Gold dipole nanoantennas embedded in an organic molecular film provide strong local electromagnetic fields to enhance both the nonlinear refractive index (n) and two-photon absorption (2PA) of the molecules. An enhancement of 53× for 2PA and 140× for nonlinear refraction is observed for BDPAS (4,4'-bis(diphenylamino)stilbene) at 600 nm with only 3.7% of gold volume fraction. The complex value of the third-order susceptibility enhancement results in a sign change of n for the effective composite material relative to the pure BDPAS film. This complex nature of the enhancement and the tunability of the nanoantenna resonance allow for engineering the effective nonlinear response of the composite film.
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http://dx.doi.org/10.1038/s41598-017-19066-3 | DOI Listing |
Chaos
January 2025
School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072, China.
Stock trend prediction is a significant challenge due to the inherent uncertainty and complexity of stock market time series. In this study, we introduce an innovative dual-branch network model designed to effectively address this challenge. The first branch constructs recurrence plots (RPs) to capture the nonlinear relationships between time points from historical closing price sequences and computes the corresponding recurrence quantifification analysis measures.
View Article and Find Full Text PDFJ Cogn Neurosci
January 2025
Queen's University, Kingston, Ontario, Canada.
Pupil responses are commonly used to provide insight into visual perception, autonomic control, cognition, and various brain disorders. However, making inferences from pupil data can be complicated by nonlinearities in pupil dynamics and variability within and across individuals, which challenge the assumptions of linearity or group-level homogeneity required for common analysis methods. In this study, we evaluated luminance evoked pupil dynamics in young healthy adults (n = 10, M:F = 5:5, ages 19-25 years) by identifying nonlinearities, variability, and conserved relationships across individuals to improve the ability to make inferences from pupil data.
View Article and Find Full Text PDFSci Adv
January 2025
Institute of Materials Research and Engineering (IMRE), Agency for Science Technology and Research (A*STAR), 2 Fusionopolis Way, #08-03 Innovis, Singapore 138634, Republic of Singapore.
Combining physics with computational models is increasingly recognized for enhancing the performance and energy efficiency in neural networks. Physical reservoir computing uses material dynamics of physical substrates for temporal data processing. Despite the ease of training, building an efficient reservoir remains challenging.
View Article and Find Full Text PDFNanomaterials (Basel)
January 2025
Institute of Clean Energy, Yangtze River Delta Research Institute, Northwestern Polytechnical University, Taicang 215400, China.
Continuous and interrupted low cycle fatigue tests were conducted on nuclear-grade S30408 stainless steel under different stress conditions at room temperature. Vickers hardness testing and microstructure characterization were performed on the fatigue samples with different fatigue states. The evolutionary mechanism of the microstructure defects in materials under fatigue cyclic loading was discussed.
View Article and Find Full Text PDFNanomaterials (Basel)
December 2024
Institute of Manufacturing Engineering, Huaqiao University, Xiamen 361021, China.
HOP-graphene is a graphene structural derivative consisting of 5-, 6-, and 8-membered carbon rings with distinctive electrical properties. This paper presents a systematic investigation of the effects of varying sizes, strain rates, temperatures, and defects on the mechanical properties of HOP-graphene, utilizing molecular dynamics simulations. The results revealed that Young's modulus of HOP-graphene in the armchair direction is 21.
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