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The electromagnetically induced transparency (EIT)-like effect can be generated in the metamaterial system, but most metamaterial systems are composed of complex and elaborated components (nanostructures) that cannot be removed or replaced easily. In this paper, a graphene grating is used to interact with random metal nanostructures (i.e., individual and connecting nanostructures) to induce the EIT-like effect through two destructive interference excitation pathways. Except for the new induced EIT-like mode, the overall original optical patterns (the shape and intensity of the transmission spectrum) remain unchanged as compared with the single metal nanostructure. Furthermore, due to the optical properties of graphene, the induced EIT-like effect was blueshifted as the Fermi energy of graphene increased. By depositing the graphene grating and the metal nanostructures on a gallium oxide substrate, the EIT-like effect was redshifted as the temperature of the environment increased. Through this study, the EIT-like effect induced by the graphene grating with a random metal nanostructure system was demonstrated by using a simple geometric system; further, the mechanism is easy and can be introduced to many different metamaterial systems to generate the EIT-like effect without changing other optical properties of the original metamaterial system. As such, this opens the door to broader applications for optical communication networks.

Chirality is important in the fields of science and engineering. In comparison to 3D nanostructures, planar nanostructures have a great advantage of easy fabrication. However, previous studies on planar chiroptical effects were limited by the mechanism of enhancing the CD effect. In this paper, a narrow gap is designed between two single planar L-shaped nanorods to facilitate gap plasmon coupling and induce the splitting of the quadrupole mode. This splitting can enhance the circular dichroism (CD) effect. Simulated results also proclaim that CD properties are manipulated by geometrical parameters. The structural design and the new mechanism of the CD effect may provide a novel method for chiral manipulations of light and chiral optical devices.

Chiral plasmonic nanostructures (CPNs) with a strong chiroptical response in visible and near-infrared regions were fabricated with homemade SiO2chiral templates through oblique angle deposition. The circular dichroism spectra of the CPNs showed that the chiroptical response was amplified with increased deposition thickness of silver. Simulation results demonstrated that only the magnetic dipole mode was excited when the deposition thickness was small. Magnetic and electric dipoles emerged and coupled to each other with increased silver deposition thickness. As a result, chiroptical enlargement occurred. This study provides a concise method of fabricating CPNs with a tunable chiroptical response.

Objective: The global epidemic of overweight/obesity in children and adolescents poses a significant public health threat. This longitudinal study aims to investigate the relationship between adolescents’ and their parents’ dietary knowledge and overweight/obesity among adolescents in China. Methods: Data were collected from the China Health and Nutrition Survey (CHNS) in 2004, 2006, 2009, 2011 and 2015. Overweight/obesity was defined according to the International Obesity Task Force (IOTF) cut-off for body mass index (BMI). A set of questions were used to assess the dietary knowledge scores of both adolescents and their parents during face-to-face interviews. Mixed effect models were used to analyze the data. Results: A total of 2035 adolescents aged 12–17 years were included in the data analysis. The mean BMI increased from 19.2 in 2004 to 20.5 in 2015, with a significant increase in the prevalence of overweight and obesity from 6.8% and 0.5% in 2004 to 15.1% and 7.8% in 2015, respectively. Adolescents with medium-score dietary knowledge were less likely to be overweight/obese compared to those with low-score dietary knowledge (OR (95% CI): 0.20 (0.05–0.80), P< 0.05). However, there was no association between parental dietary knowledge and adolescents’ BMI or overweight/obesity (P> 0.05). Additionally, a significant interaction between adolescents’ dietary knowledge score and education in relation to adolescents’ BMI (Pfor interaction < 0.05). Conclusion: Adolescents with medium dietary knowledge were less likely to be overweight/obese than those with low knowledge, but no association was found with parental knowledge. Promoting nutritional education and healthy eating habits is vital to prevent overweight/obesity.

Circular dichroism (CD) of nanostructures is in great demand for applications in biological molecules, photocurrent devices, and photocatalysis. Planar nanostructures can be prepared in a concise manner, and their CD effects have gained much research interest. In this study, tilted zigzag-shaped nanohole (TZSN) arrays are proposed, and the CD effect is studied by the finite element method. A strong resonance occurs in the gap by tuning the charge distributions between adjacent nanoholes. Meanwhile, the CD effect of TZSN arrays is strongly dependent on the structural parameters of TZSN. Results provide a novel method for tuning the CD effects of nanohole arrays on a film.

Circular dichroism (CD) is a signal that characterizes the optical properties of chiral structures. Structures with intense CD signals have valuable applications in molecular chemistry, pharmaceuticals, and biosensing. This work proposes the use of a nanowire to increase the CD signal of crossed nanorods. The separation of resonant wavelengths of transmission under left-handed and right-handed circular polarization incidence (LCP and RCP) increases because the electric interaction between the upper nanorod and nanowire under LCP incidence is different from that under RCP incidence. The increased separation of resonant wavelengths, in turn, enhances the CD signals. In addition, two new CD modes appear, and these modes can be tuned by changing the structural parameters of the proposed structure. The present results will guide the design of plasmonic chiral nanostructures for enhancing the CD signal.

The circular dichroism (CD) effect plays an important role in biological detection, analytical chemistry, and plasmonic sensing. Tilted 3D structures can generate CD signals under normal illumination. However, fabricating tilted 3D structures is complex and expensive. In this study, we fabricate a tilted U-shaped nanostructure (TUSN) on a polystyrene (PS) nanosphere through the glancing angle deposition method. One branch of the U-shaped nanostructure is tilted by raising a sheet of SiO_2 on the PS nanosphere. And the CD signal of the TUSN is enhanced because the phase difference increases with increasing thickness of the SiO_2 sheet. This work proposes a method for fabricating tilted nanostructures and elucidates the mechanism of the CD effect for future research.

Asymmetric transmission (AT) has significant applications in optical polarization control. In this paper, we propose a kind of periodic nanoslit rather than the protruding planar structures, such as G-shaped structure and coupled split-ring resonators, to realize the AT effect. The planar periodic obliquely intersecting nanoslits (OINs) in the gold film, composed of gratings with an infinite length and tilted nanoslits with a finite length, are proposed to realize the AT effect by performing the finite element method. Obvious dips in the AT spectra result from the circular localized surface plasmon resonance around the two terminals of the tilted nanoslits and from the surface plasmon polariton resonances on the film and in the gratings or tilted nanoslits. In addition, the AT effect strongly depends on the geometric parameters of the OINs. The film can be straightly powered on as an in-plane electrical conductor, which broadens its applications in optoelectronic devices. Overall, these results are beneficial in designing devices to achieve AT for polarization transformation.