An approach for vibration measurement based on laser frequency splitting technology

Abstract

An approach for vibration measurement based on He-Ne laser frequency splitting technology is presented and experiments have been performed. While a quartz crystal wedge, which is placed in the laser cavity, vibrates with the object to be measured, the frequency difference of the laser is modulated by the vibration signal. The vibration signal is restored by demodulating the laser frequency difference signal. In the experiments a 15 nm resolution and a ±1.6×10-4 reproducibility of the vibrational amplitude are obtained with the system. The frequency range of vibration measurement is only up to the limit of mechanical structures. The method has a good potential prospect for application in high-resolution, low or middle frequency vibration measurement.

A vibrating reed apparatus to measure the natural frequency of multilayered thin films

“…The instrument designed for such an aim must provide high accuracy and low experimental uncertainty, and a vibratory device seems to be excellent candidate for such a task. Although a few existing vibratory instruments may satisfy these requirements [19][20][21][22], they either do not provide the precision demanded for thin film architectures, measure the resonant frequency (instead of the natural one) and/or need cumbersome instrumentation. In a previous work [22], the authors developed a simpler vibratory device for measuring the resonant frequency of thin cantilever beams, based on frequency sweeps using piezo electric excitation.…”

Absolute Angular Displacement Determination Based on Laser-Frequency Splitting Technology

“…They are being developed and used to measure displacement, [11] the retardation of wave plates, [12] force [13] and vibration. [14] In this Letter, a diode-pumped dual-frequency microchip Nd:YAG laser is proposed for angular displacement determinations. It has high sensitivity and a large measurement range, and possesses the advantage of absolute angular displacement determination.…”