|
Recently Frenkel exciton polaritons (EPs) in organic materials and biological structures attracted considerable interest in relation to their Bose-Einstein condensation, low threshold polariton lasing, and polariton chemistry in microcavity. The concept of EPs suggests strong light-matter interaction that is supported by a considerably larger oscillator strength of organic systems compared to inorganic semiconductors. Polariton absorption of electron-vibrational systems was considered in nanofibers of organic dyes using a realistic non-Markovian model of molecular vibrations [1], and in a single-mode cavity in the presence of Brownian dissipation [2]. Theoretical description of EP luminescence in molecular systems is a challenge since in this case both the interaction with radiation field and electron-vibrational interaction are strong. Elastic cavity emission of polaritons in a single-mode microcavity in the presence of Brownian dissipation from molecular vibrations was considered in Ref.[2] for a specific case when polariton linewidth is the mean of cavity and molecular linewidth, although only at resonance when the cavity frequency is equal to that of a molecular resonance. Meanwhile, the interaction of the polariton with molecular vibrations should depend on exciton contribution to EP. In this work using a realistic non-Markovian theory for the description of the polariton-molecular vibrations interaction we calculate polariton luminescence in the polariton basis. We show that the frequency shift and broadening of polariton luminescence spectra strongly depend on the exciton contribution to the exciton polariton that is a function of frequency. Our non-Markovian theory predicts Fano resonances in EP luminescence and narrowing of its spectrum with an increase in the number of molecules in a single-mode microcavity. We also consider non-equilibrium (hot) EP luminescence that opens a way for its observation in organic-based nanodevices.
[1] B.D. Fainberg, J. Phys. Chem. C 123, 7366 (2019).
[2] K.S.U. Kansanen, J.J. Toppari, and T.T. Heikkila, J. Chem. Phys. 154, 044108 (2021).
|
