scholarly journals Polarized optical properties of hollowed-out 2D-gold-nanosheets studied using FDTD simulations

AIP Advances ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 085026
Author(s):  
Yu Chen ◽  
Tao Xu ◽  
Min Liu ◽  
Han Huang ◽  
Fangping Ouyang
Author(s):  
Bhagirath Duvvuri ◽  
Anurag Kumar ◽  
Hua Bao ◽  
Haoxiang Huang ◽  
Timothy Fisher ◽  
...  

In this work, thermal radiative properties of vertical graphene petal arrays are theoretically and experimentally investigated to show that they are superior absorbers of radiation. Finite difference time domain (FDTD) simulations are first performed to calculate optical properties of vertical graphitic arrays of different configurations, namely, graphitic gratings, periodic graphitic cavities, and random graphitic cavities. The effect of polarization of incident radiation on optical properties of such structures is systematically evaluated. When the incident electric field is parallel to the graphitic plane (S polarization) in graphitic gratings, the absorptance is very high, but the reflectance low but still significant when compared to reflectance from a MWCNT array. On the other hand, when the electric field is polarized perpendicular to the graphitic plane (P polarization), the absorptance is significantly lower, as well as the reflectance. This contrast is due to the stronger optical response for the S polarization. Ordered graphitic petal cavity arrays show optical properties falling between the above two cases because of the presence of both polarizations. The random graphitic petal cavity arrays with various angles of orientation show similar properties with ordered petal arrays, and the simulated reflectance agrees very well with experimental data measured on a fabricated thin graphite petal sample.


Solar Energy ◽  
2021 ◽  
Vol 230 ◽  
pp. 166-176
Author(s):  
Atiyeh Jamali ◽  
Mohaddeseh Saffari ◽  
Meysam Bagheri Tagani ◽  
H. Rahimpour Soleimani

2018 ◽  
Author(s):  
Yoshiaki Nishijima ◽  
Armandas Balcytis ◽  
Shin Naganuma ◽  
Gediminas Seniutinas ◽  
Saulius Juodkazis

<div>Maximum absorption of light using plasmonic perfect absorbers (PPAs) is highly desired in the field of energy harvesting. We reveal how optical properties of several</div><div>popular metals and insulators are affecting performance of PPAs at mid-infrared (IR) wavelengths. Optical properties of experimentally prepared (by plasma sputtering) structures follow expected scalings, however, departure from the finite difference time domain (FDTD) simulations are significant when roughness of the first metal baselayer is not taken into account. Electrical conductivity is shown to strongly affect</div><div>performance of PPAs.</div>


2015 ◽  
Vol 11 (3) ◽  
Author(s):  
Jian-Bo Liu ◽  
Lin Long ◽  
Yu-Shi Zhang ◽  
Yue-Ping Wang ◽  
Feng-Shou Liu ◽  
...  

2018 ◽  
Author(s):  
Yoshiaki Nishijima ◽  
Armandas Balcytis ◽  
Shin Naganuma ◽  
Gediminas Seniutinas ◽  
Saulius Juodkazis

<div>Maximum absorption of light using plasmonic perfect absorbers (PPAs) is highly desired in the field of energy harvesting. We reveal how optical properties of several</div><div>popular metals and insulators are affecting performance of PPAs at mid-infrared (IR) wavelengths. Optical properties of experimentally prepared (by plasma sputtering) structures follow expected scalings, however, departure from the finite difference time domain (FDTD) simulations are significant when roughness of the first metal baselayer is not taken into account. Electrical conductivity is shown to strongly affect</div><div>performance of PPAs.</div>


Author(s):  
K. Tsuno ◽  
T. Honda ◽  
Y. Harada ◽  
M. Naruse

Developement of computer technology provides much improvements on electron microscopy, such as simulation of images, reconstruction of images and automatic controll of microscopes (auto-focussing and auto-correction of astigmatism) and design of electron microscope lenses by using a finite element method (FEM). In this investigation, procedures for simulating the optical properties of objective lenses of HREM and the characteristics of the new lens for HREM at 200 kV are described.The process for designing the objective lens is divided into three stages. Stage 1 is the process for estimating the optical properties of the lens. Firstly, calculation by FEM is made for simulating the axial magnetic field distributions Bzc of the lens. Secondly, electron ray trajectory is numerically calculated by using Bzc. And lastly, using Bzc and ray trajectory, spherical and chromatic aberration coefficients Cs and Cc are numerically calculated. Above calculations are repeated by changing the shape of lens until! to find an optimum aberration coefficients.


Author(s):  
A. Strojnik ◽  
J.W. Scholl ◽  
V. Bevc

The electron accelerator, as inserted between the electron source (injector) and the imaging column of the HVEM, is usually a strong lens and should be optimized in order to ensure high brightness over a wide range of accelerating voltages and illuminating conditions. This is especially true in the case of the STEM where the brightness directly determines the highest resolution attainable. In the past, the optical behavior of accelerators was usually determined for a particular configuration. During the development of the accelerator for the Arizona 1 MEV STEM, systematic investigation was made of the major optical properties for a variety of electrode configurations, number of stages N, accelerating voltages, 1 and 10 MEV, and a range of injection voltages ϕ0 = 1, 3, 10, 30, 100, 300 kV).


Author(s):  
Marcos F. Maestre

Recently we have developed a form of polarization microscopy that forms images using optical properties that have previously been limited to macroscopic samples. This has given us a new window into the distribution of structure on a microscopic scale. We have coined the name differential polarization microscopy to identify the images obtained that are due to certain polarization dependent effects. Differential polarization microscopy has its origins in various spectroscopic techniques that have been used to study longer range structures in solution as well as solids. The differential scattering of circularly polarized light has been shown to be dependent on the long range chiral order, both theoretically and experimentally. The same theoretical approach was used to show that images due to differential scattering of circularly polarized light will give images dependent on chiral structures. With large helices (greater than the wavelength of light) the pitch and radius of the helix could be measured directly from these images.


Author(s):  
R. B. Queenan ◽  
P. K. Davies

Na ß“-alumina (Na1.67Mg67Al10.33O17) is a non-stoichiometric sodium aluminate which exhibits fast ionic conduction of the Na+ ions in two dimensions. The Na+ ions can be exchanged with a variety of mono-, di-, and trivalent cations. The resulting exchanged materials also show high ionic conductivities.Considerable interest in the Na+-Nd3+-ß“-aluminas has been generated as a result of the recent observation of lasing in the pulsed and cw modes. A recent TEM investigation on a 100% exchanged Nd ß“-alumina sample found evidence for the intergrowth of two different structure types. Microdiffraction revealed an ordered phase coexisting with an apparently disordered phase, in which the cations are completely randomized in two dimensions. If an order-disorder transition is present then the cooling rates would be expected to affect the microstructures of these materials which may in turn affect the optical properties. The purpose of this work was to investigate the affect of thermal treatments upon the micro-structural and optical properties of these materials.


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