title: Observation of speckle pattern formation in transparent nonlinear random media.
abstract: We report on the experimental observation of speckle formation from a transparent crystal formed by a random distribution of nonlinear domains. The angular distribution of second-harmonic light generated by a transparent strontium barium niobate crystal is measured for different diameters of the fundamental beam and crystal thicknesses. Distinct manifestations of speckle pattern formation are found in these experiments. By using a theoretical Green's function formalism, we explain the reported observations as a result of the linear interference among the second-harmonic waves generated in all directions by each of the nonlinear domains forming the nonlinear crystal.
authors.affiliation: ICFO-Institut de Ciències Fotòniques, Mediterranean Technology Park, E-08860 Castelldefels (Barcelona), Spain. francisco.rodriguez@icfo.es
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Rodríguez
authors.forename: Can
authors.initials: C
authors.lastname: Yao
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Domínguez-Juárez
authors.forename: Jorge
authors.initials: J
authors.lastname: Bravo-Abad
authors.forename: Jordi
authors.initials: J
authors.lastname: Martorell