Light detection and ranging (lidar): introduction.

In this introduction we provide an overview of the papers that were accepted for publication in the special issue on light detection and ranging (lidar). Four of the papers were published in JOSA A, and four were published in JOSA B. They represent different aspects of this important and fast-growing field while showing the relevant state-of-the-art achievements currently existing in the field of lidars in the world of science and engineering.

Nonlinear target count rate estimation in single-photon lidar due to first photon bias.

The use of time-tagging single-photon lidar for high-resolution ranging and backscattered count rate measurements requires special attention to mitigate biases and distortions typically not seen in full-waveform lidar sensors. Specifically, sub-pulse sampling and the presence of non-zero receiver dead-time generates an effect named first photon bias (FPB). FPB manifests itself as an intensity-induced ranging offset, previously documented, and a nonlinear count rate with integrated distribution distortions.

High resolution photon time-tagging lidar for atmospheric point cloud generation.

The application of time-correlated single photon counting hardware and techniques to atmospheric lidar is presented. The results establish the viability of adapting photon time-tagging techniques to atmospheric lidar systems, facilitating high-range resolution (millimeter-level precision) and dynamic system observing capabilities that address the variety of atmospheric scatterers often present in atmospheric lidar profiles. The technique is demonstrated through measurements made by a high repetition rate, low pulse energy, elastic scattering, photon counting lidar.