Connecting optical intensities and electric fields using a triple interferometer

We consider the issue of validating the relationship between electric fields and optical intensity as proposed by the classical theory of electromagnetism. We describe an interference scenario in which this can be checked using only intensity measurements and without any other information regarding the details of the arrangement of the associated fields. We implement this experimentally using a triple Michelson interferometer and the results strongly suggest that the method validates the classical relationship between optical intensity and the associated classical field.