  A method is presented for the unbiased numerical computation of two-particle
response functions of correlated electron materials via a solution of the
dynamical mean-field equations in the presence of a perturbing field. The power
of the method is demonstrated via a computation of the Raman $B_{1g}$ and
$B_{2g}$ scattering intensities of the two dimensional Hubbard model, in
parameter regimes believed to be relevant to high-temperature
superconductivity. The theory reproduces the `two-magnon' peak characteristic
of the Raman intensity of the insulating parent compounds of high-$T_c$ copper
oxide superconductors and shows how it evolves to a quasiparticle response as
carriers are added. The method can be applied in any situation where a solution
of the equilibrium dynamical mean-field equations is feasible.
