  The response to the field sequence of nonresonant hole burning, a
pump-wait-probe experiment originally designed to investigate slow relaxation
in complex systems, is calculated for a model of Brownian oscillators, thus
including inertial effects. In the overdamped regime the model predictions are
very similar to those of the purely dissipative stochastic models investigated
earlier, including the possibility to discriminate between dynamic homogeneous
and heterogeneous relaxation. The case of underdamped oscillations is of
particular interest when low-frequency excitations in glassy systems are
considered. We show that also in this situation a frequency selective
modification of the response should be feasable. This means that it is possible
to specifically address various parts of the spectrum. An experimental
realization of nonresonant holeburning in the Terahertz regime therefore is
expected to shed further light on the nature of the vibrations around the
so-called boson peak.
