Compact cryogenic Kerr microscope for time-resolved studies of electron   spin transport in microstructures
  A compact cryogenic Kerr microscope for operation in the small volume of high-field magnets is described. It is suited for measurements both in Voigt and Faraday configuration. Coupled with a pulsed laser source, the microscope is used to measure the time-resolved Kerr rotation response of semiconductor microstructures with ~1 micron spatial resolution. The microscope was designed to study spin transport, a critical issue in the field of spintronics. It is thus possible to generate spin polarization at a given location on a microstructure and probe it at a different location. The operation of the microscope is demonstrated by time-resolved measurements of micrometer distance diffusion of spin polarized electrons in a GaAs/AlGaAs heterojunction quantum well at 4.2 K and 7 Tesla. 
P. J. Rizo, A. Pug\v{z}lys, J. Liu, D. Reuter, A. D. Wieck, C. H. van   der Wal, and P. H. M. van Loosdrecht