Broadband Terahertz Imaging in Hyperbolic Metamaterial Slab

In this paper, we theoretically and numerically investigate the image transmission properties of a highly anisotropic metamaterial slab at terahertz (THz) frequencies. Our theoretical analysis shows that resonant higher-order modes cause severe image distortion in metamaterial slabs that substantially hinder the broadband operation of the device. We show that the resonant nature of the slab can be reduced by adjusting the imaginary part of the in-plane refractive index, Im(nxx) of the slab, yielding broad-band imaging at THz frequencies. Finally, using a figure of merit (FOM), we compare our method with existing postprocessing methods, showing improvement in imaging, particularly at lower THz frequencies.