A high speed magneto-optic camera system

Abstract

A 7 nsec exposure time magneto-optic camera system has been constructed for observation of dynamic magnetic phenomena such as occurs in magnetic bubble domain devices. The system employs a super-radiant nitrogen pulsed dye laser as a light source, a polarizing microscope to make the magnetic features visible, and a low light level T. V. system for recording the observed phenomena. The laser pulse is synchronized within 1 nsec to the dynamic magnetic process to be observed and the video system framing rate may be synchronized to the laser so that each recorded video picture is a record of one instant in one dynamic process. A coil assembly and drive electronics were constructed to permit optical access to the magnetic sample and simultaneous application of high frequency (to 1 MHz) rotating magnetic fields (to 60 Oe) required to drive a bubble memory. To make the magnetic domains, which may be smaller than one micron, visible, polarizing optics and the Kerr or Faraday magneto-optic effects are employed. Techniques for optimizing the visibility of magnetic domains in such a system are discussed in detail. The system has made possible the visual observation of high speed magnetic bubble domain phenomena and has contributed significantly to the understanding of bubble domain dynamics. © 1977, SPIE.