  We experimentally demonstrate the dynamical tuning of the acoustic field in a
surface acoustic wave (SAW) cavity defined by a periodic arrangement of metal
stripes on LiNbO3 substrate. Applying a DC voltage to the ends of the metal
grid results in a temperature rise due to resistive heating that changes the
frequency response of the device up to 0.3%, which can be used to control the
acoustic transmission through the structure. The time scale of the switching is
demonstrated to be of about 200 ms. In addition, we have also performed finite
element simulations of the transmission spectrum of a model system which
exhibit a temperature dependence consistent with the experimental data. The
advances shown here enable easy, continuous, dynamical control and could be
applied for a variety of substrates.
