Time-resolved photon echoes from donor-bound excitons in ZnO epitaxial layers
| Autor: | Sergey Sadofev, Torsten Meier, Dmitri R. Yakovlev, M. Albert, Sandro Phil Hoffmann, Joachim Puls, Cedrik Meier, A. N. Kosarev, Manfred Bayer, I. A. Akimov, S. V. Poltavtsev |
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| Rok vydání: | 2017 |
| Předmět: |
Physics
education.field_of_study Photon Dephasing Exciton Population 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Picosecond 0103 physical sciences Atomic physics 010306 general physics 0210 nano-technology Spectroscopy education Excitation Order of magnitude |
| Zdroj: | Physical Review B. 96 |
| ISSN: | 2469-9969 2469-9950 |
| Popis: | The coherent optical response from 140 nm and 65 nm thick ZnO epitaxial layers is studied using four-wave-mixing spectroscopy with picosecond temporal resolution. Resonant excitation of neutral donor-bound excitons results in two-pulse and three-pulse photon echoes. For the donor-bound A exciton (${\mathrm{D}}^{0}{\mathrm{X}}_{\text{A}}$) at temperature of 1.8 K we evaluate optical coherence times ${T}_{2}=33--50$ ps corresponding to homogeneous line widths of $13--19\phantom{\rule{0.222222em}{0ex}}\ensuremath{\mu}\mathrm{eV}$, about two orders of magnitude smaller as compared with the inhomogeneous broadening of the optical transitions. The coherent dynamics is determined mainly by the population decay with time ${T}_{1}=30--40$ ps, while pure dephasing is negligible. Temperature increase leads to a significant shortening of ${T}_{2}$ due to interaction with acoustic phonons. In contrast, the loss of coherence of the donor-bound B exciton (${\mathrm{D}}^{0}{\mathrm{X}}_{\text{B}}$) is significantly faster (${T}_{2}=3.6\phantom{\rule{0.16em}{0ex}}\mathrm{ps}$) and governed by pure dephasing processes. |
| Databáze: | OpenAIRE |
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