scholarly journals Plasmonics Induced Multifunction Optical Device via Hoof-Shaped Subwavelength Structure

2020 ◽  
Vol 10 (8) ◽  
pp. 2713 ◽  
Author(s):  
Kui Wen ◽  
Zhaojian Zhang ◽  
Xinpeng Jiang ◽  
Jie He ◽  
Junbo Yang
Keyword(s):  
Surface Plasmon ◽  
Near Infrared ◽  
Optical Switch ◽  
Incident Light ◽  
Infrared Range ◽  
Polarization Angle ◽  
Electromagnetic Spectrum ◽  
Optical Device ◽  
Integrated Devices ◽  
Structure Array

The electromagnetic spectrum includes the frequency range (spectrum) of electromagnetic radiation and its corresponding wavelength and energy. Due to the unique properties of different frequency ranges of the electromagnetic spectrum, a series of functional devices working in each frequency rang have been proposed. Here, we propose a periodic subwavelength hoof-shaped structure array, which contains a variety of geometric configurations, including U-shaped and rectangle structures. The results show that the enhanced optical transmission (EOT) effect of the surface plasmon excited by the hoof-shaped structure is highly sensitive to the polarization of the incident light, which leads to the peak’s location shift and the amplitude intensity variety of transmission peaks of U-shaped structure in the case of coupling based on the surface plasmon of rectangle structure. In addition, take advantage of the EOT effect realized in the periodic hoof-shaped structure array, we propose a multifunctional plasmon optical device in the infrared range. By adjusting the polarization angle of the incident light, the functions of the optical splitter in the near-infrared range and the optical switch in the mid-infrared range are realized. Moreover, with the changes of the polarization angle, different proportions of optical intensities split are realized. The device has theoretically confirmed the feasibility of designing multifunctional integrated devices through a hoof-shaped-based metamaterial nanostructure, which provides a broad prospect for the extensive use of multiple physical mechanisms in the future to achieve numerous functions in simple nanostructures.

scholarly journals New evaluation method to detect physiological stress in fruit trees by airborne hyperspectral image spectroscopy

2010 ◽  
Vol 16 (1) ◽  
Author(s):  
J. Tamás
Keyword(s):  
Precision Agriculture ◽  
Near Infrared ◽  
Evaluation Method ◽  
Hyperspectral Image ◽  
Physiological Stress ◽  
Incident Light ◽  
Hyperspectral Data ◽  
Data Cube ◽  
Infrared Range ◽  
Image Spectroscopy

Nowadays airborne remote sensing data are increasingly used in precision agriculture. The fast space-time dependent localization of stresses in orchards, which allows for a more efficient application of horticultural technologies, could lead to improved sustainable precise management. The disadvantage of the near field multi and hyper spectroscopy is the spot sample taking, which can apply independently only for experimental survey in plantations. The traditional satellite images is optionally suitable for precision investigation because of the low spectral and ground resolution on field condition. The presented airborne hyperspectral image spectroscopy reduces above mentioned disadvantages and at the same time provides newer analyzing possibility to the user. In this paper we demonstrate the conditions of data base collection and some informative examination possibility. The estimating of the board band vegetation indices calculated from reflectance is well known in practice of the biomass stress examinations. In this method the N-dimension spectral data cube enables to calculate numerous special narrow band indexes and to evaluate maps. This paper aims at investigating the applied hyperspectral analysis for fruit tree stress detection. In our study, hyperspectral data were collected by an AISADUAL hyperspectral image spectroscopy system, with high (0,5-1,5 m) ground resolution. The research focused on determining of leaves condition in different fruit plantations in the peach orchard near Siófok. Moreover the spectral reflectance analyses could provide more information about plant condition due to changes in the absorption of incident light in the visible and near infrared range of the spectrum.

scholarly journals Broadband Absorber Using Ultra-thin Plasmonic Metamaterials Nanostructure in the Visible and Near-Infrared Regions

2021 ◽  
Author(s):  
Ali Elrashidi
Keyword(s):  
Glass Substrate ◽  
Near Infrared ◽  
Incident Light ◽  
Polarization Angle ◽  
Perfect Absorber ◽  
Broadband Absorber ◽  
Absorption Bandwidth ◽  
Metal Insulator Metal ◽  
Silver Substrate ◽  
Unit Cell Dimensions

