2010/03/25 by Umberto Bertolozzo, Bertolozzo, Umberto, Stefania Residori +3
Physics and Astronomy · #Disordered Systems and Neural Networks (cond-mat.dis-nn) #FOS: Physical sciences #Nonlinear Photonic Systems #Optics (physics.optics) #Quantum optics and atomic interactions #Random lasers and scattering media #cond-mat.dis-nn #physics.optics
paper · pdf · doi:10.48550/arxiv.1003.4931
Soumis à Phys. Rev. Lett.
arxiv created 2010/03/25 · openalex publication_date 2010/03/25 · arxiv updated 2010/04/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04
In a disordered medium with Kerr-type nonlinearity, the transmitted speckle pattern was predicted to become unstable, as a result of the positive feedback between the intensity fluctuations and the nonlinear dependence of the local refractive index. We present the first experimental evidence of speckle instability of light transversally scattered in a liquid crystal cell. A two-dimensional controlled disorder is imprinted in the medium through a suitable illumination of a photoconductive wall of the cell, whereas the nonlinear response is obtained through optical reorientation of the liquid crystal molecules. Speckle patterns with oscillating intensity are observed above a critical threshold, which is found to depend on the scattering mean free path, as predicted by theory.