Photocathode subdivision calibration for accurate optical exposure time measurement in ultrafast gated image...

This study presents a photocathode subdivision calibration method to improve the accuracy of optical gate length measurement in ultrafast gated image intensifiers. By dividing the photocathode into subregions and calibrating them individually, it decouples the effects of gating pulse width and propagation delay. Experiments show local gate lengths decrease to 195 ± 22 ps from a global value of 332 ps. The method enables both shorter integration times and larger effective detection areas. It also reduces timing errors in time-resolved single-photon imaging, offering a practical approach to optimize ultrafast gated intensifier performance for high-precision optical diagnostics.