Abstract In this work, an ultra-thin plasmonic metamaterial nanostructure absorber is simulated using finite difference time domain method in the visible and near infrared regions. A metamaterial, metal-insulator-metal, of a periodic structure of titanium-silica cap mounted on a top of a silver substrate covered by glass substrate is introduced in this paper. The glass substrate is used to enhance the absorption bandwidth by 276%, from 510 nm to 1410 nm. An almost perfect absorber, over 90% of the incident light, has been obtained for wavelengths from 440 nm to 1850 nm which produces an absorption bandwidth of 1410 nm. The square base unit cell dimensions of the silver substrate and of the cap are simulated and found as 250 nm and 200 nm consequently. The effect of using different materials for the top of the cap and for the insulator are also tested. The considered materials are titanium, nickel, silver, aluminum, and gold; however, the insulators are silica, quartz, vanadium dioxide, methyl methacrylate, and aluminium dioxide. In addition, aluminium, silver, copper, and gold are then simulated as a substrate metal. The optimum structure, which produce the maximum absorber bandwidth, 1410 nm, with a higher absorption, over 90%, is Glass-Ti-SiO2-Ag. Finally, the absorption bandwidth is calculated using different polarization angle, from 100 to 700 with a step100.

scholarly journals Mineral mapping by hyperspectral remote sensing in West Greenland using airborne, ship-based and terrestrial platforms

2018 ◽  
pp. 47-50 ◽  
Author(s):  
Sara Salehi ◽  
Simon Mose Thaarup
Keyword(s):  
Near Infrared ◽  
Hyperspectral Data ◽  
Geological Mapping ◽  
Infrared Range ◽  
Remote Measurement ◽  
Electromagnetic Spectrum ◽  
Similar Data ◽  
Data Set ◽  
Specific Chemical ◽  
West Greenland

While multispectral images have been in regular use since the 1970s, the widespread use of hyperspectral images is a relatively recent trend. This technology comprises remote measurement of specific chemical and physical properties of surface materials through imaging spectroscopy. Regional geological mapping and mineral exploration are among the main applications that may benefit from hyperspectral technology. Minerals and rocks exhibit diagnostic spectral features throughout the electromagnetic spectrum that allow their chemical composition and relative abundance to be mapped. Most studies using hyperspectral data for geological applications have concerned areas with arid to semi-arid climates, and using airborne data collection. Other studies have investigated terrestrial outcrop sensing and integration with laser scanning 3D models in ranges of up to a few hundred metres, whereas less attention has been paid to ground-based imaging of more distant targets such as mountain ridges, cliffs or the walls of large pits. Here we investigate the potential of using such data in well-exposed Arctic regions with steep topography as part of regional geological mapping field campaigns, and to test how airborne hyperspectral data can be combined with similar data collected on the ground or from moving platforms such as a small ship. The region between the fjords Ikertoq and Kangerlussuaq (Søndre Strømfjord) in West Greenland was selected for a field study in the summer of 2016. This region is located in the southern part of the Palaeoproterozoic Nagssugtoqidian orogen and consists of high-grade metamorphic ortho- and paragneisses and metabasic rocks (see below). A regional airborne hyperspectral data set (i.e. HyMAP) was acquired here in 2002 (Tukiainen & Thorning 2005), comprising 54 flight lines covering an area of c. 7500 km2; 19 of these flight lines were selected for the present study (Fig. 1). The target areas visited in the field were selected on the basis of preliminary interpretations of HyMap scenes and geology (Korstgård 1979). Two different sensors were utilised to acquire the new hyperspectral data, predominantly a Specim AisaFenix hyperspectral scanner due to its wide spectral range covering the visible to near infrared and shortwave infrared parts of the electromagnetic spectrum. A Rikola Hyperspectral Imager constituted a secondary imaging system. It is much smaller and lighter than the Fenix scanner, but is spectrally limited to the visible near infrared range. The results obtained from combining the airborne hyperspectral data and the Rikola instrument are presented in Salehi (2018), this volume. In addition, representative samples of the main rock types were collected for subsequent laboratory analysis. A parallel study was integrated with geological and 3D photogrammetric mapping in Karrat region farther north in West Greenland (Rosa et al. 2017; Fig. 1).

