  Bolometers have proven to be good detectors for the search of neutrinoless
double beta decay. By operating at cryogenic temperatures, they feature
excellent energy resolution and low background. The detection of the possible
light emitted when particles interact in the bolometer is a promising method to
lower the background of the experiments. The different amount of light emitted
in beta/gamma and alpha interactions, whether due to scintillation or Cerenkov
emission, allows to discriminate the two interaction types. Because of the
cryogenic environment, light detectors are often bolometers. In this work we
present a software algorithm to lower the energy threshold of bolometric light
detectors coupled to luminescent bolometers. The application to data from Ge
light detectors coupled to ZnMoO4 and TeO2 bolometers shows that the energy
threshold can be lowered substantially, increasing the discrimination power
when the amount of emitted light is small.
