A Nanoscale Amplitude Measurement Method of Medium and High Frequency Vibration Under Low Frequency Random Disturbance

Abstract

The invention discloses a nanoscale amplitude measuring method of medium-high frequency vibration under low-frequency random disturbance, and relates to an amplitude measuring method of nanoscale medium-high frequency mechanical vibration under environmental low-frequency large-amplitude random disturbance. The nanoscale amplitude measuring method comprises the following steps: 1, detecting the surface of a measured object by utilizing a Michelson interference system to obtain the modulating signal of an optical path difference between reference light and measuring light; 2, utilizing a photoelectric detector to receive a laser interference signal, and converting an optical signal into an interference electrical signal; 3, carrying out frequency analysis on the reference electrical signal by utilizing a discrete Fourier transform algorithm to obtain an amplitude sequence and a frequency sequence, utilizing the amplitude sequence and the frequency sequence to calculate the frequency fs of nanoscale vibration to be measured, determining an odd frequency shift attenuation ratio Ro and an even frequency shift attenuation ratio Re, and utilizing the odd frequency shift attenuation ratio Ro and the even frequency shift attenuation ratio Re to determine a characteristic ratio R; 4, utilizing the characteristic ratio R obtained in the step 3, and utilizing an interpolation method to calculate the amplitude As of the nanoscale vibration. The method is suitable for measuring the nanoscale amplitude of medium-high frequency vibration under low-frequency random disturbance.

Description

technical field

[0001] The invention relates to a method for measuring the amplitude of nanoscale medium-high frequency mechanical vibration under the submersion of low-frequency and large-amplitude random disturbances in the environment. Background technique

[0002] Engineering often encounters the problem of measuring medium and high frequency nanoscale vibrations under low frequency random disturbances, such as the measurement of the amplitude of water surface acoustic waves. Water surface acoustic waves are generated by the sound waves radiated outward from underwater sound sources, and the amplitude of such surface acoustic waves is usually on the order of 10 -9 m. For such weak vibrations, laser interferometry is usually used to measure the amplitude of weak vibrations based on phase demodulation laser interferometry has been widely used in engineering. When the system performance is ideal, this method can achieve 0.1nm resolution. However, weak vibrations such as ...

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