International Journal of Physics

International Journal of Physics | Vol. 7, No. 1, January 2016 | pp. 1–8

DOI: 10.46882/2016/IJP/000069

Research Article

Title: Optical Properties and Exciton-Polariton Dynamics of Monolayer Tungsten Disulfide on Plasmonic Nanogate Arrays

Names of Authors: Y. S. Kim¹, M. G. Nielsen²

Authors’ Affiliations: ¹Department of Physics and Astronomy, Seoul National University, Seoul, South Korea; ²Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark

Abstract: Monolayer transition metal dichalcogenides have attracted significant interest due to their strong light-matter interactions and potential for nanoscale valleytronic devices. This study characterizes the optical properties and exciton-polariton dynamics of monolayer tungsten disulfide (WS²) integrated onto plasmonic gold nanogate arrays. The monolayer flakes were synthesized via chemical vapor deposition and transferred onto the nanostructured substrates using a dry-transfer technique. We performed micro-photoluminescence and angle-resolved reflectivity measurements under mechanical tensile strains from 0.0% to 1.8% at a room temperature of 300 K. The unstrained monolayer coupled to the plasmonic array exhibits a strong Rabi splitting of 45.0 meV, confirming the transition into the strong light-matter coupling regime. Applying a 1.2% tensile strain shifts the exciton resonance energy from 2.01 eV to 1.94 eV, yielding a strain tuning factor of 58.3 meV/% strain. Time-resolved photoluminescence spectroscopy revealed a shortened polariton decay lifetime, dropping from 14.5 ps down to 4.2 ps due to the plasmonic Purcell effect. Our numerical models confirm that the localized electromagnetic field enhancement within the nanogates increases the exciton-photon coupling rate by 40.0%. These findings demonstrate that plasmonic strain engineering offers an effective route for controlling exciton-polariton states in thin-film optoelectronic architectures.

Keywords: Tungsten disulfide; plasmonic nanogates; photoluminescence; exciton-polariton; tensile strain; light-matter coupling

Manuscript Timeline: Received: October 12, 2015; Revised: November 24, 2015; Accepted: December 15, 2015; Published: January 12, 2016

Citation: Kim, Y. S., & Nielsen, M. G. (2016). Optical Properties and Exciton-Polariton Dynamics of Monolayer Tungsten Disulfide on Plasmonic Nanogate Arrays. International Journal of Physics, 7(1), 1–8.