Terahertz Metamaterial Sensor in a High-Q Photonic Crystal Cavity

We investigate whether metamaterial (MM) embedded in a one-dimensional high-Q photonic crystal (PC) cavity has the potential to be a better terahertz (THz) sensor than a MM (or a PC cavity) alone, when the MM strongly couples with the cavity photons. The resonant frequency shift induced by an analyte on the MM in the cavity is smaller than that obtained with the MM alone. This is attributed to the larger mode volume according to the dielectric perturbation theory. However, the phase sensitivity of the MM is larger than that of the MM alone, which opens a new route for the realization of improved THz phase-sensitive sensors.