  We present a design and characterization of optically transparent electrodes
suitable for atomic and molecular physics experiments where high optical access
is required. The electrodes can be operated in air at standard atmospheric
pressure and do not suffer electrical breakdown even for electric fields far
exceeding the dielectric breakdown of air. This is achieved by putting an ITO
coated dielectric substrate inside a stack of dielectric substrates, which
prevents ion avalanche resulting from Townsend discharge. With this design, we
observe no arcing for fields of up to 120 kV/cm. Using these plates, we
directly verify the production of electric fields up to 18~kV/cm inside a
quartz vacuum cell by a spectroscopic measurement of the dc Stark shift of the
$5^2S_{1/2} \rightarrow 5^2P_{3/2}$ transition for a cloud of laser cooled
Rubidium atoms. We also report on the shielding of the electric field and
residual electric fields that persist within the vacuum cell once the
electrodes are discharged. In addition, we discuss observed atom loss that
results from the motion of free charges within the vacuum. The observed
asymmetry of these phenomena on the bias of the electrodes suggests that field
emission of electrons within the vacuum is primarily responsible for these
effects and may indicate a way of mitigating them.
