Electrically controlled waveguide polariton laser

Abstract

Exciton–polaritons are mixed light–matter particles offering a versatile solid state platform to study many-body physical effects. In this work, we demonstrate an electrically controlled polariton laser, in a compact, easy-to-fabricate and integrable configuration, based on a semiconductor waveguide. Interestingly, we show that polariton lasing can be achieved in a system without a global minimum in the polariton energy-momentum dispersion. The cavity modes for the laser emission are obtained by adding couples of specifically designed diffraction gratings on top of the planar waveguide, forming an in-plane Fabry–Perot cavity. It is due to the waveguide geometry that we can apply a transverse electric field to finely tune the laser energy and quality factor of the cavity modes. Remarkably, we exploit the system sensitivity to the applied electric field to achieve an electrically controlled population of coherent polaritons. The precise control that can be reached with the manipulation of the grating properties and of the electric field provides strong advantages to this device in terms of miniaturization and integrability, two main features for the future development of coherent sources for polaritonic technologies.

Semiconductor waveguide quantum well lasers

“…Coherent arrays of lasers were extensively researched in the case of laser diodes as they are an ideal platform for coupled cavities [6,7]. Equally, In-plane lasing in polariton lasers has been demonstrated, in which the gain is sufficient to interact with metallic gratings and electrode structures, while still supporting a polariton state [8]. The excitonic dipole in a semiconductor quantum well (QW) sample lies on the plane perpendicular to the growth direction of the QWs and parallel to the surface of the wafer, and therefore photonic emission and lasing is possible in the direction parallel to the surface plane.…”

Ridge polariton laser: different from a semiconductor edge-emitting laser

“…The polariton waveguide geometry has been explored for about a decade [18][19][20][21][22][23][24][25][26][27]. In the context of the current work, it presents the advantage to allow a selective excitation of only a part of the horizontal optical cavity confining the laser mode and revisit, thereby, laser interpretative frameworks.…”

“…Polariton dispersion -In order to assess the strong coupling regime between photons and excitons, the most direct method would be to monitor the dispersion of polaritons using diffraction gratings on top of the core layer. This geometry was exploited for polariton waveguides based on GaAs [18,23], GaN [20,29], and ZnO [22]. It allowed measuring the lower polariton branch (LPB) dispersion and observing the anticrossing between lower and upper polariton branches (UPB).…”

Highly non-linear interlayer exciton-polaritons in bilayer MoS$_2$

“…The small ratio of interaction to dissipation rates resulted in only a weak violation of classical correlations. Formation of polaritons with excitons that possess a permanent dipole moment has been shown to enhance the polariton interactions both in resonant 8,9 and non-resonant excitation schemes 10 .…”