samples, between ten and forty samples, between twenty and thirty sample samples.

[0105] Fig.11 Another graph of multiple individually sensed shifted spectral signals of a sample is shown. In this particular example, two measurements shifted by 27 wavenumbers are shown, where the main peaks of the spectral signal include wavenumbers of 977nm and 1004nm. In this particular example, closely spaced lasers at 783nm and 785nm provide two spectra shifted by 27 wavenumbers.

[0106] Fig.12 Yet another graph of multiple individually sensed shifted spectral signals of a sample is shown. In this particular example, a rotating grating, shiftable detector, and / or other components of the spectrometer optical system provide multiple shifts over a range of wavenumbers (e.g., multiple shifts over a total range of 21 wavenumbers in multiple steps).

[0107] FIG. 13A to FIG. 13B A graph showing the resolution comparison of the results obtained from a multiple excitation wavelength system for an L-thyroxine sample and the results obtained from a system including multiple individually sensed shifted spectral signals is shown. The spectrum calculated from the multi-step rotating grating system is able to better resolve the peaks than the dual-step dual laser system. In this example, Fig. 13BAs shown in , the resolution is comparable to that of a 1064 nm Raman spectrometer without fluorescence.

[0108] Fig.14 An example illustrating the importance of fluorescence suppression in Raman spectroscopy applications is illustrated. Identification of materials is often performed by measuring how well a sample spectrum correlates with a library spectrum. This correlation can be performed by a dot product measurement of the area under the spectral curves. When the spectra do not exhibit fluorescence, the dot product is very dependent on the similarity between the spectra. However, when the spectra include fluorescence, the area under the spectra is dominated by signals that are independent of Raman scattering. The result is a very imprecise or uncertain correlation. For example, in Fig.15 In the present study, Raman spectra extracted from lactulose were incorrectly interpreted as isopropanol or were indeterminate.

[0109] Fig.15 The fluorescence suppression values ​​are shown in Figure 2. In this case, the fluorescence suppression values ​​have been calculated as in reference Figure 1 The spectrum of lactulose was obtained using the rotating grating described in Figure 9. The fluorescence was removed by applying the mathematical algorithm described with reference to Figure 9. As a result, an accurate correlation with the library spectrum was achieved. Fig.15 The incorrect match to isopropanol obtained when no spectral shift was applied was also compared.

[0110] In various embodiments, by moving the spectral signal relative to the detector of the spectrometer optical system, the spectrometer is allowed to increase flexibility in selecting the excitation laser wavelength based on the different laser wavelengths and / tunability available for a specific application rather than based on a specific laser. For example, the use of multiple lasers means that the laser wavelength is easily changed by a small wavelength distance with another closely spaced laser or by temperature tuning. This limits many systems to 783nm and 785nm, and limits temperature tunable DBR lasers to the 785nm range. In some applications, it may be advantageous to be able to use a wide variety of available laser wavelengths, such as lasers operating at 532nm or even 405nm, due to their much higher efficiency. These lasers cannot jump to new wavelengths, but as described herein, the spectral signals obtained using these excitation laser wavelengths are shifted. These wavelengths are also more prone to fluorescence, so the shifted independently sampled spectral signals obtained using these wavelengths can provide values ​​for wavelengths such as these. In addition, the ability to use a single non-tunable laser can provide significant power savings compared to driving multiple laser excitation sources or controlling the temperature of a tunable excitation laser source and driving a tunable excitation laser source.

[0111] Fig.16300 is a schematic diagram of an example embodiment of a spectrometer 300 including a lamp, the spectrometer 300 being adapted to provide a method for returning a movable component of an optical system 305 (e.g., a dispersive element such as a grating, a detector, a filter, an optical plane, a micro-electromechanical system (MEMS) element, a mirror, etc.) to a consistent initial position after acquiring a plurality of shifted spectra. In this embodiment, the spectrometer includes an optical system 305 that provides an excitation incident signal to a sample, receives a spectral signal from the sample, and directs the spectral signal to a reference signal such as the above. Figure 1 Describe the detector.

