Dual-band terahertz switch with stretchable Bloch-mode metasurface

A polydimethylsiloxane (PDMS)-based stretchable metadevice for dual-band switching of terahertz radiation is experimentally demonstrated. The metasurface can efficiently excite dipole resonance of the metal structure and the surface Bloch mode generated by the periodic lattice substrate. In the tensile deformation operation, these two resonant modes show significant frequency shift sensitivity characteristics, which provides a feasible solution for the realization of dual-band terahertz switches. A transmittance modulation depth of 90% is achieved by the dipole resonance, with a frequency shift of 0.14 THz. The other transmittance modulation depth of 65% is achieved by the surface Bloch mode, with a frequency shift of 0.4 THz. The broad tuning of 0.4 THz is attributed to the surface mode is period-sensitive. This approach provides a promising method for broad frequency tuning of stretchable metasurfaces.