TRIM: Simultaneous Thermometry, Ranging, and Imaging via a Monolithic Metalens.

While metasurfaces offer a pathway beyond the discrete architectures of conventional LWIR systems, physically fusing high-precision thermometry and passive ranging onto a single metalens remains a formidable challenge. Here, we demonstrate a monolithic, dual-focus metalens capable of simultaneous multidimensional sensing. By multiplexing two distinct focal lengths into a single metasurface, the system enables the parallel acquisition of spectral and spatial information. For thermal sensing, we implement a dual-band (9.6 and 10.6 µm) ratiometric method that effectively mitigates target emissivity uncertainty under the gray-body assumption. This approach yields a mean absolute temperature error of 13.58°C (∼3% relative error) and exhibits exceptional linearity (R2 > 0.916) across 100°C-450°C. Concurrently, the dual-focus architecture facilitates passive depth acquisition by capturing differential defocus signatures. A depth retrieval model based on the normalized defocus response establishes a robust linear relationship with inverse depth (R2 = 0.916), with measurement deviations primarily confined within the 95% confidence interval across the 15-25 cm range. Our approach opens a pathway for transitioning from discrete sensors to monolithic, chip-scale intelligent perception platforms, enhancing simultaneous thermometry and ranging for remote targets without compromising diffraction-limited imaging performance.