We present quasi-analytical solutions (QANS) of hybrid platform (HP) comprising metallic grating (MG) and stacked dielectric layers for terahertz (THz) radiation. The QANS are validated by finite difference time domain simulation. It is found that the Wood’s anomalies induce the high-order spoof surface plasmon resonances in the HP. The QANS are applied to optimize a new perfect absorber for THz sensing of large-area thin film with an ultrahigh figure of merit reaching a fifth order of magnitude for the film thickness 0.0001p (p:MG period). The first-order Wood’s anomaly of the insulator layer and the Fabry–Perot resonance in the slit’s cavity account for the resonance of the perfect absorber. The QANS and the new perfect absorber may lead to a highly sensitive and practical nano-film refractive index sensor for THz radiation.
|Number of pages||10|
|Journal||Journal of the Optical Society of America B: Optical Physics|
|Publication status||Published - 2016|
ASJC Scopus subject areas
- Statistical and Nonlinear Physics
- Atomic and Molecular Physics, and Optics