Deep-elliptical-silver-nanowell arrays (d-EAgNWAs) fabricated by stretchable imprinting combining colloidal lithography: A highly sensitive plasmonic sensing platform

Elliptical metallic nanohole arrays possess much higher transmission and enhanced sensitivity compared with circular nanohole arrays.However,fabricating elliptical metallic nanohole arrays in large area with highly tunable aspect ratio remains a challenge.Herein,a brand-new method combining stretchable imprinting with colloidal lithography is figured out to fabricate deep-elliptical-silver-nanowell arrays (d-EAgNWAs).In this method,large area highly ordered silicon nanopillar arrays fabricated by colloidal lithography were taken as a master to transfer large area polydimethylsiloxane (PDMS) nanohole arrays.Benefit from the high elasticity of PDMS mold,the aspect ratio of d-EAgNWAs achieved can be facilely regulated from 1.7 to 5.0.Through optimization of polarization direction and the structural parameters including nanowell depth,aspect ratio,and hole size,the sensing performance of d-EAgNWAs was finally improved up to 1,414.1 nm/RlU.The best sensing behaved d-EAgNWAs were employed as an immunoassay platform finally to prove their great potential in label-free biosensing.

Polarization distribution in the image of a synchrotron emitting ring around a regular black hole

The polarized images of a synchrotron emitting ring are studied in the regular Hayward and Bardeen black hole spacetimes.These regular black holes carry a magnetic field in terms of gravity coupled to nonlinear electrodynamics.Results show that the main features of the polarization images of the emitting rings are similar in these two regular black hole spacetimes.As the magnetic charge parameter increases,the polarization intensity and the electric vector position angle in the image plane increase in Hayward and Bardeen black hole spacetimes.Moreover,the polarization intensity and electric vector position angle in the image of the emitting ring in the Hayward black hole spacetime are closer to those in the Schwarzschild case.The effects of the magnetic charge parameter on the Strokes Q-U loops are also slightly smaller in the Hayward black hole spacetime.This information stored in the polarization images around Hayward and Bardeen black holes could help understand regular black holes and the gravity coupled to nonlinear electrodynamics.

Highly sensitive deep-silver-nanowell arrays （d-AgNWAs） for refractometric sensing

Large-area deep-silver-nanowell arrays （d-AgNWAs） for plasmonic sensing were manufactured by combining colloidal lithography with metal deposition. In contrast to most previous studies, we shed light on the outstanding sensitivity afforded by deep metallic nanowells （up to 400 nm in depth）. Using gold nanohole arrays as a mask, a silicon substrate was etched into deep silicon nanowells, which acted as a template for subsequent Ag deposition, resulting in the formation of d-AgNWAs. Various geometric parameters were separately tailored to study the changes in the optical performance and further optimize the sensing ability of the structure. After several rounds of selection, the best sensing d-AgNWA, which had a Ag thickness of 400 nm, template depth of 400 nm, hole diameter of 504 nm, and period of 1 ~m, was selected. It had a sensitivity of 933 nm.RIU-1, which is substantially higher than those of most common thin metallic nanohole arrays. As a proof of concept, the as-prepared structure was employed as a substrate for an antigen-antibody recognition immunoassay, which indicates its great potential for label-free real-time biosensing.