Affiliation:
1. Gwangju Institute of Science and Technology
2. National Institute for Materials Science
3. University of Florida
4. Philipps-University
Abstract
We report on new THz electromagnetic emission mechanism from deformational coupling of acoustic (AC) phonons with electrons in the propagation medium of non-polar Si. The epicenters of the AC phonon pulses are the surface and interface of a GaP transducer layer whose thickness (d) is varied in nanoscale from 16 to 45 nm. The propagating AC pulses locally modulate the bandgap, which in turn generates a train of electric field pulses, inducing an abrupt drift motion at the depletion edge of Si. The fairly time-delayed THz bursts, centered at different times (
t
1
T
H
z
,
t
2
T
H
z
, and
t
3
T
H
z
), are concurrently emitted only when a series of AC pulses reach the point of the depletion edge of Si, even without any piezoelectricity. The analysis on the observed peak emission amplitudes is consistent with calculations based on the combined effects of mobile charge carrier density and AC-phonon–induced local deformation, which recapitulates the role of deformational potential coupling in THz wave emission in a formulatively distinct manner from piezoelectric counterpart.
Funder
Korea Electric Power Corporation
National Research Foundation of Korea
Ministry of Education
Deutsche Forschungsgemeinschaft
Air Force Office of Scientific Research
Subject
Atomic and Molecular Physics, and Optics
Cited by
1 articles.
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