Quantum Beat Spectroscopy of Excitons in Semiconductors

摘要: In this contribution, recent investigations are described in which quantum beat spectroscopy is employed to reveal and quantitatively characterize the coherence of exciton states semiconductors ionic crystals. Coherence that case signifies existence a well-defined phase relationship between time-dependent mechanical wavefunctions. Following creation system coherent state by optical excitation with short laser pulse, scattering will destroy relation and, depending on specific interactions, may lead rapid loss coherence. Besides pure dephasing elastic scattering, also energy relaxation inelastic destroys general, these processes advance simultaneously finally terminated recombination takes excited back into crystal ground state. Even though excitons extremely fast proceeding pico- or subpicosecond time scale, advances ultrafast now allow directly investigate dynamics processes.