Space and time variables in optics and holography: recent experimental aspects.

Assuming some parallelism between space and time variables, namely, in the frequency domain, that occurs in the description of optical signals as functions of space or/and space and time, the Abbe theory applies to temporal distributions. The concept of temporal response of any optical system, space invariant, working at the time frequency nu = c/lambda, is then brought out. A method of temporal encoding of optical information is also reported, leading to a consideration of the output of spectroscopic devices as a Temporal Fourier Hologram (TFH). This applies to metrology (interferometry in white light, surface testing, roughness measurements) and image processing by temporal holography. Holograms of extended self-luminous objects have been recorded in white light, and reconstructed images are presented.