scholarly journals A simple Mie-resonator based meta-array with diverse deflection scenarios enabling multifunctional operation at near-infrared

Nanophotonics ◽  
2020 ◽  
Vol 9 (15) ◽  
pp. 4589-4600
Author(s):  
Majid Aalizadeh ◽  
Andriy E. Serebryannikov ◽  
Ekmel Ozbay ◽  
Guy A. E. Vandenbosch
Keyword(s):  
Near Infrared ◽  
Specular Reflection ◽  
Polarization State ◽  
Diffraction Order ◽  
Spatial Filtering ◽  
Zero Order ◽  
Ultra Wideband ◽  
Wide Angle ◽  
Large Area ◽  
Phase Gradient

AbstractDeflection, a basic functionality of wavefront manipulation is usually associated with the phase-gradient metasurfaces and the classical blazed gratings. We numerically and experimentally demonstrate an unusually wideband and simultaneously wide-angle deflection achieved at near-infrared in reflection mode for a periodic (nongradient), ultrathin meta-array comprising only one silicon nanorod (Mie resonator) per period. It occurs in the range where only the first negative diffraction order and zero order may propagate. Deflection serves as the enabler for multifunctional operation. Being designed with the main goal to obtain ultra-wideband and wide-angle deflection, the proposed meta-array is also capable in spatial filtering and wide-angle splitting. Spatial filtering of various types can be obtained in one structure by exploiting either deflection in nonzero diffraction orders, or the specular-reflection (zero-order) regime. Thus, the role of different diffraction orders is clarified. Moreover, on–off switching of deflection and related functionalities is possible by changing polarization state of the incident wave. The suggested device is simple to fabricate and only requires cost-effective materials, so it is particularly appropriate for the large-area fabrication using nanoprint lithography. Ultra-wideband wide-angle and other deflection scenarios, along with the other functionalities, are promising for applications in optical communications, laser optics, sensing, detection, and imaging.

scholarly journals Multifunctional Gratings for Multiband Spatial Filtering, Retroreflection, Splitting and Demultiplexing Based on C2 Symmetric Photonic Crystals

2021 ◽  
Author(s):  
Andriy E. Serebryannikov ◽  
Diana C. Skigin ◽  
Guy A. E. Vandenbosch ◽  
Ekmel Ozbay
Keyword(s):  
Photonic Crystals ◽  
Specular Reflection ◽  
Diffraction Order ◽  
Spatial Filtering ◽  
Frequency Variation ◽  
Angle Of Incidence ◽  
Reflection Mode ◽  
Negative Order ◽  
Wide Range ◽  
Incident Wave Energy

Abstract The concept of multifunctional reflection-mode gratings based on rod-type photonic crystals with C2 symmetry is introduced and examined. The specific modal properties lead to the vanishing dependence of the first-negative-order maximum on the angle of incidence within a wide range, and the nearly sinusoidal redistribution of the incident-wave energy between zero order (specular reflection) and first negative diffraction order (deflection) at frequency variation that are the key features enabling various functionalities in one structure and functionality merging. The elementary functionalities offered by the studied structures, of which multifunctional scenarios can be designed, include but are not restricted to multiband spatial filtering, multiband splitting, and demultiplexing. The proposed structures are shown to be capable in multifunctional operation in case of an obliquely incident polychromatic wave. The generalized demultiplexing is demonstrated for the case when several polychromatic wavesare incident at different angles. The same deflection properties yield multiband splitting, and merging demultiplexing and splitting functionalties in one functionality, which may contribute to various multifunctional scenarios. The proposed gratings arealso studied in transmissive configuration.

scholarly journals Reflected energy flux anomaly under grazing incidence: the Brewster angle analogy

2019 ◽  
Keyword(s):  
Energy Flux ◽  
Near Infrared ◽  
Specular Reflection ◽  
Grazing Angle ◽  
Diffraction Order ◽  
Grazing Incidence ◽  
Grating Period ◽  
Incident Radiation ◽  
Angle Of Incidence ◽  
High Contrast

The paper presents thorough theoretical and numerical analysis of the anomalies accompanying light diffraction on periodical structures (gratings). We have developed appropriate theoretical approach allowing to consider strong anomalous effects. Obtained results are presented in the form of analytical expressions for the quntities of interest, both diffracted field amplitudes and the outgoing waves energy fluxes. It is proved existence of the fluxes extrema at the specific grazing angle of incidenceб or wavelength. Namely, the specular reflection can be suppressed even for rather shallow gratings up to approximately total suppression.This effect is accompanied by essential energy redistribution between all outgoing waves depending on the grating profile. It is of essence that the energy maxima exist in all nonspecular diffraction orders at the same point (angle, wavelength) as the minimal specular reflectivity. For small period gratings, such that there do not exist other outgoing waves except the specular one, the reflectance minimum is attended by approximately total absorption of the incident radiation. Thus, we show that the grazing anomaly (GA) can be accompanied by redirection of the incident wave energy into nonspecular diffraction channels and into absorption. The results are applicable in the wide spectral region, from visible and near-infrared to terahertz and high-frequency regions for metals and semiconductors with high permittivity. The anomaly considered is well expressed for high electromagnetic contrast of the adjacent media, say, air and metal or semiconductor. Then the high contrast is due to the high value of the metal/semiconductor dielectric permittivity  ,  1 , and the anomaly corresponds to incidence of TM polarized wave. It is shown that the grazing anomaly (GA) is of rather general type and can take place if other than the specular diffraction order experiencies grazing propagation also. This property follows from the results obtained by strict application of the optical reciprocity theorem to the geometry under consideration. The specific case of harmonic relief grating is discussed in detail. It is demomstrated existence of the characteristic inclination, cr a , of the relief inclinatuion for the grating period comparable with the incident radiation wavelength, 1 cr a  , where  stays for the surface impedance,  1  . The condition cr a a , or greater, corresponds to highly expressed GA. The theoretical results are illustrated by numerical applications to gratings on Cu\vacuum (air) interface in THz region. The results obtained can be simply transferred to the TE polarized waves. For this we have to consider the adjacent media with high contrast magnetic properties, i.e., high value of the magnetic permeability  ,  1 . This case is of high interest for nowaday applications in nanophotonics and metamaterials development. As compared with other anomalies GA is attributed to the resonance-type behaviour of the energy flux, not wave amplitudes, the latter change monotonically within this anomaly contrary to the well known Rayleigh and resonance anomalies, where the wave amplitude experiences fast nonmonotonous dependence on the angle of incidence and wavelength.

