Abstract
In this study, we design a vertical split-ring resonator for an active plasmonic polarizer. By using E-beam lithography, we can define the arm length and arm width of the VSRR. Then we deposited Ni and Au bilayer and do the lift-off process. Further, we utilized CF4-assisted inductively coupled plasma reactive ion etching (ICP-RIE) to isotropically etch the sacrificial layer below. The arms of the pattern were then simultaneously released and self-folded because of the residual stress in the metal film. Due to the vertical anisotropic structure, we can achieve different phase accumulation along the x and y-axis. When we illuminate linear polarized light at a certain polarization angle, we can achieve a reflective circular polarized light. By applying current on the device, the joule heat would lead the vertical structure to bend toward the substrate. The resonance changes as the curvature of the arm, then we will again get a linear polarized light. By the simulation, now we can get a full change in the reflection light from circularly polarized light to linear polarized light at 55 THz. This VSRR polarizer can also be applied in the transmittance mode. The transmittance can also get a full change from circular to linear polarized light at 37 THz. Overall, this method of fabricating VSRR can easily tune the structure to fit into different resonance frequencies, and the design can achieve a high-efficiency polarizer both in reflection and transmittance modes.