Patent ID: 7920263
Filing Date: 2011-04-05
Classification: G01R

Abstract:
1. An apparatus for measuring an electric field while minimally perturbing the electric field being measured, the apparatus comprising: an analyzing stage, including a laser and polarization optics configured to measure the electric field by analyzing a phase modulated laser beam which has passed through an electro optic crystal exposed to the electric field; and a sensor head configured to detect the electric field, wherein the sensor head is optically coupled to the analyzing stage by a first optical fiber lead and a second optical fiber lead, wherein the sensor head includes a plexiglass holder, an electro optic crystal disposed between a first gradient index lens and a second gradient index lens, wherein the electro optic crystal and the first gradient index lens and the second gradient index lens are mounted in the plexiglass holder, wherein the first gradient index lens emits a laser beam transmitted from the analyzing stage to the sensor head that is linearly polarized at a 45 degree angle with respect to an optic axis of the crystal prior to reaching the crystal and propagates along one of an x axis and a y axis of the electro optic crystal, wherein the electric field is applied to the sensor head and upon application of the electric field to the electro optic crystal, the electro optic crystal produces a phase modulation within the laser beam, wherein the second gradient index lens receives the phase modulated laser beam and sends the phase modulated laser beam to the second optical fiber lead, wherein the second optical fiber lead is oriented with one of a fast axis and a slow axis of the second optical fiber lead aligned parallel to the optic axis of the electro optic crystal and the second optical fiber lead transmits the phase modulated beam to the analyzing stage, and wherein the phase modulated laser beam is converted to an electrical signal representing a field strength and a phase of the electric field applied to the sensor head.