A Reusable and High-Sensitive Terahertz Metasurface Sensor Interated Ultra-Thin Microfluidic Channel for Detection of Trace Solution

To solve the challenge that terahertz (THz) metasurface sensor has low sensitivity (S) and hard to directly detect trace solution, this paper numerically calculated and experimentally verified a reusable and high-sensitivity terahertz metasurface sensor integrated a 4 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$u$</tex>m ultra-thin microfluidic channel. Compared the state of art, the proposed sensor is not only reusable but also has a high sensitivity of 0.568 THz/RIU for only 0.3 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mu \mathrm{L}$</tex> analyte, which is 2.59 ~ 5.65 times higher than the sensitivity of the conventional THz metasurface sensor structure. The experiment, basically consistent with the simulation, shows the frequency shift <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\Delta f)$</tex> corresponding to 0.3 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$u$</tex>L, ethanol, methanol and glycerin are 363 GHz, 400 GHz, and 475 GHz, respectively. This work is of great significance for the high sensitivity detection of trace solution in the field of THz sensing.