Researchers at Aalto University have designed a new microscopic spectral sensor capable of identifying a wide range of materials with exceptional precision. This sensor could reshape how we approach healthcare, food safety, and more.
Researchers at Aalto University hold a tiny chip, designed to accommodate hundreds of ultra-compact spectral sensors. Image Credit: Aalto University / Faisal Ahmed and Andreas Liapis
Imagine a smartphone that can diagnose diseases, detect counterfeit drugs, or alert you to spoiled food. Spectral sensing, a method that analyzes how materials interact with light, reveals details far beyond what the human eye can perceive. Historically, this technology required large, expensive equipment restricted to laboratories or industrial settings. But what if this powerful capability could be miniaturized to fit in the palm of your hand?
Researchers at Aalto University in Finland have done just that, creating a compact, cost-effective spectral sensor that could tackle real-world challenges across diverse fields, from healthcare to food safety and autonomous driving.
It’s similar to how artists train their eyes to distinguish hundreds of subtle colors,’ explains professor and lead researcher. Our device is ‘trained’ to recognize complex light signatures that are imperceptible to the human eye, achieving a level of precision comparable to the bulky sensors typically found in laboratories.
Zhipei Sun, Professor, Aalto University
Unlike traditional spectral sensors that rely on large optical components such as prisms or gratings, this new sensor identifies materials through its electrical responses to light. Its compact design makes it ideal for integration into small devices like smartphones and wearables.
The team demonstrated the sensor’s ability to identify materials based on their luminescence, successfully distinguishing organic dyes, metals, semiconductors, and dielectrics.
Our innovative spectral sensing approach simplifies challenges in material identification and composition analysis.
Xiaoqi Cui, Study Lead Author, Aalto University
During its development, the sensor was exposed to a broad spectrum of light colors, allowing it to “learn” and generate unique electrical fingerprints for each type of light. These fingerprints are then decoded by intelligent algorithms, enabling accurate material identification based on light interactions.
Measuring just 5 micrometers by 5 micrometers—an area 200 times smaller than the cross-section of a human hair—the sensor delivers an impressive wavelength identification accuracy of approximately 0.2 nanometers. This remarkable precision allows it to distinguish thousands of colors.
The sensor’s tunability is powered by a specially designed optoelectronic interface, which precisely controls electrical flow via voltage adjustments. This flexibility creates a “multi-dimensional photoresponse,” enabling the device to interact with light in highly specific ways.
This work is a major step forward in bringing spectroscopic identification to everyone’s fingertips. By integrating this ultra-compact hardware with intelligent algorithms, we have taken a significant step toward miniature, portable spectrometers that could one day transform consumer electronics.
Fedor Nigmatulin, Study Joint First Author and Doctoral Researcher, Aalto University
With its unmatched performance, tunable design, and versatility, the researchers are optimistic that their sensor could soon make advanced spectroscopy accessible in everyday devices.
Journal Reference:
Cui, X., et. al. (2025) Miniaturized spectral sensing with a tunable optoelectronic interface. Science Advances. doi.org/10.1126/sciadv.ado6886