Optical sensor for the vectorial analysis of the plasma induced electric field

Summary form only given. We here present recent developments related to electro-optical (EO) sensors dedicated to vectorial characterization of intense electric (E) field. This technique is based on the Pockels effect, which results in the linear modification of the refractive indices of a crystal, induced by the E-field. A typical EO measurement system involves a pigtailed E-field probe (the transducer itself) and an optoelectronic unit. This latter one feeds optically the transducer. It also ensures the optical treatment of the useful signal (optical modulation) in order to deliver electrical signals proportional to the E-field vector components.This EO system has already demonstrated unprecedented performances: a dynamic range exceeding 120 dB from less than 1 V/m up to more than 1 MV/m, a frequency bandwidth covering more than 9 decades from 30 Hz to several tens of GHz, the adaptation of the measurement both to time-and frequency-domain. Due to the millimeter size of the dielectric transducer, the disturbance on the field to be measured remains very weak. These properties fulfill the requirements of intense E-field assessment. Indeed, measurement within a plasma jet or in the closest vicinity of an electrical discharge has already been demonstrated. Moreover, the analysis includes the actual transient evolution of the each component o, the E-field vector2. Latest advances concern the spatio-temporal characterization of the E-field vector ,or the diagnostic of the plasma source. The field contribution of the ionization potential, together with the plasma itself, are thoroughly investigated. Measurement results have demonstrated that the plasma source behavior can be disrupted by parasitic discharges linked to plasma gas pollution.