Spectrally resolved nonlinear optical response of weakly confined excitons under femtosecond laser pulse excitation in GaAs thin films

O. Kojima, T. Isu, J. Ishi-Hayase, M. Tsuchiya

Research output: Contribution to journalConference article

Abstract

We have investigated the dynamical properties of the weakly confined excitons in GaAs thin films by a transient grating method (three-beam four-wave mixing) with the use of femtosecond-laser pulses. The time-domain signals under the exciton-excitation conditions show a nonlinear optical response with a rise time of 4 ps and a long decay time of 120 ps. Moreover, in the case of that the probe pulse is parallel polarized to the two excitation pulses, the ultrafast optical response comparable to the pulse width appears. These characteristics of the nonlinear optical response is different from the experimental results by the picosecond-laser-pulse excitation. The spectra of the transient grating signals at the various time delays show several peaks at the energies, which agree with the energies of excitons confined in the thin films. This fact demonstrates that the characteristics of the nonlinear optical response of the weakly confined excitons are drastically changed by the spectral width of the excitation laser-pulse.

Original languageEnglish
Pages (from-to)675-678
Number of pages4
JournalPhysica Status Solidi C: Conferences
Volume3
Issue number3
DOIs
Publication statusPublished - 2006 May 8
Event32nd International Symposium on Compound Semiconductors, ISCS-2005 - Rust, Germany
Duration: 2005 Sep 182005 Sep 22

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ASJC Scopus subject areas

  • Condensed Matter Physics

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