3D-Printed Terahertz Metamaterial for Electromagnetically Induced Reflection Analogue

The electromagnetically induced transparency (EIT) phenomenon in the metamaterials has been extensively investigated and applied in light storage, slow-light devices, and nonlinear devices. Most studies on the EIT-like phenomenon have been focused on the transmissive devices instead of reflective devices. Here we have proposed a 3D reflective metamaterial composed of two horizontal bars and a vertical bar (VB) to unfold the EIT-like effect in the terahertz frequency. Both computational simulation and theoretical analysis demonstrate that the coupling between the bright and dark mode starts when the structure symmetry is broken by the offset of the VB, giving rise to a transparency window in the reflection spectra. The EIT-like phenomenon can also be tailored by the lateral displacement of the VB. By combining the projection micro-stereolithography 3D printing and electron beam evaporation coating technology, two illustrative metamaterials are manufactured to characterize the EIT phenomenon. The reflection spectra measured by THz-TDS agree well with the theoretical results and validate the 3D design mechanism of reflective EIT-like devices. Our results unveil a practical and facile approach to designing and fabricating reflective EIT-like metamaterials and shed light on its potential application in multifunctional terahertz devices.