Two-level tunnelling systems and backward-wave phonon echoes in neutron-irradiated quartz
L Michiels; N Vanreyten; L Michiels; Dept. Natuurkunde, Katholieke Univ., Leuven, Belgium; N Vanreyten; Dept. Natuurkunde, Katholieke Univ., Leuven, Belgium
Журнал:
Journal of Physics C: Solid State Physics
Дата:
1988-09-20
Аннотация:
Backward-wave phonon echoes (BWE) in neutron-irradiated quartz crystals are studied experimentally before and after annealing. It is argued that the annealing behaviour of the echo is consistent with a BWE generation mechanism in two-level tunnelling systems (for low input powers). The authors derive a theoretical expression, based on the theory of the mixing of two laser fields, which gives a good agreement with their experimental results.
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