Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 59: Poster Wednesday: Plasmonics and Nanooptics 2

O 59.8: Poster

Mittwoch, 7. September 2022, 18:00–20:00, P4

Probing Excitons-Photon interaction in WSe2 beyond the Non-Recoil Approximation — •Fatemeh Chahshouri, Masoud Taleb, and Nahid Talebi — Institute of Experimental and Applied Physics, Kiel University, 24118 Kiel, Germany

Cherenkov radiation from electrons propagating in materials with a high refractive index have applications in particle-detection mechanisms. However, the theory of the Cherenkov radiation has been treated up to now using the non-recoil approximation, which neglects the effect of electron deceleration in materials. Here, we report on the effect of the electron-beam deceleration on the radiated spectrum and exciton-photon interactions in nm-thick WSe2 crystals beyond the non-recoil approximation. The calculation of the Cherenkov radiation is performed by simulating the energy distribution of an electron beam propagating inside a thick WSe2 using the Monte Carlo method, and ascertaining the radiating power from electron beams with Liénard-Wiechert retarded potentials. Using this approach, we numerically demonstrate that in thick flakes the radiation due to the electron-beam deceleration is the dominating radiation mechanism. Our numerical findings agrees well with the experimental cathodoluminescence spectra. We further demonstrated that the captured CR in thick slabs could cause Fabry-Perot resonances that emerge as fine structures in the acquired CL spectra and demonstrate the fully coherent process of CR emission, happening due to its phase-matched excitation nature. Our findings pave the way for an accurate design of particle scintillators and detectors, based on the strong-coupling phenomenon.