Real time and polarimetric analysis of intense electric field using electro-optic probe
Résumé
We present herein our latest results concerning the comprehensive characterization of the electric (E) field vector obtained thanks to high performances electro-optic (EO) technique. The EO probe, ensuring the absolute measurement of the E field, consists in a millimetre sized optical arrangement and involves only dielectric material. The disturbance of the field to be measured is thus minimized. This sensor is pigtailed and is linked to an optoelectronic unit delivering an analog electric signal directly proportional to one component of the E-field vector. The specifications of the whole setup are as follows:
- dynamic range greater than 120 dB, spreading from lower than 0.05 V/m up to more than
1 MV/m,
- frequency bandwidth covering instantaneously more than 9 decades up to > 60 GHz,
- rejection of the unwanted component of the field vector higher than 50 dB,
These performances are in a complete agreement with the real time and non-interfering E-field analysis and have een used for the characterization of intense pulsed fields, especially associated to dielectric barrier discharges and plasma jets. The real time and
vectorial measurement allows to extract the polarimetric behaviour of the field vector which describes ellipses. These ellipses are driven by the ionizing field and by the temporal dynamics of the ionized particles. A mapping of these ellipses has been performed and the velocity of the ionization wave has been extracted. A lot of experimental results will be presented during the conference.