LIDAR

LIDAR stands for Light Detection And Ranging. LIDAR is a sensor system that uses laser beams to detect and identify objects, much as radar uses radio waves. It is a mostly active sensor system, as targets do not naturally emit laser energy unless using a LIDAR system of their own. Even if a remote laser emission was detected, the data would only give a direction, not a range, since LIDAR measures the return delay from its own emissions to calculate range.

Military applications tend more toward mapping and identification than detection.

LIDAR is a common sensor system in modern science fiction, particular the rebooted Battlestar Galactica and Space: Above and Beyond.