Absolute measurement of small-amplitude vibrations by time-averaged heterodyne holography with a dual local oscillator

TL;DR

This paper demonstrates a method using time-averaged heterodyne holography with a dual local oscillator to measure tiny vibrations with sub-nanometer precision, enabling absolute amplitude measurements.

Contribution

It introduces a novel holographic technique combining dual local oscillators and frequency-division multiplexing for precise vibration measurement.

Findings

Successfully measured small-amplitude vibrations.

Achieved absolute measurement of sub-nanometric vibrations.

Validated the method with sinusoidal vibration experiments.

Abstract

We report a demonstration of the measurement of the ratio between an optical modulation side band component and the non-shifted light component by time-averaged heterodyne holography in off-axis and frequency-shifting configuration, through coherent frequency-division multiplexing with a dual optical local oscillator. Experimental results of sinusoidal vibration sensing are reported. This technique enables absolute measurements of sub-nanometric out-of-plane vibration amplitudes.