Subnanosecond time-resolved imaging using a rf phase-sensitive image converter camera

摘要

Abstract: high-speed gated proximity focused multichannel plate image intensifiers allow for a typical gate width of 3 to 5 ns. We have studied an alternative way to accomplish sub-nanosecond time-resolved imaging by operating a gatable proximity focused intensifier as a radio-frequency phase-sensitive camera. In this operating mode, we apply a dc bias voltage between the photocathode and the microchannel plate input that brings the effective intensity transfer function to 50% relative to the `ON' state. Then we add a rf signal to the dc voltage which is phase- locked to the intensity modulation phase of the imaging light source. This phase-locking causes a steady-state image at the intensifier output screen which is recorded using a CCD camera, and stored in an image processor. At least two images are recorded at two different intensifier modulation phase settings relative to the light source modulation phase. Finally, the two images are subtracted, or divided, pixel-by-pixel to create the time-resolved image. The rf phase-sensitive camera has been applied to distance-selective image suppression. We have created black-and-white contrasts for target distance differences of 3.75 cm, i.e., for photon transit time differences of 0.25 ns. The camera also can be used to accomplish lifetime-selective fluorescence suppression. !9