Guiding of visible photons at the ångström thickness limit

Abstract

Optical waveguides are vital components of data communication system technologies, but their scaling down to the nanoscale has remained challenging despite advances in nano-optics and nanomaterials. Recently, we theoretically predicted that the ultimate limit of visible photon guiding can be achieved in monolayer-thick transition metal dichalcogenides. Here, we present an experimental demonstration of light guiding in an atomically thick tungsten disulfide membrane patterned as a photonic crystal structure. In this scheme, two-dimensional tungsten disulfide excitonic photoluminescence couples into quasi-guided photonic crystal modes known as resonant-type Wood’s anomalies. These modes propagate via total internal reflection with only a small portion of the light diffracted to the far field. Such light guiding at the ultimate limit provides more possibilities to miniaturize optoelectronic devices and to test fundamental physical concepts.

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Fig. 1: Atomically thick WS2 PhC membranes.
Fig. 2: Experimental demonstration of WS2 guided-mode resonances.
Fig. 3: The angle dependence of WS2 guided-mode resonances.
Fig. 4: The thickness dependence of WS2 guided-mode resonances.
Fig. 5: Observation of monolayer WS2 guided-mode resonance.
Fig. 6: Coupling of the WS2 waveguide mode to guided-mode resonance.

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Acknowledgements

This work was partially supported by the National Science Foundation (NSF) under the NSF 2-DARE Program (EFMA-1542879 and EFMA-1542863) and DMR-1709996. We thank R. Agarwal and R. Bratschitsch for useful discussions during the early stages of this work.

Author information

X.Z. and E.C. conceived the idea. X.Z. and C.D.-E. fabricated the devices. J.G., A.L.B. and V.M.M. provided the WS2 crystals and their reflection spectra. X.Z. performed theoretical modelling. X.Z. and C.D.-E. performed optical measurements and data analysis. C.D.-E. performed the atomic force microscopy measurements. J.K provided the theoretical support for the original 2D waveguiding analysis. E.C. supervised the study. All the authors contributed to the writing of the paper.

Correspondence to Ertugrul Cubukcu.

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Supplementary information

Supplementary Sections 1–18, Supplementary Figs. 1–25, Supplementary Refs. 1–36.

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