PROPAGATION OF MUTUAL INTENSITY EXPRESSED IN TERMS OF THE FRACTIONAL FOURIER-TRANSFORM

The propagation of mutual intensity through quadratic graded-index med ia or free space can be expressed in terms of two-dimensional fraction al Fourier transforms for one-dimensional systems and in terms of four -dimensional fractional Fourier transforms for two-dimensional systems . As light propagates, its mutual intensity distribution is continuall y fractional Fourier transformed. These results can also be generalize d to arbitrary first-order optical systems. Furthermore, the Wigner di stribution associated with a partially coherent field rotates in the s ame manner as the Wigner distribution associated with a deterministic field. (C) 1996 Optical Society of America