Peculiarities of THz-electromagnetic wave transmission through the GaN films under conditions of cyclotron and optical phonon transit-time resonances

Abstract

The theory of THz radiation transmission through the film of compensated GaN of cubic modification under action of electric and magnetic fields has been developed. In the THz frequency range, spectra of the dynamic mobility tensor have been obtained for applied steady-state electric fields of several kV/cm and magnetic fields of several T. The spectra of transmission, reflection and loss coefficients have been analyzed for the Voigt configuration used for the applied fields. It has been shown that the transmitted wave becomes elliptically polarized, and the spectra of polarization characteristics such as ellipticity and rotation angle of the large axis of polarization ellipse were investigated under conditions of cyclotron resonance and optical phonon transit-time one. It has been found that, in certain frequency bands, polarization characteristics have the features valid for both resonances. The new optical method based on the analysis of ellipticity and rotation angle spectra is offered for determination of the low-field mobility.