Real-time terahertz wave sensing via infrared detection interacted with evanescent terahertz waves

A novel sensing technique is developed that makes use of evanescent terahertz (THz) waves without directly detecting the THz wave. The technique is demonstrated for measuring changes in the electric field of near-infrared light, transcribed from changes in the electric field of THz waves. The method will enable sensing of various materials in the THz-frequency region, to provide knowledge about chemical reactions that require real-time tracking.