Coherent Effects in Femtosecond Spectroscopy: A Simple Picture Using the Bloch Equation

Anand T. N. Kumar

A.C. García-Wong, A. A. C. de Almeida, N. R. de Melo +1 more

A mode-locked 1 GHz femtosecond laser together with a diode laser is used to perform coherent spectroscopy of the D2 rubidium line. The results are well described using the Bloch equations in the frequency domain picture.

Markus Lindberg, Rolf H. Binder

The possibility of creating dark states (a concept well known in atomic systems) in semiconductors is discussed. Based on the semiconductor Bloch equations, the analysis shows that, in spite of complications due to band-structure and strong excitonic many-body effects, signatures of dark states should be observable in femtosecond nonlinear optical excitation experiments.

Charles V. Shank, Robert W. Schoenlein, Daniel M. Mittleman +1 more

Jing Lu, Soo‐Y. Lee, Kangnian Fan

S. W. Koch, Rolf H. Binder, Markus Lindberg

The availability of femtosecond pulses in the optical-frequency regime allows the study of coherent effects in the interaction between semiconductors and light. Because the properties of the exciting pulses become important ingredients in spectroscopy, the theoretical analysis must treat the complete time dependence of the system. For this purpose we use the semiconductor Bloch equations (SBE),1-3 which are the coupled equations of motion for the interband polarization and the electron and hole populations for an interacting electron-hole system in the random-phase approximation. The equations describe the electron-hole Coulomb attraction leading to excitonic features; they contain phasespace filling and band-gap renormalization effects, as well as the dipole interaction with the applied light field.