A coupled quantum dot intersubband optical amplifier structure is reported.
InGaAsP/GaAs supperlattice is used to effectively generate population inversion between
the excited states and the ground state of the QD. Due to the
confinement, normal incidence optical amplification with low threshold current density
can be expected. Such an intersubband optical amplifier is promising for highly-sensitive
middle infrared (MWIR) and longwave infrared sensing and imaging.
"InAs quantum-dot intersubband optical amplifier", Proc. SPIE 7055, Infrared Systems and Photoelectronic Technology III, 705503 (3 September 2008); doi: 10.1117/12.796706; https://doi.org/10.1117/12.796706