Imaging light in motion and its application to tracking hidden objects

Abstract

It is well known that light, the fastest entity in the universe, moves at a staggering speed of 300 millions meters per second. The ability to stop its flight on a centimetre scale or lower requires a detector with temporal resolution of around a hundred picoseconds. Freezing light in motion at this scale is a feat worth achieving, as it leads to a variety of exciting applications, from observing dynamical light phenomena to measuring distances and depths with high precision, as in LIDAR technology. In the past decades, different technologies have been developed to image light in motion; in this thesis, we propose a new method that exploit a recently-developed single-photon detector technology to capture movies of light in motion at very low intensity levels. We use this method to develop novel imaging applications and detection techniques. In particular, this thesis reports on the observation and study of dynamical light phenomena such as laser propagation in air, laser-induced plasma, propagation in optical fibres and slow light. We also show how the ability to record light in motion can be used to capture light signals scattered from around an obstacle, leading to the ability to locate and track moving objects hidden from view.