Thermostimulated THz Radiation Emission of GaAs at Surface Plasmon-Phonon Polariton Frequencies

The THz radiation reflection, absorption and emission spectra of conductive n -GaAs/air surface are considered. The influence of thermostimulated surface plasmon-phonon (SPP) polariton oscillations on THz radiation reflection, absorption and emission of high conductivity GaAs polished plates with electron density n = 7∙10 17 cm –3 and 4∙10 18 cm –3 and thickness of 350 mm is studied experimentally. The frequencies of thermostimulated transverse and longitudinal optical phonons and SPP oscillations, which characterize a heated lattice state, were determined. It is found that the heated highly doped interface layer (GaAs/air) emits the THz radiation at selected frequencies of SPP oscillations in the (7 – 8) THz and (10 – 15) THz ranges. It is shown that thermal heating of the GaAs/air interface enhances the absorption of the incident THz radiation. The huge decrease of the incident radiation reflectivity at the SPP frequencies with an increase of GaAs temperature is observed experimentally. DOI: http://dx.doi.org/10.5755/j01.ms.20.2.6318