Multi-wavelength excitation-based fluorescence elimination method for Raman spectrum

Abstract

The invention discloses a multi-wavelength excitation-based fluorescence elimination method for Raman spectrum, which relates to a method of chemical analysis and photoelectric signal processing and comprises the steps of: sequentially exciting mixed spectra consisting of fluorescence and Raman light by irradiating a plurality of similar wavelength lasers sequentially generated by a laser source to the same measured sample; when a spectrograph acquires various mixed spectrum signals, aligning the mixed spectra, and normalizing and correcting the amplitude of the spectrum signals through a full spectrum integral value to obtain spectra of which the X-coordinates are aligned and the amplitude of the Y-coordinates is corrected; evaluating a difference value between each two mixed spectra, wherein the difference value is a differential value of a fluorescence signal; calculating an inverse difference of the differential value, wherein the inverse difference is divided by a differential step to obtain the sum of a fluorescence background value and a constant; and finally, deducting the fluorescence background value from the mixed spectra to separate a pure Raman spectrum so as to achieve the aim of fluorescence elimination of the Raman spectrum. The method is reasonable, can eliminate background fluorescence effectively, has low cost and convenient use, and is easy to popularize and use.

Description

【Technical field】: [0001] The invention relates to a method for chemical analysis and photoelectric signal processing, in particular to a method for eliminating fluorescence based on multi-wavelength excited Raman spectrum. 【Background technique】: [0002] Raman spectroscopy is a non-destructive testing technique applicable to various physical forms of substances. Its applications include materials, chemical engineering, biomedicine, environmental protection, archaeology, geology, as well as commerce and criminal justice. There are three directions of light irradiated on the material, part of which is transmitted, part of which is absorbed, and part of which is reflected or scattered; the scattered light includes direct reflection light with the same wavelength as the incident light, and part of which is different from the wavelength of the incident light. Changes in light related to the molecular properties of substances, among which Raman light is caused by wavelength chan...

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Problems solved by technology

[0005] The existing fluorescence background processing uses baseline correction methods such as spline fitting, Fourier transform, and wavelet transform. Based on the baseline correction method, it can be seen from the principle that the purity of the Raman spectrum cannot be guaranteed; , but the fluorescence spectrum is far less stable than the Raman spectrum, the measurement conditions have a great influence on the shape of the spectrum, and there are few compilations of fluorescence spectra, which do not have practical value

In practical applications, it is generally used to adjust the excitation wavelength to the area where no fluorescence is generated, thereby bypassing the passive method of fluorescence generation. However, it is difficult to achieve a solution for a micro-sized Raman spectrometer with a fixed detection range.

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