We report on the tunable edge-plasmon-enhanced absorption of phosphorene nanoribbons supported on a dielectric substrate. Monolayer anisotropic black phosphorous (phosphorene) nanoribbons are explored for light trapping and absorption enhancement on different dielectric substrates. We show that these phosphorene ribbons support infrared surface plasmons with high spatial confinement. The peak position and bandwidth of the calculated phosphorene absorption spectra are tunable with low loss over a wide wavelength range via the surrounding dielectric environment of the periodic nanoribbons. Simulation results show strong edge plasmon modes and enhanced absorption as well as a red-shift of the peak resonance wavelength. The periodic Fabry-Perot grating model was used to analytically evaluate the absorption resonance arising from the edge of the ribbons for comparison with the simulation. The results show promise for the promotion of phosphorene plasmons for both fundamental studies and potential applications in the infrared spectral range.

The adhesion layer used in nanofabrication process of metallic nanostructures affects the surface plasmon modes. We characterize the localized surface plasmon resonances (SPRs) of gold nanodisks of various diameters and heights while varying the thickness of the Ti adhesion layers. Scattering, absorption, and extinction coefficient calculations show a significant dependence of the SPR on the size of nanostructures and the adhesion layer thickness. Comparisons of peak resonance wavelengths of different Ti adhesion layer thicknesses indicate a significant red shift and a reduction in amplitude as the Ti thickness increases. A comparison of spectral broadening of the plasmon mode indicates a linear increase with Ti thickness and percentage. In addition, the decay time of the plasmon mode decreased significantly as the adhesion layer size increases. These observations aid in understanding size dependent adhesion layer effects and optimized fabrication of single nanoplasmonic structures.

Metallic, especially gold, nanostructures exhibit plasmonic behavior in the visible to near-infrared light range. In this study, we investigate optical enhancement and absorption of gold nanobars with different thicknesses for transverse and longitudinal polarizations using finite element method simulations. This study also reports on the discrepancy in the resonance wavelengths and optical enhancement of the sharp-corner and round-corner nanobars of constant length 100 nm and width 60 nm. The result shows that resonance amplitude and wavelength have strong dependences on the thickness of the nanostructure as well as the sharpness of the corners, which is significant since actual fabricated structure often have rounded corners. Primary resonance mode blue-shifts and broadens as the thickess increases due to decoupling of charge dipoles at the surface for both polarizations. The broadening effect is characterized by measuring the full width at half maximum of the spectra. We also present the surface charge distribution showing dipole mode oscillations at resonance frequency and multimode resonance indicating different oscillation directions of the surface charge based on the polarization direction of the field. Results of this work give insight for precisely tuning nanobar structures for sensing and other enhanced optical applications.

Infiltrationof apricot (Prunu.s ameniuca L.), Patterson cultivar fruits, which are susceptible to rapid softening, with calcium chloride before processing resulted in definite firming of the canned apricots. Nonsusceptible fruits treated with citrate buffers (pH 3.7) showed dramatic post-process softening.In individual, untreated, early, green fruit, firmness after processing was directly correlated with the bound calcium:citrate ratio. Based on a chelation hypothesis, it was proposed that softening was accelerated when chelators such as organic acid anions removed structural calcium from the cell wall once cell membranes were lysed by heating. INTRODUCTIONCALIFORNIA GROWERS produce over 95% of the U.S.

This work studies how the local current density in a metal-semiconductor-metal photodetector (MSM PD) corresponds to the plasmonic enhancement and therefore affects the overall enhancement of the device. For this type of semiconductor photodetector, the enhancement of incident light due to plasmonic structures is most critical inside the substrate, where the photocurrent is generated. This work develops a relationship between the total device optical enhancement and the current density by considering the average optical enhancement, weighted by the current density in the GaAs layer of a simulated MSM PD. This corresponds to an increased overall current in the device. Effects of the wire and nanoslit widths on the total weighted optical enhancement were studied. The results showed that both widths have a significant impact on the total weighted optical enhancement, improving it by two orders of magnitude when using the smallest possible wire widths and nanoslits.