  For light fields, the coherence in longitudinal direction is governed by both
the frequency spectra and angular spectra they possess. In this work, we
develop and report a theoretical formulation to demonstrate the effect of the
angular spectra of electromagnetic light fields in quantifying their
longitudinal spatial coherence. The experimental results obtained by measuring
the electromagnetic longitudinal spatial coherence and degree of
cross-polarization of uniformly polarized light fields for different angular
spectra validate the theoretical findings.
