(a) Chiral metamaterial made of an array of rolled-up InGaAs/GaAs/Ti/Au microhelices realized by Prinz and coworkers. The material exhibits circular dichroism and linear polarization rotation in the operation frequency range around 2 THz. The image is taken from [34]. (b) Metamaterial made of an array of rolled-up InGaAs/GaAs/Cr microtubes. The zoom-in shows a single microtube. As sketched in the bottom right, the microtubes exhibit slightly more than one rotation resembling the concept of a split ring resonator [3]. We showed by means of finite difference time domain simulations that these structures might be used to obtain a magnetic response at THz frequencies.
