Amplification and generation of surface plasmon polaritons in a semiconductor film – dielectric structure

The peculiarities of propagation and amplification of surface waves of plasmon polariton type in a planar semiconductor film – dielectric structure are considered for the THz frequency region, with allowance for dissipation in a semiconductor. Two spectral regions are found, where the group velocity of surface plasmon polaritons is negative. It is shown that in these regions the structure can be considered as an amplifying waveguide with distributed feedback and a high gain with respect to the reflected and transmitted signals. The possibility of generation of electromagnetic radiation in such structures is established. (paper)