Frequency Coding Metasurface for Multiple Directions Manipulation of Terahertz Energy Radiation

A multifunctional frequency coding metasurface is proposed in terahertz frequency band. Different from the previous coding metasurface with a fixed phase difference of the neighbor coding unit cells in the whole working frequency band, the proposed frequency coding metasurface has the linear change phase difference in the operating frequency band with different phase sensitivity. It can flexibly control the reflected terahertz waves to the numerous directions by changing the working frequency without redesign the coding metasurface structure. Additionally, we demonstrate the polarization insensitive properties of our frequency coding metasurface by using 1-bit frequency coding metasurface with the periodic sequences of “0-0, 0-1” along the x-direction, 2-bit random frequency coding metasurface and non-periodic frequency coding metasurface. Our frequency coding metasurface provides a novel and flexible way to manipulate the energy radiation of terahertz wave and has tremendous values in terahertz systems.