Polarization-Insensitive Dielectric Metamaterials Absorber for Near-Unity UV-Light Trapping in Monolayer Graphene

2020 ◽  
Author(s):  
Yinong Xie ◽  
Xueying Liu ◽  
Yijun Cai ◽  
Jinfeng Zhu
Keyword(s):  
Magnetic Resonance ◽  
High Performance ◽  
Uv Light ◽  
Light Trapping ◽  
Normal Incidence ◽  
Resonant Absorption ◽  
Base Layer ◽  
Absorption Enhancement ◽  
Monolayer Graphene ◽  
Polarization Insensitive

Abstract With the aim of improving UV light trapping capability in monolayer graphene, a metamaterials absorber is proposed, which exhibits the polarization-insensitive feature due to the geometrical symmetry. Through the functional combination of magnetic resonance and UV mirror, the absorption of unpolarized UV light in monolayer graphene can reach 99.5% under normal incidence. The absorption enhancement is induced by the magnetic resonance mode between the dielectric silica nanomesh and the calcium fluoride base layer. The effects of geometric parameters on the absorption spectra are systematically investigated. By optimizing the metamaterials design, two distinct resonant absorption peaks can be excited simultaneously for monolayer graphene. Our work paves the way for applications on high-performance UV metamaterials devices by using two-dimensional materials.

scholarly journals Off-Resonant Absorption Enhancement in Single Nanowires via Graded Dual-Shell Design

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1740 ◽  
Author(s):  
Wenfu Liu ◽  
Xiaolei Guo ◽  
Shule Xing ◽  
Haizi Yao ◽  
Yinling Wang ◽  
...  
Keyword(s):  
Refractive Index ◽  
High Efficiency ◽  
Light Trapping ◽  
Resonant Absorption ◽  
Photocurrent Density ◽  
Absorption Enhancement ◽  
Graded Index ◽  
Shell Design ◽  
Transition Modes ◽  
Single Nanowires

Single nanowires (NWs) are of great importance for optoelectronic applications, especially solar cells serving as powering nanoscale devices. However, weak off-resonant absorption can limit its light-harvesting capability. Here, we propose a single NW coated with the graded-index dual shells (DSNW). We demonstrate that, with appropriate thickness and refractive index of the inner shell, the DSNW exhibits significantly enhanced light trapping compared with the bare NW (BNW) and the NW only coated with the outer shell (OSNW) and the inner shell (ISNW), which can be attributed to the optimal off-resonant absorption mode profiles due to the improved coupling between the reemitted light of the transition modes of the leak mode resonances of the Si core and the nanofocusing light from the dual shells with the graded refractive index. We found that the light absorption can be engineered via tuning the thickness and the refractive index of the inner shell, the photocurrent density is significantly enhanced by 134% (56%, 12%) in comparison with that of the BNW (OSNW, ISNW). This work advances our understanding of how to improve off-resonant absorption by applying graded dual-shell design and provides a new choice for designing high-efficiency single NW photovoltaic devices.

scholarly journals Off-Resonant Absorption Enhancement in Single Nanowires via Graded Dual-Shell Design

2020 ◽  
Author(s):  
Wenfu Liu ◽  
Xiaolei Guo ◽  
Shule Xing ◽  
Haizi Yao ◽  
Yinling Wang ◽  
...  
Keyword(s):  
Refractive Index ◽  
High Efficiency ◽  
Light Trapping ◽  
Resonant Absorption ◽  
Photocurrent Density ◽  
Absorption Enhancement ◽  
Graded Index ◽  
Shell Design ◽  
Transition Modes ◽  
Single Nanowires

