Achiral dielectric metasurfaces for spectral and polarization control of valley specific light emission from monolayer MoS2

TL;DR

This paper demonstrates how achiral dielectric metasurfaces can enhance and control valley-specific light emission from monolayer MoS2, enabling improved polarization control and spectral tuning for potential valleytronic applications.

Contribution

The study introduces a novel integration of MoS2 with silicon disk metasurfaces to manipulate valley-specific emission and polarization at near-room temperatures.

Findings

Enhanced emission intensity and lifetime of excitons, trions, and defect states.

Achieved up to 24% DOP for excitons and 34% for trions at 100K.

Spectral shape modification via metasurface coupling.

Abstract

Excitons in two-dimensional transition metal dichalcogenides have a valley degree of freedom that can be optically accessed and manipulated for quantum information processing. Here, we integrate MoS2 with achiral silicon disk array metasurfaces to enhance and control valley-specific absorption and emission. Through the coupling to the metasurface Mie modes, the intensity and lifetime of the emission of neutral excitons, trions and defect bound excitons can be enhanced, while the spectral shape can be modified. Additionally, we demonstrate the symmetric enhancement of the degree-of-polarization (DOP) of neutral exciton and trions via valley-resolved PL measurements, and find that the DOP can be as high as 24% for exciton emission and 34% for trion emission at 100K. These results can be understood by analyzing the near-field impact of metasurface resonators on both the chiral absorption of MoS2 emitters as well as the enhanced emission from the Purcell effect. Combining Si-compatible photonic design with large-scale (mm-scale) 2D materials integration, our work makes an important step towards on-chip valleytronic applications approaching room-temperature operation.