scholarly journals Wideband, wide-angle coding phase gradient metasurfaces based on Pancharatnam-Berry phase

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Qiqi Zheng ◽  
Yongfeng Li ◽  
Jieqiu Zhang ◽  
Hua Ma ◽  
Jiafu Wang ◽  
...  
Keyword(s):  
Berry Phase ◽  
Wide Angle ◽  
Phase Gradient

Ultra-wideband and wide-angle perfect solar energy absorber based on Ti nanorings surface plasmon resonance

2021 ◽  
Author(s):  
Fengqi Zhou ◽  
Feng Qin ◽  
Zao Yi ◽  
Wei-Tang Yao ◽  
Zhimin Liu ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Solar Energy ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Wide Band ◽  
Ultra Wideband ◽  
Wide Angle ◽  
Successful Development ◽  
Solar Absorber ◽  
Important Field

Solar energy absorption is a very important field in photonics. The successful development of an efficient, wide-band solar absorber will be an extremely powerful impetus in this field. We proposed...

Ultra-wideband and wide-angle linear-to-circular polarizer based on single-layer dielectric substrates

2021 ◽  
Vol 127 (11) ◽  
Author(s):  
Shuangshuang Zhu ◽  
Guodong Zhao ◽  
Zhongming Yan ◽  
Yu Wang ◽  
Hongcheng Zhou
Keyword(s):  
Single Layer ◽  
Ultra Wideband ◽  
Wide Angle ◽  
Dielectric Substrates ◽  
Circular Polarizer

scholarly journals Design and Fabrication of Moth-Eye Subwavelength Structure with a Waist on Silicon for Broadband and Wide-Angle Anti-Reflection Property

Coatings ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 360 ◽  
Author(s):  
He Lin ◽  
Mingzhao Ouyang ◽  
Bingxu Chen ◽  
Qifan Zhu ◽  
Jinshuang Wu ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Incidence Angle ◽  
Structural Parameters ◽  
Diffraction Order ◽  
Wide Angle ◽  
Subwavelength Structure ◽  
Inductively Coupled ◽  
Beam Laser ◽  
Interferometric Lithography ◽  
Rigorous Coupled Wave

Reflection loss on the optical component surface is detrimental to performance. Several researchers have discovered that the eyes of moths are covered with micro- and nanostructured films that reduce broadband and wide-angle light reflection. This research proposes a new type of moth-eye subwavelength structure with a waist, which is equivalent to a gradient refractive index film layer with high–low–high hyperbolic-type fill factor distribution. The diffraction order characteristics of a moth-eye subwavelength structure are first analyzed using a rigorous coupled wave analysis. The moth-eye structural parameters are optimized within the spectral range of 2–5 μm using the finite-difference time-domain method. The experimental fabrication of the moth-eye structure with a waist array upon a silicon substrate is demonstrated by using three-beam laser interferometric lithography and an inductively coupled plasma process. The experimental and simulation results show good agreement. The experimental results show that the reflectivity of the moth-eye structure with a waist is less than 1.3% when the incidence angle is less than 30°, and less than 4% when the incidence angle is less than 60°. This research can guide the development of AR broadband optical components and wide-angle applications.

scholarly journals Chemometric Tools for NIRS and NIR Hyperspectral Imaging

2012 ◽  
Vol 69 (1) ◽  
Author(s):  
Laura M. DALE ◽  
André THEWIS ◽  
Ioan ROTAR ◽  
Juan A. FERNANDEZ PIERNA ◽  
Christelle BOUDRY ◽  
...  
Keyword(s):  
Hyperspectral Imaging ◽  
Near Infrared ◽  
Agricultural Sector ◽  
Spatial Information ◽  
Imaging System ◽  
Agricultural Products ◽  
Chemical Information ◽  
Special Focus ◽  
Large Area ◽  
Analytical Tools

Nowadays in agriculture, new analytical tools based on spectroscopic technologies are developed. Near Infrared Spectroscopy (NIRS) is a well known technology in the agricultural sector allowing the acquisition of chemical information from the samples with a large number of advantages, such as: easy to use tool, fast and simultaneous analysis of several components, non-polluting, noninvasive and non destructive technology, and possibility of online or field implementation. Recently, NIRS system was combined with imaging technologies creating the Near Infrared Hyperspectral Imaging system (NIR-HSI). This technology provides simultaneously spectral and spatial information from an object. The main differences between NIR-HSI and NIRS is that many spectra can be recorded simultaneously from a large area of an object with the former while with NIRS only one spectrum was recorded for analysis on a small area. In this work, both technologies are presented with special focus on the main spectrum and images analysis methods. Several qualitative and quantitative applications of NIRS and NIR-HSI in agricultural products are listed. Developments of NIRS and NIR-HSI will enhance progress in the field of agriculture by providing high quality and safe agricultural products, better plant and grain selection techniques or compound feed industry’s productivity among others.

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