The Effect of Wavelength of Light on Solar Electrical Performance

2020 ◽  
Author(s):  
Nagwa Ibrahim Ibrahim ◽  
Manahil Mohammed Baher Edin Omer
Keyword(s):  
Solar Cells ◽  
Near Infrared ◽  
Photovoltaic Effect ◽  
Short Circuit ◽  
Maximum Power ◽  
Electrical Performance ◽  
Infrared Range ◽  
Electromagnetic Spectrum ◽  
Radio Waves ◽  
Wavelength Radiation

Abstract The photovoltaic effect takes place at the junction of two semiconducting materials. The relation between energy (E) of light (photons) and wavelength (lambda) is given the energy of the incident photons is inversely proportional to their wavelengths. Violet is the Short-wavelength radiation, occupy the end of the electromagnetic spectrum which includes ultraviolet radiation and gamma rays. On the other hand, long-wavelength radiation occupies the red end and includes infrared radiation, microwaves, and radio waves. The wavelengths of visible light occur between 400 and 700 nm, so the bandwidth wavelength for silicon solar cells is in the very near-infrared range. Any radiation with a longer wavelength, such as microwaves and radio waves, lacks the energy to produce, electricity from a solar cell. The cost-efficiency of photovoltaic solar panels maybe reducing by reflection losses is a major field of study in the solar glass market. The color from glass cover is an important factor for the performance of photovoltaic panels as it can turn out to be an active component in the design of PV panels. Indeed, different glass covers perform very differently under direct and diffuse radiance. Several factors poignant the parameters of the solar cells, wherever these factors influence the performance on the solar cells. An experiment was carried out to investigate current interdependence on each color’s wavelength, and to give the effect regarding color cover, what part of the light of spectrum would produce a maximum power out, and also the effect of changing the wavelength (color) on short circuit current, and open voltage circuit. The results show the smallest value of maximum power in the violet zone and the biggest value of maximum power in the red zone.

scholarly journals Design of Narrow-Band Absorber Based on Symmetric Silicon Grating and Research on Its Sensing Performance

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 553
Author(s):  
Miao Pan ◽  
Huazhu Huang ◽  
Wenzhi Chen ◽  
Shuai Li ◽  
Qinglai Xie ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
Incident Light ◽  
Geometric Parameters ◽  
Absorption Peak ◽  
Basic Unit ◽  
Polarization Angle ◽  
Refractive Index Sensitivity ◽  
Absorption Mechanism ◽  
Strong Light ◽  
Surface Plasmon Waves

In this paper, using the surface plasmon and Fabry–Pérot (FP) cavity, the design of a symmetric silicon grating absorber is proposed. The time-domain finite difference method is used for simulation calculations. The basic unit structure is a dielectric grating composed of silicon dioxide, metal and silicon. Through the adjustment of geometric parameters, we have achieved the best of the symmetric silicon grating absorber. A narrowband absorption peak with an absorption rate greater than 99% is generated in the 3000–5000 nm optical band, and the wavelength of the absorption peak is λ = 3750 nm. The physical absorption mechanism is that silicon light generates surface plasmon waves under the interaction with incident light, and the electromagnetic field coupling of surface plasmon waves and light causes surface plasmon resonance, thereby exciting strong light response modulation. We also explore the influence of geometric parameters and polarization angle on the performance of silicon grating absorbers. Finally, we systematically study the refractive index sensitivity of these structures. These structures can be widely used in optical filtering, spectral sensing, gas detection and other fields.

scholarly journals Suppressing material loss in the visible and near-infrared range for functional nanophotonics using bandgap engineering

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Mingsong Wang ◽  
Alex Krasnok ◽  
Sergey Lepeshov ◽  
Guangwei Hu ◽  
Taizhi Jiang ◽  
...  
Keyword(s):  
Near Infrared ◽  
High Efficiency ◽  
Incident Light ◽  
Resonant Mode ◽  
Higher Order ◽  
Visible Range ◽  
Infrared Range ◽  
Bandgap Engineering ◽  
Material Loss ◽  
Near Infrared Range

