Numerical Calculation and Experimental Study of a Large-Format Streak Tube with High Spatiotemporal Resolution

Large-format streak tubes with high spatiotemporal resolution are essential for ultrafast diagnostic systems, such as inertial confinement fusion (ICF) experiments, compressed ultrafast photography (CUP), and imaging lidar. However, simultaneously achieving a large working area on the photocathode and high spatial resolution remains challenging because off-axis aberrations can significantly degrade imaging performance. In this work, a large-format streak tube based on a spherical electron-optical configuration is designed, numerically analyzed, and experimentally demonstrated. The proposed structure integrates a spherical photocathode, a spherical-slit accelerating electrode, and a spherical phosphor screen to suppress off-axis aberrations and improve spatial-resolution uniformity over a large working area. Three-dimensional electromagnetic simulations show that the streak tube achieves a spatial resolution exceeding 16.2 lp/mm within a 36 mm × 6 mm effective photocathode area, while maintaining a simulated physical temporal resolution better than 4.5 ps. A prototype streak tube was fabricated and experimentally characterized. The measured results demonstrate a photocathode spectral response covering 400–750 nm, a full-area static spatial resolution above 14.25 lp/mm, a magnification range of 0.76–0.86, and a deflection sensitivity of 62.8 mm/kV. The experimental results agree well with the numerical predictions, confirming that the proposed spherical electron-optical design provides an effective approach for achieving large-format detection with high spatiotemporal resolution. This streak tube offers a practical technical route for wide-field ultrafast optical diagnostics and high-precision time-resolved imaging applications.