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.
@article{arxiv.1506.01964,
title = {2D Fourier Transform Spectroscopy of exciton-polaritons and their interactions},
author = {N. Takemura and S. Trebaol and M. D. Anderson and V. Kohnle and Y. Léger and D. Y. Oberli and M. T. Portella-Oberli and B. Deveaud},
journal= {arXiv preprint arXiv:1506.01964},
year = {2015}
}