  The frequency-dependent polar dynamics of strained SrTiO3 films grown on
DyScO3 are investigated using time-resolved confocal scanning optical
microscopy. Microwave frequency electric fields are synchronized with a
mode-locked laser and applied in-plane to the sample, while the temporal
response is probed optically. Local spectroscopic information is obtained with
<1 um spatial resolution over the frequency range 2-4 GHz. Investigation of the
SrTiO3/DyScO3 system reveals resonances that are localized both in space and in
frequency.
