Banca de DEFESA: MANOEL LEONARDO DA SILVA NETO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : MANOEL LEONARDO DA SILVA NETO
DATE: 19/07/2021
TIME: 14:00
LOCAL: Programa de Pós-Graduação em Ciência de Materiais
TITLE:

EVALUATING OPTICAL NONLINEARITIES AND APPLICATIONS OF PHOTONIC NANOMATERIALS

KEY WORDS:

Nanomaterials, Nonlinear optical properties, Transition Metal Dichalcogenides, Gold Nanoclusters, Graphene Quantum Dots, NaNbO3 Nanocrystals.

PAGES: 207
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

The development of new materials is crucial for applications in the most diverse areas. In this sense, nanomaterials in their diverse types, shapes and sizes, have been synthesized. The miniaturization of materials with at least one dimension smaller than 100 nm, gives rise to interesting properties that significantly increase their applicability. In this work, the nonlinear optical properties of four types of materials were investigated: Transition Metal Dichalcogenides (TMD’s), gold nanoclusters, graphene quantum dots and NaNbO3 nanocrystals, using the Z-Scan technique and Hyper-Rayleigh Scattering (HRS) Interesting properties were found in TMD’s. A high value for the first hyperpolarizability of ZrTe2 monolayers suspended in acetonitrile (ACN) was measured using the HRS technique, and a dipolar behavior for nonlinear polarization was demonstrated. The nonlinear refractive index of ZrTe2 monolayers also suspended in ACN was characterized for the first time. Also, as an application, ZrTe2 monolayers were used as scatterers for Random Laser operation. For NbS2 monolayers suspended in ACN, it was observed a change in the sign of the nonlinear refractive index from negative to positive, and the transition from two-photon absorption (TPA) to a saturation regime with increasing intensity. In MoS2 monolayers, the fifth-order nonlinear refractive index was determined for the first time. In metallic gold clusters with 6 atoms [Au6(GSH)2(MPA)2] suspended in water, the first hyperpolarizability was characterized using the HRS technique. The increase of the hyperpolarizability with decrease of the number of atoms, which had already been reported in the literature, was corroborated in this work. For two different graphene quantum dots, the first hyperpolarizability was determined using the HRS technique; a quadrupolar behavior was demonstrated through polarization measurements. Also for graphene quantum dots, the TPA cross section was characterized by the twophoton absorption-induced luminescence technique. Finally, NaNbO3 nanocrystals with different temperatures of synthesis (ToS) were characterized using the HRS technique. An increase in the first hyperpolarizability with the growth of ToS was observed.

BANKING MEMBERS:
Externa à Instituição - Isabel Cristina dos Santos Carvalho - PUC - RJ
Externo à Instituição - LINO MISOGUTI - USP
Presidente - 1129726 - CID BARTOLOMEU DE ARAUJO
Interno - 1806089 - EDUARDO HENRIQUE LAGO FALCAO
Interno - 2457389 - EDUARDO PADRON HERNANDEZ