Investigation of enhancement of near-field probing for sensing at terahertz waveband

Enhancement of localized surface plasmon resonance (LSPR) for near-field probing working at terahertz waveband is an important issue. Optimization of an apertureless metallic probe is presented for the purpose of sensing and detection in high resolution. Numerical calculation is carried out for the purpose of design and optimization of the probe. Corresponding results demonstrate that performance enhancement of the probe at terahertz waveband is different from that of the visible regime. Unlike the visible case that the smaller size of the probe apex results in stronger LSPR, actually, it is opposite to the case of visible for the terahertz regime while the size of probe apex d is ranging from 0 to 20 nm. The enhancement of the probe working at terahertz regime is mainly dominated by surface effect. In addition, the numerical results give a proof again that exciting SPP enhanced LSPR signal at near-field for the terahertz wavelength is surely difficult than that of the visible case.