Highly directional and tunable mid-infrared transmission induced by resonant optical tunneling with VO2

Abstract

We present a mid-infrared (MIR) band-pass filter (BPF) realized via a prism-coupled multilayer architecture that incorporates an air gap and leverages vanadium dioxide (VO2) as a phase-change material. The design exploits resonant optical tunneling (ROT) phenomena, facilitated by the precise control of the air gap and multilayer architecture. The VO2 layer’s insulator-to-metal transition (IMT) at 341 K allows dynamic tuning of the filter’s transmission properties by adjusting the temperature. Additionally, the incidence angle of light on the prism significantly impacts the resonant tunneling conditions, providing an additional degree of control over the passband wavelength and bandwidth. Through rigorous transfer matrix and coupled-mode theoretical analysis, the filter achieves sharp resonance peaks with high transmittance in the desired spectral range and strong attenuation outside the passband. The proposed design offers a reconfigurable platform for MIR applications, including thermal imaging, environmental monitoring, and tunable optical filtering.