论文标题
Pauli-Blocking效应对WSE2薄膜光学限制特性的影响
Impact of Pauli-blocking effect on optical limiting properties of WSe2 thin films
论文作者
论文摘要
我们介绍了使用以不同激发波长为中心的超短脉冲脉冲，对RF分解的WSE2薄膜的厚度依赖性三阶（\ c {hi}^（3））的非线性光学特性。在可见光谱中基于Z Z扫描的研究揭示了Pauli-Blocking在各种厚度的WSE2薄膜中诱导饱和吸收或光学限制的重要作用。该研究还探讨了WSE2薄膜中三阶非线性敏感性（\ c {hi}^（3））中的分散体。有趣的是，任何厚度的WSE2薄膜都表现出描述阳性非线性折射率（N2> 0）的自我关注效果。频率依赖性的非线性吸收（\ b {eta}）与膜的带隙具有不同的相关性，这也通过基于密度功能理论（DFT）的模拟进行了研究。频段结构的改变主要是由于WSE2薄膜中的缺陷诱导的缺陷带，这对光学限制特性具有明显的影响。
We present a detailed investigation on thickness-dependent third-order (\c{hi}^(3)) nonlinear optical properties of RF-sputtered WSe2 thin-films using ultrashort pulses centered at different excitation wavelengths. The single-beam Z-scan based investigation in the visible spectrum reveals the prominent role of Pauli-blocking towards inducing saturable absorption or optical limiting in WSe2 thin-films of various thicknesses. The study also explores the dispersion in third-order nonlinear susceptibility (\c{hi}^(3)) in WSe2 thin films. Interestingly, WSe2 thin-films of any thickness exhibit a self-focusing effect depicting a positive nonlinear refractive index (n2 > 0). The frequency-dependent nonlinear absorption (\b{eta}) bear distinct correlations with the bandgap of the films which is also investigated through density-functional-theory (DFT) based simulations. The alteration in bandstructure is primarily due to the Se-deficiency induced defect bands in WSe2 thin-films which has discernible impact on the optical limiting characteristics.
