Application of a mode-locked laser to holography

A system that uses a mode-locked laser to record double exposure holograms of a rapidly changing object is described. A saturable absorber is used to mode-lock a ruby laser, producing a train of pulses of very short duration. Two of the pulses are selected by rapidly switching a Kerr cell shutter arrangement. When these two pulses are used to produce a hologram of a moving object, an interference pattern results from which information about the object motion can be extracted. Experimental results are presented that show the state of motion of a thin mirror. Some features of the motion, which would be difficult to detect using a system with less time resolution, are clearly visible in the hologram reconstructions.