title: Two-grating diffraction and Lau effect under laser illumination.
abstract: We first describe an unconventional Lau experiment that is performed with a collimated He-Ne laser beam. We then describe an elegant experimental arrangement in which a collimated He-Ne laser beam is gradually rendered spatially incoherent; this demonstrates the evolution of the Lau fringes from the Fraunhofer diffraction pattern of the two gratings in the Lau setup.
authors.forename: K V
authors.initials: KV
authors.lastname: Avudainayagam
authors.forename: S C
authors.initials: SC
authors.lastname: Nayagam