Banca de QUALIFICAÇÃO: VANDEILMA BEZERRA DA SILVA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : VANDEILMA BEZERRA DA SILVA
DATA : 16/08/2022
HORA: 15:00
LOCAL: Google Meet
TÍTULO:

Effects of the Phase Behavior Reflected off Ferrimagnets and Antiferromagnets on Magneto-Optical Structures

PALAVRAS-CHAVES:

Ferrimagnet. Antiferromagnet. Nonreciprocity. Guided Waves. Microwave. Terahertz

PÁGINAS: 50
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Física
RESUMO:

We investigate, through numerical simulations, optical effects associated with non-reciprocity of the phase of the reflected wave, at microwave and terahertz frequencies, in magnetic materials. We show calculations of reflectivity, phase and displacement of the reflected beam, in the absence and presence of damping, considering an external magnetic field of ±0.33 T and radiation obliquely incident at 45° on a YIG ferrimagnet. Although reflectivity is essentially reciprocal in simple reflection, we show how the reflection of a structure formed by air, silicon and YIG shows a highly non-reciprocal reflectivity. We also investigate, through the calculation of dispersion curves, the excitation of guided modes in a waveguide formed by copper, air and YIG. We compared these results with those obtained previously for an antiferromagnetic material in a waveguide formed by copper, vacuum and MnF₂ in the presence of an external magnetic field of +0.01 T, at terahertz frequencies. We observe that the energy flow in the waveguide with YIG can occur in the opposite direction to the corresponding wave vector. This does not occur in the waveguide with MnF₂. Both guides, with YIG or MnF₂, can have the direction of propagation of the energy flow of the tunable guided mode by reversing the signal of the external magnetic field. Additionally, we verified that by inserting a block of MnF2 in a copper, vacuum, copper waveguide, we can block the propagation of light in a certain direction, functioning as an optical diode. The propagation direction of the energy flow in the diode is tunable by reversing the sign of the external magnetic field. Thus, the block acts as a reversible optical diode. We intend to extend these studies to three-dimensional structures, and if possible, experimentally verify the results obtained. In addition to verifying the possibility of negative refraction in YIG.

MEMBROS DA BANCA:
Presidente - 7958 - JOSÉ ALZAMIR PEREIRA DA COSTA
Interno - 635.107.314-68 - IDALMIR DE SOUZA QUEIROZ JÚNIOR - UFERSA
Interno - 1881 - VAMBERTO DIAS DE MELLO