  The IceCube neutrino observatory uses $1\,\mathrm{km}^{3}$ of the natural
Antarctic ice near the geographic South Pole as optical detection medium. When
charged particles, such as particles produced in neutrino interactions, pass
through the ice with relativistic speed, Cherenkov light is emitted. This is
detected by IceCube's optical modules and from all these signals a particle
signature is reconstructed. A new kind of signature can be detected using light
emission from luminescence. This detection channel enables searches for exotic
particles (states) which do not emit Cherenkov light and currently cannot be
probed by neutrino detectors. Luminescence light is induced by highly ionizing
particles passing through matter due to excitation of surrounding atoms. This
process is highly dependent on the ice structure, impurities, pressure and
temperature which demands an in-situ measurement of the detector medium. For
the measurements at IceCube, a $1.7\,\mathrm{km}$ deep hole was used which
{vertically} overlaps with the glacial ice layers found in the IceCube volume
over a range of $350\,\mathrm{m}$. The experiment as well as the measurement
results are presented. The impact {of the results, which enable new kind of}
searches for new physics with neutrino telescopes, are discussed.
