Using laser Doppler vibrometry to measure capillary surface waves on fluid-fluid interfaces
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Updated: Jun 10, 2026

Microtensiometer for Confocal Microscopy Visualization of Dynamic Interfaces
Published on: September 9, 2022
1Department of Mechanical and Aerospace Engineering, MicroNanophysics Research Laboratory, Monash University, Melbourne VIC 3800, Australia.
Abstract:
Capillary wave phenomena are challenging to study, especially for microfluidics where the wavelengths are short, the frequencies are high, and the frequency distribution is rarely confined to a narrow range, let alone a single frequency. Those that have been studying Faraday capillary waves generated by vertical oscillation have chosen to work at larger scales and at low frequencies as a solution to this problem, trading simplicity in measurement for issues with gravity, boundary conditions, and the fidelity of the subharmonic capillary wave motion. Laser Doppler vibrometry using a Mach-Zehnder interferometer is an attractive alternative: The interface's motion can be characterized at frequencies up to 40 MHz and displacements of as little as a few tens of picometers.
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