Enhanced Directional Emission from Monolayer WSe₂ Integrated onto a Multiresonant Silicon-Based Photonic Structure

Abstract

Two-dimensional transition-metal dichalcogenides such as WSe 2 show great promise as versatile atomic-scale light sources for on-chip applications due to their advanced optoelectronic properties and compatibility with a silicon photonics platform. However, the sub-nanometer thickness of such active materials limits their emission efficiency. Hence, new approaches to simultaneously enhance the emission and control its directionality are required. Here, we demonstrate enhanced and directional emission from a WSe 2 monolayer integrated onto a silicon photonic structure. This is achieved by coupling of the WSe 2 layer to a multiresonant silicon grating-waveguide structure. The interaction with the multiple resonant modes supported by the structure provides simultaneous excitation and emission enhancement, while the dispersion of the modes further routes the emission into specified directions. In addition, our hybrid structure offers the opportunity for ultrafast emission modulation, owing to the reduced emission lifetime of WSe 2 . Such a silicon-based hybrid platform is fully scalable and promising as efficient chip-integrated and spatially multiplexed light sources.

Strain-Tunable Single Photon Sources in WSe2 Monolayers

“…The discovery of single photon emitters (SPEs) in 2D materials has stimulated an intensive research effort, aimed at the exploitation of such sources for quantum photonics 10 as well as at the understanding of their physical origin. In the last years, SPEs have been reported on TMDs monolayers at cryogenic temperatures [11][12][13][14][15] and on layered hexagonal boron nitride at room temperature 16 . The origin of SPEs has been attributed to either presence of defects in the crystalline structure of the crystals 16,17 or bandgap modulation of the material due to local bending of the material itself, which naturally occurs on bubbles or wrinkles 18 .…”

Electro-Optical Manipulation Based on Dielectric Nanoparticles

“…Besides changing the optical properties of Mie resonators intrinsically, active tuning may also be realized via coupling with 2D materials. Neshev et al have theoretically demonstrated the PL modulation of 2D materials based on the directional emission caused by Mie resonators [26]. Recently, the first experimental work has been done, in which a forward-to-backward emission ratio of 20 was realized because of the interaction between MoS 2 monolayer and Mie resonators [27].…”

Polarization-sensitive beam steering from quantum emitters coupled with birefringent metamaterials

“…Furthermore, the anomalous dispersion of periodically patterned structures enables beam steering in quantum emitters via near-field coupling of optical resonances. Owing to recent advances in monolayer transition metal chalcogenides with a direct band gap, theoretical and experimental research has explored 1D periodic grooves [10], two-dimensional (2D) photonic crystals [11,12], and hyperbolic metamaterials [13][14][15][16][17]. For example, Zhang et al reported unidirectional radiation with a narrow divergence angle from monolayer MoS 2 by exploiting Fano resonance in 2D freestanding photonic crystal slabs [11].…”