Magneto-optics is the study of how magnetic fields affect the behavior of light in materials. This phenomenon occurs when the presence of a magnetic field alters the polarization, reflection, or transmission of light passing through or reflecting off a material. One common application of magneto-optics is in optical isolators, which allow light to pass in one direction while blocking it in the opposite direction. This technology is essential in laser systems to prevent feedback that could destabilize the laser output.