Measurement of wall voltage in barrier discharges using an electro-optic nonlinear crystal

The wall voltage in a barrier discharge has been directly measured using an electro-optic crystal, KDP. One of the barriers is made up of a plate of KDP. A wall voltage due to charges accumulated on KDP surface is measured at various discharge conditions from the change of polarization of a laser transmitting through KDP. The value of the wall voltage at applied voltage of 1 kV and Ar gas pressure of 3 Torr is about 120 V. This indicates that the accumulated charge is about 1.1 nC.