Ultraviolet thermally tunable silicon magnetic plasmon induced transparency

Pushing a tunable metamaterial magnetic plasmon resonance with a narrow linewidth into the ultraviolet region still remains a challenge, which is desirable for the applications of optoelectronic devices in the ultraviolet (UV) range. Here, a thermally tunable narrow UV magnetic plasmon induced transparency (PIT) is explored in a metamaterial consisting of Si vertical split ring resonator (Si VSRRs) array. With the 3D metamaterials suspended in air to minimize the dielectric substrate effect, the plasmonic interference between the bright broad Si UV magnetic plasmon and the dark narrow Wood-Rayleigh anomaly mode produces a narrow PIT with a bandwidth of 5.2 nm and a Rabi splitting energy of 87 meV in the UV, revealed by the coupled Lorentz oscillator theory. Moreover, a dynamic tuning of the UV magnetic PIT and the associated slow light is achieved via temperature change of the encapsulated ethanol. With a high-level sensitivity of 180 nm/RIU and a figure of merit of 45, the lifted Si VSRR is applicable to detecting sub nanometre-thick analytes, indicating the potential for developing UV plasmonic biosensing.