Exciton–Photon Interactions in Two-Dimensional Semiconductor Microcavities

Abstract

Investigation of light–matter interactions in two-dimensional (2D) semiconductors is essential to understand many-body effects and explore their applications in photonics. 2D semiconductor microcavities can be formed by the integration of 2D semiconductor active media with planar Fabry–Perot resonant cavities. The emerging exciton–photon interactions between the strongly bound excitons in 2D semiconductors and the cavity photons allow exploring on the wealthy photonic and polaritonic physics of bosonic quasiparticles in the 2D limit. This Perspective focuses on recent advances in exciton–photon interactions of 2D semiconductor microcavities and their inspiring applications. First, we picture the research scope of 2D semiconductor microcavities, sort out the historical development from conventional semiconductor microcavities to the emerged 2D semiconductor microcavities, and illustrate mostly employed device structures. Second, we classify exciton–photon interactions in 2D semiconductor microcavities according to their coupling strengths. In the weak coupling regime, control of spontaneous emission and photon lasing are discussed together with the Purcell effect. In the strong coupling regime, we summarize experimental observations and theoretical predictions on Rabi splitting, Bose–Einstein condensation, polariton lasing, superfluidity, and superconductivity. Third, four types of leading-edge applications are outlined, including on-chip coherent light sources, microcavity-enhanced single-photon sources, topological photonics, and other nonlinear optics. Finally, we highlight the remaining challenges and future opportunities for fundamental physics of 2D semiconductor microcavities and their technological applications.

All-optic logical operations based on the visible-near infrared bipolar optical response

“…2d). Consequently, the density of effective carriers in MoS2 is reduced, resulting in a negative photoresponse under NIR illumination 33 . Under visible illumination, MoS2 is the primary absorption layer, and the increase of effective carrier density in the MoS2 channel produces a positive photocurrent.…”

Second Harmonic Generation Control in 2D Layered Materials: Status and Outlook

“…[383] Apart from excitons resonance enhanced SHG, excitons open up new prospects for strong coupling systems. [384][385][386] The strong coupling of excitons with well-designed optical cavities leads to the formation of hybrid light-matter quasiparticles, known as exciton-polaritons (EPs), [384][385][386][387][388][389][390][391][392][393][394][395][396][397] which provides flexible tunability in controlling the light-matter interactions for the modulation and enhancement of SHG response in 2DLMs. When the exchange rates between the excitons and the optical cavities are faster than their dissipation rates, strong coupling occurs, resulting in Rabi splitting and anticrossing behavior in the optical spectra.…”

“…This strategy can be extended to other dielectric resonant metasurfaces. In addition, the strong excitonphoton interactions between the strongly bound excitons in 2D layered semiconductors and the photons of microcavities have garnered researchers' attention recently, [309,389,396,401] allowing for the exploration of the modulation and enhancement of SHG response in the 2D limit. Shi et al proposed a F-P microcavity formed by coupling an atomically thin WS 2 film with a Si hole matrix to enhance the SH emission (Figure 10j).…”

Light-emitting devices based on atomically thin MoSe2

“…(c) Structures of monolayer MoSe 2 integrating into an open cavity (left) and a monolithic cavity (right), respectively [33] . (d) Schematic of the self-hybridized F−P cavity in bulk TMDs [78] . illustrated in Fig.…”

“…illustrated in Fig. 7(d) can also be utilized for the low-quality resonators, which is strongly correlated with its high background permittivity [78] . In fact, Munkhbat observed the splitting of angle-resolved reflection (ARR) map of mechanically exfoliated thick layers of MoSe 2 , where the A and B excitons hybridized with the FP modes of MoSe 2 , resulting in the formation of three EP bands [78] .…”