Ultra-broadband absorber based on cascaded nanodisk arrays

An ultra-broadband perfect absorber consisting of cascaded nanodisk arrays is demonstrated by placing insulatormetal-insulator-metal nanodisks on insulator-metal film stacks.The absorber shows over 90% absorption in a wavelength range between 600 nm and 4000 nm under transverse magnetic(TM) polarization,with an average absorptivity of 91.5%and a relative absorption bandwidth of 147.8%.The analysis of the electric field and magnetic field show that the synergy of localized surface plasmons,propagating surface plasmons,and plasmonic resonant cavity modes leads to the ultrabroadband perfect absorption,which accords well with the results of impedance-matched analysis.The influences of structural parameters and different metal materials on absorption performance are discussed.Furthermore,the absorber is polarization-independent,and the absorption remains more than 90% at a wide incident angle up to 400 under TE polarization and TM polarization.The designed ultra-broadband absorber has promising prospects in photoelectric detection and imaging.

Bidirectional visible light absorber based on nanodisk arrays

A perfect bidirectional broadband visible light absorber composed of titanium nitride and tungsten nanodisk arrays is proposed.The average absorption of the absorber exceeds 89%at 400 nm–800 nm when light is normally incident on the front-side.Illumination from the opposite direction(back-side)results in absorption of more than 75%.Through the theoretical analysis of the electric and magnetic fields,the physical mechanism of the broadband perfect absorption is attributed to the synergy of localized surface plasmons,propagating surface plasmons,and plasmonic resonant cavity modes.Furthermore,the absorber also exhibits excellent polarization-independence performance and a high angular tolerance of~30°for both front-and back-side incidence.The designed bidirectional broadband visible light absorber here has wide application prospects in the fields of solar cells and ink-free printing.

Rapid quantitative detection of mineral oil contamination in vegetable oil by near-infrared spectroscopy

This study provides a rapid method for quantification of mineral oil in rapeseed oil using near-infrared spectroscopy.The data were processed by direct orthogonal signal correction(DOSC),successive projections algorithm(SPA),partial least squares,and principal component regression(PCR).Good correlation coefficients(R)of 0.998 and root-mean-squared error(RMSE)of 0.005 were obtained,and the DOSC-SPA-PCR model was identified as the optimal method.A satisfactory accuracy with R and RMSE of prediction by DOSC-SPA-PCR of 0.990 and 0.006,was obtained.The results demonstrate that the proposed methodology is a promising method for the rapid quantitative detection of mineral oil in vegetable oil.