Pulsed laser determination of surface electric charge distributions

We propose a new method for high resolution determination of surface electric charge distributions on a dielectric plate. The method is based on the measurement of the variation of the charges induced on a probe when the charges to be measured are being displaced. This local perturbatidn is achieved by means of a laser pulse focused on a thin absorbing target adjacent to the dielectric. By sweeping the laser beam and the probe parallel to the dielectric surface, the distribution can be determined with a resolution better than 0.2 mm. This method could open new approaches in various fields, such as electrophotography, image processing or medical instrumentation.