Plasmonic metasensor for simultaneous detection of relative humidity and temperature in terahertz band

A terahertz plasmonic metasensor is demonstrated for simultaneous measurement of relative humidity (RH) and temperature at the first time. Double golden rings can excite electromagnetic induced transparency (EIT) with dual plasmonic resonances. By studying the relationship between resonance frequencies at both resonance dips and environmental parameters, the RH sensitivities are 0.14 GHz/% (−282 nm/%) at low frequency (dip A) and 0.27 GHz/% (−210 nm/%) at high frequency (dip C), while the temperature sensitivities are 1.35 GHz/°C (−2718 nm/°C) at dip A and 2.45 GHz/°C (−1906 nm/°C) at dip C. Additionally, the influences of temperature and RH are proven independent on frequency shifts, indicating a suitability with RH and temperature changes simultaneously. The proposed metasenor covers advantages of polarization-incident insensitivity, high sensitivity, easy integration and low cost, making wide applications in industrial manufacturing, clinical medicine, weather forecasting and human health.