  The low temperature properties of amorphous solids are usually explained in
terms of atomic-scale tunneling two level systems (TLS). For almost 20 years,
individual TLS have been probed in insulating layers of superconducting quantum
circuits. Detecting individual TLS in mechanical systems has been proposed but
not definitively demonstrated. We describe an optomechanical system that is
appropriate for this goal and describe our progress toward achieving it. In
particular, we show that the expected coupling between the mechanical mode and
a resonant TLS is strong enough for high visibility of a TLS given the
linewidth of the mechanical mode. Furthermore, the electronic noise level of
our measurement system is low enough and the anomalous force noise observed in
other nanomechanical devices is absent.
