This book explicates the optical controls of antiferromagnetic spins by intense terahertz (THz) electromagnetic waves. The book comprises two key components: (1) the experimental demonstration of the enhancement of a THz magnetic field using a split-ring resonator (SRR) and (2) the control of the direction of magnetization by using the enhanced THz magnetic field to break the symmetry of optically-induced phase transition. These make up the first step leading to future spintronics devices.

In the beginning of the book, the author reviews the basics of the ultrafast laser and...