Abstract-An exciton-polariton bolometer for terahertz radiation detection

G. G. Paschos, T. C. H. Liew, Z. Hatzopoulos, A. V. Kavokin, P. G. Savvidis, G. Deligeorgis,

https://www.nature.com/articles/s41598-018-28197-0

We experimentally investigate the feasibility of a bolometric device based on exciton-polaritons. Initial measurements presented in this work show that heating – via thermal expansion and bandgap renormalization – modifies the exciton-polariton propagation wavevector making exciton-polaritons propagation remarkably sensitive to thermal variations. By theoretical simulations we predict that using a single layer graphene absorbing layer, a THz bolometric sensor can be realized by a simple exciton-polariton ring interferometer device. The predicted sensitivity is comparable to presently existing THz bolometric devices with the convenience of being a device that inherently produces an optical signal output.

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.