Seeing with Invisible Photons: Chip-Scale Technologies Leveraging the Unseen Spectrum
Juejun (JJ) Hu
John F. Elliott Professor of Materials Science and Engineering, MIT
Infrared photons, though invisible to the human eye, are rapidly moving to the forefront of technology, enabling breakthroughs in how we sense, measure, and see the world. In my group, we are developing chip-scale photonic technologies that render the invisible visible, turning tiny chips into powerful tools for sensing and imaging.
On the sensing front, we are creating low-cost, high-performance photonic chips that harness a wide range of optical signatures in the infrared, including Raman scattering, absorption, and refractive index perturbations. These platforms bring laboratory-grade spectroscopy into compact and robust form factors, enabling real-time detection of trace chemicals across diverse industries. Several of these technologies have already moved beyond the laboratory: InSpek is advancing process control in pharmaceutical and agri-food sectors, Lightfinder Inc. is enabling continuous monitoring in energy and chemical industries, and other platforms are addressing urgent challenges such as the detection of heavy metal contamination in water.
In parallel, we are reshaping imaging optics at the chip scale. By transforming chips into flat optical elements, we can achieve performance once thought impossible with conventional lenses. A salient example is our flat fisheye lens, now commercialized by 2Pi Inc., which provides panoramic imaging in a wafer-thin form factor. Building on this foundation, we are extending the concept further, creating optical components that conform seamlessly to curved surfaces and developing active elements that reconfigure their functions on demand through tunable materials.
Together, these advances chart a vision where invisible photons become an accessible and ubiquitous resource. From real-time chemical monitoring to adaptive infrared imaging, chip-scale photonics offers a new sensory frontier — one that blends fundamental science with tangible societal impact.