Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Observation of anomalous exciton polariton bands in PEPI perovskite based microcavity at room temperature

Chunzi Xing, Xiaokun Zhai, Chenxi Yang, Peilin Wang, Jiaxiang Mu, Xinmiao Yang, Yao Li, Xianxiong He, Yong Zhang, Haitao Dai, Liefeng Feng, Tingge Gao

TL;DR

The paper addresses non-Hermitian effects in exciton-polariton systems, reporting room-temperature observation of anomalous polariton bands in a PEPI perovskite microcavity. It combines angle-resolved photoluminescence measurements with a non-Hermitian coupled-oscillator model, defining H(k) = Ecav(k) + i Gamma1 Omega + i Gamma3 Omega - i Gamma3 Eexc + i Gamma2 and Ecav(k) = hbar^2 k^2/(2 m_eff) + delta to reproduce the observed dispersions. The key findings include the appearance of anomalous dispersion with negative mass at large k, tunable by cavity loss Gamma1 and influenced by thickness variations, corroborated by simulations. This work provides a platform for exploring room-temperature non-Hermitian polariton dynamics and informs design strategies for tunable non-Hermitian photonic devices.

Abstract

Recently anomalous energy bands with negative mass attract intensive attention where non Hermiticity plays an important role. In this work we observe anomalous exciton polariton bands in PEPI perovskite based microcavity at room temperature. We simulate the anomalous band structure using a non-Hermitian coupled oscillator model which agree with experiments very well. Our results offer to study non-Hermitian polariton wave dynamics at room temperature.

Observation of anomalous exciton polariton bands in PEPI perovskite based microcavity at room temperature

TL;DR

The paper addresses non-Hermitian effects in exciton-polariton systems, reporting room-temperature observation of anomalous polariton bands in a PEPI perovskite microcavity. It combines angle-resolved photoluminescence measurements with a non-Hermitian coupled-oscillator model, defining H(k) = Ecav(k) + i Gamma1 Omega + i Gamma3 Omega - i Gamma3 Eexc + i Gamma2 and Ecav(k) = hbar^2 k^2/(2 m_eff) + delta to reproduce the observed dispersions. The key findings include the appearance of anomalous dispersion with negative mass at large k, tunable by cavity loss Gamma1 and influenced by thickness variations, corroborated by simulations. This work provides a platform for exploring room-temperature non-Hermitian polariton dynamics and informs design strategies for tunable non-Hermitian photonic devices.

Abstract

Recently anomalous energy bands with negative mass attract intensive attention where non Hermiticity plays an important role. In this work we observe anomalous exciton polariton bands in PEPI perovskite based microcavity at room temperature. We simulate the anomalous band structure using a non-Hermitian coupled oscillator model which agree with experiments very well. Our results offer to study non-Hermitian polariton wave dynamics at room temperature.
Paper Structure (2 sections, 3 equations, 4 figures)

This paper contains 2 sections, 3 equations, 4 figures.

Table of Contents

  1. 2. Results and Discussion
  2. 3. Conclusion

Figures (4)

  • Figure 1: Schematic graph of the PEPI perovskite microcavity. (a) The structure of the PEPI microcavity. (b) Exciton polariton band structure, exhibiting conventional dispersion along the k direction or anomalous dispersion along the k direction, depending on the non-Hermiticity of the microcavity.
  • Figure 2: Structural and optical characterization of PEPI perovskite crystals grown on a DBR substrate. (a) Fluorescence microscopy image of the as-grown PEPI crystals. (b) Corresponding SEM image showing the platelet-like morphology.(c) AFM topography of the crystal surface. (d) Height profile across the step edge, revealing the thickness of the PEPI. (e) XRD pattern of the PEPI perovskite film, confirming its single-crystal characteristics. (f) Room-temperature photoluminescence (PL) spectrum of PEPI, with the red dashed curve indicating the Gaussian fit.
  • Figure 3: Schematic of the home-built ARPL spectra system.
  • Figure 4: Anomalous exciton polariton bands of the PEPI-based microcavity. (a) Angle-resolved photoluminescence (ARPL) dispersion spectra of exciton polaritons in PEPI perovskite. The dashed lines are the fitted dispersion branches of exciton polariton modes. (b) Anomalous dispersion curves observed along the k$_x$ direction at a different sample position. The white dashed box highlights regions where the sign of the effective mass changes twice. The color bar indicates the photoluminescence intensity.