Defect Engineered Layer Dependent Nonlinear Optical Response in Two Dimensional Muscovite for Efficient Optical Limiting

TL;DR

This study reveals that 2D muscovite exhibits layer-dependent nonlinear optical responses, with monolayer showing superior optical limiting performance due to quantum confinement and defects, promising for optical limiter applications.

Contribution

It demonstrates for the first time the layer-dependent nonlinear absorption and optical limiting properties of 2D muscovite, highlighting the role of defects and quantum confinement in enhancing TPA.

Findings

Monolayer muscovite has a TPA coefficient of ~6.94x10^5 cm GW^-1.

Optical limiting threshold of monolayer muscovite is 1.46 mJ/cm^2.

Layer-dependent nonlinear optical response is confirmed by experiments and DFT calculations.

Abstract

Light-matter interactions in two-dimensional (2D) materials have gained significant interest due to their distinctive optical and electronic properties. Recently, silicates have emerged as a promising new class of 2D materials, but their nonlinear optical properties remain largely unexplored. In this study, we demonstrate layer-dependent nonlinear absorption and optical limiting capabilities of 2D muscovite using femtosecond laser excitation at 450 nm. The two-photon absorption (TPA) coefficient is highly sensitive to both the number of layers and excitation intensity, increasing markedly from (3.91+/-0.06)x10^3 cm GW^-1 in multilayer structures to (6.94+/-0.17)x10^5 cm GW^-1 in the monolayer limit at a peak intensity of 68 GW cm^-2, highlighting a strong layer-dependent enhancement in nonlinear absorption. Additionally, monolayer muscovite exhibits an optical limiting threshold of 1.46 mJ cm^-2, outperforming graphene and other 2D dichalcogenides. This enhanced TPA arises from quantum confinement and intrinsic lattice defects that facilitate nonlinear optical transitions. Density functional theory reveals that liquid-phase exfoliation disrupts potassium interlayers and induces oxygen vacancies, generating mid-gap electronic states that significantly enhance TPA. These insights open new avenues for designing low-fluence, high-efficiency optical limiters using 2D silicates.