New Greece partner to strengthen the STIMULUS consortium

STIMULUS is delighted to welcome a new partner, the National Technical University of Athens NTUA to the project team. NTUA joining the team was enabled by a successful grant from the EU Hop-On Facility, which aims to improve the inclusiveness of Horizon Europe by involving more research institutions from widening countries in collaborative projects. The main selection criteria are excellence and added value of the new tasks brought in by the partner.

The STIMULUS consortium develops new non-invasive, accessible, easy-to-use imaging technology that can measure new digital biomarkers from microcirculation for early detection of cardiovascular diseases. For both heart failure and chronic kidney disease patients, it is important to diagnose microvascular dysfunction and monitor the deterioration of microvascular function in early phases of the disease progress. STIMULUS technology, the HEMI-speckle system is an integrated solution of two existing prototypes, a multi-spectral optical sensory system and a speckle plethysmography (SPG) system. Strengthened by the new partner NTUA’s expertise, the technology’s sensing capabilities will be expanded, adding new dimensions to our approach.

Towards real-time, detailed cardiovascular health monitoring

In order to explore pathways for miniaturizing the technology for integration into consumer electronics and wearable devices, NTUA will leverage miniature vertical cavity surface emitting laser (VCSEL) sources to measure blood flow dynamics at various tissue depths, integrating these with the HEMI-speckle imaging system.

VCSELs are known for their compact size, low power consumption, and suitability for wearable tech, with applications ranging from optical communication to eye tracking, 3D sensing and gesture recognition. Self-Mixing Interferometry (SMI), or Optical Feedback Interferometry (OFI), is a fundamental property of laser sources, where external reflections re-entering the laser cavity directly modulate its optoelectronic properties (light output, junction voltage). This enables the light source itself to act simultaneously as the detector, eliminating the need for bulky external optics. Within STIMULUS, this principle is harnessed for non-invasive monitoring of blood flow dynamics across multiple tissue depths, from the superficial layers down to several hundred microns, paving the way for compact, wearable sensing solutions.

The incorporation of SMI-VCSELs into the STIMULUS concept will enhance the technology’s precision and efficiency. This integration will facilitate the development of a miniaturized component that combines sensing and illumination, improving the technology’s performance and enabling its application in consumer electronics and wearable devices like smartwatches and augmented reality eyewear. The ultimate goal is to create a system that offers real-time, detailed cardiovascular health monitoring, making advanced diagnostics both accessible and affordable.