[0112] The spectrometer 300 also includes an emission light source 310 that does not change wavelength. An example is a low pressure neon lamp that emits atomic emission lines across the same wavelength region as the Raman spectrum. When components of the optical system 305 (e.g., grating dispersion elements) are moved (e.g., rotated or translated), the emission lines (e.g., neon emission lines) will move like Raman emission lines. This is in Fig.17 is shown in the figure. Fig.17 Multiple spectra of neon emission extracted at different positions of movable components of the optical system such as dispersive elements (gratings), detectors, filters, optical planes, micro-electromechanical systems (MEMS) elements, mirrors, etc. are shown. These positions can be used to calibrate the spectrum at each new grating position. These lines can also be used to ensure that the components of the optical system 305 (e.g., grating dispersive elements) are returned to their origin or initial positions. By activating the emitting light source 310 and comparing the position of the spectrum with a calibration signal related to the initial position, the spectrometer 300 can determine whether one or more peaks (or other components / features) (of the signal) are in the correct position on the detector to determine whether the movable component is in its correct initial position and ensure that there is no misalignment after acquisition. If the spectral component / feature is not in the correct position, the movable component can be moved until the correct position is determined.

[0113] Although the above embodiment is described with certain specificity, without departing from the spirit or scope of the present invention, those skilled in the art may make many changes to the disclosed embodiment. All directions refer to (for example, up, down, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise and counterclockwise) only for identification purposes, to help readers understand the present invention, and do not form restrictions particularly on the position, orientation or use of the present invention. Engagement reference (for example, attachment, coupling, connection, etc.) will be interpreted broadly, and may include the relative movement between the intermediate member and the element between the connection of the element. Therefore, engagement reference does not necessarily imply that two elements are directly connected and are in a fixed relationship to each other. All contents contained in the above description or shown in the accompanying drawings are intended to be interpreted as being only illustrative and non-restrictive. Changes in details or structure are made without departing from the spirit of the present invention as defined in the appended claims.

Claims

1. A Raman spectrometer, comprising: Excitation light source; a detector adapted to detect a spectrum from the signal; an optical system configured to direct an excitation signal from an excitation light source toward the sample, receive a spectral signal from the sample, and direct the spectral signal toward a detector; a filter configured to filter the spectral signal before the spectral signal reaches the detector, wherein the optical system comprises a controller adapted to control the movable optical component to repeatedly move the spectral signal relative to at least one sensor of the detector, and the detector is adapted to detect from the spectral signal a plurality of discrete shifted Raman spectra each corresponding to a different position of the movable optical component, and Therein, the filter is a movable optical component.

2. The Raman spectrometer according to claim 1, wherein: The movable optical component includes a diffraction grating.

3. The Raman spectrometer according to claim 2, wherein: The diffraction grating is adapted to rotate the diffraction grating to shift the spectral signal across the detector in a plurality of steps, thereby providing the plurality of discrete shifted Raman spectra from the spectral signal.

4. The Raman spectrometer according to claim 2, wherein: The rotatable diffraction grating is configured to shift the dispersed spectral signal across the plurality of sensors of the detector in a plurality of steps.

5. The Raman spectrometer according to claim 3, wherein: The rotatable diffraction grating is configured to disperse the spectral signal to different relative positions of the detector to provide the plurality of discrete shifted Raman spectra from the spectral signal.

6. The Raman spectrometer according to claim 2, wherein: The diffraction grating is configured to rotate via a piezoelectric element.

7. The Raman spectrometer according to claim 6, wherein: The rotatable diffraction grating is fixed to the flexible element, and the flexible element is configured to move via the piezoelectric element.

8. The Raman spectrometer according to claim 1 or 5, wherein: A mathematically decomposed spectral signal is derived from the plurality of detected discrete shifted Raman spectra.

9. The Raman spectrometer according to claim 8, wherein: The mathematically decomposed spectral signal is used to reduce noise.

10. The Raman spectrometer according to claim 9, wherein: The noise includes at least one of fluorescence and background radiation.

