Ultra-fast cinematography

In order to break down movements of objects that are too fast to be captured by the eye, optical cinematography has, since its inception [1] , made use of the three dimensions contained in each image (two spatial dimensions and one intensity dimension). The "time base," which provides a regular succession of images, makes it possible to locate the evolution of an object at different moments and to measure its speed and even its acceleration; if the object is deformed, the speed of deformation can also be measured. Transposed to an industrial or laboratory environment, this technique also allows for the measurement of timing and synchronization of events. The dimension of light intensity, when linked to spectral information, can also provide access to the temperature evolution of the objects observed.

The 1950s made analysis times ranging from milliseconds to microseconds accessible for the most sophisticated equipment of the time. Many industrial applications correspond to this time range.

The 1960s saw these optical cameras gradually reach their ultimate resolution limits. They were then replaced by electronic cameras, which offer higher temporal resolution and use double conversion (photon-to-electron and electron-to-photon) in an electronic tube known as an "image converter." The increase in speed achieved through electronic manipulation of the intermediate image provides access to the time domain between microseconds (10 ^-6 s) and picoseconds (10 ^-12 s) for standard cameras, thus opening up a particularly wide range of applications in laboratories.

The most powerful cameras currently achieve a temporal resolution of around a few hundred femtoseconds (1 femtosecond = 10- ^-15 s) in "slit scanning" mode, which is still two to three orders of magnitude above the shortest light pulses currently produced.