Design Of Atmospheric Environment NC-AFM Low Noise Measurement System And Signal Detection

In recent years,the precision measurement technology of atomic force microscope has made great progress.Non-Contact FM Atomic Force Microscope(NC-FM-AFM)is a new technology for ultra-high vacuum imaging.The existing commercial AFM has been widely used and improved in the field of material science and life science.However,although AFM has not achieved the breakthrough in nano and sub nano resolution on a single biomacromolecule after years of effort,it has a great constraint on the characterization ability and application range of samples.At present,the research based on AFM aims to improve the resolution of the system,but few institutions are studying the method of reducing the instrument noise level in FM measurement mode.It is obvious that it is very important to develop a NCFM-AFM with high sensitivity,low noise and reducing the contact force between probe and sample.Based on this paper,the multi-level noise traceability suppression system of atmospheric environment is designed,and the unit module optimization processing and driving structure with higher precision than commercial AFM regulation in atmospheric environment are designed.The specific research is as follows:First,the design theory of traditional active noise reduction and vibration isolation mode is studied.A new non-contact noise traceability suppression model based on OBD method and a multi-stage vibration isolation device for active vibration isolation of mechanical vibration noise are designed,which can effectively suppress the system noise in the atmosphere.Secondly,compared with the atmospheric environment commonly used stepper motor driving sample and light path adjustment,this paper designs a smaller high-precision displacement adjustment device based on the atmospheric environment light path adjustment system.Compared with the mechanically adjusted OBD system,our designed system has a highprecision three-dimensional and easily adjustable optical structure.Thirdly,the measurement unit module is optimized to realize the system functional joint debugging.The OBD method is researched theoretically,and a new OBD system is designed.In atmospheric environment,the probe vibration test and system noise measurement are carried out with the designed optical deflection detection system,and the resonance frequency and quality factor of the probe are obtained.Through the fitting of the total noise of the system,the noise level of the system is calibrated,and the performance of our atmospheric environment measurement system is verified.Fourth,the atmospheric environment will verify the function of the designed measurement system in the Non-contact mode.Through the four quadrant position detector and signal solution circuit,the high-precision detection,feedback and phase lock of the probe vibration signal are realized,thus laying the measurement foundation of NC-FM-AFM mode in the atmosphere.In conclusion,the design of this measurement system effectively reduces the traceability noise of atmospheric environment measurement system,improves the adjustment accuracy and sensitivity of the OBD detection system,realizes the functional joint adjustment of AFM system,and opens up a new way for the independent research and development of precision measuring instruments.