Near-Field Imaging of a TeraHertz deep-subwavelength Metasurface

In this paper, we present a study on the near-field distribution on a metasurface consisting of deep-subwavelength rectangular apertures. The metasurface is made out of a free-standing stainless steel sheet of thickness 100 microns, by making periodic perforation using LASER milling techniques. We measured the near-field distribution inside the aperture cavity, which shows a resonance in the near-field intensity. This resonance in a near electric field can be leveraged for various applications such as high-resolution sensing and imaging.