THIckness determination via COHERENt TERAhertz detection

What better way to measure thin films than by using a material that is just one atom thick?Society requires materials in user products and infrastructure to function properly, which requires quality control through non-destructive testing, ideally without physical contacts. One particularly important quality test is the thickness determination of thin films, such as car paint, coatings of wind turbines, and different material layers in chips. Low-energy (sub)terahertz light offers several benefits over current techniques for non-destructive thickness determination, which are based on high-energy light or sound. However, current terahertz-based strategies typically require femtosecond lasers, which comes with several technology adoption barriers.In this project, we will develop proof-of-concept demonstrators for contactless, in-situ thickness determination of thin films that do not require femtosecond lasers. Our approach builds on our very recent demonstration of a graphene-based (sub)terahertz photodetector that simultaneously acts as an integrated interferometer. This enables the coherent detection of (sub)terahertz light and the determination of the thickness of thin films placed in the path towards the detector-interferometer. The detector exploits the exceptional properties of hot electrons in graphene, as explored during the ERC StG project “CUHL”. The two main objectives of the project are i) to develop compact, graphene-based proof-of-concept thickness determination demonstrators tailored towards concrete applications, which outcompete existing technologies; and ii) to develop business cases and commercialization strategies for this thickness determination technology. These objectives will be addressed by an experienced and multidisciplinary team consisting of scientists, technologists and business developers. By continuous alignment of the technical performance and socio-economic demands, we expect to optimize value creation for society.