High Precision Laser Self-mixing Measurement System And Implementation With LabVIEW

With the birth of laser,optical interference has made significant progress in terms of measuring range,resolution,anti-interference ability,and measurement accuracy.Laser self-mixing interference(SMI)technique is produced in the research of optical feedback effect and the elimination of adverse optical feedback.Due to its inherent simplicity,compactness and easy collimation,SMI technique replaced the traditional complex interference system in many applications.In recent years,SMI has gradually formed a new research field with far-reaching prospects.Nowadays,many scholars have been working to improve the measurement precision,which greatly expand the application of SMI.At present SMI has been widely employed in vibration,velocity,displacement,terahertz imaging,medicine,and high-precision nanometer measurement.Firstly,this paper introduces the SMI effect and its characteristics.Then,we summarize the historical background,research progress and application progress of SMI.Based on the FP three-mirror theory,we establish the corresponding mathematics model.The model uses MATLAB to analyze the influence of each parameter on the SMI signal.In addition,the phase unwrapping method and phase modulation method are used to reconstruct the displacement of the target.According to the theoretical derivation and simulation analysis,a SMI experimental measurement system based on semiconductor laser is built.The experiments with PZT and tuning fork as the targets are carried out to observe the SMI phenomenon of different vibrating targets.In addition,this paper proposes an integrated measurement technique based on multiple reflection and even-power fast algorithm.This method not only overcomes the shortcomings of multiple reflections,but also compensates for the insufficiency of the even-power fast algorithm when the measured amplitude is much smaller than half a wavelength.Compared with the even power fast algorithm,this method expands the measurement range and achieves higher fringe accuracy.Based on the principle of the integrated measurement technology,a real-time vibration measurement system based on SMI is designed by using Lab VIEW and MATLAB.This system can monitor the vibration amplitude of the target in real time and has nanometer resolution.In summary,the designed system fully shows the broad application prospect of virtual instrument technology in laser self-mixing interference.