Single nanowires (NWs) are of great importance for optoelectronic applications, especially solar cells serving as powering nanoscale devices. However, weak off-resonant absorption can limit its light-harvesting capability. Here, we propose a single NW coated with the graded-index dual shells (DSNW). We demonstrate that with appropriate thickness and refractive index of the inner shell, the DSNW exhibits significantly enhanced light trapping compared with the bare NW (BNW), and the NW only coated with the outer shell (OSNW) and the inner shell (ISNW), which can be attributed to the optimal off-resonant absorption mode profiles due to the improved coupling between the reemitted light of the transition modes of the leak mode resonances of the Si core and the nanofocusing light from the dual shells with the graded refractive index. We found that the light absorption can be engineered via tuning the thickness and the refractive index of the inner shell, the photocurrent density is significantly enhanced by 134% (56%, 12%) in comparison with that of the BNW (OSNW, ISNW). This work advances our understanding of how to improve off-resonant absorption by applying graded dual-shell design and provides a new choice for designing high-efficiency single NW photovoltaic devices.

scholarly journals Off-Resonant Absorption Enhancement in Single Nanowires via Graded Dual-Shell Design

2020 ◽  
Author(s):  
Wenfu Liu ◽  
Xiaolei Guo ◽  
Shule Xing ◽  
Haizi Yao ◽  
Yinling Wang ◽  
...  
Keyword(s):  
Refractive Index ◽  
High Efficiency ◽  
Light Trapping ◽  
Resonant Absorption ◽  
Photocurrent Density ◽  
Absorption Enhancement ◽  
Photovoltaic Devices ◽  
Graded Index ◽  
Single Nanowires ◽  
Absorption Mode

Single nanowires (NWs) are of great importance for various optoelectronic applications, especially solar cells serving as powering nanoscale devices. However, weak off-resonant absorption can limit its light-harvesting capability. Here, we propose a single NW coated with the graded-index dual shells (DSNW). We demonstrate that with the proper thickness and refractive index of the inner shell, the DSNW exhibits significantly enhanced light trapping compared with the bare NW (BNW), and the NW only coated with the outer shell (OSNW) and inner shell (ISNW), which can be attributed to the optimal off-resonant absorption mode profiles due to the improved coupling between the reemitted light of the leak mode resonances of the Si core and the nanofocusing light from the dual shells with the graded refractive index. We found that the light absorption can be adjusted via tuning the thickness and refractive index of the inner shell, the photocurrent density is significantly enhanced by 134% (56%, 12%) in comparison with that of the BNW (OSNW, ISNW). This work advances our understanding of how to improve off-resonant absorption by applying graded dual shells and provides a new choice for designing high-efficiency single NW photovoltaic devices.

Spin Resonance

2018 ◽  
Author(s):  
M. M. Glazov
Keyword(s):  
Magnetic Resonance ◽  
Nuclear Spin ◽  
Electromagnetic Waves ◽  
Zeeman Splitting ◽  
Resonant Absorption ◽  
Magnetic Interactions ◽  
Spin Effects ◽  
Crystalline Environment ◽  
Spin Resonance ◽  
Optically Detected

This chapter is devoted to one of key phenomena in the field of spin physics, namely, resonant absorption of electromagnetic waves under conditions where the Zeeman splitting of spin levels in magnetic field is equal to photon energy. This method is particularly important for identification of nuclear spin effects, because resonance spectra provide fingerprints of different involved spin species and make it possible to distinguish different nuclear isotopes. As discussed in this chapter the nuclear magnetic resonance provides also an access to local magnetic fields acting on nuclear spins. These fields are caused by the magnetic interactions between the nuclei and by the quadrupole splittings of nuclear spin states in anisotropic crystalline environment. Manifestations of spin resonance in optical responses of semiconductors–that is, optically detected magnetic resonance–are discussed.

