Coherence and polarization in stationary random electromagnetic fields

Theory of coherence and polarization in stationary random electromagnetic fields is reviewed. Degree of coherence for electromagnetic fields is examined in the space–time domain and the conditions for complete coherence are discussed. The space–time domain correlation matrix is then transformed to the corresponding space–frequency domain quantity, the cross-spectral density matrix, which is then employed in defining the degree of spectral coherence and the coherent-mode representation for partially coherent electromagnetic fields. Theory is then employed in the coherence study of laser resonators. Relations between the degree of polarization and the degree of coherence is briefly discussed.