Study of a laser echo in an inhomogeneous dust environment with a continuous field Monte Carlo radiative transfer model.

A continuous field Monte Carlo radiative transfer model with an improved semianalytic approach is developed to study laser propagation in an inhomogeneous dust environment. In the proposed model, the photon step size can vary with the mass concentration of the dust environment. Additionally, the scattering properties of the dust particles are calculated with the T-matrix method and the T-matrix scattering phase function is applied to the Monte Carlo simulation with a rejection method. Using this model, the influences of the particle sizes and shapes on the backscattering properties are studied. Finally, the laser echoes simulated by our proposed model are compared with those of traditional Monte Carlo method and experimental results. Different mass concentration distributions indeed influence the simulated laser echo. The simulated results (of our proposed model) agree well with the measured data, demonstrating the effectiveness and accuracy of our approach for inhomogeneous media.