Effect of Wood's anomalies on the THz transmission spectra of free-standing metallic hole arrays

A free-standing periodic array of subwavelength rectangular apertures has been designed to exhibit peak transmission which is dominated by localized aperture resonance in the THz region. By varying the incident angle, Wood's anomalies can be introduced; the observed effect upon the localized aperture resonance is reported and compared to FDTD simulations in the absence of plasmonic surface modes. Peak frequency transmission shifts of up to 150 GHz (~15%) while maintaining normalized peak transmission >85% have been observed by VNA CW frequency domain measurements.