2D Fourier Transform Spectroscopy of exciton-polaritons and their interactions

TL;DR

This study uses two-dimensional Fourier transform spectroscopy to analyze exciton-polariton interactions in a semiconductor microcavity, revealing self and cross-interactions and the influence of polariton dispersion, supported by theoretical simulations.

Contribution

It provides the first detailed 2DFT spectroscopic analysis of both self and cross polariton interactions, including the role of dispersion in a microcavity system.

Findings

Detection of lower-lower and upper-upper polariton self-interactions.

Observation of lower-upper cross-interaction peaks.

Qualitative agreement between experimental spectra and Gross-Pitaevskii simulations.

Abstract

We investigate polariton-polariton interactions in a semiconductor microcavity through two-dimensional Fourier transform (2DFT) spectroscopy. We observe, in addition to the lower-lower and the upper-upper polariton self-interaction, a lower-upper cross-interaction. This appears as separated peaks in the on-diagonal and off-diagonal part of 2DFT spectra. Moreover, we elucidate the role of the polariton dispersion through a fine structure in the 2DFT spectrum. Simulations, based on lower-upper polariton basis Gross-Pitaevskii equations including both self and cross-interactions, result in a 2DFT spectra in qualitative agreement with experiments.