A family of interconnected analogs of the radiance or specific intensity from classical radiometry are defined for coherent monochromatic wave fields. These generalized radiances are explicitly conserved along rays, regardless of wavelength. Unlike several previous definitions, the new forms are suitable for the description of fields propagating in all directions.
© 2001 Optical Society of America
M. A. Alonso, "Radiometry and wide-angle wave fields. I. Coherent fields in two dimensions," J. Opt. Soc. Am. A 18, 902-909 (2001)