What if your next smartwatch could monitor your hydration, your blood oxygen levels, or even help detect signs of illness—without a single drop of blood? A new invention out of North Carolina State University might be the key to making that possible.
Researchers at NC State have developed an ultra-compact spectrometer that’s so small, it could literally sit on a contact lens. This isn’t science fiction—it’s cutting-edge science packed into a footprint smaller than a grain of rice. And unlike traditional spectrometers, which use prisms or diffraction gratings to break light into its component wavelengths, this one analyzes light in a completely different way.
A New Way to See Light
Conventional spectrometers require physical space to spread light into its spectral components—space that makes them bulky and hard to integrate into wearables or consumer electronics. But the NC State team has eliminated the need for that space-hogging optical setup.
Instead, their design uses a vertical stack of photodiodes, each one sensitive to a slightly different part of the light spectrum. When light hits the stack, each layer absorbs a different slice of it, depending on the wavelength. By measuring the intensity at each layer, the spectrometer builds a fingerprint of the incoming light—all within a tiny chip.
“It’s essentially a 3D spectrometer,” said Professor Michael Kudenov, co-author of the study. “You get all the spectral information you need without physically separating the light. That’s a big deal.”
Tiny, Tough, and Ready for Real Devices
Just as important as its function is how it’s made. The spectrometer was fabricated using CMOS-compatible techniques, meaning it can be manufactured using the same processes used for most modern electronics. That opens the door to easy integration into commercial products—like fitness trackers, smartphones, or diagnostic tools.
Despite its size, the tiny device doesn’t skimp on durability or performance. It’s power-efficient, works well with visible and near-infrared light, and could potentially be tuned for even more precise measurements in the future.
Big Potential in Small Spaces
The real excitement lies in where this tech could go next. Because it’s so small and low-power, it could enable a whole new class of wearable or implantable health sensors. Think smart glasses that monitor UV exposure, smart rings that analyze blood flow, or even contact lenses that track blood sugar levels through the eye.
“Miniaturized spectrometers have been around, but this is pushing the limits,” said co-author Dr. Zhengyuan Zhu. “We’re imagining a world where light analysis is happening passively, continuously, and invisibly in the background.”
The implications go far beyond health tech. Agriculture, environmental monitoring, and even food safety are all fields where fast, on-the-go spectral analysis can be game-changing. And with a spectrometer that’s this compact and scalable, those applications suddenly become a lot more realistic.
Original Story: https://news.ncsu.edu/2025/07/tiny-spectrometer/
