Silicon metasurface boosts infrared imaging with record conversion efficiency

By AI, Created 10:29 AM UTC, May 20, 2026, /AGP/ – Researchers at Nanchang University developed an ultra-thin silicon metasurface that converts infrared light into visible green light at room temperature, enabling clear imaging without conventional cooled detectors. The advance could make infrared sensing smaller, cheaper and more practical for security, industrial monitoring and consumer devices.

Why it matters: - Infrared imaging usually depends on costly sensors that often need cooling. - The new silicon metasurface shifts infrared scenes into visible light, where standard silicon cameras work well. - The approach could support compact, room-temperature systems for security, automation, industrial inspection and scientific sensing.

What happened: - Researchers at Nanchang University reported a nonlinear silicon metasurface that upconverts infrared light into visible green light. - The work was published in Opto-Electronic Advances under DOI 10.29026/oea.2026.250257. - The team demonstrated direct imaging by projecting infrared patterns onto the chip and capturing clear visible images.

The details: - The device uses paired silicon nanodisks arranged in a one-directional asymmetric unit cell. - The design creates a quasi-bound state in the continuum, or quasi-BIC, resonance. - The metasurface reached a measured quality factor as high as 4000. - That high-Q resonance traps light and increases the local electric field inside the nanostructures. - The device achieved third-harmonic generation efficiency of 3×10-5. - The researchers described that performance as a benchmark for CMOS-compatible silicon metasurfaces. - The imaging demo showed test patterns and custom targets with about 6 μm resolution. - The system worked with a single pump laser at room temperature.

Between the lines: - Conventional infrared detectors face material limits and often require cooling, which adds cost and complexity. - Upconversion imaging can bypass those limits by translating infrared information into the visible spectrum before detection. - Bulk nonlinear crystals helped establish the field, but their size and alignment demands have limited miniaturization. - Metasurfaces offer a flat, integrated platform, but low nonlinear efficiency has been the main barrier to practical use. - The quasi-BIC approach shows that engineered resonances can sharply improve light-matter interaction at the nanoscale.

What’s next: - The research points toward smaller infrared imaging modules that may be easier to mass produce. - The platform could be adapted for autonomous systems, industrial monitoring and future consumer electronics. - Further work will likely focus on turning the lab demonstration into deployable sensing hardware.

The bottom line: - A carefully engineered silicon metasurface has pushed infrared upconversion imaging closer to practical use by combining high efficiency, room-temperature operation and direct visible-light readout.

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