11. The Raman spectrometer according to claim 9, wherein: The noise is reduced without using a tunable laser or multiple lasers adapted to vary the excitation signal wavelength for multiple discrete shifted Raman spectra.

12. The Raman spectrometer according to claim 9, wherein: The noise is reduced without changing the frequency of the excitation signal.

13. The Raman spectrometer according to claim 9, wherein: The processor is configured to assemble a matrix from the plurality of individually sensed spectral signals.

14. The Raman spectrometer according to claim 13, wherein: The processor is configured to decompose the plurality of individually sensed Raman spectra using the matrix to reduce noise.

15. The Raman spectrometer according to claim 1, wherein: The excitation light source includes a single laser operated at a substantially uniform operating frequency.

16. The Raman spectrometer according to claim 1, wherein: The movable optical assembly includes the detector.

17. The Raman spectrometer according to claim 16, wherein: The detector is adapted to be translated relative to the optical path of the optical system to shift the spectral signal across the detector in a plurality of steps, thereby providing the plurality of discrete shifted Raman spectra.

18. The Raman spectrometer according to claim 17, wherein: The detector is configured to shift the spectral signal across a plurality of sensors of the detector in a plurality of steps.

19. The Raman spectrometer according to claim 1, wherein: The movable optical assembly includes at least one of a dispersive element, a diffraction grating, the detector, an optical plane, a micro-electromechanical system (MEMS) element, and a mirror.

20. The Raman spectrometer according to claim 19, wherein: The movable optical component is adapted to shift the spectral signal relative to the optical path of the optical system in a plurality of steps, thereby providing the plurality of discrete shifted Raman spectra.

21. The Raman spectrometer according to claim 19, wherein: The movable optical assembly is adapted to shift the dispersed spectral signal across the plurality of sensors of the detector in a plurality of steps.

22. A method for obtaining a Raman spectrum from a sample, the method comprising: directing an excitation signal from an excitation light source toward the sample; receiving a spectral signal from a sample; directing the spectral signal toward a detector; as well as The spectral signal is filtered before it reaches the detector. wherein the spectral signal is repeatedly moved relative to at least one sensor of the detector via a movable component of the optical system to provide a plurality of discrete shifted Raman spectra from the spectral signal, and Therein, the filter is a movable optical component.

23. The method according to claim 22, wherein: The movable component of the optical system includes at least one of a dispersive element, a diffraction grating, the detector, an optical plane, a micro-electromechanical system (MEMS) element, and a mirror.

24. The method according to claim 23, wherein: The movable component is adapted to be moved via a piezoelectric element.

25. The method according to claim 24, wherein: The rotatable diffraction grating is fixed to a flexible cantilever element, and the flexible cantilever element is configured to move via the piezoelectric element.

26. The method of claim 22, wherein: A mathematically decomposed spectral signal is derived from the plurality of detected discrete shifted Raman spectra.

27. The method according to claim 26, wherein: The mathematically decomposed spectral signal is used to reduce noise.

28. The method according to claim 27, wherein: The noise includes at least one of fluorescence and background radiation.

29. The method according to claim 27, wherein: The noise is reduced without using a tunable laser or multiple lasers adapted to vary the excitation signal wavelength for multiple discrete shifted Raman spectra.

30. The method of claim 27, wherein: The noise is reduced without changing the frequency of the excitation signal.

31. The method of claim 22, wherein: The excitation light source includes a single laser operated at a substantially uniform operating frequency.

32. The method of claim 22, wherein: The method includes superimposing data from each of the plurality of discrete shifted Raman spectra to create a vector.

33. The method of claim 32, wherein: The method includes establishing a mathematical matrix operator.

34. The method of claim 33, wherein: The method includes using the mathematical matrix operator to solve a linear problem.

35. The method of claim 34, wherein: The method involves using an iterative approach to solve the linear problem of determining the Raman signal.

36. The method of claim 35, wherein: The Raman signal includes a baseline Raman signal.

37. The method of claim 35, wherein: The iterative method is also used to solve for the unknown vector of noise.

38. The method of claim 35, wherein: The Raman signal does not contain fluorescence and is a baseline Raman spectroscopy signal.

Images