02/07/2021 Colóquio (WEBINAR) Shedding Light on Nonlinear Optics in 2D Layered Transition Metal Dichalcogenides - Anderson S. L. Gomes (Departamento de Física-UFPE)
Shedding Light on Nonlinear Optics in 2D Layered Transition Metal Dichalcogenides
Anderson S. L. Gomes
Departamento de Física-UFPE
2D Layered Transition Metal Dichalcogenides (LTMDs) are bi-dimensional nanostructures consisting of atomically thin monolayers of the type MX2, with M representing a transition metal atom and X a chalcogen atom. Besides the well-known and studied semiconducting MoS2 and WS2, semi-metallic ZrTe2 and metallic NbS2 are examples of 2D LTMDs. In this talk, I shall review the relevant properties of the four above-mentioned nanomaterials, highlight the fabrication methods, and will describe nonlinear optical studies covering a range of excitation regimes and different physical mechanisms explaining the nonlinear optical response. Using CW or CW/ML (>1MHz repetition rate) excitation sources with linearly or circularly polarized light, we show that the intensity dependent refractive changes are thermal in origin, ~10-6cm2/W, and lead to ring formation due to spatial self-phase modulation. Using optical sources with 1kHz repetition rate and 100fs pulse duration, we determined the intensity dependent nonlinear refractive index (~10-16cm2/W) of electronic origin, besides, in some cases, the nonlinear absorption. We also show how ZrTe2 can be used as a scatterer for a colloidal dye-based random laser.