Seminarium Fizyki Ciała Stałego

Over the years, coherent nonlinear spectroscopy has been used to investigate the ultrafast dynamics of light-matter interactions in condensed matter systems. In modern semiconductor nanostructures, light emission and absorption are often governed by excitons, i.e. correlated ensembles of electron-hole pairs in bulk or quantum well structures, and down to the level of single electron-hole pairs in quantum dots. In this seminar, I will first highlight our recent advances in measuring the coherent ultrafast dynamics of excitons in two-dimensional materials. To efficiently measure optical responses, we employ wave-mixing spectroscopy, which offers multiple advantages that I will discuss. For example, I will demonstrate how this approach enables us to measure the spatial propagation of excitonic coherence and density in homogeneously broadened CdTe quantum well systems grown at the University of Warsaw. Next, I will discuss the collective super-radiant effects observed in wave-mixings of a halide perovskite multilayer system. Finally, I will demonstrate how wave-mixing spectroscopy can be used to monitor the variation in the quantum confinement of excitons in a double-gated MoSe₂ device. I will conclude by providing some alluring prospects that emerge from the synergy of coherent spectroscopy and magneto-optics, which are merging into prospective coherent magneto-spectroscopy experiments that we are currently setting up here, at Nowa Hoża, as part of the NCN OPUS grant. If time permits, I will also introduce my research on the coherence of colour centres in diamond photonic nanostructures, which I am conducting within the framework of the International Research Laboratory involving the CNRS, the University of Tsukuba, and the University of Grenoble Alpes.