Engineers have developed a microscopic spectral sensor capable of identifying a wide range of materials with remarkable precision.
The new microscopic spectral sensor has the potential to revolutionize how we approach healthcare, food safety, and numerous other fields.
Imagine using smartphones that can detect diseases, spot fake medications, or alert users to spoiled food. Spectral sensing is a robust technique used to identify materials by studying their interactions with light, uncovering details that the human eye cannot perceive.
Historically, this technology relied on large and costly systems that were limited to laboratory and industrial settings. However, imagine if this technology could be shrunk down to fit in smartphones or wearable gadgets?
Researchers from Aalto University in Finland have merged compact hardware with advanced algorithms to produce an effective tool that is small, affordable, and able to tackle real-world challenges in sectors such as healthcare, food safety, and autonomous vehicles.
“It’s akin to how artists learn to differentiate between countless subtle colors,” explains Zhipei Sun, the leading professor and researcher. “Our device is ‘trained’ to identify complex light patterns that are invisible to the naked eye, achieving a level of accuracy comparable to that of large sensors found in labs.”
Unlike conventional spectral sensors that rely on sizable optical elements like prisms or gratings, this new sensor differentiates spectral data through its electrical reactions to light, making it perfect for incorporation into compact devices. The researchers showcased its ability to identify materials based on their luminescence, which includes organic dyes, metals, semiconductors, and dielectrics.
“Our pioneering spectral sensing technique simplifies the challenges of material identification and composition analysis,” says Xiaoqi Cui, the lead author of the study who recently defended his PhD thesis at Aalto University. This remarkable innovation merges adjustable optoelectronic interfaces with sophisticated algorithms, paving the way for new applications in integrated photonics and beyond.
During the training process, the device was exposed to various light colors, allowing it to “learn” and create unique electrical patterns for each type of light. These patterns are then interpreted by an intelligent algorithm, enabling the sensor to accurately identify materials and assess their properties based on how they interact with light.
Measuring just 5 micrometers by 5 micrometers — an area 200 times smaller than a human hair’s diameter — the sensor achieves an impressive peak wavelength identification accuracy of approximately 0.2 nanometers, allowing it to differentiate between thousands of colors. Central to this sensor is a precisely crafted optoelectronic interface that allows for accurate control of electrical flow through voltage modifications. This outstanding flexibility enables the sensor to engage with light in various unique ways, creating a “multi-dimensional photoresponse.”
“This work is a significant advancement in making spectroscopic identification accessible to all,” says doctoral researcher and co-first author, Fedor Nigmatulin. “By merging this ultra-compact hardware with intelligent algorithms, we’ve moved closer to developing miniature, portable spectrometers that could ultimately revolutionize consumer electronics.”
With its innovative performance, adjustable design, and adaptability, the research team envisions that this tiny sensor will soon empower everyday devices with advanced spectroscopy features.
The research was published online on January 22nd in Science Advances.
