Excitation of terahertz plasmon-polariton in a grating coupled two-dimensional electron gas with a Fabry-Perot cavity

Terahertz plasmon-polariton modes are excited and probed in a grating coupled GaN/AlGaN two-dimensional electron gas embedded in a Fabry-Perot cavity using a terahertz time-domain spectroscopy at 8K. A strong coupling between the plasmon modes and the cavity modes was observed. Electromagnetic simulations confirmed that both the cavity and the grating coupler play important roles in coupling the terahertz field and the plasmons. The finding suggests that the manipulation of terahertz plasmon-polariton could be achieved by engineering the Q-factor and the mode number of the cavity to further enhance the coupling strength. (C) 2013 AIP Publishing LLC.