Many-body correlation effects in complex quantum systems often lead to phase transitions that bear great technological potential. However, the underlying microscopic driving mechanisms or even the quantum-mechanical properties of the novel ground state often remain elusive. Here we employ phase-locked ultrabroadband terahertz (THz) pulses to disentangle two coexisting orders in the charge density wave phase 1T-TiSe2 via their individual non-equilibrium multi- THz dynamics. Furthermore, we demonstrate that few-cycle THz pulses can project out the matter part of a transient cold exciton-polariton condensate, providing novel insights into the very nature of this macroscopic quantum state.
We report results from a systematic study of the linear refractive
index of thin films made of As-S-Se glasses which are part of
the chalcogenide family. We have studied eight different
compositions. The refractive index are measured by the mean of a
grating coupling experiment. The measurements are performed around
1.5μm for both annealed and non-annealed glasses. We observe
that annealing the samples increases their refractive index. We
also note that the increase of Selenium concentration increases
the refractive index and the decrease of Arsenic concentration
decreases the refractive index.