Abstract: The present invention relates to corona charge deposition systems that use High Voltage (HV) amplifiers for precisely controlling corona charge deposition. Some implementations, provide a corona charge deposition system that uses multiple voltage sources to maintain specified voltages applied on several electrodes to precisely control the corona current required to deposit a desired amount of charge on a sample. The HV amplifiers are able to source and sink currents to maintain stable voltages applied on control electrodes in the presence of a higher voltage applied on a needle electrode. The proposed apparatus and method of monitoring multiple signals, controlling multiple voltages, and predicting charge profile deposited on a sample can precisely control charge deposition processes.

Abstract: Methods are disclosed for improving one or more of jitter/timing, signal-to-noise ratio, signal integrity, stability, and repeatability of generation and measurement of Second Harmonic Generation (SHG) signals generated by a sample upon illumination by a light beam. The method may use precision hardware to control the generation of SHG signal and synchronize it with the optical detection process to improve the reliability and accuracy of measured SHG signals. A precise measurement of the initial SHG signal (Io) involves accurate temporal alignment between optical excitation and detection of the resulting SHG signal. Various disclosed systems and methods use high-speed Pockels Cell (PC) for controlling incident light, and precision electronics for synchronization.