Abstract-Dual resonance phonon–photon–phonon terahertz quantum-cascade laser: physics of the electron transport and temperature performance optimization

 

Aleksandar Demić, Zoran Ikonić, Paul Dean, Dragan Indjin

Schematic diagram of effectively two (a), three (b,c) and four (d,e,f) level schemes of common THz QCL designs. The rectangles illustrate the typical wavefunction localisation (probability density) of each state within the QCL period. The dotted arrow line denotes the tunnelling process between two adjacent periods, while the solid arrow lines denote the transitions. Each level (apart from ULL) may be envisaged as a cluster of narrowly spaced quasi–bound levels, transitions between the effective "levels" also exist, however dominant mechanisms are shown.

https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-28-26-38788&id=444650

The state of the art terahertz-frequency quantum cascade lasers have opened a plethora of applications over the past two decades by testing several designs up to the very limit of operating temperature, optical power and lasing frequency performance. The temperature degradation mechanisms have long been under the debate for limiting the operation up to 210 K in pulsed operation in the GaAs/AlGaAs material system. In this work, we review the existing designs and exploit two main temperature degradation mechanisms by presenting a design in which they both prove beneficial to the lasing operation by dual pumping and dual extracting lasing levels. We have applied the density matrix transport model to select potential candidate structures by simulating over two million active region designs. We present several designs which offer better performance than the current record structure.

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