Ultrahigh-speed photography of picosecond light pulses

Ultrashort (6 psec) green light pulses have been photographed in flight by an ultrahigh-speed camera with a framing time of 10 psec. The green laser pulses are made visible from the side by passing them through a colloidal suspension of milk particles in water, which linearly scatters a small fraction of the light. The green pulses are photographed from a direction normal to the beam by a camera positioned behind a shutter with a 10-psec framing time. The shutter is an ultrafast Kerr cell driven by infrared laser pulses 8 psec in duration. The ultrafast camera is sufficiently fast to "stop" the green pulses but not enough to resolve their detailed shape. As compared to the two-photon fluorescence technique for the display of picosecond light pulses, this new ultrahigh-speed photographing technique is much more sensitive and of much easier interpretation.