3D-printed mechanically reconfigurable all-dielectric metagrating for terahertz filters

We demonstrate a mechanically reconfigurable terahertz filter implemented by the 3D-printed all-dielectric metagrating, providing a versatile platform for adaptive photonic devices. The structure consists of parallel supporting bars connected by vertical grating elements, forming a lattice that can be mechanically reconfigured. By applying a controlled lateral displacement to the supporting bars, the grating elements are tilted, effectively reducing the grating period and inducing a systematic blue shift in the transmission dip frequency. By tilting the metagrating, we experimentally observed a 15% frequency modulation and a 95% transmission modulation. The numerical simulations show consistent results with the experimental results. In contrast to conventional approaches that rely on refractive index modulation, phase-change materials, or other active tuning mechanisms, this method achieves tunability purely through geometric reconfiguration. This strategy offers a simple, low-cost, and robust route to dynamic terahertz filtering, and it can be readily extended to other reconfigurable metamaterials and photonic devices requiring adaptive control of their optical response.