The effect of strongly nonreciprocal reflected phase behavior on waveguiding structures containing antiferromagnets

• Published in: Journal of magnetism and magnetic materials Vol. 555; p. 169329
• Main Authors: Silva, V.B., Dumelow, T.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.08.2022; Elsevier BV
• Subjects: Antiferromagnet; Antiferromagnetism; Damping; Low temperature; Magnons; Optical switching; Terahertz; Wave propagation; Waveguide; Waveguides; Antiferromagnet; Waveguide; Terahertz
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2022.169329

We investigate how nonreciprocal waveguiding structures using antiferromagnets in the terahertz range should be possible within the magnon reststrahl region of such materials. Application of a external magnetic field should make these structures nonreciprocal. In particular, we relate this nonreciprocity to strong nonreciprocity in the phase of radiation reflected off an antiferromagnet at oblique incidence. We confirm the effect using simulations for a copper–vacuum–MnF2 waveguide structure at low temperature, and show that only a small applied field is necessary to induce nonreciprocal propagation in the waveguide. We consider how such a waveguide may be used as a two-way optical switch or a reversible optical diode, and show how damping effects may be minimized. •Nonreciprocal phase change can occur on terahertz reflection off antiferromagnets•Only small applied magnetic fields are required.•One-way propagation in waveguides can be induced based on this principle•The effect can be used for two-way optical switches•A one-way optical diode can be incorporated using a finite antiferromagnetic block