Related Experiment Video
Updated: Sep 27, 2025

Determination of the Excitation and Coupling Rates Between Light Emitters and Surface Plasmon Polaritons
Published on: July 21, 2018
Transition from surface phonon-polariton to surface phonon-plasmon-polariton by thermal injection of free carriers
Y El-Helou1,2, K-T Wu2,3,4, A Bruyant2
1Department of Physics, American University of Beirut, PO Box 11-0236, Riad El-Solh, Beirut 1107-2020, Lebanon.
Abstract:
Surface phonon-polariton, surface plasmon-polariton, and surface phonon-plasmon-polariton are evanescent electromagnetic waves confined to the surfaces of different classes of materials, which gives each of them particular characteristics suitable for diverse applications. Natural or forced injection of free carriers in a dielectric may change the surface phonon-polariton into a surface phonon-plasmon-polariton. Understanding this effect provides an insight into the fundamental physics of surface electromagnetic waves on dielectrics and offers tools that can be used to develop new technologies. In this contribution, we experimentally study the transition from surface phonon-polariton to surface phonon-plasmon-polariton on a yttrium-doped aluminum nitride polycrystalline substrate by thermal injection of free carriers. We perform this study using reflectivity measurements in the far- and mid-infrared spectral range and at a variable temperature, taking the necessary precautions to eliminate any errors that may arise from measurement artifacts and inaccurate analysis of the spectra. We demonstrate that thermal injection of a significant free carrier density can tune the surface phonon-polariton into a much shorter mean free path surface phonon-plasmon-polariton.
Related Concept Videos
Carrier Generation and Recombination
This process is given by the generation rate G and is efficient due to the conservation of momentum between the valence band maximum and conduction band minimum.
Indirect generation involves an...
Types of Semiconductors
Potential Due to a Polarized Object
Carrier Transport
Drift Current:
The drift of charge carriers is started by an external electric field (E). Charged particles, such as electrons and holes, experience an acceleration between collisions with lattice atoms. For electrons, this results in a drift velocity (vd) given by:
Phase Transitions: Vaporization and Condensation
Phase Transitions: Melting and Freezing

