Sub-THz coherent phonon coupling between solid and liquid water

Abstract

Sub-THz coherent acoustic phonon coupling between solid and liquid water was studied by the femtosecond pump-probe technique. We used InGaN/GaN heterostructures to generate narrow-band coherent acoustic phonons at frequencies up to 1.4 THz. The measured ratio of reflectivities at GaN-water interfaces to that at GaN-air interfaces was found to strongly decrease and exhibit an abnormal oscillation with the increase in phonon frequency. The possible mechanisms resulting in the characteristics of experimental observations are briefly discussed in this report. © 2007 IOP Publishing Ltd.