The circular transmission spectra for (a) the single-layered chiral metamaterial, (b) the symmetric bilayer metamaterial (SBM), and (c) the asymmetric bilayer metamaterial (ASBM). Correspondingly, calculated circular dichroism is presented in panel (d) for the single-layered chiral metamaterial, in panel (e) for SBM, and in panel (f) for ASBM.