Subwavelength hole arrayed stack: Towards terahertz high resolution imaging systems

Abstract

We report on the electromagnetic response of a stack of sub-wavelength hole metal arrays. The samples were designed for exhibiting left-handed dispersion branches under normal incidence and their transmissivity were optimized via the fabrication of elliptic-shaped holes. An experimental evidence of ground left handed dispersion branches was found around 0.45 THz by time-domain terahertz spectroscopy, supported by full wave simulations. The insertion losses are 3dB for a five-layer structure, this good level being explained by successful impedance matching. This result paves the way of high transmissivity high resolution focusing devices.