A method and system for classifying a tissue specimen is provided. The method includes: a) interrogating a tissue specimen with a first interrogation light; b) detecting first light from the tissue specimen resulting from the interrogation, wherein the first light includes a first scattered light component and a first fluorescence light component, and producing first signals; c) interrogating the tissue specimen with a second interrogation light at a second excitation wavelength, wherein the first and second excitation wavelengths are within about 2 nm of each other; d) detecting second light from the tissue specimen resulting from the interrogation, wherein the second light includes a second scattered light component and a second fluorescence light component, and producing second signals; e) determining a difference between the first and second lights; f) determining a fluorescence spectrum produced by the interrogation of the tissue specimen; and g) classifying the tissue specimen.

Systems and methods for reducing fluorescence and systematic noise in time-gated spectroscopy are disclosed. Exemplary methods include: a method for reducing fluorescence and systematic noise in time-gated spectroscopy may comprise: providing first light using an excitation light source; receiving, by a detector, first scattered light from a material responsive to the first light during a first time window; detecting a peak intensity of the first scattered light; receiving, by the detector, second scattered light from the material responsive to the first light during a second time window; detecting a peak intensity of the second scattered light; recovering a spectrum of the material by taking a ratio of the peak intensity of the first scattered light and the peak intensity of the second scattered light; and identifying at least one molecule of the material using the recovered spectrum and a database of identified spectra.

A method and system for identifying a Raman spectrum component of an observed spectrum is provided. The observed spectrum is produced by interrogating a material such as a tissue sample with light at the one or more predetermined wavelengths, and the observed spectrum includes a background fluorescence component representative of fluorescent emissions resulting from the light interrogation and a Raman spectrum component representative of a Raman scattering resulting from the light interrogation. The method includes a) creating a reconstructed fluorescence spectrum representative of the background fluorescence component of the observed spectrum using one or more empirically determined fluorescent spectral profiles; and b) identifying the Raman spectrum of the observed spectrum using the reconstructed fluorescence spectrum.

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.

A measuring device for time-resolved measurement of a measurement signal and for temporal separation of at least a first portion of the measurement signal, having a light source for emitting a pulsed excitation signal, at least one detector for receiving the measurement signal, the detector generating a detector signal from the measurement signal, at least one first forming unit for generating a first comparison signal, and at least one evaluation unit, the first comparison signal correlating with the excitation signal. At least one first logic function is provided which links at least the first comparison signal with a signal dependent on the detector signal so that the output of the logic function provides a measure of the intensity of the first portion of the measurement signal or of the detector signal. The output of the first logic function is connected to the at least one evaluation unit.

There are disclosed methods and apparatus (10) for measuring Raman spectral features (52) of a sample (12), from which background light of variable intensity is also received, for example due to the incidence of ambient light (14) or due to variable fluorescence. Detection pixels (42) and storage pixels (44) are defined on a CCD device (40). Laser probe light (22) is directed to the sample. In a repeated cycle of first and second intervals, in each first interval background light is received at detection pixels, and in each second interval both background light and scattered laser probe light is received at the detection pixels. The accumulated signal from each of the first and second intervals is retained in the storage pixels during the second and first intervals respectively. In other aspects laser probe light is directed to the sample during both of the first and second intervals, but has a different wavelength in each interval.

A compact, portable Raman spectrometer makes fast, sensitive standoff measurements at little to no risk of eye injury or igniting the materials being probed. This spectrometer uses differential Raman spectroscopy and ambient light measurements to measure point-and-shoot Raman signatures of dark or highly fluorescent materials at distances of 1 cm to 10 m or more. It scans the Raman pump beam(s) across the sample to reduce the risk of unduly heating or igniting the sample. Beam scanning also transforms the spectrometer into an instrument with a lower effective safety classification, reducing the risk of eye injury. The spectrometer's long standoff range automatic focusing make it easier to identify chemicals through clear and translucent obstacles, such as flow tubes, windows, and containers. And the spectrometer's components are light and small enough to be packaged in a handheld housing or housing suitable for a small robot to carry.

A method and system for identifying a Raman spectrum component of an observed spectrum is provided. The observed spectrum is produced by interrogating a material such as a tissue sample with light at the one or more predetermined wavelengths, and the observed spectrum includes a background fluorescence component representative of fluorescent emissions resulting from the light interrogation and a Raman spectrum component representative of a Raman scattering resulting from the light interrogation. The method includes a) creating a reconstructed fluorescence spectrum representative of the background fluorescence component of the observed spectrum using one or more empirically determined fluorescent spectral profiles; and b) identifying the Raman spectrum of the observed spectrum using the reconstructed fluorescence spectrum.

A compact, portable Raman spectrometer makes fast, sensitive standoff measurements at little to no risk of eye injury or igniting the materials being probed. This spectrometer uses differential Raman spectroscopy and ambient light measurements to measure point-and-shoot Raman signatures of dark or highly fluorescent materials at distances of 1 cm to 10 m or more. It scans the Raman pump beam(s) across the sample to reduce the risk of unduly heating or igniting the sample. Beam scanning also transforms the spectrometer into an instrument with a lower effective safety classification, reducing the risk of eye injury. The spectrometer's long standoff range automatic focusing make it easier to identify chemicals through clear and translucent obstacles, such as flow tubes, windows, and containers. And the spectrometer's components are light and small enough to be packaged in a handheld housing or housing suitable for a small robot to carry.

A multi-dispersive spectrometer is provided in which the spectrometer comprises an 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.