MEASUREMENT OF FAR-INFRARED INTERSUBBAND SPONTANEOUS EMISSION FROM OPTICALLY PUMPED QUANTUM-WELLS

We present the results of an experiment to measure far-infrared inters ubband spontaneous emission from optically pumped quantum wells. A fou r-level laser design scheme was implemented using a coupled triple qua ntum well structure for optical pumping from E-1 to E-4 with a CO2 las er. The phonon scattering rates were designed to optimize the far- inf rared emission efficiency and population inversion between E-3-E(2)sim ilar to 30 meV. The spontaneous emission spectrum was successfully res olved to reveal an emission peak at 30.8 meV with a linewidth of 7 meV . (C) 1998 American Institute of Physics. [S0003-6951(98)01847-6].