Additively manufactured multi-spectral NIR-THz sensor systems

• Applicants: Professor Dr. Sascha Preu; Professor Dr.-Ing. Oliver Stübbe
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering ; Communication Technology and Networks, High-Frequency Technology and Photonic Systems, Signal Processing and Machine Learning for Information Technology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 502254396

The proposed project aims for the development of an additively manufactured, multi-spectral sensor system with a low cost, disposable or reusable sensor element for applications in spectroscopy and life sciences. The compact, photonic-Tearhertz (THz; 100 GHz-10 THz) co-integrated sensor will synchronously capture spectroscopic data in the near infrared range (~1550 nm; NIR) and in the THz range (0.1 THz- 1.25 THz with potential extension towards 2 THz) whilst using only one NIR laser system driving both parts of the sensor. The THz system will be a homodyne photomixing setup. The sensor system will be composed of additively manufactured dielectric waveguide circuitry for both the near infrared as well as the Terahertz range. Both the actual sensor element as well as the photonic backbone will be composed of such waveguide structures and components like splitters or in- and outcoupling optics that will be developed in WP1. THz waveguide materials will be TOPAS, polyethylene, polypropylene or high impact polystyrene. For the NIR domain PLA, HD glass or ABS will be used. The substrate will be polyethylene, quartz or metallized quartz glass. WP2 focuses on the sensor elements with sufficient sensitivity. Three different system architectures are targeted: Architecture i will be tailored to samples under test with low or medium absorption, such as oils. Resonator structures will be implemented. Architecture ii will focus on samples under test with high THz absorption. The sensor will be a microfluidic cell. The sensor element of architecture i and ii will be disposable. Architecture iii will be a reusable transmission, total internal reflection, or reflection-based setup, with an active sensor element integrated at the tip of a co-parallel NIR and THz waveguide. In WP3, the system will be integrated with active structures (sources and receivers) in order to carry out benchmarking applications. To verify the capabilities of the system we focus on life-science-relevant substances such asvitamins in oils, sugars in water and also more complex substances. Analytical modelswill be implemented in order to discriminate several mixtures of lifescience-relevant substances. The technologies developed in this project will have large potential for further sensor technologies and integrated NIR & THz systems. The project will be carried out in a collaboration between the Terahertz Devices and Systems Laboratory of TU Darmstadt (Sascha Preu) with profound experience in THz spectroscopy and dielectric THz waveguides and the TH Ostwestfalen-Lippe (Oliver Stübbe) with a long-term background in additive manufacturing of optical components and in optical communication and sensor systems.

• DFG Programme: Research Grants