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Updated: Oct 9, 2026

Cooling an Optically Trapped Ultracold Fermi Gas by Periodical Driving
Published on: March 30, 2017
Ultrafast dynamics of intersubband excitations in a quasi-two-dimensional hole gas
R A Kaindl1, M Wurm, K Reimann
1Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2A, D-12489 Berlin, Germany.
Abstract:
We present the first study of ultrafast hole dynamics after resonant intersubband excitation in a quasi-two-dimensional semiconductor. p-type Si0.5Ge 0.5/Si multiple quantum wells are studied in pump-probe experiments with 150 fs midinfrared pulses. Intersubband scattering from the second heavy-hole back to the first heavy-hole subband occurs with a time constant of 250 fs, followed by intrasubband carrier heating within 1 ps. Such processes give rise to a strong reshaping of the intersubband absorption line, which is accounted for by calculations of the subband structure, optical spectra, and hole-phonon scattering rates.
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