NIR - Near-infrared thin-film image sensors

Next-level biometric monitoring
with NIR gets under your skin

At Holst Centre we are at the forefront of developing large-area image sensors that create innovative medical detectors for visible light and X-rays. By extending this technology platform into near-infrared (NIR) we are opening up a whole new range of innovative biomedical monitoring and detection applications.

By changing the chemical compound of the light-absorbing layer of our optical sensors, we are able to move beyond the visible light, into near-infrared territory with wavelengths of up to 1000 nm. This light passes through skin, but is absorbed by haemoglobin in the blood, making it ideal for vein detecting.

To demonstrate the potential of large-area NIR sensors, we created a prototype image sensor for contactless biometric security through vein pattern detection. The pattern of veins in your hand is as unique to you as your fingerprint, and unlike your fingerprint, it can't be copied. But reading that unique pattern required the ability to see into your hand.

Innovative medical applications

Having demonstrated the potential of large-area NIR sensors for vein detection, we continue to refine the technology and push its sensitivity deeper into the NIR region. We created solution-processed organic photodetectors with enhanced light sensitivity in the near infrared region of the optical spectrum (650-1100nm). When integrated in large area arrays these were used to image vein patterns and monitor health parameters, such as optical heart rate (PPG), oxygen saturation and pulse wave velocity. Vein detection offers a whole new range of monitoring applications, including large area oxygen saturation (SpO2) measurements for monitoring skin grafts or arterial disease due to diabetes, conformable optical brain scans, or cuffless blood pressure monitoring.

Our NIR-sensitive thin film imager technology makes for extremely thin and flexible sensors that allow for comfortable, continuous and unobtrusive patient monitoring with great precision. Our work on vein pattern detection was awarded with a Distinguished Paper Award at the SID Display Week 2020.