Abstract-Strong coupling and stimulated emission in single parabolic quantum well microcavity for terahertz cascade

A. Tzimis^1,2, A. V. Trifonov³, G. Christmann², S. I. Tsintzos², Z. Hatzopoulos^2,4, I. V. Ignatiev³, A. V. Kavokin^3,5 and P. G. Savvidis^1,2
 http://scitation.aip.org/content/aip/journal/apl/107/10/10.1063/1.4930165
1 Department of Materials Science and Technology, University of Crete, 71003 Heraklion, Crete, Greece
2 Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, 71110 Heraklion, Crete, Greece
3 Spin Optics Laboratory, State University of Saint-Petersburg, 1 Ulianovskaya, 198504 St. Petersburg, Russia
4 Department of Physics, University of Crete, 71003 Heraklion, Crete, Greece
5 School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, United Kingdom
Appl. Phys. Lett. 107, 101101 (2015); http://dx.doi.org/10.1063/1.4930165

We report observation of strong light-matter coupling in an AlGaAs microcavity (MC) with an embedded single parabolic quantum well. The parabolic potential is achieved by varyingaluminum concentration along the growth direction providing equally spaced energy levels, as confirmed by Brewster angle reflectivity from a reference sample without MC. It acts as an active region of the structure which potentially allows cascaded emission of terahertz (THz) light. Spectrally and time resolved pump-probe spectroscopy reveals characteristic quantum beats whose frequencies range from 0.9 to 4.5 THz, corresponding to energy separation between relevant excitonic levels. The structure exhibits strong stimulated nonlinear emission with simultaneous transition to weak coupling regime. The present study highlights the potential of such devices for creating cascaded relaxation of bosons, which could be utilized for THz emission.