EAGER: Imaging and sensing through the skin using diffractive networks

This project will conduct basic scientific research toward a new wearable technology that can capture images through human skin using advanced optical layers. Current imaging devices used in research to see through the skin are relatively large, expensive, and not practical for everyday use. This new technology will be lightweight, cost-effective, and wearable. Such compact and power-efficient wearable computational imagers and sensors will be transformative for various applications, including counting of blood cells, implantable optical sensing, and the detection of infections and bacteria through the skin. The research team will also engage in outreach, offering research opportunities for high school and college students and spreading awareness about the potential impact of this innovation through media and public platforms. This project will demonstrate proof of concept of a novel wearable technology platform to image and sense through the skin using diffractive optical networks formed by successive transmissive layers spatially engineered at the sub-wavelength scale. Diffractive optical networks consist of multiple spatially engineered layers designed using deep learning to optimize light propagation for inference. These passive diffractive processors do not need electrical power to run, and they complete their image reconstruction or sensing task at the speed of light propagation through structured diffractive layers, filtering out the optical distortions created by random tissue scattering and absorption while passing the rest of the desired information beneath the tissue onto an imager chip. The system will be designed to operate in the near-infrared (NIR) spectrum, ideal for tissue imaging, and fabricated using high-precision nanofabrication techniques like two-photon polymerization. Testing will involve skin-phantom models integrated with microfluidics to simulate biological conditions, including blood flow. This proposal aims for transformative advancements in wearable tissue imaging technology to democratize wearable diagnostics devices, sensors and in vivo imaging cytometers that operate through the skin. The results of the project will lead to subsequent in vivo animal testing and performance quantification through superficial blood vessels for target cell counting/detection and to miniaturization of the developed technology into a wearable form factor. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.