Polariton hyperspectral imaging of two-dimensional semiconductor crystals.
Christian GebhardtMichael FörgHisato YamaguchiIsmail BilginAditya D MohiteChristopher GiesMatthias FlorianMalte HartmannTheodor W HänschAlexander HögeleDavid HungerPublished in: Scientific reports (2019)
Atomically thin crystals of transition metal dichalcogenides (TMDs) host excitons with strong binding energies and sizable light-matter interactions. Coupled to optical cavities, monolayer TMDs routinely reach the regime of strong light-matter coupling, where excitons and photons admix coherently to form polaritons up to room temperature. Here, we explore the two-dimensional nature of TMD polaritons with scanning-cavity hyperspectral imaging. We record a spatial map of polariton properties of extended WS2 monolayers coupled to a tunable micro cavity in the strong coupling regime, and correlate it with maps of exciton extinction and fluorescence taken from the same flake with the cavity. We find a high level of homogeneity, and show that polariton splitting variations are correlated with intrinsic exciton properties such as oscillator strength and linewidth. Moreover, we observe a deviation from thermal equilibrium in the resonant polariton population, which we ascribe to non-Markovian polariton-phonon coupling. Our measurements reveal a promisingly consistent polariton landscape, and highlight the importance of phonons for future polaritonic devices.
Keyphrases
- room temperature
- high resolution
- energy transfer
- ionic liquid
- transition metal
- single cell
- gene expression
- molecular dynamics
- single molecule
- density functional theory
- high speed
- dna methylation
- mass spectrometry
- fluorescence imaging
- molecular dynamics simulations
- functional connectivity
- resting state
- current status
- high density
- dna binding