Mechanical Large Deformation 3D Chiral THz Metamaterial

This paper reports an actuation method of a MEMS spiral metamaterial designed for THz (terahertz) electromagnetic frequency. Two-dimensional micro spirals with a diameter of 150 μm transform into three-dimensional micro spirals by the center of each micro spiral being pulled to the out-of-plane direction individually (Fig. 1). At the center, each micro spiral, arrayed on a silicon substrate, have an SU-8 bonding to another Parylene coated silicon substrate, and the micro spirals were stretched by separating the two substrates. It was confirmed that micro spirals were stably stretched to 536 μm at the maximum. The transmission characteristics obtained with THz-TDS (time domain spectroscopy) presented a large increase of polarization effect by the increase of micro spiral height.