Inverse problem of optical properties in one-dimensional semitransparent plane-media with graded index

Based on the conjugate gradient method, the refractive index, absorption and scattering coefficients in one-dimensional graded index media are estimated for the case in which the boundary is subjected to single square pulse. The discontinuous finite element method is extended to solve the direct problem, and then the conjugate gradient method is used to solve the inverse problem by optimizing the objective function. The results show that, by using the time-resolved hemisphere reflectance and transmittance as the test value, the optical property and its distribution in a one-dimensional graded index medium are effectively estimated.