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Title: Nano-optical imaging of WSe2 waveguide modes revealing light-exciton interactions

We report on a nano-optical imaging study of WSe2 thin flakes with scanning near-field optical microscopy (NSOM). The NSOM technique allows us to visualize in real space various waveguide photon modes inside WSe2. By tuning the excitation laser energy, we are able to map the entire dispersion of these waveguide modes both above and below the A exciton energy of WSe2. We found that all the modes interact strongly with WSe2 excitons. The outcome of the interaction is that the observed waveguide modes shift to higher momenta right below the A exciton energy. At higher energies, on the other hand, these modes are strongly damped due to adjacent B excitons or band-edge absorptions. Lastly, the mode-shifting phenomena are consistent with polariton formation in WSe2.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [5] ;  [3] ;  [6] ;  [6] ;  [3] ;  [3] ;  [3] ;  [6] ;  [3] ;  [2]
  1. Argonne National Lab. (ANL), Lemont, IL (United States); Iowa State Univ., Ames, IA (United States)
  2. Univ. of Washington, Seattle, WA (United States)
  3. Argonne National Lab. (ANL), Lemont, IL (United States)
  4. Argonne National Lab. (ANL), Lemont, IL (United States); William Paterson Univ., Wayne, NJ (United States)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
  6. Fudan Univ., Shanghai (China)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 94; Journal Issue: 8; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1369571
Alternate Identifier(s):
OSTI ID: 1369571