Valley polarized relaxation and upconversion luminescence from Tamm-Plasmon Trion-Polaritons with a MoSe2 monolayer

Abstract

Transition metal dichalcogenides represent an ideal testbed to study excitonic effects, spin-related phenomena and fundamental light-matter coupling in nanoscopic condensed matter systems. In particular, the valley degree of freedom, which is unique to such direct band gap monolayers with broken inversion symmetry, adds fundamental interest in these materials. Here, we implement a Tamm-plasmon structure with an embedded MoSe2 monolayer and study the formation of polaritonic quasi-particles. Strong coupling conditions between the Tamm-mode and the trion resonance of MoSe2 are established, yielding bright luminescence from the polaritonic ground state under non-resonant optical excitation. We demonstrate, that tailoring the electrodynamic environment of the monolayer results in a significantly increased valley polarization. This enhancement can be related to change in recombination dynamics shown in time-resolved photoluminescence measurements. We furthermore observe strong upconversion luminescence from resonantly excited polariton states in the lower polariton branch. This upconverted polariton luminescence is shown to preserve the valley polarization of the trion-polariton, which paves the way towards combining spin-valley physics and exciton scattering experiments.

15 pages, 4 figures

References in corpus (6)

• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Polarization and time-resolved photoluminescence spectroscopy of excitons in MoSe2 monolayers
• Dark excitons and the elusive valley polarization in transition metal dichalcogenides
• Ultra-low power threshold for laser induced changes in optical properties of 2D Molybdenum dichalcogenides
• Exciton-polaritons gas as a nonequilibrium coolant
• Nonlinear spectroscopy of exciton-polaritons in a GaAs-based microcavity

Cited by in corpus (6)

• Exciton optics, dynamics and transport in atomically thin semiconductors
• Roadmap for Photonics with 2D Materials
• Observation of macroscopic valley-polarized monolayer exciton-polaritons at room temperature
• Long-lived spin polarization in n-doped MoSe${}_2$ monolayers
• Circumventing the polariton bottleneck via dark excitons in 2D semiconductors
• Fabrication of high-quality PMMA/SiO${}_x$ spaced planar microcavities for strong coupling of light with monolayer WS${}_2$ excitons