Imagine a smartphone that can check for spoiled food, detect counterfeit drugs, or even diagnose diseases.
This futuristic vision is becoming a reality thanks to a tiny, powerful sensor developed by researchers at Aalto University in Finland.
The breakthrough technology, described in Science Advances, brings advanced spectral sensing—once limited to bulky, expensive lab equipment—into a compact, affordable form that can fit into everyday gadgets.
Spectral sensing is a technique that identifies materials by analyzing how they interact with light, revealing details far beyond what the human eye can detect.
Traditionally, this technology required large systems using optical components like prisms or gratings.
Now, researchers have created a sensor that uses electrical signals to analyze light, making it small enough to integrate into smartphones, wearables, and other portable devices.
“It’s like training an artist’s eye to distinguish subtle colors,” explains lead researcher Professor Zhipei Sun.
“Our sensor learns to recognize complex light patterns that are invisible to the human eye, offering the same precision as lab-based equipment.”
The key innovation lies in the sensor’s ability to measure light using its electrical responses rather than bulky optical hardware.
During experiments, the sensor identified materials by their luminescence, including organic dyes, metals, semiconductors, and other substances. This makes it useful for a wide range of applications, from health care and food safety to autonomous driving.
The device, which measures just 5 micrometers by 5 micrometers (about 200 times smaller than the width of a human hair), achieves incredible precision.
It can identify thousands of colors with an accuracy of around 0.2 nanometers in wavelength.
This is made possible by a carefully designed optoelectronic interface that allows precise control of electrical signals through voltage adjustments, creating what the researchers call a “multi-dimensional photoresponse.”
During development, the sensor was “trained” by exposing it to a wide range of light colors. Each type of light generated a unique electrical fingerprint, which advanced algorithms then decoded. This enables the sensor to accurately identify materials based on their interaction with light.
“This is a big step toward making advanced spectroscopy available to everyone,” says Fedor Nigmatulin, a doctoral researcher and co-author of the study. “By combining this ultra-compact sensor with intelligent algorithms, we’ve moved closer to creating portable spectrometers for consumer electronics.”
With its small size, powerful performance, and versatility, this groundbreaking chip could soon transform everyday devices, offering tools to improve health, safety, and quality of life at our fingertips.
Source: Aalto University.
