Abstract

When studying the regularities of variations of laser beam parameters, a problem arises to measure the intensity I(ρ, t) in the beam cross section. One of the possible methods of intensity measurement is its reconstruction from the temperature field T(ρ, t) on the target surface The theory of solving of the inverse heat transfer problem and results of numerical experiment for uniform target irradiated by nonuniform laser beam was reported¹ In the case of a thin thermally insulated target the following relationship was obtained, where R is the reflection coefficient; a² and k are the thermal diffusivity and conductivity, respectively; L is the target thickness; Δ_⊥ = ∂/∂x²+ ∂/∂y² is the transverse Laplacian operator Deriving algorithms for this equation we use the difference procedure For decreasing of the effect of random errors we performed filtration of initial data. A simple and effective filter that ensures satisfactory accuracy is the convolution of initial data with a stabilizing function sinc(x) = sin (æ_max x)/π x, æ_max ≈ 2 cm^–1

© 1996 IEEE