Optical measurement of high electric and magnetic fields

Electric fields are determined by interferometrically measuring the phase difference introduced between light polarized parallel and perpendicular to the electric field. The phase difference is introduced by nitrobenzene in the electric-field volume. Magnetic fields are determined by interferometrically measuring the phase difference introduced between left and right circularly polarized light by Faraday rotational glass placed in the magnetic field. The result of either measurement is a finite fringe interference pattern. The position displacement of the fringes is observed in time using a continuous laser and a streak camera to yield the time behavior of the field or in space using a pulsed laser and photographic film to yield the spatial behavior of the field.