Radiometric properties of the generalized radiance function as defined in terms of the Wigner function in six-dimensional phase space are considered in connection with the traditional definition of classical radiance and the space–time transport equation of classical radiometry in free space. In the asymptotic limit of short wavelength and sufficient incoherence, we show that the main properties of this generalized radiance function can be attributed to classical radiance in a nonstationary field. In addition, a correction to the transport equation in which the wavelength is finite is derived, and errors in this equation and the energy-conservation law of classical radiometry, are estimated.
© 1998 Optical Society of America
(030.1640) Coherence and statistical optics : Coherence
(030.5620) Coherence and statistical optics : Radiative transfer
(030.5630) Coherence and statistical optics : Radiometry
(030.6600) Coherence and statistical optics : Statistical optics
Kyu Yoshimori, "Radiometry and coherence in a nonstationary optical field," J. Opt. Soc. Am. A 15, 2730-2734 (1998)