Аннотация:Detailed investigation of ultrashort pulse propagation in biotissue-like media is of high interest currently due to development of biomedical diagnostics tools based on IR femtosecond radiation, such as optical coherence tomography or multiphoton fluorescence microscopy. Applying these techniques for subsurface imaging at depths exceeding 1 mm is significantly restricted by dispersion of probing pulse due to scattering in biotissue and, consequently, by loss of axial resolution and decrease of peak power. In present work we report on a study of femtosecond pulse modification at propagation in biotissue-like media with highly anisotropic scattering (g = 0.9). We have proposed original analytical approach for calculating the pulse structure based on expanding the light field in Neumann series over scattering orders with account of multiple scattering. Small-angle approximation of radiative transfer equation accounting for photon multiple passage effect was employed for calculation of contributions of least scattering orders. The proposed model was applied for study of ultrashort pulse propagation through a plain layer of biotissue-like media. Optical thickness of the sample and scattering anisotropy factor were varied in the range of values typical for biotissues and biotissue-like phantoms. The influence of phase function shape on structure of scattered pulse was investigated. The analysis of the contributions of different scattering orders into pulse profile was performed for various scattering parameters of the medium. Results of analytical study are in good agreement with those obtained by Monte Carlo simulations. The proposed theoretical method reveals new approach for solving the inverse problem in biomedical diagnostics.