Electromagnetic radiation in the THz frequency regime (300 GHz – 10 THz) reveals a high potential for chemical or biochemical sensors. A THz based application for chemical analysis with highly integrated devices was hardly ever demonstrated up to now. The low ability to integrate conventional sensor and analysis principles stems from the relatively large wave-length of the THz radiation compared e.g. to optics. Furthermore, due to the high absorption of THz radiation, e.g. by water, the possible application area of traditional sensor concepts, like in lab-on-chip applications, is highly constrained.

This project investigates novel THz sensor concepts for microfluidic applications. Therefore, the concept focuses on the usage of surface plasmon polaritons (SPPs).

SPPs and the related field of Plasmonics are characterized by the high confinement of elec-tromagnetic waves beyond the diffraction limit. Due to this, SPPs are under intense investi-gation and used for nano-scaled sensors and for optical near-field systems at optical fre-quencies. Similar concepts at longer wavelength have not been considered intensely up to now.

Cross-section of the developed SPP-Sensor consisting of two coupling gratings, a microfluidic channel and a rounded sealing glass which contains a transparent and conductive coating.