Design strategy of ultrasmall Gd2O3 nanoparticles for T1 MRI with high performance

2021 ◽  
Author(s):  
Jianfeng Yang ◽  
Pengyuan Shan ◽  
Qingling Zhao ◽  
Shuquan Zhang ◽  
Lanlan Li ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Performance ◽  
Design Strategy ◽  
Resonance Imaging ◽  
Relative Time ◽  
Time Parameters ◽  
Gd2o3 Nanoparticles

It is still a big challenge for designing Gd3+ based nanoparticles (NPs) for T1 MRI (Magnetic Resonance Imaging) with high performance and clarifying the effects of relative time parameters for...

scholarly journals 2D MoS2 Encapsulated Silicon Nanopillar Array with High-Performance Light Trapping Obtained by Direct CVD Process

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 267
Author(s):  
Minyu Bai ◽  
Zhuoman Wang ◽  
Jijie Zhao ◽  
Shuai Wen ◽  
Peiru Zhang ◽  
...  
Keyword(s):  
Silicon Substrate ◽  
High Performance ◽  
Low Cost ◽  
Light Trapping ◽  
Incident Light ◽  
Single Layer ◽  
Chemical Vapor ◽  
Optoelectronic Device ◽  
Planar Silicon ◽  
Shortwave Infrared

Weak absorption remains a vital factor that limits the application of two-dimensional (2D) materials due to the atomic thickness of those materials. In this work, a direct chemical vapor deposition (CVD) process was applied to achieve 2D MoS2 encapsulation onto the silicon nanopillar array substrate (NPAS). Single-layer 2D MoS2 monocrystal sheets were obtained, and the percentage of the encapsulated surface of NPAS was up to 80%. The reflection and transmittance of incident light of our 2D MoS2-encapsulated silicon substrate within visible to shortwave infrared were significantly reduced compared with the counterpart planar silicon substrate, leading to effective light trapping in NPAS. The proposed method provides a method of conformal deposition upon NPAS that combines the advantages of both 2D MoS2 and its substrate. Furthermore, the method is feasible and low-cost, providing a promising process for high-performance optoelectronic device development.

Patulin Surveillance in Apple Cider and Juice Marketed in Michigan

2009 ◽  
Vol 72 (6) ◽  
pp. 1255-1261 ◽  
Author(s):  
KERRI L. HARRIS ◽  
GERD BOBE ◽  
LESLIE D. BOURQUIN
Keyword(s):  
High Performance ◽  
Apple Juice ◽  
Solid Phase ◽  
Uv Light ◽  
Grocery Store ◽  
Grocery Stores ◽  
Apple Cider ◽  
Shelf Stable ◽  
Retail Grocery

Patulin is the most common mycotoxin found in apples and apple juices. The objective of this study was to determine the concentrations of patulin in (i) apple cider produced and marketed by Michigan apple cider mills during the fall seasons of 2002 to 2003 and 2003 to 2004 and (ii) apple juice and cider, including shelf-stable products, marketed in retail grocery stores in Michigan throughout 2005 and 2006. End product samples (n = 493) obtained from 104 Michigan apple cider mills were analyzed for patulin concentration by using solid-phase extraction followed by high-performance liquid chromatography. Patulin was detected (≥4 μg/liter) in 18.7% of all cider mill samples, with 11 samples (2.2%) having patulin concentrations of ≥50 μg/liter. A greater percentage of cider samples obtained from mills using thermal pasteurization contained detectable patulin (28.4%) than did those from mills using UV light radiation (13.5%) or no pathogen reduction treatment (17.0%). Among retail grocery store samples (n = 159), 23% of apple juice and cider samples contained detectable patulin, with 18 samples (11.3%) having patulin concentrations of ≥50 μg/liter. The U.S. Food and Drug Administration (FDA) action level for patulin is 50 μg/kg. Some apple juice samples obtained from retail grocery stores had exceptionally high patulin concentrations, ranging up to 2,700 μg/liter. Collectively, these results indicate that most apple cider and juice test samples from Michigan were below the FDA action level for patulin but that certain apple cider and juice processors have inadequate controls over patulin concentrations in final products. The industry, overall, should focus on improved quality of fruit used in juice production and improve culling procedures to reduce patulin concentrations.

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