Optically pumped intersubband emission of short-wave infrared radiation with GaN/AlN quantum wells

Optically pumped pulsed emission of short-wave infrared radiation based on intersubband transitions in GaN/AlN quantum wells is demonstrated. Nanosecond-scale pump pulses are used to resonantly excite electrons from the ground states to the second-excited subbands, followed by radiative relaxation into the first-excited subbands. The measured room-temperature output spectra are peaked near 2 mu m with integrated powers of a few hundred nanowatts. The intersubband origin of the measured luminescence is confirmed via an extensive study of its polarization properties and pump wavelength dependence, as well as simulations of the quantum well subband structure.