Raman Spectroscopy With Dual Linewidth Excitation for Fluorescence Removal
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Solution Overview
Problem
Conventional methods for removing fluorescent light components in Raman spectroscopy measurements are inadequate, leading to reduced Raman scattered light intensity and difficulty in accurately acquiring the original Raman light scattering spectrum due to issues with wavelength dependence, laser availability, and computational complexity.
Innovation Solution
A Raman spectroscopy device that uses first and second excitation lights with different line widths, combined with a selective optical system to filter out unwanted light components, and a method to calculate a difference spectrum to effectively remove fluorescent light influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional methods (increasing excitation light wavelength or using broad line width) are used to remove fluorescent light components, then fluorescent light interference is reduced, but Raman scattered light intensity decreases and measurement precision deteriorates
Solution Approach 1:
The patent changes the line width parameter of excitation light from narrow (conventional) to broad, while maintaining the same center wavelength. This allows effective fluorescent light removal through spectral averaging without requiring wavelength changes that would reduce Raman intensity. The broad line width excitation light sources (supercontinuum light source, LED, or laser with broadening mechanism) enable this parameter change approach.
Solution Approach 2:
The patent employs periodic switching between broad line width excitation light and narrow line width excitation light. By alternately irradiating the sample with these two types of excitation light and subtracting the resulting spectra, fluorescent light components are removed while preserving Raman scattered light information. This periodic action enables temporal separation of the two measurement modes.
2Stability of the object's composition
If broad line width excitation light is used to remove fluorescent light, then fluorescent light spectrum similarity increases, but Raman scattering peak line width increases and spectral resolution deteriorates
Solution Approach 1:
The patent uses periodic switching between broad and narrow line width excitation light modes. The broad line width mode is used to acquire a spectrum with averaged fluorescent light, while the narrow line width mode is used to acquire a high-resolution Raman spectrum. By subtracting these spectra obtained through periodic action, the patent achieves both fluorescent light removal and high spectral resolution simultaneously.
Solution Approach 2:
The patent introduces a narrow line width excitation light as an intermediary to obtain a reference Raman spectrum with high resolution. This reference spectrum serves as a mediator that preserves the high-resolution Raman information while the broad line width spectrum handles the fluorescent light removal function. The combination of these two intermediary measurements achieves the desired result.
3Object-affected harmful factors
If difference spectrum calculation is performed to remove fluorescent light, then fluorescent light components are eliminated, but computational complexity increases and original Raman spectrum accuracy may be lost
Solution Approach 1:
The patent changes the line width parameter of excitation light to create two distinct measurement modes (broad and narrow). This parameter change approach simplifies the computational process compared to more complex algorithms, as it relies on straightforward spectral subtraction of two directly measured spectra rather than complex mathematical transformations or iterative calculations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device achieves effective removal of fluorescent light interference, allowing for accurate acquisition of Raman scattered light spectra by minimizing the impact of Rayleigh scattered light and maintaining similarity in fluorescent light spectra across different line widths.
Implementation Method 1
a first selective optical system that has a first transmission band and a first stop band, and filters the first measurement light and the second measurement light that are incident on the spectroscopy measurer
Implementation Method 2
Raman scattered light generated from the sample
Implementation Method 3
fluorescent light may be generated from the sample together with the Raman scattered light
Data Source
AI summary
A Raman spectroscopy device includes: an irradiator that irradiates a sample with first excitation light having a first line width and second excitation light having a line width broader than the first line width; a spectroscopy measurer that, when first measurement light emitted from the sample when the sample is irradiated with the first excitation light and second measurement light emitted from the sample when the sample is irradiated with the second excitation light are incident, performs spectroscopy measurement on the first measurement light and the second measurement light; and a first selective optical system that has a first transmission band and a first stop band, and filters the first measurement light and the second measurement light incident on the spectroscopy measurer. The first excitation light and the second excitation light each have a main component in the first stop band, and the second excitation light has substantially no component in the first transmission band.