Generation of GHz-ultrasound packets in water using an Er-laser

Summary form only given.A Cr,Er:YScGG laser with its wavelength of 2.8 /spl mu/m being close to the water OH-absorption band is characterized by a very small penetration length (1 /spl mu/m) and high efficiency of ultrasound excitation. We present a variety of schemes suitable for the temporally and spatially controlled excitation of gigahertz ultrasound waves.