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Proceedings Paper

Ultrafast coherent and incoherent dynamics of intersubband excitations in quasi-two-dimensional semiconductors
Author(s): Thomas Elsaesser; Robert A. Kaindl; Stephan Lutgen; Michael Woerner; Andreas Hase; Harald Kuenzel
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Paper Abstract

Intersubband excitations play an important role for ultrafast carrier dynamics in quasi-two-dimensional semiconductors and for device applications. We present a study of the ultrafast coherent and incoherent dynamics of intersubband excitations in a pure electron plasma by means of femtosecond spectroscopy in the mid-infrared. The different relaxation processes following intersubband excitation of electrons in GaInAs/AllnAs quantum wells are observed in real-time and the relevant microscopic scattering mechanisms are identified. We find a decay of coherent intersubband polarizations on a time scale of several hundreds of femtoseconds which is governed by electron-electron scattering. Electrons excited to the n equals 2 conduction subband undergo intersubband scattering to the n equals 1 subband by emission of longitudinal optical phonons with characteristic time constants of 1 ps. This is followed by thermalization of the backscattered electrons on a similar time scale, involving both electron-electron and electron-phonon scattering. Eventually, the hot electron distribution cools down to lattice temperature within about 50 ps.

Paper Details

Date Published: 23 April 1998
PDF: 8 pages
Proc. SPIE 3277, Ultrafast Phenomena in Semiconductors II, (23 April 1998); doi: 10.1117/12.306140
Show Author Affiliations
Thomas Elsaesser, Max-Born-Institut fuer Nichtlineare Optik und Kurzzeitspektroskopie (Germany)
Robert A. Kaindl, Max-Born-Institut fuer Nichtlineare Optik und Kurzzeitspektroskopie (Germany)
Stephan Lutgen, Max-Born-Institut fuer Nichtlineare Optik und Kurzzeitspektroskopie (Germany)
Michael Woerner, Max-Born-Institut fuer Nichtlineare Optik und Kurzzeitspektroskopie (Germany)
Andreas Hase, Heinrich-Hertz-Institut fuer Nachrichtentechnik Berlin GmbH (Germany)
Harald Kuenzel, Heinrich-Hertz-Institut fuer Nachrichtentechnik Berlin GmbH (Germany)


Published in SPIE Proceedings Vol. 3277:
Ultrafast Phenomena in Semiconductors II
Kong-Thon F. Tsen; Harold R. Fetterman, Editor(s)

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