Abstract
Investigation of non-stationary optical radiation, by means of a spectrometer or interferometer, results in a signal that is related to a functional of the electric field strength, the so-called radiation functional. The output spectrum of a spectrochronograph (which consists of a grating spectrometer combined with square-law detectors, e.g. a streak camera), depends on a radiation functional of second order in field strength. In the present paper a new general class of second-order radiation functionals is introduced that includes as special cases the time-dependent spectrum and the Wigner distribution function (recently used in treating this problem). Utilizing the aspect of time-ordering in spectral measurement, the suitability of various radiation functionals for the representation of the relationship between the input properties of the radiation and the measured output spectrum is studied. A radiation functional of first order in field strength is also introduced. Making use of a ‘generalized spectrochronograph’, more information (the magnitude as well as the phase of the complex amplitude) about the input signal can be obtained than is possible using an ordinary spectrochronograph.

This publication has 11 references indexed in Scilit: