Multispectral Mid‐Infrared Imaging With Incoherent Light via Adiabatic Upconversion

Abstract

Multispectral mid‐infrared imaging is a critical capability across science, offering a window into the vibrational landscape of matter that is inaccessible to visible sensors. It bridges microscopic molecular interactions with macroscopic sensing technologies, with applications in environmental sensing, defense and molecular diagnostics. However, current mid‐IR cameras require cryogenic cooling and have limited pixel resolution, high cost and restricted spectral access. Optical up‐conversion provides a pathway to overcome these limitations, but existing systems typically rely on narrowband phase matching, mechanical scanning, or angular tuning, limiting imaging speed and feasability. Here, we demonstrate a room‐temperature broadband MIR imaging system based on adiabatic upconversion driven by a Q‐switched pump laser and operating with thermal illumination. The small‐foot‐print system simultaneously upconverts the spectral range to the visible domain, while maintaining a smooth broadband spectral response, all achieved without scanning, thermal control or cryogenic operation, directly recording images on a silicon detector. We present broadband imaging using a resolution target, with spatial resolution below , and spectrally selective imaging of dielectric mid‐IR metamaterials, resolving wavelength‐ and polarization‐dependent scattering resonances. This compact and robust approach bridges the gap between laboratory‐grade infrared sensors and silicon‐based technologies suitable for real‐world deployment.