A streak camera is an instrument for measuring the variation in a pulse of light's intensity with time.
They are used to measure the pulse duration of some ultrafast laser systems and for applications such as time-resolved spectroscopy and LIDAR.
Mechanical streak cameras use a rotating mirror or moving slit system to deflect the light beam.
[1] Optoelectronic streak cameras work by directing the light onto a photocathode, which when hit by photons produces electrons via the photoelectric effect.
[2] A linear detector, such as a charge-coupled device (CCD) array is used to measure the streak pattern on the screen, and thus the temporal profile of the light pulse.