Research overview
This paper shows that two stacked metallic wire-grid metasurfaces (MWGMs) can produce Fano resonances whose strength and shape are tuned simply by rotating one grid relative to the other. The authors develop an original model, combining a circulating-field approach with an extended Jones formalism, that reveals how the grids’ linear polarization properties give rise to these polarization-induced resonances within the Fabry–Pérot-like cavity formed between them. The theory was validated experimentally using a pair of commercially available wire-grids in a terahertz time-domain spectrometer, with measured resonances in very good agreement with the predicted trends. Near 0.21 THz the quality factor reached 386, 162 and 65 for relative angles of 20°, 30° and 45°. The approach needs no complex unit-cell design or custom materials, making polarization an additional degree of freedom for tunable, high-Q optical resonators.
Key findings
- Stacked metallic wire-grid metasurfaces produce polarization-induced Fano resonances
- Resonance tuned simply by the relative rotation angle between the two grids
- Circulating-field model with an extended Jones formalism validated by THz-TDS measurements
- Quality factors up to 386 near 0.21 THz using commercially available wire-grids
