Research On Micro-vibration Measurement Based On Higher Mode Light Field

Precision measurement is a crucial method for exploring the world.Throughout history,people have strived to leverage quantum technology to achieve higher measurement accuracy and broader measurement ranges.High-precision measurement techniques not only deepen our understanding of the microscopic world and drive scientific and technological advancements but also play a vital role in our daily lives.Today,there is an increasing demand for precision measurement in various fields,including science,technology,industrial production,and aerospace.Consequently,precision measurement technology has gained significant attention.Light beams have long been applied to non-contact high-precision measurement.Since the advent of lasers,quantum optics has rapidly evolved,highlighting its significance in precision measurement.Utilizing light beams for micro-vibration measurement allows for accurate acquisition of vibration information since the measurement system does not directly contact the object being measured,offering advantages over traditional measurement methods.This paper primarily focuses on the study of micro-vibration measurement based on higher-order mode optical fields.The key aspects covered are as follows:1.A high-order mode small displacement measurement system based on balanced homodyne detection is designed.Displacement measurements are conducted using the HG₀₀ and HG₁₀ modes as the signal light and background light for balanced homodyne detection,respectively.The distribution of environmental noise in the experiment is measured.The minimum detectable displacement of the measurement system under different optical powers is experimentally measured,demonstrating that increasing the optical power of the signal light can reduce the minimum detectable displacement of the system and improve the measurement capability.With a signal light power of 90μW,the minimum detectable displacement obtained is 1.76（?）.In addition,we analyzed the error of the system,which is approximately 0.01（?）.2.A high-order mode small tilt angle measurement system based on balanced homodyne detection and weak value amplification is designed.Tilt angle measurements are conducted using theHG₀₀ andHG₁₀ modes as the signal light and background light for balanced homodyne detection,respectively.By introducing weak value techniques,the limitation of the saturated power of the balanced homodyne detector on the signal light power is overcome,and the signal light power is increased to the order of m W.The relationship between the measured tilt angle information and the power of the dark port output light of the weak value system is studied under the condition of constant signal light power.It is demonstrated that with higher signal light power,the minimum detectable tilt angle of the measurement system becomes smaller,and the measurement accuracy becomes higher.A minimum detectable tilt angle of 3.8 nrad is measured at 2MHz when the signal is raised to 1 m W.The measurement range of measurement system is calculated by analyzing the coefficient of HG₁₀.