Free-standing guided-mode resonance humidity sensor in terahertz

• Published in: Sensors and actuators. A. Physical. Vol. 268; pp. 27 - 31
• Main Authors: Shin, Hee Jun, Kim, Sae-Hyung, Park, Kisang, Lim, Min-Cheol, Choi, Sung-Wook, Ok, Gyeongsik
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.12.2017; Elsevier BV
• Subjects: Computer simulation; Finite difference time domain method; Giant magnetoresistance sensing devices; Guided mode resonance; Humidity; Humidity sensing; Photomixing; Polymer; Polymers; Polyvinyl alcohol; Relative humidity; Sensors; Studies; Terahertz; Polymer; Terahertz; Guided mode resonance; Humidity sensing; Photomixing
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2017.10.060

[Display omitted] •A new type of humidity sensor by using polymer is proposed.•The mechanism of the sensor is based on guided mode resonance effect.•The humidity sensor is successfully demonstrated using terahertz spectroscopy. We theoretically and experimentally investigate a polymer-based guided-mode resonance (GMR) structure and its application for relative humidity (RH) sensing in the terahertz region. We obtained RH-dependent resonance frequency shifts and transmittance changes of the free-standing polymer GMR sensors with PVA material coating at 20°C. We numerically simulated the GMR structure in the same frequency region by using the FDTD method. It shows that the water contents in the polyvinyl alcohol (PVA) film are increased up to 6% as RH is increased up to 70%. As a result, we propose a highly sensitive RH sensor, which can be fabricated by a simple method at low cost for widespread usage.