Spoof plasmon resonance with 1D periodic grooves for terahertz refractive index sensing

We analyze the use of spoof plasmon resonance due to the excitation of spoof surface plasmons in a 1D array of rectangular grooves for terahertz refractive index sensing in an Otto configuration. The dependence of the resonant angle on the change of the refractive index is numerically investigated and a high angular sensitivity about S=320°/RIU is demonstrated, which leads to a high resolution of 3×10−7 RIU assuming 1×10−4 degree for angular resolution. We further show that by using a slanted geometry an even higher sensitivity up to 452°/RIU can be achieved. These results provide a novel method for terahertz refractive index sensing.