Polarization dependent state to polarization independent state change in THz metamaterials

Abstract

We experimentally demonstrated a polarization dependent state to polarization independent state change in terahertz (THz) metamaterials. This is accomplished by reconfiguring the lattice structure of metamaterials from 2-fold to 4-fold rotational symmetry by using micromachined actuators. In experiment, it measures resonance frequency shift of 25.8% and 12.1% for TE and TM polarized incidence, respectively. Furthermore, single-band to dual-band switching is also demonstrated. Compared with the previous reported tunable metamaterials, lattice reconfiguration promises not only large tuning range but also changing of polarization dependent states, which can be used in photonic devices such as sensors, optical switches, and filters. V

Dynamic electromagnetic metamaterials

“…Displacing the movable element relative to the fixed one deforms the lattice structure and subsequently changes the near-field coupling between the metamaterial unit cells. response [55,57] of comb-drive based metamaterials. Figure 4c shows a fabricated reconfigurable metamaterial device with an array of asymmetric SRRs, with one portion of the unit-cell lying on anchors, with the other part on a floating frame.…”

“…The experimentally determined responsivity from a single pixel metamaterial element at room temperature was 16 500 V/W and a noise equivalent power of 10 À8 W/Hz 1/2 was also shown. Another type of MEMS based reconfigurable metamaterial utilizes comb-drive electrostatic actuators and was more recently reported [53][54][55][56][57]. One common feature of these devices is that one element of the metamaterial is fixed on an isolated anchor while the other neighboring portion is on a floating frame driven by actuators.…”

Reconfigurable liquid metal based terahertz metamaterials via selective erasure and refilling to the unit cell level

“…In addition to the size of the CRRs, it is also well known that the lattice constant along the axis of the THz electric field polarization (perpendicular to injection channels) can also affect the resonant frequencies. 17 In contrast, the liquid metal present in the main injection channels appears to have little effect on the transmission spectrum. This is expected when the incident polarization is perpendicular to a set of straight metallic lines.…”

Electrothermally actuated microelectromechanical systems based omega-ring terahertz metamaterial with polarization dependent characteristics

“…Micromachined MEMS metamaterial has been demonstrated to display larger tuning range through electrostatic actuation by either changing the in-plane gap 18,19 or the structural layout of the unit cell. 20,21 However, electrostatic actuators suffer from pull-in phenomenon and so are not an ideal choice for continuously tunable metamaterial application.…”