University of Wisconsin-Madison electrical engineers have dramatically improved a semiconductor-based imaging system that makes near-infrared light visible to the naked eye.

Near-infrared is the band of electromagnetic radiation between roughly 750 and 1,400 nanometers; it carries more information than visible light, making it useful in an array of applications, including noninvasive inspection of food, pharmaceuticals, plastics, textiles, semiconductors and other electronics. It is also used in bioimaging, agriculture, communications, machine vision, astronomy and night-vision technology.

The researchers’ system, which operates passively, or without the need for an external power source, could improve the efficiency and portability of near-infrared devices used for these and other emerging applications.

UW-Madison electrical and computer engineering PhD student Rabeeya Hamid led the research, along with Demeng Feng (PhDECE ’24) and Mikhail Kats, a professor of electrical and computer engineering. The team also included collaborators in Dan Congreve’s group at Stanford University and a scientist at Argonne National Lab. The researchers describe the nanoscale enhancements in a paper published in November 2025, in the journal Advanced Functional Materials.

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