Phase-locking of oscillating images using laser-induced spin-polarized pulse TEM

Pulse-mode operation was realized in spin-polarized transmission electron microscopy (SP-TEM) using a laser-driven electron gun with a GaAs-GaAsP strained-layer-superlattice photocathode. TEM images were acquired with a pulsed electron beam with a 5-μs pulse duration. Phase locking of wobbling TEM images was demonstrated using a pulsed beam with a 1-kHz repetition frequency, which matched the image wobbling frequency. It was found that in composite images formed by superimposing 2 × 10(4) separate single-pulse exposures, the amount of image blurring due to wobbling was a linear function of the pulse duration. These results suggest the possibility of pump-probe measurements in SP-TEM using the pulsed electron beam as a probe, allowing nanometer-scale time-resolved spin mapping.