Suboptimal Coding Metasurfaces for Terahertz Diffuse Scattering

Flexible controls of scattering clouds using coding metasurfaces

Metamaterials or metasurfaces have been designed to precisely manipulate the scattering at every angle. Here, we propose to control the probability of random scattering appearing in the desired range of angles, which is defined in this letter as scattering cloud. We present a controllable random metasurface by simply adding a random coding sequence to gradient coding sequence. It is shown that ...

Planar Holographic Metasurfaces for Terahertz Focusing

Scientists and laymen alike have always been fascinated by the ability of lenses and mirrors to control light. Now, with the advent of metamaterials and their two-dimensional counterpart metasurfaces, such components can be miniaturized and designed with additional functionalities, holding promise for system integration. To demonstrate this potential, here ultrathin reflection metasurfaces (als...

Planar integrated metasurfaces for highly-collimated terahertz quantum cascade lasers

We report planar integration of tapered terahertz (THz) frequency quantum cascade lasers (QCLs) with metasurface waveguides that are designed to be spoof surface plasmon (SSP) out-couplers by introducing periodically arranged SSP scatterers. The resulting surface-emitting THz beam profile is highly collimated with a divergence as narrow as ~4° × 10°, which indicates a good waveguiding property ...

Tailoring the slow light behavior in terahertz metasurfaces

Extraordinary sensitivity enhancement by metasurfaces in terahertz detection of antibiotics

We have detected trace amounts of molecules of antibiotics (kanamycin sulfate) dispersed on metasurfaces with terahertz (THz) spectroscopy. Utilizing the extraordinary optical transmission resonance of an array of square-shaped slits on a silicon substrate at ~0.3 THz, we were able to monitor varying concentrations of kanamycin sulfate as low as ~100 picogram/L. In contrast, the lowest detectab...