Microstructured diamond for optical systems

Press, Federal Ministry of Education and Research, 2017.10. ➜ Microstructured diamond for optical systems – scalable basic technology and use in ATR infrared spectroscopy.

Diamond as a material platform for robust infrared sensors

The so-called ATR sensor technology (ATR, attenuated total reflection) is a long-known infrared optical measurement technology that can be used, for example, to analyze the composition of highly absorbent liquids and, in particular, the presence of pollutants. For example, this spectroscopic method can be used to determine the ingredients of drinks such as beer, fruit juices or soft drinks. So far, however, its use has been limited to the laboratory scale, as the measurement technology is currently not robust enough for industrial use. Especially in the important long-wave infrared range, there is still no sensor solution suitable for industrial use. The targeted use of cost-efficient, nanocrystalline diamond coatings is expected to provide a remedy. Their material properties can be specifically adjusted and optimized by selecting the process parameters. Above all, unlike most other materials, diamond remains transparent even at high temperatures or power densities, especially in the long-wave infrared spectral range. The overall aim of the project is therefore to develop a process technology for the production and micromachining of diamond thin films on various substrate materials and to demonstrate the potential of the technology for applications in optical sensor technology. The production of customized diamond microstructures for optical applications using cost-efficient, wafer-based, semiconductor technology processes is being investigated for the first time.

Infrared spectroscopy for process control in beverage production

The monitoring of liquid media in industry places the highest demands on optical process sensors; they must be highly sensitive and at the same time very robust. Only diamond is able to combine optimum optical properties with the requirements for chemical resistance, abrasion resistance and temperature resistance. Until now, however, diamond has been too expensive for this application. The project aims to solve the cost problem with nanocrystalline diamond coatings that can be produced at low cost and their microtechnical processing. The ATR sensor element is to be designed as an integrated micro-optical element for this purpose. Different variants of micro-integration are being investigated in the group with the aim of developing a micro-integrated sensor for the medium and long-wave spectral range (2.5 – 11 μm wavelength) with a performance comparable to that of today’s laboratory devices.

Following the demonstration in beverage production, a whole range of applications for ATR spectroscopy are to be opened up, from the chemical and pharmaceutical industries to food production and medical technology, once the corresponding low-cost sensors are available.

Source: Federal Ministry of Education and Research, 01.10.2017