A measure for the twist of Gaussian light is expressed in terms of the second-order moments of the Wigner distribution function. The propagation law for these second-order moments between the input plane and the output plane of a first-order optical system is used to express the twist in one plane in terms of moments in the other plane. Although in general the twist in one 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 between conjugate planes, (ii) adaptation of the signal to the system, and (iii) the case of symplectic Gaussian light.
© 2000 Optical Society of America
(030.5630) Coherence and statistical optics : Radiometry
(070.2580) Fourier optics and signal processing : Paraxial wave optics
(080.2730) Geometric optics : Matrix methods in paraxial optics
Martin J. Bastiaans, "Wigner distribution function applied to twisted Gaussian light propagating in first-order optical systems," J. Opt. Soc. Am. A 17, 2475-2480 (2000)