Coherent control of gigahertz surface acoustic and bulk phonons using ultrafast optical pulses

We demonstrate the coherent generation and control of gigahertz acoustic phonons with ultrafast optical pulses. Two distinct acoustic phonon modes, a surface acoustic phonon mode and a longitudinal acoustic phonon mode, are generated simultaneously by irradiating nanolithographic absorption gratings on semiconductor substrates. Two material systems are examined: suboptical wavelength aluminum absorption gratings on Si and GaAs substrates. Constructive and complete destructive interference conditions are demonstrated using two pump pulses derived from a single Michelson interferometer. (C) 2008 American Institute of Physics.