Notes

Abstract:
Frequency selective structures (FSS) are fundamental tools in the design of terahertz (THz)
photonic crystals, filters and subwavelenght metallic hole arrays [1]. Most common methods
to design terahertz filters use FSS based on metamaterial resonators [2]. In this poster we
propose a new filter design consisting on a double wire metamaterial array which is able to
produce extremely high values of quality (Q) factor.The working principle of the filter is
based on a technique that leads simultaneously to peak cancellation and sharpening with
exceptional dynamic range.
Text:
Figure 1a) shows the geometry of a filter implemented with this
technique and its dimensions – the materials are gold for the wires and fused silica for the
substrate, a material with low losses at THz frequencies and a relative dielectric constant ~3.8.

Fig. 1b) shows the magnitude of the reflection coefficient obtained by numerical simulation of
the structure (blue line), along with the theoretical results for the complete structure (red line)
and the slab without the wires (green line).

Based on the numerical results we measured a Q factor of about 870 at a resonance frequency
of 435 GHz. Perhaps the most remarkable feature of this filter is that it can change from a
situation of complete opacity to full transparency at the target frequency.