Stimulated emission from p‐Ge due to transitions between light‐hole Landau levels and excited states of shallow impurities

We investigate the far infrared emission spectra obtained from the so‐called p‐Ge light‐heavy‐hole laser. The occurrence of a frequency gap between the observed low‐frequency and high‐frequency range is for the first time explained by self‐absorption due to impurity transitions. In the high‐frequency range we find evidence of transitions between light‐hole Landau levels and excited states of shallow impurities to be responsible for the lasing transitions.