optical properties in both linear and non-linear regimes. [1][2][3][4] They have also been shown to be capable of hosting single-photon emitters. [5][6][7] Besides the tunability of their bandgap in response to electric fields, [8,9] TMDs' exciton dynamics can be further modified through stacking into van der Waals heterostructures, [10] chemical doping, [11] and application of mechanical strain. [12] These properties are of particular interest in the context of Photonic integrated circuits (PICs) where the goal is to couple a photon-routing structure to elements with strong and tunable optical response. [13] Such circuits find applications in optical communication, [14] computation, [15] and sensing. [16][17][18] Integration of TMDs into photonic waveguides can be readily achieved by direct transfer, taking advantage of the material's van der Waals bonding nature. [19,20] To date, most hybrid systems with an optically coupled 2D material realize placement away from the photonic mode's maximum (off-center placement) or at a dielectric interface, for example, close to an exposed fiber core, [21,22] at the end-faceThe effective integration of 2D materials such as monolayer transition metal dichalcogenides (TMDs) into photonic waveguides and integrated circuits is being intensely pursued due to these materials' strong exciton-based optical response. This work presents a platform where a 2D heterostructure (WS 2 -hBN) is directly integrated into the photonic mode-center of a novel polymer ridge waveguide. Finite-difference time-domain simulations and collection of photoluminescence from the guided mode indicate that this system exhibits significantly improved waveguide-emitter coupling and mode confinement over a previous elastomer platform. This is facilitated by the platform's enhanced refractive-index contrast and a new method for mode-center integration of the coupled TMD. The integration is based on a simple dry-transfer process that is applicable to other 2D materials, and the platform's elastomeric nature is a natural fit to explore strain-tunable hybridphotonic devices. The demonstrated ability of coupling photoluminescence to a polymer waveguide opens up new possibilities for hybrid-photonic systems in a variety of contexts.
excitons [3,4] and their complexes [5][6][7] and hybrid quasi-particles such as cavity polariton and plexciton at room temperature. [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. Exciton energy and oscillator strength are altered by various effects such as transfer of oscillator strength, [15] Pauli blocking, [16] binding energy reduction, [17] and renormalization of quasiparticle band gap. [18,19] The modulation of optical response in exciton energy is particularly pronounced in high quality samples. For example, it has been shown that the reflectance of a monolayer of MoSe 2 encapsulated by hexagonal boron nitride (hBN) can be electrostatically tuned by as much as 87%. [20][21][22][23][24] 2D semiconductors are attractive candidates for on-chip electro-optic modulators due to their ease of integration and rich exciton-mediated phenomena. While electrostatic doping and out-of-plane field effect have been extensively studied, in-plane field-induced phenomena remain largely unexplored. Here electro-optic response of monolayer WSe 2 subject to modulating in-plane electric fields probed by electroabsorption and electroreflectance spectroscopy is reported. The devices are found to exhibit spatially varying response near exciton resonance, which cannot be explained by predicted effects such as Pockels and excitonic Stark effect. It is shown that the modulation signal is dominated by exciton linewidth broadening and narrowing associated with local accumulation and depletion of free holes. The field and frequency dependence of the devices is distinct from those of charge modulation devices. The observed behavior is ascribed to elastic scattering of excitons with field-driven intrinsic free carriers.
Effective integration of 2D materials such as monolayer transition metal dichalcogenides (TMDs) into photonic waveguides and integrated circuits is being intensely pursued due to the materials' strong exciton-based optical response. Here, we present a platform where a WS 2 -hBN 2D heterostructure is directly integrated into the photonic mode-center of a novel polymer ridge waveguide. FDTD simulations and collection of
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.