Plásmon poláritons de superfície em grafeno sobre um substrato com épsilon próximo a zero

• Autor(a) principal: Alvarenga, Vinicius Tadin
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações do Mackenzie
• Texto Completo: http://dspace.mackenzie.br/handle/10899/24504
• topic: plásmons de Superfície; poláritons de superfície; nanofotônica; materiais 2D; materiais; epsilon near zero.; grafeno; CNPQ::ENGENHARIAS::ENGENHARIA ELETRICA

In this work, a method to facilitate the excitation of surface plasmon polaritons in graphene is proposed and demonstrated by using a substrate with its dielectric fuction close to zero. Silicon carbide was used as the substrate, as its dielectric function its close to zero in the mid infrared region, which is the spectral region in which graphene plasmons can be excited. The use of this kind of substrate for plasmon polariton excitation in graphene has not yet been explored in the literature and is expected to increase the plasmon wavelength, which depends on the dielectric media wherein the 2D material is inserted, facilitating phase matching with incident light. The calculations presented estimate a plasmon wavelength of the order of micrometers, which is one order of magnitude longer than those observed on silicon oxide substrates. A similar increase is observed in the polariton’s effective propagation length. The preparation and characterization of exfoliated and epitaxial graphene samples, both on silicon carbide, are described, as well as a new way of characterizing the real part of the substrate’s dielectric funcion. Scattering-type scanning near-field optical microscopy (s-SNOM) measurements are presented with the intent of detecting plasmonic excitation. The experiments show indications of plasmon polaritons, even though more experiments are need to confirm the theoretical results.