Electrooptic measurement of 500-kV pulsed voltages

This paper describes a voltage probe in which the electrooptic Pockels effect is used in the measurement of ultrafast 500 kV pulses. Electrical isolation is provided between the high-voltage and the measurement circuits, and the probe is suitable for use in many applications where more conventional techniques are inapplicable. A special-purpose capacitive voltage divider attenuates the 500 kV to a level acceptable by the crystal of a Pockels cell. The attenuated voltage then modulates light from a laser system passing through the crystal, with the emerging signal being converted into electrical form and fed to a digital storage oscilloscope to provide a very accurate recording proportional to the divider input voltage. Experimental results confirm both the very fast response of the probe and its high-voltage capability.