Authors

Gwenaël Gaborit, Jean Dahdah, Frédéric Lecoche, Pierre Jarrige, Yann Gaeremynck, Eric Duraz, and Lionel Duvillaret

Abstract

Pulsed power and intense electric field now apply to a large variety of domains for which the need of in situ nonperturbative measurements remains a challenge. The main requirements that sensors should fulfill for that purpose are nonmetallic composition, small size, ultrawide bandwidth, compatibility with liquids and gases, possibility for remote measurements at long distances, true vectorial (field direction) time-domain measurements, capability of measuring electric fields up to the electric breakdown of air, and a large dynamic range. Obviously, all these requirements cannot be achieved by a unique sensor. However, most of them are fulfilled by pigtailed electrooptic (EO) sensors. In this paper, after recalling the principle of the EO effect and its use for electric field measurement, we deal with the measurement linearity and selectivity of the EO sensor. Associated with the nonperturbative behavior of the EO sensor, the measurement dynamics of EO sensors exceeds 100 dB. Furthermore, EO sensors present an intrinsic flat response from quasi d.c. (10 Hz) up to a few tens of gigahertz. Thanks to their composition of high dielectric strength materials and their optical pigtail, EO sensors are completely immune to the electromagnetic environment except on a very small volume (10 mm³) corresponding to the transducer element of the sensor. This leads to a very high spatial resolution. We finally illustrate the capabilities of this technology through in situ measurement of the electric discharge transients and vectors.

Introduction

Pulsed electric (E) field measurements require sensors providing intrinsic flat frequency response for ultrawide band (UWB) characterization. While commonly used antennas offer rather good sensitivity and dynamics, they remain bandwidth-limited because of their dimensions and their metallic structure [1], [2]. Moreover, their galvanic wire also makes them sensitive to parasitic electromagnetic radiations. On the contrary, electrooptic (EO) sensors are fully dielectric and allow measurements from quasi d.c. to some 10 GHz, even for single-shot signals (up to about 10 THz when sampling repetitive pulses) [3], [4]…

Reference

IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 41, NO. 10, OCTOBER 2013

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