Flexible THz Metamaterials Bonded to Paper for Chemical Sensing

We report on THz metamaterials for chemical sensing fabricated on low-loss, plastic, flexible substrates. The metamaterial is bonded to a paper sheet, which is saturated with the liquid to be analysed. Liquids in contact with the metamaterial surface with different refractive indices result in a shift of the metamaterial resonant frequency. This shift in frequency can be detected by measuring its complex transmission using a THz vector network analyser, in the frequency range 0.75-1.1 THz. The sensitivity of the metamaterial is 0.0015 refractive index units for a spectral resolution of 1 GHz which is well achievable with the VNA system.