Vectorial complex ray model and application to two-dimensional scattering of plane wave by a spheroidal particle.

A vectorial complex ray model is introduced to describe the scattering of a smooth surface object of arbitrary shape. In this model, all waves are considered as vectorial complex rays of four parameters: amplitude, phase, direction of propagation, and polarization. The ray direction and the wave divergence/convergence after each interaction of the wave with a dioptric surface as well as the phase shifts of each ray are determined by the vector Snell law and the wavefront equation according to the curvatures of the surfaces.

Time gate, optical layout, and wavelength effects on ballistic imaging.

A method to distinguish a hidden object from a perturbing environment is to use an ultrashort femtosecond pulse of light and a time-resolved detection. To separate ballistic light containing information on a hidden object from multiscattered light coming from the surrounding environment that scrambles the signal, an optical Kerr gate can be used. It consists of a carbon disulfide (CS(2)) cell in which birefringence is optically induced.

Ultrashort pulse propagation through a strongly scattering medium: simulation and experiments.

Forward light scattering of femtosecond pulses through strongly scattering media is investigated experimentally and numerically. Computations are based on a semi-Monte Carlo method including polarization effects when experiments depend on a Ti:sapphire regenerative amplifier (100 fs, 1 kHz, 1 mJ@ 800 nm). The temporal separation between ballistic light and scattered light is exhibited and used to perform optical depth measurements up to 22 (transmission factor of approximately 10(-10)).

Four-flux model for a multilayer, plane absorbing and scattering medium: application to the optical degradation of white paint in a space environment.

We generalize the four-flux radiative transfer model to the case of a multilayer medium. A concrete application, that of the study of the optical degradation of white paint in a simulated space environment, is presented. The degraded material is decomposed in a damaged layer and in an unaffected layer, and we assume that the degradation is due to a variation Dkappa of the imaginary part of the refractive index in the damaged layer.

Light-transmittance predictions under multiple-light-scattering conditions. II. Inverse problem: particle size determination.

Our aim is to present the application of the hybrid method presented in part I to an inverse procedure to determine particle size and concentration under multiple-scattering conditions. The hybrid method is introduced as a combination of the four-flux method with coefficients obtained from Monte Carlo statistical simulations to take into account the actual three-dimensional geometry. Then an inversion scheme is expanded to enable the application of the hybrid method to particle size and concentration determination.