Two-beam interference experiments in the frequency-domain to measure the complex degree of spectral coherence

Correlation-induced spectral changes in two-beam interference experiments i n the space-frequency domain are used to determine the amplitude and phase of the complex degree of spectral coherence. The spectral modifications are observed either as a shift in the peak wavelength or as sinusoidal modulat ions within the bandwidth of the white light spectrum due to the complex de gree of spectral coherence of the secondary source and the path difference between the interfering beams. These correlation-induced spectral changes w ere analysed using a theoretical model to establish the behaviour of the re al and imaginary parts of the complex degree of spectral coherence over the entire visible region of the spectrum.