Extraordinary optical transmission through metallic gratings is a well established effect based on the collective resonance of corrugated screens. Being based on plasmonic resonances, its bandwidth is inherently narrow, in particular, for thick screens and narrow apertures. We introduce here a different mechanism to achieve total transmission through an otherwise opaque screen, based on an ultrabroadband tunneling that can span from dc to the visible range at a given incidence angle. This phenomenon effectively represents the equivalent of Brewster transmission for plasmonic and opaque screens.
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http://dx.doi.org/10.1103/PhysRevLett.106.123902 | DOI Listing |
In this Letter, an omni-directional reflector (ODR) with a thin hybrid dielectric layer (hybrid-ODR) is proposed to enhance the light extraction efficiency (LEE) for inclined-sidewall-shaped AlGaN-based deep ultraviolet light-emitting diode (DUV LED) by inserting a thin diamond with high refraction index into a conventional Al/AlO-based ODR. The three-dimensional finite-difference time-domain (3D FDTD) simulation results show that the LEE of TM-polarized light for the DUV LED with hybrid-ODR is enhanced by 18.5% compared with Al/AlO-based ODR.
View Article and Find Full Text PDFTerahertz time-domain spectroscopy (THz-TDS) at room temperature and standard atmosphere pressure remains so far the backbone of THz photonics in numerous applications for civil and defense levels. Plasmonic microstructures and metasurfaces are particularly promising for improving THz spectroscopy techniques and developing biomedical and environmental sensors. Highly doped semiconductors are suitable for replacing the traditional plasmonic noble metals in the THz range.
View Article and Find Full Text PDFEchelle grating plays an essential role in spectral analysis due to its broadband blaze, high dispersion, and high resolution; however, its absorption properties have received no attention. In this paper, we investigate the effect of parameters including incident wavelength, incident angle, and blaze angle on the absorption properties of the Al echelle grating. Based on calculations by the boundary integral equation method, we observe that the Al grating with a large blaze angle has an absorption enhancement effect on TM-polarized waves, and its intensity increases as the incident angle approaches the pseudo-Brewster angle (maximum absorption over 87%).
View Article and Find Full Text PDFNanotechnology
May 2022
College of Electronic and Optical Engineering & College of Microelectronics, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu, 210046, People's Republic of China.
Bilayer graphene, composed of two layers of monolayer graphene in AB stacking order, has emerged as an alternative platform for atomically thin plasmonic and optoelectronic devices. However, its behavior of photonic spin hall effect remains largely unexplored. In this work, we have theoretically observed that bilayer graphene has two obvious discontinuities but monolayer graphene only has a single step in the spectra of the spin shifts as a function of wavelength at the Brewster angle over the midinfrared frequency range, which enables a possible route of distinguishing monolayer graphene and bilayer graphene.
View Article and Find Full Text PDFIn this Letter, we report the significant enhancement of the photonic spin Hall effect (SHE) in a plasmonic metasurface with ${\rm S}_4$ symmetry. We find that an enhanced SHE of reflected light can occur in both horizontally and vertically polarized incident beams, and the maximum transverse displacement can approach half of the beam waist. Such a large displacement is caused by the non-resonant and near-zero pseudo-Brewster angles in the plasmonic metasurface.
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