Abstract-Doubly dressed bosons: Exciton-polaritons in a strong terahertz field

B. Piętka, N. Bobrovska, D. Stephan, M. Teich, M. Król, S. Winnerl, A. Pashkin, R. Mirek, K. Lekenta, F. Morier-Genoud, H. Schneider, B. Deveaud, M. Helm, M. Matuszewski, and J. Szczytko

https://journals.aps.org/prl/accepted/c907bY09Q031096c935669a975ce3e5d3c82b8c69

We demonstrate the existence of a novel quasiparticle: an exciton in a semiconductor doubly dressed with two photons of different wavelengths: near infrared cavity photon and terahertz (THz) photon, with the THz coupling strength approaching the ultra-strong coupling regime. This quasiparticle is composed of three different bosons, being a mixture of a matter-light quasiparticle. Our observations are confirmed by a detailed theoretical analysis, treating quantum mechanically all three bosonic fields. The doubly dressed quasiparticles retain the bosonic nature of their constituents, but their internal quantum structure strongly depends on the intensity of the applied terahertz field.

Abstract-Doubly dressed bosons - exciton-polaritons in a strong terahertz field

B. Piętka, N. Bobrovska, D. Stephan, M. Teich, M. Król, S. Winnerl, A. Pashkin, R. Mirek, K. Lekenta, F. Morier-Genoud, H. Schneider, B. Deveaud, M. Helm, M. Matuszewski, J. Szczytko

(Submitted on 21 Apr 2017)

https://arxiv.org/abs/1704.06547

We demonstrate the existence of a novel quasiparticle: an exciton in a semiconductor doubly dressed with two photons of different wavelengths: near infrared cavity photon and terahertz (THz) photon, with the THz coupling strength approaching the ultra-strong coupling regime. This quasiparticle is composed of three different bosons, being a mixture of a matter-light quasiparticle. Our observations are confirmed by a detailed theoretical analysis, treating quantum mechanically all three bosonic fields. The doubly dressed quasiparticles retain the bosonic nature of their constituents, but their internal quantum structure strongly depends on the intensity of the applied terahertz field.

Abstract-Inter-sublevel dynamics in single InAs/GaAs quantum dots induced by strong terahertz excitation

D. Stephan1,2,a), J. Bhattacharyya1,b), Y. H. Huo3,4, O. G. Schmidt3, A. Rastelli3,4, M. Helm1,2 and H. Schneider1


1 Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden, Germany
2 Technische Universität Dresden, 01062 Dresden, Germany
3 Institute for Integrative Nanosciences, IFW Dresden, 01069 Dresden, Germany
4 Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria
a) Electronic mail: d.stephan@hzdr.de
b) Present address: Indian Institute of Technology Madras, IIT P.O., Chennai 600 036, India.
Appl. Phys. Lett. 108, 082107 (2016); http://dx.doi.org/10.1063/1.4942893

We combine micro-photoluminescence(PL) with terahertz excitation to investigate the response of singleself-assembled InAs/GaAs quantum dots to intense terahertz pulses tuned to the s-to-p transition. Spectra and transients of single photoluminescence lines reveal the dynamics of electrons upon excitation and subsequent relaxation back into the initial state. Under certain circumstances, the terahertz pulse can release trapped charge carriers, which relax into the quantum dot. Furthermore, we demonstrate near-total depletion of the positive trionPL by an intense terahertz pulse.