title: Optical generation of coherent surface acoustics: an optically based probe of surface structure and dynamics.
abstract: Above-band-gap picosecond pulses are used to generate holographically high-frequency, coherent, surface acoustic modes on semiconductor surfaces. Optical diffraction from the surface acoustics is in superposition to a free-carrier phase grating that acts as an amplifying cross term in the diffraction process. The detection limits are of the order of 10(-4) nm for the surface displacement. Frequencies up to 2 GHz have been realized, with frequencies >20 GHz possible. A quantitative theory for the photothermal coupling has been developed. In addition, propagation of the optically generated surface modes has revealed a solid-liquid phase transition of the water layer at TiO(2)-H(2)O interfaces.
authors.forename: J J
authors.initials: JJ
authors.lastname: Kasinski
authors.forename: L
authors.initials: L
authors.lastname: Gomez-Jahn
authors.forename: K J
authors.initials: KJ
authors.lastname: Leong
authors.forename: S M
authors.initials: SM
authors.lastname: Gracewski
authors.forename: R J
authors.initials: RJ
authors.lastname: Miller