  We have studied a variety of different disordered materials, including
molecular and ionic liquids, supercooled liquids and glasses, ionic conductors,
and doped semiconductors, in ac electromagnetic fields over an exceptional
broad dynamic range including the rarely investigated GHz to THz region. We
show that all classes of disordered matter exhibit an astonishingly similar
response: In addition to Jonscher's time-honored "Universal Dielectric
Response", a superlinear power-law increase of the frequency-dependent
conductivity shows up bridging the gap between the classical dielectric and the
infrared region. We demonstrate that the universal dielectric behavior of
disordered matter extends up to much higher frequencies than thought until now
and covers the range from ultra-low (mHz) to phonon (THz) frequencies.
