Imaging exciton-plasmon polaritons in WSe2/Au heterostructures

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excition-plasmon polaritons imaging
Illustration of the setup for the imaging of the exciton-plasmon polaritons (left) and energy-dependence imaging data revealing interference fringes of plasmons on gold and exciton-plasmon polaritons in WSe2 (right).

Scientific Achievement

Exciton-plasmon polaritons in WSe2/Au heterostructures are imaged, which show a strong coupling between excitons in WSe2 and surface plasmons on gold.

Significance and Impact

Due to the strong exciton-plasmon coupling, polaritons have shown a record-high spatial confinement and a strong field enhancement. These highly-confined and strongly-enhanced polaritons are desirable for future applications in nanophotonic sensing and signal processing. 

Research Details

  • Interference fringes from exciton-plasmon polaritons were imaged at various excitation energies.
  • The dispersion diagram of the polaritons demonstrate a strong exciton-plasmon coupling.
  • The polariton wavelength can be controlled by varying the WSe2 thickness. It can reach as low as 210 nm, 4 times smaller than the photon wavelength.

R. B. Iyer, Y. Luan, R. Shinar, J. Shinar, Z. Fei, “Nano-optical imaging of exciton-plasmon polaritons in WSe2/Au heterostructures,” Nanoscale 14, 15663 (2022).