Abstract
We report on a nano-optical imaging study of thin flakes with scanning near-field optical microscopy (NSOM). The NSOM technique allows us to visualize in real space various waveguide photon modes inside . By tuning the excitation laser energy, we are able to map the entire dispersion of these waveguide modes both above and below the exciton energy of . We found that all the modes interact strongly with excitons. The outcome of the interaction is that the observed waveguide modes shift to higher momenta right below the exciton energy. At higher energies, on the other hand, these modes are strongly damped due to adjacent excitons or band-edge absorptions. The mode-shifting phenomena are consistent with polariton formation in .
- Received 6 April 2016
- Revised 9 July 2016
DOI:https://doi.org/10.1103/PhysRevB.94.081402
©2016 American Physical Society