The precise identification of substances — from industrial gases to human tissues — could soon stop relying on large, expensive equipment. A European project led by VTT, Finland’s technical research center, is developing a new generation of miniature sensors based on photonics and metalenses that promises to transform environmental, industrial, and medical measurement.
The project, called EPheS (Efficient Photonics for Sustainable Imaging and Sensing), aims to create compact spectral imaging and gas measurement technologies capable of analyzing materials in real time using, among other resources, infrared light. The goal is clear: smaller, more sustainable, and more affordable devices built with readily available, non-toxic materials.
Photonics for a More Circular Economy
EPheS focuses on innovations based on the science of light, photonics, with special attention to spectral and infrared technologies. One of its main objectives is to improve how dangerous gases are detected, industrial processes are monitored, and the safety of food and pharmaceuticals is verified — not to mention applications in medical diagnosis, such as tissue analysis.
According to Aapo Varpula, the project’s coordinator and head of the miniature medical systems team at VTT, new technologies for spectral imaging and gas measurement are key to advancing toward a circular economy. They enable reducing the carbon footprint across multiple sectors and, at the same time, increasing the “positive carbon footprint” — the beneficial environmental impact these technologies can have by optimizing processes and reducing waste.
The 3-year project, launched at the beginning of 2025, is part of the Chip Zero ecosystem driven by Applied Materials. Its total budget amounts to €4.2 million, and it brings together four companies and two research institutions: VTT, the University of Tampere, Vaisala, Gasera, Schott Primoceler, and Applied Materials.
From Large Equipment to Miniaturized Sensors
Traditionally, precise gas measurement or hyperspectral imaging required bulky, costly, and often specialized equipment for a single type of compound. EPheS aims to challenge this model by combining technologies that are quite unusual together:
- Metaoptic and metalenses
- Adjustable spectral filters based on MEMS (Microelectromechanical Systems)
- Integrated optical systems for long-wave infrared (LWIR)
The approach is ambitious: to combine metalenses and tunable infrared filters in compact systems capable of spectral gas detection and hyperspectral imaging with high sensitivity.
Metalenses are flat, nanostructured lenses that can replace traditional optics. By manipulating light through nanometric-scale structures, they enable the design of much simpler, lighter, and more resource- and cost-efficient systems. In Finland, metaoptics has rarely been used in industrial applications so far, so this project opens a new field in the long-wave infrared spectrum.
More Eco-Friendly Materials and Smarter Sensors
One of EPheS’s core principles is sustainable materials. Instead of relying on traditional, expensive, rare, or potentially toxic infrared compounds, the project uses silicon and other widely available, non-toxic materials. This reduces dependence on critical raw materials and facilitates scalable solutions.
The new tunable LWIR filters, manufactured using MEMS technology, are based on miniaturized Fabry-Pérot interferometers. Practically, they are constructed with optical membranes separated by a small air gap. A layered stack including an ultra-thin silicon membrane allows efficient operation within the long-wave infrared band.
Compared to conventional solutions — large, costly, and often limited to a single gas — these tunable components enable:
- Detection of multiple gases with a single device.
- Size and cost reduction of equipment.
- More versatile and adaptable gas measurement systems.
When Light Becomes Sound: Photoacoustic in Action
Developing photonic technologies allows gases and materials to be analyzed in real time, with high sensitivity and without interference from other compounds. They use methods like infrared spectroscopy and photoacoustic technique.
In the photoacoustic approach, the gas is introduced into a measurement chamber and illuminated with infrared light. When the gas absorbs this radiation at a specific wavelength, an acoustic signal is generated. This signal only appears if the gas present matches the “pattern” to which the wavelength has been adjusted, making it a sort of unique sound signature for each compound.
The gas sensors and equipment being developed utilize microfabricated tunable LWIR filters, which allow dynamic wavelength switching. This enables identification of different gases without needing a dedicated device for each one.
From Industry to Operating Room: A Wide Range of Applications
The potential scope of EPheS technologies is broad:
- Environmental monitoring and detection of dangerous gases, critical for industrial safety and environmental protection.
- Green energy initiatives, where precise measurement of emissions and processes is vital.
- Food safety and pharmaceuticals, with rapid analysis of raw materials and finished products.
- Medical diagnosis, for example, through spectral analysis of tissues or fluids.
By miniaturizing and reducing the cost of these systems, the project aims to make tools that currently are only found in large laboratories or specialized facilities accessible for production lines, warehouses, hospitals, or even portable devices.
Building a National Cluster of Advanced Photonics
EPheS also represents a strategic effort to establish a national cluster of photonics expertise within the Chip Zero ecosystem. Finland seeks to position itself in key technologies such as metaoptics, optical MEMS, atomic layer deposition (ALD), and integrated photonic systems.
From Applied Materials, senior scientist Jesse Kalliomäki emphasizes the importance of ALD for achieving high-quality, reliable coatings on advanced optical components. Whether for multiband filters or resistant layers for MEMS, nanometric precision is essential for these technologies to operate stably in real environments.
Similarly, Professor Humeyra Caglayan of the University of Tampere highlights the goal of developing metaoptical components capable of manipulating light with nanometer precision. Within EPheS, their focus is on designing metalenses and metasurfaces that enable advanced imaging and sensing functions in compact, integrated formats.
From Design to Cleanroom: Next Steps
According to VTT, collaboration among partners has started strongly. The consortium is in the design phase, with component fabrication scheduled to begin in the VTT cleanroom for 200mm wafers around the turn of the year. Following this, the next milestone will be demonstrating these new infrared technologies in specific applications, from gas sensors to hyperspectral imaging systems.
If all goes according to plan, in a few years we may see markets flooded with more compact, sustainable, and affordable instruments capable of identifying substances with infrared light and metalenses, contributing to more efficient industry and more precise medicine.
Frequently Asked Questions About the EPheS Project and Metalenses
What is a metalens, and how does it differ from a traditional lens?
A metalens is a flat lens made of nano-structures that control light at the nanometric scale. Unlike conventional lenses, which are thick and curved, a metalens can be practically flat and much thinner. This allows for the design of lighter, more compact, and more material- and cost-efficient optical systems, crucial for sensors integrated into small devices.
What practical applications will sensors based on metalenses and infrared photonics have?
The sensors being developed in EPheS are intended to detect gases and analyze materials in real time. They can be used to monitor industrial emissions, detect hazardous gases, improve quality control in food and pharmaceuticals, and support medical applications like tissue analysis. Their compact and tunable nature makes integration into production lines, robots, portable devices, and clinical equipment easier.
Why are these technologies considered more sustainable than current measurement systems?
The project emphasizes using abundant, non-toxic materials like silicon instead of costly, rare, or potentially hazardous infrared compounds. Miniaturization reduces material use and often energy consumption. Moreover, by enabling more precise, real-time measurements, these tools can optimize industrial processes and reduce waste, supporting a circular economy.
Who are the participants in the EPheS project, and what is Finland’s role?
EPheS is led by VTT, Finland’s technical research center, with the University of Tampere and four companies: Applied Materials, Vaisala, Gasera, and Schott Primoceler. Finland provides expertise in photonics, MEMS, and advanced manufacturing, utilizing infrastructure like 200mm wafer cleanrooms and capabilities in metaoptics and atomic layer deposition to develop next-generation optical components.
Sources:
• VTT Info release about the EPheS project (Efficient Photonics for Sustainable Imaging and Sensing).
via: prnewswire