title: Visualization of Surface Acoustic Waves in Thin Liquid Films.
abstract: We demonstrate that the propagation path of a surface acoustic wave (SAW), excited with an interdigitated transducer (IDT), can be visualized using a thin liquid film dispensed onto a lithium niobate (LiNbO3) substrate. The practical advantages of this visualization method are its rapid and simple implementation, with many potential applications including in characterising acoustic pumping within microfluidic channels. It also enables low-cost characterisation of IDT designs thereby allowing the determination of anisotropy and orientation of the piezoelectric substrate without the requirement for sophisticated and expensive equipment. Here, we show that the optical visibility of the sound path critically depends on the physical properties of the liquid film and identify heptane and methanol as most contrast rich solvents for visualization of SAW. We also provide a detailed theoretical description of this effect.
authors.affiliation: Soft Matter Group, Lehrstuhl für Experimentalphysik I, Universität Augsburg, Universitätsstr, 1, D-86159 Augsburg, Germany.
authors.forename: R W
authors.initials: RW
authors.lastname: Rambach
authors.affiliation: Soft Matter Group, Lehrstuhl für Experimentalphysik I, Universität Augsburg, Universitätsstr, 1, D-86159 Augsburg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Taiber
authors.affiliation: Soft Matter Group, Lehrstuhl für Experimentalphysik I, Universität Augsburg, Universitätsstr, 1, D-86159 Augsburg, Germany.
authors.forename: C M L
authors.initials: CM
authors.lastname: Scheck
authors.affiliation: Soft Matter Group, Lehrstuhl für Experimentalphysik I, Universität Augsburg, Universitätsstr, 1, D-86159 Augsburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Meyer
authors.affiliation: Division of Biomedical Engineering, School of Engineering, University of Glasgow, Oakfield Avenue, G12 8LT Glasgow, UK.
authors.forename: J
authors.initials: J
authors.lastname: Reboud
authors.affiliation: Division of Biomedical Engineering, School of Engineering, University of Glasgow, Oakfield Avenue, G12 8LT Glasgow, UK.
authors.forename: J M
authors.initials: JM
authors.lastname: Cooper
authors.affiliation: Soft Matter Group, Lehrstuhl für Experimentalphysik I, Universität Augsburg, Universitätsstr, 1, D-86159 Augsburg, Germany.|Division of Biomedical Engineering, School of Engineering, University of Glasgow, Oakfield Avenue, G12 8LT Glasgow, UK.
authors.forename: T
authors.initials: T
authors.lastname: Franke