Nonlinear polaritons in a monolayer semiconductor coupled to optical bound states in the continuum

Vasily Kravtsov; Ekaterina Khestanova; Fedor A Benimetskiy; Tatiana Ivanova; Anton K Samusev; Ivan S Sinev; Dmitry Pidgayko; Alexey M Mozharov; Ivan S Mukhin; Maksim S Lozhkin; Yuri V Kapitonov; Andrey S Brichkin; Vladimir D Kulakovskii; Ivan A Shelykh; Alexander I Tartakovskii; Paul M Walker; Maurice S Skolnick; Dmitry N Krizhanovskii; Ivan V Iorsh

doi:10.1038/s41377-020-0286-z

Nonlinear polaritons in a monolayer semiconductor coupled to optical bound states in the continuum

Light Sci Appl. 2020 Apr 9:9:56. doi: 10.1038/s41377-020-0286-z. eCollection 2020.

Authors

Vasily Kravtsov^#¹, Ekaterina Khestanova^#¹, Fedor A Benimetskiy^#¹, Tatiana Ivanova¹, Anton K Samusev¹, Ivan S Sinev¹, Dmitry Pidgayko¹, Alexey M Mozharov², Ivan S Mukhin^{1

2}, Maksim S Lozhkin³, Yuri V Kapitonov³, Andrey S Brichkin⁴, Vladimir D Kulakovskii⁴, Ivan A Shelykh^{1

5}, Alexander I Tartakovskii⁶, Paul M Walker⁶, Maurice S Skolnick^{1

6}, Dmitry N Krizhanovskii^{1

6}, Ivan V Iorsh¹

Affiliations

¹ 1ITMO University, Saint Petersburg, 197101 Russia.
² 2St. Petersburg Academic University, Saint Petersburg, 194021 Russia.
³ 3Saint Petersburg State University, ul. Ulyanovskaya 1, Saint Petersburg, 198504 Russia.
⁴ 4Institute of Solid State Physics, RAS, Chernogolovka, 142432 Russia.
⁵ 5Science Institute, University of Iceland, Dunhagi 3, IS-107, Reykjavik, Iceland.
⁶ 6Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7RH UK.

^# Contributed equally.

Abstract

Optical bound states in the continuum (BICs) provide a way to engineer very narrow resonances in photonic crystals. The extended interaction time in these systems is particularly promising for the enhancement of nonlinear optical processes and the development of the next generation of active optical devices. However, the achievable interaction strength is limited by the purely photonic character of optical BICs. Here, we mix the optical BIC in a photonic crystal slab with excitons in the atomically thin semiconductor MoSe₂ to form nonlinear exciton-polaritons with a Rabi splitting of 27 meV, exhibiting large interaction-induced spectral blueshifts. The asymptotic BIC-like suppression of polariton radiation into the far field toward the BIC wavevector, in combination with effective reduction of the excitonic disorder through motional narrowing, results in small polariton linewidths below 3 meV. Together with a strongly wavevector-dependent Q-factor, this provides for the enhancement and control of polariton-polariton interactions and the resulting nonlinear optical effects, paving the way toward tuneable BIC-based polaritonic devices for sensing, lasing, and nonlinear optics.

Keywords: Nonlinear optics; Photonic crystals; Polaritons.