THz Spectroscopy Sensitivity Enhancement of Metamaterial by Reduction of the Fabry-Pérot Oscillations Using Optical De-Coupler Meta-Plates

We present a new optical interaction of dielectric-back plates, meta-plates, when attached to THz metamaterials (MM) wafer. It is found out that coupling between MM resonance and substrate’s Fabry-Pérot (FP) oscillations, plays is crucial in spectral shift (ΔF) of the MM resonance, and thus its sensitivity in THz impedance spectroscopy. This makes the MM resonance spectra free from substrate losses when attaching external meta-back plates to the substrate. It also demonstrates the de-coupling of MM-resonance from the FP-oscillations as well as plasmonic enhancement on the MM surface along with introduction of a broadband enhancement of transparency through the substrates by considerably reducing FP oscillations. We found out that in this mechanism these meta-back plates de-trap THz radiation from the semiconductor substrate, thus decoupling the MM-resonance from FP-oscillations. In addition, the quality-factor of the MM resonance is improved and maintained throughout the THz spectrum, thereby demonstrating eight-fold sensitivity enhancement in terms of ΔF. This research is supported with system-level CST simulations and experimental THz impedance spectroscopy, leading to maximization of dielectric spectral sensitivity. This method is CMOS compatible and has potential applications for any resonant MM fabricated on a substrate to maximize dielectric sensing sensitivity for biosensing and nanoparticle THz spectroscopy