Non-markovian dynamics of spectral narrowing for excitons in the layered semiconductor GaSe observed using optical four-wave mixing spectroscopy.
Phys Rev Lett
; 107(3): 037402, 2011 Jul 15.
Article
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| MEDLINE
| ID: mdl-21838404
ABSTRACT
We have investigated non-markovian dephasing by using time-resolved and spectrally resolved four-wave mixing measurements in a layered semiconductor GaSe. When the time interval between the first and second excitation pulses is increased, photon echo spectra exhibit narrowing only in a regime of a few picoseconds. In the initial dephasing of these signals, fast damping is observed. The narrowing of the spectrally resolved signal is consistent with the Fourier transformation of the time-resolved signals. Spectral narrowing is crucial evidence of the transition from non-markovian to markovian dynamics. By comparing experimental data with calculation results based on the non-markovian theory, we have found that the correlation time of the exciton-phonon interaction is 1.1 ps.