Extraordinary THz transmission through subwavelength semiconductor slits under antiparallel external magnetic fields

• Published in: Applied physics. A, Materials science & processing Materials science & processing, 2011-12, Vol.105 (4), p.819-825
• Main Authors: Liu, Zhifeng, Jin, Guojun
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Collective excitations (including excitons, polarons, plasmons and other charge-density excitations); Condensed Matter Physics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Machines; Manufacturing; Microwave and radio-frequency interactions (excluding resonances); Nanotechnology; Optical and Electronic Materials; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other interactions of matter with particles and radiation; Physics; Physics and Astronomy; Processes; Surface and interface electron states; Surfaces and Interfaces; Thin Films
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-011-6632-5

We theoretically study the resonant transmission of electromagnetic waves at the THz frequencies through subwavelength semiconductor slits under external static magnetic fields. The dispersion relations of the surface plasmon polaritons (SPPs) inside a subwavelength slit are analytically derived. It is found that the SPPs propagating along one direction and its reverse are symmetric when parallel external magnetic fields are applied, but are asymmetric when antiparallel external magnetic fields are applied. The transmission properties of periodic subwavelength semiconductor slit arrays with the antiparallel magnetic fields in each unit cell are investigated by the mode expansion technique. The two significant transmission characteristics are observed: (i) The resonant peaks are redshifted with increasing external magnetic fields; (ii) The transmissions in the two opposite directions through the slit arrays are asymmetric. The origin of the transmission asymmetry is reasonably explained by the magnetic-field induced asymmetric SPP propagation losses.