Coherence peaks in picosecond sampling experiments

Anne Débarre, J. Keller, J.-L. Le Gouët +1 more

A. Laubereau, W. Kaiser

A. Bouchene, Anne Débarre, J. Keller +2 more

Field cross correlation is used to attain picosecond or sub-picosecond resolution in the time domain analysis of coherent optical emission triggered by long broad bandwidth light pulses. Optical data recording and retrieval is demonstrated in gaseous and in solid samples.

Dai‐Sik Kim

Gombojav O. Ariunbold, Michael M. Kash, Vladimir A. Sautenkov +4 more

We study the superfluorescence (SF) from a gas of rubidium atoms. The atoms of a dense vapor are excited to the $5D$ state from the $5S$ state by a two-photon process driven by 100-fs laser pulses. The atoms decay to the $6P$ state and then to the $5S$ state. The SF emission at 420 nm on the $6P$--$5S$ transition is recorded by a streak camera with picosecond time resolution. The time duration of the generated SF is tens of picoseconds, which is much shorter than the time scale of the usual relaxation processes, including spontaneous emission and atomic coherence dephasing. The dependence of the time delay between the reference input pulse and SF is measured as a function of laser power. The experimental data are described quantitatively by a simulation based on the semiclassical atom-field interaction theory. The observed change in scaling laws for the peak intensity and delay time can be elucidated by an SF theory in which the sample length is larger than the cooperation length.

B. Wilhelmi, Joachım Herrmann

An investigation is made of resonance absorption of picosecond pulses when time-delayed approximately collinear or exactly counterpropagating pump and probe pulses are superposed in a sample. The coherent and incoherent components of the influence of the probe beam on the absorption are calculated as a function of the delay time. In addition, the influence of phase modulation of the pump wave and emission of waves of different diffraction orders is studied.