Study On The High-stablity Reflective Micro-area Raman Spectrum Measuring Technique

Raman spectroscopy analysis technology is an important analytical method in the field of nano-new materials.Micro-area Confocal Raman Spectroscopy,as an important research direction of Raman spectroscopy,not only has the advantages of Raman spectroscopy but also has the function of real-time imaging of micro-area on the surface of samples.It is more capable of collecting Raman signals in the range of?200-1200?nm.The purpose of this master's thesis is to develop and construct a set of high-stability reflective micro-area Raman spectroscopy measurement system.The device combines micro-area confocal Raman spectroscopy technology with differential confocal Microscopy technology,which can achieve accurate nanometer-level positioning,micro-level positioning stroke,and long-term stable Raman spectroscopy detection in focus.Firstly,the existing Raman spectroscopy and differential confocal microscopy are investigated,the principles of various Raman spectroscopies are analyzed,and the advantages and disadvantages of various Raman spectroscopies in their related application fields are compared.On this basis,a micro-confocal Raman spectroscopy detection system is designed by using micro-confocal Raman spectroscopy.The micro-confocal Raman spectroscopy detection system is realized by combining the single-lens optical fiber spatial coupling technology,and the angle error introduced by the optical fiber is eliminated through the calculation of Snell's law.In the field of surface topography measurement,the principle of differential confocal microscopy is described,and a differential confocal measurement system is constructed based on the axial response characteristics of the technology.The system uses feedback control technology to achieve 1.25 nm precision positioning function,the positioning range of 400?m,and the focus spot is kept stable at the focal level for a long time during the measurement process.Secondly,in order to get the Raman scattering signal of the exciting substance faster at the focal point,a set of reflective micro-area Raman spectroscopy system with high-stability is developed and constructed by combining the micro-area confocal Raman spectroscopy detection system with the differential confocal measurement system.The device can realize the Raman spectroscopy measurement at the focal point.The device is used to carry out the spectral measurement experiments of inorganic samples and analyze the optimal measuring strips of inorganic samples such as pure matter sulfur and single-walled carbon nanotubes.Lots of repeatability measurements show that when the laser of pure matter sulfur is 532 nm and the power is greater than 4 mW,the Raman spectrum image with high signal-to-noise ratio can be detected by selecting the grating density of 1800 line/mm and the spectral integration time of 1 s.When single-walled carbon nanotubes laser is 532 nm and power is 1 mW,the grating density is 1200line/mm and the spectral integration time is 20 s,the obvious characteristic peaks at the Raman frequency shifts of 1581.051 cm^-1 and 2681.06 cm^-11 can be detected,and the complete Raman spectrum can be obtained.In order to enhance the Raman spectra of single-walled carbon nanotubes,the optical intensity at the Raman characteristic peak of single-walled carbon nanotubes was increased by 1.8 times by replacing the cover glass substrate with the gold nanoparticles reinforced substrate.Finally,in order to verify the stability of the reflective micro-area Raman spectroscopy measurement system,several single-point focusing measurement experiments were carried out.The standard deviation of repeatability of focus position was calculated by Bessel function,and the repeatability accuracy of the system device was 5 nm.On this basis,the precise axial motion of the objective lens and the y-direction movement of the three-dimensional nanometer-displacement table are controlled by the C++host computer software.The single-line detection experiment of single-walled carbon nanotubes samples is completed,and the three-dimensional images of single-walled carbon nanotubes Raman spectra distributed in the?10-38?nm line length range are obtained.The experimental results further show that the device has nanometer-scale axial resolution and high-stability,fully meets the measurement requirements of micro-Raman spectroscopy of inorganic samples.