Abstract: A two-dimensional image of the voltage distribution across a surface at a large plurality voltage test points of a panel under test is extracted by illuminating the surface with an input beam of optical energy through an electro-optic modulator wherein the modulator is disposed to allow longitudinal probing geometries such that a voltage on the surface of the panel under test causes a power modulation in the optical energy which can be observed through an area optical sensor (a camera) for use to directly produce a two-dimensional spatially-dependent power modulation image directly representative of the spatially corresponding voltage state on the surface of the panel under test. Surface crosstalk is minimized by placing the face of the modulator closer to the panel under test than the spacing of voltage sites in the panel under test. The device may operate in a passthrough mode or in a reflective mode.