Wigner distribution function applied to twisted Gaussian light propagatingin first-order optical systems

A measure for the twist of Gaussian light is expressed in terms of the seco nd-order moments of the Wigner distribution function. The propagation law f or these second-order moments between the input plane and the output plane of a first-order optical system is used to express the tri ist in one plane in terms of moments in the other plane. Although in general the twist in o ne plane is determined not only by the twist in the other plane but also by other combinations of the moments, several special cases exist for which a direct relationship between the twists can be formulated. Three such cases , for which zero twist is preserved, are considered: (i) propagation betwee n conjugate planes, (ii) adaptation of the signal to the system, and (iii) the case of symplectic Gaussian Light. (C) 2000 Optical Society of America [S0740-3232(00)00712-2] OCIS codes: 070.2580, 080.2730, 030.5630.