Study On The Control System Of Tip-enhanced Raman Device

Tip-enhanced Raman Spectroscopy(TERS)is a new technology based on Scanning Probe Microscopy and Raman Spectroscopy.It can achieve detection sensitivity up to the single molecule level,and has a wide application prospect in the structure detection and morphology characterization of nano-scale samples.In this paper,the control system of tip enhanced Raman device is taken as the research object,and the following aspects are studied:The overall structure and working principle of the device are analyzed.The performance information of each hardware device that needs to be controlled in the device and the functions to be realized are studied.Based on C++ programming,MFC programming and dynamic link library programming technology,the computer software interface of TERS control system is designed.The communication and interaction between the computer software and the hardware equipment of the TERS control system are studied,and the control program of each module of the TERS system is designed.The gray gradient image processing algorithm was studied,and the focusing state was characterized by calculating the variance value of the spot image captured by the CCD camera.The control program of fast coarse focusing and slow fine focusing was designed to realize the automatic focusing control between the laser and the sample surface and the tip.The results of multiple focusing experiments show that the designed autofocusing control program can focus the incident light on the surface and the tip of the sample through the high numerical aperture objective lens.The proximity characteristics of the tip to the sample surface and the principle of atomic force measurement are studied.Through the control of the hardware equipment in the TERS system,the proximity control of the tip to the sample surface and the dynamic maintenance of the working point position of the tip are realized.The experimental results show that the working range of the tip increases with the increase of the excitation signal,and the tip can be maintained between-1.3nm and 2.3nm at the working point,which meets the design requirements.Through the study and comparison of various AFM measurement methods,the sample surface topography measurement program is designed.The X,Y and Z axes of the nanometer displacement table are controlled separately by using the multithreading technology developed by C++ to realize continuous and uninterrupted measurement in the measurement process.The mean value algorithm is used to restore the surface information of the sample.The spacing deviation is 7.91 nm and the height deviation is 0.53 nm,which can meet the actual measurement needs.