title: Nanometer-resolved collective micromeniscus oscillations through optical diffraction.
abstract: We study the dynamics of periodic arrays of micrometer-sized liquid-gas menisci formed at superhydrophobic surfaces immersed into water. By measuring the intensity of optical diffraction peaks in real time, we are able to resolve nanometer-scale oscillations of the menisci with submicrosecond time resolution. Upon driving the system with an ultrasound field at variable frequency, we observe a pronounced resonance at a few hundred kilohertz, depending on the exact geometry. By modeling the system using the unsteady Stokes equation, we find that this low resonance frequency is caused by a collective mode of the acoustically coupled oscillating menisci.
authors.affiliation: Physics of Complex Fluids, University of Twente, The Netherlands. helmut.rathgen@web.de
authors.forename: Helmut
authors.initials: H
authors.lastname: Rathgen
authors.forename: Kazuyasu
authors.initials: K
authors.lastname: Sugiyama
authors.forename: Claus-Dieter
authors.initials: CD
authors.lastname: Ohl
authors.forename: Detlef
authors.initials: D
authors.lastname: Lohse
authors.forename: Frieder
authors.initials: F
authors.lastname: Mugele