  We consider theoretically the realization of a tunable terahertz light
emitting diode from a quantum well with dressed electrons placed in a highly
doped p-n junction. In the considered system the strong resonant dressing field
forms dynamic Stark gaps in the valence and conduction bands and the electric
field inside the p-n junction makes the QW asymmetric. It is shown that the
electrons transiting through the light induced Stark gaps in the conduction
band emit photons with energy directly proportional to the dressing field. This
scheme is tunable, compact, and shows a fair efficiency.
