1. A method for optically inspecting a sample, the method comprising: illuminating the sample with an incident field; measuring the resulting output field to determine an optical response of the sample; generating measurement parameters that correspond to the measured optical response by performing the following operations: a) searching a database to locate a pre-computed optical response and associated measurement parameters, b) interpolating between pre-computed responses in the database to generate an interpolated optical response and associated measurement parameters, and c) iteratively evaluating a theoretical model to generate a theoretical optical response and associated measurement parameters.