Elastomeric Waveguide on-Chip Coupling of an Encapsulated MoS₂ Monolayer

Abstract

We propose a robust photonic platform for encapsulation and addressing of optically active 2D-and nano-materials. Our implementation utilises a monolayer of MoS 2 transition metal dichalcogenide embedded in an elastomeric waveguide chip. The structure is manufactured from PDMS using soft-lithography and capable of sustaining a single mode of guided light. We prove that this setup facilitates addressing of the 2D material flake by pumping it with polarised laser light and gathering polarisation-resolved photoluminescence spectra with the extinction ratio of 31, which highlights the potential for selection-rule dependent measurements. Our results demonstrate improved handling of the material and experimental simplification compared to other techniques.

Mode‐Center Placement of Monolayer WS2 in a Photonic Polymer Waveguide

“…The detection of excitonic PL here is an important illustration of the device's improved materialguide coupling since the previous system did not show a signal in this configuration. [29] In these experiments, we moved the excitation spot along the waveguide-region covered by WS 2 and recorded the edge-collected PL for two different devices that realize either mode-center placement or off-center placement (with a material offset from the mode center by 1 μm).…”

“…[24][25][26][27][28] As a proof of concept, we have previously demonstrated the integration of a TMD into an elastomeric ridge waveguide. [29] However, the optical coupling efficiency in this system is limited by the material's off-center placement in between highand low-refractive index layers and a relatively low index contrast (n 1 − n 2 ≈ 0.001). A low index contrast also impedes mode confinement, limiting the performance of waveguide bends required, for example, for on-chip interferometers and more complex photonic circuits.…”

“…The broadband, single-mode device supports propagation distances of several thousand micrometers and displays markedly enhanced emitter-mode coupling compared to the previous elastomer platform. [29] The enhancement relies on two factors. First, the newly developed system employs two (commercially available) polymer formulations that increase the index contrast by two orders of magnitude (n 1 − n 2 ≈ 0.1).…”

Mode-center Placement of Monolayer WS$_{2}$ in a Photonic Polymer Waveguide

“…[24][25][26][27][28] Previously, we have demonstrated integration of a TMD into an elastomeric ridge waveguide. 29 However, the optical coupling efficiency in this system was limited by the material's off-center placement in between high-and low-refractive index layers and a relatively low index contrast (n 1 -n 2 ˜0.001). Addressing this limited coupling efficiency is desirable, since elastomeric waveguides are an exciting platform for hybrid photonic systems due to elasticity, as well as a simple, mild and fast fabrication cycle that is cost effective and favours integration with additional micro-and nanostructures.…”

In‐Plane Field‐Driven Excitonic Electro‐Optic Modulation in Monolayer Semiconductor

“…[8,9] These van der Waals semiconductors display various exciton-mediated electrooptic phenomena that are not seen in conventional semiconductors. Along with their ease of integration onto a photonic integrated circuit platform, [10][11][12][13] they hold great potential for on-chip electro-optic modulators. [14] The charge modulation of the optical response of 2D TMDs has been most widely studied in the static limit, proving useful for revealing their rich many-body physics.…”