Effects of spatial coherence and dispersive diffraction on spectral changes

This paper describes the peak shift in a Gaussian-like spectrum caused by the effects of spatial coherence and dispersive diffraction. The peak shift depends greatly on the ratio of the coherence area A(c) produced by a primary incoherent source to the area pi rho(2) Of a circular aperture in the secondary source plane. The measured results are in reasonably good agreement with the numerical computational results. The peak shift is caused by a mixture of spatial coherence and dispersive diffraction in the region 0<A(c)/pi rho(2)<1. In the coherent limit A(c)/pi rho(2-->infinity), dispersive diffraction is most dominant and results in the maximum peak shift, whereas in the incoherent limit A(c)/pi rho(2) similar to 0 no spectral change takes place.