Intersubband Polariton-Polariton Scattering in a Dispersive Microcavity
Matthias Knorr, Jean‐Michel Manceau, Joshua Mornhinweg, Jacopo Nespolo, G. Biasiol, Ngoc-Linh Tran, Mario Malerba, Paul Goulain, Xavier Lafosse, Mathieu Jeannin, M. Stefinger, Iacopo Carusotto, C. Lange, R. Colombelli, R. Huber
Abstract
The ultrafast scattering dynamics of intersubband polaritons in dispersive cavities embedding GaAs/AlGaAs quantum wells are studied directly within their band structure using a noncollinear pump-probe geometry with phase-stable midinfrared pulses. Selective excitation of the lower polariton at a frequency of ∼25 THz and at a finite in-plane momentum k_{‖} leads to the emergence of a narrowband maximum in the probe reflectivity at k_{‖}=0. A quantum mechanical model identifies the underlying microscopic process as stimulated coherent polariton-polariton scattering. These results mark an important milestone toward quantum control and bosonic lasing in custom-tailored polaritonic systems in the mid and far infrared.