High-Resolution Photon Time Tagging for Multifunctional Atmospheric Lidar Studies

A wide breadth of measurements are achievable with photon counting lidar systems, establishing them as multi-functional in their ability to observe a variety of phenomena and properties by a single instrument. However, the desire to observe highly dynamic targets at high resolution often introduces stringent spatial and temporal requirements that cannot be met due to the prescribed nature of most lidar acquisition systems. Time-correlated single photon counting (TCSPC) hardware and techniques have potential for solving the problem of limited resolution by providing extremely high resolution measurements at low computational cost and data overhead. The application of TCSPC to atmospheric lidar will be analyzed and examples presented. This presentation will establish the viability of adapting photon time-tagging techniques to atmospheric lidar systems, facilitating high-range resolution (millimeter-level precision at kHz repetition rates) and dynamic system observing capabilities that address the variety of atmospheric scatterers often present in atmospheric lidar profiles. The adapted techniques enable agility in temporal/spatial resolutions that are driven by parameter accuracy and limited only by the timing resolution of the time-to-digital converter. The results show an ability to preserve backscattered intensities over the full atmospheric profile while generating photon detections at picosecond resolution from a variety atmospheric scatterers. The presented research will emphasize the measurement precisions, associated measurement errors, and applications to existing photon counting lidar systems.