Coherent interaction of ultrashort frequency-tunable dye laser pulses withexcitons in a semiconductor.

В. С. Днепровский, Valentin N. Chumash, E. V. Zimenko

F. Bruckner, Arkadii Z Grasiuk, V. Dneprovsky +7 more

Wolfgang Zinth, R. Leonhardt, W. Holzapfel +1 more

Synchronous pumping of a femtosecond and a tunable picosecond dye laser provides synchronized trains of ultrashort pulses at variable frequency difference. The system allows the authors to study coherently excited Raman transitions with femtosecond time resolution. Fast dephasing processing with decay times of a few hundred femtosecond are measured.>

J.‐Y. Bigot, Mary‐Ann Mycek, Shimon Weiss +2 more

Using a combination of interferometric-correlation and time-resolved intensity measurement techniques, we characterize the phase and amplitude of the coherent emission of semiconductor quantum wells resonantly excited by ultrashort optical pulses. We demonstrate that exciton-exciton interaction produces nonlinear phase shifts of the instantaneous frequency relative to the incident laser.

Ida Maria Catalano, Aldo Cingolani, Michele Ferrara +2 more

Petr P Vasil'ev

An analysis is made of the conditions for the generation of superfluorescence pulses in an inverted medium of electron—hole pairs in a semiconductor. It is shown that strong optical amplification in laser semiconductor amplifiers characterised by α L ≫ 1 (α is the small-signal gain and L is the amplifier length) leads to suppression of phase relaxation of the medium during the initial stages of evolution of superfluorescence and to formation of a macroscopic dipole from electron—hole pairs. Cooperative emission of radiation in this system results in generation of a powerful ultrashort pulse of the optical gain, which interacts coherently with the semiconductor medium. It is shown that coherent pulsations of the optical field, observed earlier by the author in Q -switched semiconductor lasers, are the result of superfluorescence and of the coherent interaction between the optical field and the medium.