Hot electron effects in optically-pumped mid-infrared intersubband semiconductor laser

Intersubband mid-infrared emission in optically pumped quantum wells

“…However, it should be noticed that eventual carrier heating effects resulting of intense pumping are not taken into account in this simple model. Separate calculations accouting for these effects show that the gain is effectively reduced at high pump intensities while remaining quite large [36]. Finally, assuming comparable losses as in the QC lasers [18], the effective gain, G CDD , required for lasing threshold would be of the order of 30 cm\.…”

“…Unlike for intersubband optical pumping, doping of the structures is not required. The population inversion term can be expressed as: elements show that 7.5;10\ [36]. As a result, population inversion is also achievable under band-to-band optical pumping.…”

Influence of complex phonon spectra on intersubband optical gain

“…3͑b͒. Barrier phonon modes are usually ignored in device analysis 17 because they are comparatively small. However, even when small, the enhancement of the intersubband scattering rate due to barrier phonon modes can change the optical gain of a QCL heterostructure, as we see in Fig.…”