Photoluminescence lifetime imaging of upconverting nanoparticles is increasingly featured in recent progress in optical thermometry. Despite remarkable advances in photoluminescent temperature indicators, existing optical instruments lack the ability of wide-field photoluminescence lifetime imaging in real time, thus falling short in dynamic temperature mapping. Here, we report video-rate upconversion temperature sensing in wide field using single-shot photoluminescence lifetime imaging thermometry (SPLIT). Developed from a compressed-sensing ultrahigh-speed imaging paradigm, SPLIT first records wide-field luminescence intensity decay compressively in two views in a single exposure. Then, an algorithm, built upon the plug-and-play alternating direction method of multipliers, is used to reconstruct the video, from which the extracted lifetime distribution is converted to a temperature map. Using the core/shell NaGdF4:Er3+,Yb3+/NaGdF4 upconverting nanoparticles as the lifetime-based temperature indicators, we apply SPLIT in longitudinal wide-field temperature monitoring beneath a thin scattering medium. SPLIT also enables video-rate temperature mapping of a moving biological sample at single-cell resolution.

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Compressed ultrafast photography (CUP) is an emerging potent technique that allows imaging a nonrepeatable or difficult-to-produce transient event in a single shot. Despite many recent advances, existing CUP techniques operate only at visible and near-infrared wavelengths. In addition, spatial encoding via a digital micromirror device (DMD) in CUP systems often limits its field of view and imaging speeds. Finally, conventional reconstruction algorithms have limited control of the reconstruction process to further improve the image quality in the recovered (x, y, t) datacubes of the scene. To overcome these limitations, this article reports a single-shot UV-CUP that exhibits a sequence depth of up to 1500 frames with a size of 1750 × 500 (x, y) pixels at an imaging speed of 0.5 trillion frames per second. A patterned photocathode is integrated into a streak camera, which overcomes the previous restrictions in DMD-based spatial encoding and improves the system's compactness. Meanwhile, the plug-and-play alternating direction method of multipliers algorithm is implemented to CUP's image reconstruction to enhance reconstructed image quality. UV-CUP's single-shot ultrafast imaging ability is demonstrated by recording UV pulses transmitting through various spatial patterns. UV-CUP is expected to find many applications in both fundamental and applied science.

Single-shot 2D optical imaging of transient scenes is indispensable for numerous areas of study. Among existing techniques, compressed optical-streaking ultrahigh-speed photography (COSUP) uses a cost-efficient design to endow ultrahigh frame rates with off-the-shelf CCD and CMOS cameras. Thus far, COSUP’s application scope is limited by the long processing time and unstable image quality in existing analytical-modeling-based video reconstruction. To overcome these problems, we have developed a snapshot-to-video autoencoder (S2V-AE)—which is a deep neural network that maps a compressively recorded 2D image to a movie. The S2V-AE preserves spatiotemporal coherence in reconstructed videos and presents a flexible structure to tolerate changes in input data. Implemented in compressed ultrahigh-speed imaging, the S2V-AE enables the development of single-shot machine-learning assisted real-time (SMART) COSUP, which features a reconstruction time of 60 ms and a large sequence depth of 100 frames. SMART-COSUP is applied to wide-field multiple-particle tracking at 20,000 frames per second. As a universal computational framework, the S2V-AE is readily adaptable to other modalities in high-dimensional compressed sensing. SMART-COSUP is also expected to find wide applications in applied and fundamental sciences.