Ultrafast oscilloscope

Abstract

An oscilloscope constructed for use in real time resolving an ultrafast voltage signal includes a streak camera having a transmission line photocarthode, a constant light source for illuminating the photocathode, an input coupled to the transmission line photocathode, an accellerating mesh, a pair of sweep electrodes, electron multiplication means, a phosphor screen and a DC high voltage source. In use, the voltage signal to be examined is applied to the input. When the voltage signal on propagating through the photocathode intersects in time and space on the photocathode with the light from the light source, a number of electrons proportional to the intensity of the voltage signal are emitted from the photocathode. These electrons are then accelerated, deflected by the pair of sweep electrodes, multiplied by the microchannel plate and then impinge upon the phosphor screen, creating an optical image having an intensity proportional to the number of impinging electrons. The image on the phosphor screen is recorded by a video camera, processed by a computer and then displayed on a monitor. In another embodiment, the streak camera includes a second photocathode with input signals being applied to either one or both photocathodes. In other embodiments, a photomultiplier tube having a pair of transmission line photocathodes are described.