Mixing of states in quantum wells for terahertz polariton emitters

I. V. Iorsh^abc, M. A. Kaliteevskii^abc, K. A. Ivanov^abc, K. V. Kavokin<sup>abc

a</sup> St. Petersburg Academic University, Nanotechnology Research and Education Center, Russian Academy of Sciences, St. Petersburg, Russia
^b Ioffe Institute, St. Petersburg
^c Saint Petersburg State University

Abstract: Two possible InGaAs/GaAs quantum-well structures ensuring the presence of radiative transitions between the polariton states in a microresonator with a quantum well, which are accompanied by generation of terahertz photons, are discussed in this work. For the first structure, symmetry breakdown that is required for the emission of a terahertz photon is conducted in a quantum well with refractive index gradient profile, which results in mixing of the states of a polariton and a dark exciton. Parameters of the quantum well, in which the energy of the second exciton level corresponds to the upper polariton energy, are determined. A double quantum well with exciton states split due to quantum-mechanical tunneling through a barrier is used in the second structure. Symmetry breakdown, which allows one to mix an exciton with a “dark” exciton, is ensured by adjusting the energy of electron levels in a double quantum well by applying an electric field to the structure. A hole remains localized in one of the wells.

Received: 03.03.2013

 English version: Technical Physics Letters, 2013, 39:8, 694–697

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