Single-Shot Multispectral Mid-Infrared Imaging with Incoherent Light via Adiabatic Upconversion

Abstract: Multispectral mid-infrared (2-5 ${μm}$) imaging is a critical capability across science and technology, offering a window into the vibrational and thermal landscape of matter that is inaccessible to visible sensors. It bridges the microscopic world of molecular interactions with macroscopic sensing technologies, with applications in environmental sensing, defense and molecular diagnostics. However, current mid-IR cameras require cryogenic cooling and exhibit 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 practicality. Here, we demonstrate the first single-shot, room-temperature multispectral mid-IR imaging of incoherent thermal light enabled by adiabatic sum-frequency conversion. Our system simultaneously converts the entire (2-5 ${μm}$) region into the visible domain, capturing the image on a Silicon detector with spatial resolution below 20 ${μm}$ and high angular tolerance. We validate full-field imaging using a USAF resolution target and demonstrate spectroscopic contrast imaging in dielectric metamaterials by resolving wavelength and polarization dependent scattering resonances, all achieved without scanning, thermal control, or cryogenic operation. This compact and robust approach bridges the gap between laboratory-grade infrared sensors and scalable Silicon-based detection technologies suitable for real-world deployment.