A STUDY OF THE PROPAGATION OF OPTICAL-SPECTRA USING A WAVELENGTH INDEPENDENT FORMULATION OF DIFFRACTION THEORY AND COHERENCE THEORY

Basic relations in diffraction theory and coherence theory are rederived in spatial coordinates in units of a wavelength for each monochromatic component of the field. It is found that each component behaves identically in these coordinates independent of wavelength. This theory makes it clear that there is an intrinsic spectral shift that always occurs for any deterministic field as it propagates from a region near its sources into the far field. This theory also leads to a set of special conditions under which a partially coherent field has the same spectrum over a plane near its sources and also at every point in its far field. These conditions are believed to be satisfied by the fields radiated by natural thermal sources. Equations are given describing the relationships between the spectra of the source, the field near the source, and the radiation field under a wide range of conditions.