We demonstrate the generation and detection of electron spin coherence in a quantum well waveguide without either an external or internal dc magnetic field. In the absence of spin precession, the induced spin coherence is detected through effects of quantum interference in the spectral domain coherent nonlinear optical response. We interpret the… (More)
The role of many-body interactions is experimentally and theoretically investigated near the saddle point absorption peak of graphene. The time and energy-resolved differential optical transmission measurements reveal the dominant role played by electron-acoustic phonon coupling in band structure renormalization. Using a Born approximation for… (More)
A generalization of Turing patterns, originally developed for chemical reactions, to patterns in quantum fluids can be realized with microcavity polaritons. Theoretical concepts of formation and control, together with experimental observations, will be presented.
High frequency differential transmission spectroscopy of graphene, probing near the M-point, is performed and analyzed theoretically. Electron-phonon coupling is identified as the chief mechanism for renormalization with an effective acoustic deformation potential of approximately 5eV.
The relation between dipole and momentum matrix elements in crystals, treated with periodic boundary conditions, is revisited. A correction term to standard expressions is found to be large for bulk GaAs, small for THz transitions.