Magneto‐optical Devices

Abstract The history of magneto‐optical effects is first introduced. Then the types of magneto‐optical effects are described, which include the varieties of the interactions of electromagnetic waves with magnetization or spins in solids. The physical origin of the magneto‐optical effects is phenomenologically discussed. Both magnetic circular/linear birefringence and dichroism, and Void and Cotton–Mouton effects are discussed. Then, some representatives of magneto‐optical materials of transmission (Faraday effect) and reflection (Kerr) types are described. Finally, the applications of magneto‐optical effects are presented, which include the isolators, circulators, modulators, deflectors, magneto‐optical imaging, field sensors, magneto‐optical sensors, and magneto‐optical recording and microwave waveguides. In particular, a recent development of magneto‐optical recording is summarized, which highlights the various novel methods of increasing recording density.