Hollow complementary omega-ring-shaped metamaterial modulators with dual-band tunability

In this Letter, we report two kinds of metamaterial modulators based on hollow complementary omega-ring-shaped (HCΩ) structures, which are fabricated on parylene-C thin film with high flexibility and can realize dual-band amplitude tunability. The first type of structure (HCΩ-I) consists of identical unit cells along a similar direction, achieving different tunability under different compression directions but suffering from polarization dependence. To investigate the effect of unit cell direction on polarization direction, the unit cells in the HCΩ-I device are rotated by 90° in sequence to form a symmetrical type of structure (HCΩ-II), which successfully produces reverse dual-band variation of transmission with good polarization independence. These two developed flexible modulators with varied tunable ability will have a promising application in terahertz detection, sensing, and imaging.