Open AccessObservation of coherent phonon-plasma coupled modes in wide gap semiconductors by transmission pump-probe measurements
Author(s) -
Hideyuki Kunugita,
Kanji Hatashita,
Yuji Ohkubo,
Takashi Okada,
Kazuhiro Ema
Publication year - 2015
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.019705
Subject(s) - phonon , semiconductor , plasma , excited state , physics , transmission (telecommunications) , optics , photon , four wave mixing , intensity (physics) , materials science , atomic physics , condensed matter physics , nonlinear optics , optoelectronics , laser , quantum mechanics , engineering , electrical engineering
We have investigated coherent LO phonon properties in zinc-based II-VI widegap semiconductors, focusing on phonon-plasma coupled modes. By a careful treatment of the time evolution of the signals in ZnS, ZnSe, and ZnTe, we found a frequency upshift as the pump intensity increases. Using a classical coupled oscillator model, we have explained the pump intensity dependence of both the shift and the decay rates by a mixing of highly damped two-photon generated plasma. From the linear dependence between them we can estimate the photo-excited carrier mobilities, leading to a new powerful estimation method to measure the mobility.