Terahertz radiation from propagating acoustic phonons based on deformation potential coupling
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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 13, 2022
- Source ID
- 10.1364/oe.460471
Entities
People
- Andreas Beyer
- Christopher J. Stanton
- Chul‐Sik Kee
- Kerstin Volz
- Kunie Ishioka
- Sang-Hyuk Park
- Sehyuk Lee
- Ulrich Höfer
- Wolfgang Stolz
- Young-dahl Jho
Organizations
- Air Force Office of Scientific Research
- German Research Foundation
- Gwangju Institute of Science and Technology
- Korea Electric Power Corporation
- Ministry of Education of the Republic of Korea
- National Institute for Materials Science
- National Research Foundation of Korea
- University of Florida