Widening of the region of coherent interaction of intersecting broad-band optical beams

It is shown theoretically that the region of coherent interaction of intersecting broad-band optical beams can be greatly widened by tilting the coherence layers as a result of spectral dispersion with the aid of a prism or a diffraction grating. The theoretical predictions are confirmed by experiments in which interference fringes were observed for broad-band radiation, including the case when the interference involved 'white' light.