Abstract All-dielectric nanostructures have recently opened exciting opportunities for functional nanophotonics, owing to their strong optical resonances along with low material loss in the near-infrared range. Pushing these concepts to the visible range is hindered by their larger absorption coefficient, thus encouraging the search for alternative dielectrics for nanophotonics. Here, we employ bandgap engineering to synthesize hydrogenated amorphous Si nanoparticles (a-Si:H NPs) offering ideal features for functional nanophotonics. We observe significant material loss suppression in a-Si:H NPs in the visible range caused by hydrogenation-induced bandgap renormalization, producing strong higher-order resonant modes in single NPs with Q factors up to ~100 in the visible and near-IR range. We also realize highly tunable all-dielectric meta-atoms by coupling a-Si:H NPs to photochromic spiropyran molecules. ~70% reversible all-optical tuning of light scattering at the higher-order resonant mode under a low incident light intensity is demonstrated. Our results promote the development of high-efficiency visible nanophotonic devices.

scholarly journals Research of an Optical Device Based on a Anisotropic Epsilon-Near-Zero Metamaterial

2021 ◽  
Author(s):  
zhibin Wang ◽  
qiufan Cheng ◽  
xin Li ◽  
zhiquan Li ◽  
shuhan Meng
Keyword(s):  
Gate Voltage ◽  
Near Infrared ◽  
Incident Light ◽  
Extinction Ratio ◽  
Narrow Channel ◽  
Light Modulator ◽  
Optical Device ◽  
Infrared Wavelength ◽  
Novel Design ◽  
Epsilon Near Zero

Abstract In this work, a novel design of an electro-tunable narrow channel based on an anisotropic epsilon-near-zero (AENZ) metamaterial is presented. The ENZ condition can be flexibly tuned by an applied gate voltage. This permittivity-tunable channel is composed of alternating layers of graphene and nanoglass with a thickness of 3nm. Additionally, this channel is utilized in a dual output light modulator to expand its application. Numerical analysis results show that the maximum transmittance of incident light can reach 96.7%, and the extinction ratio (ER) of the device is 14.8dB when the gate voltage is added to 4.96V at the near-infrared wavelength based on the finite element method (FEM). This ultracompact optical device may open a new realm in highly integrated photonic circuits, especially on the nano-chips.

scholarly journals Graphene Electro-Optical Switch Modulator by Adjusting Propagation Length Based on Hybrid Plasmonic Waveguide in Infrared Band

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2864 ◽  
Author(s):  
Ming Cai ◽  
Shulong Wang ◽  
Zhihong Liu ◽  
Yindi Wang ◽  
Tao Han ◽  
...  
Keyword(s):  
Near Infrared ◽  
Modulation Depth ◽  
Optical Switch ◽  
Incident Light ◽  
Plasmonic Waveguide ◽  
Infrared Band ◽  
Propagation Length ◽  
Sio2 Substrate ◽  
Hybrid Plasmonic Waveguide ◽  
High Modulation

A modulator is the core of many optoelectronic applications such as communication and sensing. However, a traditional modulator can hardly reach high modulation depth. In order to achieve the higher modulation depth, a graphene electro-optical switch modulator is proposed by adjusting propagation length in the near infrared band. The switch modulator is designed based on a hybrid plasmonic waveguide structure, which is comprised of an SiO2 substrate, graphene–Si–graphene heterostructure, Ag nanowire and SiO2 cladding. The propagation length of the hybrid plasmonic waveguide varies from 0.14 μm to 20.43 μm by the voltage tunability of graphene in 1550 nm incident light. A modulator with a length of 3 μm is designed based on the hybrid waveguide and it achieves about 100% modulation depth. The lower energy loss (~1.71 fJ/bit) and larger 3 dB bandwidth (~83.91 GHz) are attractive for its application in a photoelectric integration field. In addition, the excellent robustness (error of modulation effects lower than 8.84%) is practical in the fabrication process. Most importantly, by using the method of adjusting propagation length, other types of graphene modulators can also achieve about 100% modulation depth.

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