A device for collecting surface-enhanced Raman scattering spectra with a full-aperture angular parabolic mirror

Abstract

The invention relates to the field of Raman spectrometers, and discloses a device for collecting surface-enhanced Raman scattering spectra with a full-aperture-angle parabolic mirror. The purpose of the invention is to provide ultra-high-sensitivity SERS-Raman probes for various portable fiber-optic Raman spectrometers. , to upgrade this product; develop a small ultra-high sensitivity SERS‑Raman spectrometer; SPR‑Raman spectroscopy probe and spectrometer; SPR‑Raman / absorption dual spectrum and refractive index triple function spectrometer, flow particle-enhanced Raman analysis probe and Near ultraviolet Raman spectrometer. Technical solution: Use the full aperture angle of the parabolic mirror to collect Raman scattering; set up a large numerical aperture objective lens confocal with the parabolic mirror, and excite the sample with a high-quality focused single-mode laser beam to ensure a high SERS enhancement factor; Raman enhancement in SPR mode realizes Ultra-high sensitivity, etc. The new generation of portable and hand-held Raman spectrometers will be widely used in various trace analysis such as food safety census, cancer census, environmental detection and warfare agent detection.

Description

technical field [0001] The invention discloses a device for collecting surface-enhanced Raman scattering spectra by using a full-aperture-angle parabola mirror, which belongs to the field of spectrum analysis, and in particular relates to surface-enhanced Raman scattering spectrum equipment. Background technique [0002] At present, in the international market, there are a variety of mature large-scale micro-Raman spectrometers for research. They adopt conventional optical elements and a large-scale structure design with a length of more than one meter, and use a surface-enhanced Raman scattering substrate, referred to as SERS-substrate, which can Realize ultra-high-sensitivity SERS-microscopic Raman spectroscopy test function. This kind of equipment has high sensitivity, good performance, expensive price and large size, but it is not suitable for popular and portable use requirements; in addition, although it has been widely used in the international market There are many t...

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Problems solved by technology

[0002] At present, in the international market, there are a variety of mature large-scale micro-Raman spectrometers for research. They adopt conventional optical elements and a large-scale structure design with a length of more than one meter, and use a surface-enhanced Raman scattering substrate, referred to as SERS-substrate, which can Realize ultra-high-sensitivity SERS-microscopic Raman spectroscopy test function. This kind of equipment has high sensitivity, good performance, expensive price and large size, but it is not suitable for popular and portable use requirements; in addition, although it has been widely used in the international market There are many types of portable small-scale Raman spectrometers. Generally, the optical fiber Raman probe designed by the US 5,122,127 patent is used. The numerical aperture NA of this type of Raman probe is mostly 0.25, and the corresponding collection aperture angle Ω is small, only Ω ~0.25sr, its sensitivity can only be applied to the analysis of samples with higher abundance and higher concentration, and its popularization and application are greatly limited. It is urgent to upgrade and develop ultra-high sensitivity portable and portable small Raman spectrometers

At present, due to the fact that the coherence of the semiconductor laser beams used to excite samples by many types of fiber optic Raman probes is not good enough, and then transmitted through multimode optical fibers, the coherence of the excitation beams is destroyed. Although some small Raman probes and spectrometers Commodities that use NA≈0.5 aspherical objective lens to focus the laser beam to excite the sample, due to factors such as the quality of the objective lens and the laser beam not meeting the requirements, can not effectively use the SERS substrate to achieve ultra-high sensitivity SERS Raman enhancement

As far as we know, under the conditions of the existing lasers and CCD photodetectors, there are three basic requirements that are most critical to obtain high SERS enhancement benefits: the need to ensure that the laser beam that excites the sample has good coherence, and the focus The focal spot is on the order of 2-6 microns and the optical system for collecting Raman scattering has a large aperture angle; however, all current portable small-scale Raman spectrometers cannot guarantee the effective realization of the above three most basic requirements for SERS Raman enhancement , therefore, their Raman detection sensitivity is not high, and they cannot be applied to the analysis of low-concentration samples, let alone the trace analysis of ultra-low-concentration samples.

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