Designing a broadband terahertz plasmonic field enhancer with a homojunction of semiconductors

We proposed a broadband THz plasmonic field enhancer taking advantage of the spatially varying charge carrier concentration in a homojunction of semiconductors. The theoretical simulation indicates that the structure has a broadband resonance response and shows a field enhancement factor greater than 10 in the majority of the THz waveband. Near 6 THz, a maximum of 30-fold field enhancement is predicted. We believe that the proposed structures are ideal candidates for broadband field enhancement and may help realize more sophisticated THz devices. (C) 2019 The Japan Society of Applied Physics.