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Light diffusion and localization in 3D nonlinear disordered media

Claudio Conti·Luca Angelani·Giancarlo Ruocco
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Abstract

Using a 3D Finite-Difference Time-Domain parallel code, we report on the linear and nonlinear propagation of light pulses in a disordered assembly of scatterers, whose spatial distribution is generated by a Molecular Dynamics code; refractive index dispersion is also taken into account. We calculate the static and dynamical diffusion constant of light, while considering a pulsed excitation. Our results are in quantitative agreement with reported experiments, also furnishing evidence of a non-exponential decay of the transmitted pulse in the linear regime and in the presence of localized modes. By using an high power excitation, we numerically demonstrate the ``modulational instability random laser'': at high peak input powers energy is transferred to localized states from the input pulse, via third-order nonlinearity and optical parametric amplification, and this process is signed by a power-dependent non-exponential time-decay of the transmitted pulse.

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Claudio Conti, Luca Angelani, Giancarlo Ruocco. 2006-11-09. Light diffusion and localization in 3D nonlinear disordered media. https://doi.org/10.1103/physreva.75.033812

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