Coherent and Propagation Effects on Accumulated Photon Echoes on Two-level System

David J. Tannor, Stuart A. Rice

M. Aihara, Humio Inaba

An analytical study of the photon echoes associated with the three-level system interacting resonantly with optical pulses possessing two different frequencies is performed. It is predicted that photon echoes arise at anomalous times corresponding to the correlation between the inhomogeneous broadenings for the different spectral lines as well as at the normal time expected in a simple two-level system. This new effect is caused by the coupling of the two resonant transitions through the common energy level. Furthermore, if the particle does not have inversion symmetry, the echoes with the sum or difference frequency of the exciting optical pulses can be observed in such a system. The quantitative analysis is also given for intensities, direction of propagation and polarizations of the anomalous echoes which depend upon the exciting pulses with different frequency.

A.I. Alekseyev, Ashat M. Basharov, Igor V. Yevseyev

Yaron R. Silberberg, Valéria Loureiro da Silva, J.P. Heritage +3 more

Optical fibers have proven to be one of the most important nonlinear media, even though in most cases the nonlinearity exploited is the notoriously weak Kerr effect of the silica-based fiber. By using doped fibers, new, stronger nonlinearities are possible. These stronger effects could allow for new phenomena and applications. Coherent effects, in particular, should be important when pulses shorter or comparable to the dephasing time of the impurity ions propagate in the fiber. Here we report, for the first time, the observation of accumulated photon-echo and free induction decay during the propagation of femtosecond pulses in Er doped fibers at 4.2°K.

Takashi Kuroda, F. Minami, Kuon Inoue +1 more

We have investigated nonlinear coherent transients of confined excitons in CuBr quantum dots with use of a three-pulse photon-echo technique. The echo signal shows quantum beats between LO-phonon coupled exciton levels, reflecting a strong electron–phonon interaction in the present quantum dots. The emission efficiency is found to be three orders of magnitude larger than those of ordinary semiconductors, implying that the significant accumulation effect is responsible for the nonlinear emission.

Ulf Elman, Stefan Kröll