Sensitive, Nonintrusive,In-SituMeasurement of Temporally and Spatially Resolved Plasma Electric Fields

Abstract

A new technique is reported for in-situ, nonintrusive, and sensitive measurement of plasma electric fields with high spatial resolution (\ensuremath{\lesssim}${10}^{\ensuremath{-}4}$ ${\mathrm{cm}}^{3}$). Fields as small as 40 V/cm are measured by spectral resolution of laser-induced fluorescence from Stark-mixed parity levels. The technique is demonstrated by excitation of the $A^{1}\ensuremath{\Pi}\ensuremath{-}X^{1}\ensuremath{\Sigma}^{+}$ band system of BCl, produced in an rf discharge through B${\mathrm{Cl}}_{3}$. The absolute measurement of sheath fields, which has been elusive, is now possible.