Remote access to electrical conductivity by charge attachment from an ambient pressure plasma

A technique for investigating the electrical conductivity of condensed matter based on softly attaching charge carriers from a plasma to the front side of a sample is presented. The attachment of the charge carriers induces an electric surface potential and consequently charge migration inside the sample which is in contact with a single metal electrode at the backside. The measurement of the current allows determining the electrical conductivity of the sample. The plasma employed is generated by focusing femtosecond laser pulses in air at ambient pressure. As a proof-of-principle, we demonstrate the measurement of the ionic conductivity of a D263T glass and its activation energy. The analysis reveals very good agreement with independent previous measurements. The approach presented is operative in positive and negative polarities. It is in principle extendable to a wide range of plasma media and pressures and can thus be expected to be applicable for remote material testing.