title: Elementary-field expansions of genuine cross-spectral density matrices.
abstract: A necessary and sufficient nonnegative definiteness condition for the cross-spectral density matrix (CDM) is derived. It is also shown that this realizability condition allows the expansion of genuine CDMs in terms of recently introduced elementary fields, namely, mean-square coherent beams, and fields with position-independent stochastic behavior. The special case of uniformly polarized electromagnetic Schell-model sources is also analyzed.
authors: Departamento de Optica, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
authors: Rosario
authors: R
authors: Martínez-Herrero
authors: Pedro M
authors: PM
authors: Mejías