Dielectric metasurfaces for surface enhanced Raman spectroscopy

Černigoj, Jernej (author), Mertelj, Tomaž (mentor)

I present the use of high refractive index dimers for the realisation of a surface enhanced Raman spectroscopy substrate. The use of low loss dielectric materials is favourable to metallic ones because of their lower light absorption and consequently much lower heating of the substrate. By combining different mechanisms of field enhancement we can overcome the main weakness of dielectric dimers: a low enhancement factor compared to the plasmonic ones. Results of finite element method simulations for two designed structures are presented. The first structure employs a gold mirror for additional field enhancement, while the second one is adapted for easier fabrication. The enhancement factors and absorption of both structures are compared to the plasmonic and other dielectric substrates.

• Language: English
• Keywords: Surface enhanced Raman spectroscopy, enhancement factor, metasurface, Mie resonances, surface lattice resonances, finite element method simulations
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FMF - Faculty of Mathematics and Physics
• Year: 2019
• PID: 20.500.12556/RUL-111131
• COBISS.SI-ID: 3373412
• Publication date in RUL: 25.09.2019

Secondary language

• Language: Slovenian
• Title: Dielektrične metapovršine za površinsko ojačeno Ramanovo spektroskopijo

Abstract

V tem magistrskem delu predstavim uporabo parov delcev z visokim lomnim količnikom za izdelavo površine za površinsko ojačano Ramanovo spektroskopijo. Uporaba dielektričnih materialov z nizkimi izgubami je v primerjavi s kovinskim materialom primernejša, zaradi manjše absorpcije in posledično manjšega segrevanja površine. S kombinacijo različnih ojačevalnih mehanizmov polja lahko premagamo glavno šibkost dielektričnih parov delcev: to je nizek ojačitveni faktor v primerjavi s plazmonskimi sipalci. Predstavljeni so rezultati simulacij z metodo končnih elementov za dve oblikovani strukturi. Pri prvi uporabimo zlato zrcalo za dodatno ojačenje polja, med tem ko je druga prilagojena za lažjo izdelavo. Ojačitveni faktorji in absorpcija obeh struktur so primerjani s plazmonskimi in dielektričnimi strukturami.

• Keywords: Površinsko ojačena Ramanova spektroskopija, ojačitveni faktor, metapovršina, Mieve resonance, mrežne resonance, simulacije z metodo končnih elementov