New Lens-Free Infrared Camera Reveals Invisible Worlds in 3D

A research team from East China Normal University has created a groundbreaking mid-infrared camera that works without lenses, using a modern update to the centuries-old principle of pinhole imaging. This innovation captures sharp, distortion-free images across long distances, even in extremely low light, while also enabling precise 3D reconstructions.
Published in Optica, the study outlines how the team used powerful laser light to form an “optical pinhole” inside a nonlinear crystal. This crystal not only acts as an aperture but also converts invisible infrared light into visible light, allowing standard silicon sensors to record the image. With this technique, the system achieved a field of view over 6 cm and a depth of field exceeding 35 cm—far greater than traditional infrared cameras.
“Many useful signals are in the mid-infrared, such as heat and molecular fingerprints, but cameras working at these wavelengths are often noisy, expensive or require cooling,” explained research leader Heping Zeng. “We developed a high-sensitivity, lens-free approach that delivers a much larger depth of field and field of view than other systems.” The team also demonstrated advanced 3D imaging. Using ultrafast laser pulses, they reconstructed the shape of a ceramic rabbit with micron-level accuracy, even when the system received as little as 1.5 photons per pulse. In another test, two-snapshot imaging captured depth and size measurements over a 6 cm range without complex timing setups.
Researcher Kun Huang emphasized the real-world impact: “This approach can enhance night-time safety, industrial quality control and environmental monitoring. Because it uses simpler optics and standard sensors, it could make infrared imaging more affordable, portable and energy efficient.”
Although still in proof-of-concept form, the team plans to refine the system, aiming for greater speed, sensitivity, and adaptability. With further development, lens-free nonlinear pinhole imaging could revolutionize night vision, industry, and environmental science.