High quantum efficiency InAs/GaInSb/AlSb interband cascade lasers

摘要

We proposed and demonstrated a new type of quantum cascade laser based on interband transitions in InAs/GaInSb/AlSb type-II quantum wells. Contrary to the conventional heterostructure or quantum well lasers, this device takes advantage of recycling carriers from valence band back to conduction band for sequential photon emissions to achieve high quantum efficiency. So far, an external differential quantum efficiency exceeding 200% has been observed from 4- $mu@m lasers under 1 $mu@s pulses and 0.1% duty cycle at 80 K. Under 5 - 10 $mu@s pulse lengths and 10% duty cycle, peak powers $GRT 160 mW have been obtained, the corresponding internal quantum efficiency was deduced to be 220%.