Optical fiber vector optical probe type tip-enhanced Raman spectroscopy and spectrum collection method

Abstract

The invention provides an optical fiber vector optical probe type tip-enhanced Raman spectroscopy and a spectrum collection method. The spectroscopy comprises an inner excitation laser generation module, a white light imaging module, a Raman signal collection module, and a sample control system. The inner excitation laser generation module is used for excitation of surface plasmons with high efficiency in an optical fiber probe with a plated metal film and excitation of locally enhanced surface plasmons with high efficiency at tip of the optical fiber probe, in order to further realize extreme field enhancement effects at the tip of a needle. The probe which is fixed without movements is adopted for a scanning mode, and a sample bench control system controls a sample bench in order to drive the sample to realize scanning of a three-dimensional shape. The structure of the apparatus is based on an upright mode, and is not limited by transparency and conductivity of the sample. The sample can be placed on a metal substrate, interaction between the sample and the tip with the plated metal film forms a gap mode, so that sensitivity of the system and spatial resolution are improved.

Description

technical field [0001] The invention relates to the technical field of needle-tip-enhanced Raman spectroscopy, in particular to an optical fiber vector optical probe-type needle-tip-enhanced Raman spectrometer and a spectrum acquisition method. Background technique [0002] Regardless of conventional Raman spectroscopy or surface-enhanced Raman spectroscopy, the spatial resolution cannot break through the optical diffraction limit, which leads to great limitations in the research objects. [0003] Tip-enhanced Raman spectroscopy (TERS for short) has been widely used in various fields since it was reported in 2000. It uses scanning probe technology to bring the (Au / Ag) tip with TERS activity close to the sample (such as 1nm), and under the excitation of laser with a certain wavelength and polarization, it can generate a very strong electromagnetic field enhancement at the end of the tip, which greatly improves the tensile strength. Mann signal with up to 1nm spatial resoluti...

AI Technical Summary

Problems solved by technology

[0006] A common feature of the above TERS instruments is that they are basically based on the scanning probe microscopy technology. They all approach the tip of a pure metal to the sample, and then use the space vector light to focus the far-field excitation of the tip, which makes the instrument’s enhancement The effect of Raman signal is poor, and there is a Raman background due to the light spot that exists due to the diffraction limit of the spatial optical entrance system

So far, the high-level research work published internationally is basically obtained on the instruments developed by the laboratory itself, and few high-level research results have been obtained on commercial TERS instruments.

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