A spherical electro-optic high-voltage sensor

A spherical electro-optic (EO) crystal is introduced for photonic measurement of pulsed high-voltage fields. A spherical shape is used in order to reduce electric field gradients in the vicinity of the sensor. The sensor is pure dielectric and is interrogated remotely using a laser. The sensor does not require the connection of any conducting components, which results in the highest electrical isolation. The spherical nature of the crystal coupled with the incident laser beam, and crossed polarizers (intensity modulation scheme), automatically produces interference figures. The fringes move with the application of an electric field applied to the EO crystal, and a photodetector senses the pattern movement. The sensor can be made small (e.g. < 3mm diam.) resulting in a large AC bandwidth, (e.g. > 4 GHz). Proof of principle results are presented for the use of a solid sphere (/spl tilde/3 mm diam.) of LiNbO/sub 3/ for measuring pulsed electric and voltage fields.