Microspectroscopy was used for spectral characterization of meta-surface MIM structures, which had a footprint with a 300μm cross-section. A Fourier transform infrared (FT-IR) spectrometer and a microscope unit (FTIR-6000 and IRT-1000, JASCCO) were used to measure the reflection spectra in the mid-infrared region. Film of Au of 350 nm thickness was used for the reflection reference, with 98% reflectance in the entire mid-infrared area.