Birefringent and Complex Optical Properties of Monolayer Graphene Investigated by Ellipsometry and Waveguide Integration

2021 ◽  
Vol 125 (3) ◽  
pp. 2124-2131
Author(s):  
Yuhui Chu ◽  
Zexu Liu ◽  
Zhenming Ding ◽  
Ziyang Zhang
Keyword(s):  
Optical Properties ◽  
Monolayer Graphene

scholarly journals Manipulating intrinsic behaviors of graphene by substituting alkaline earth metal atoms in its structure

RSC Advances ◽  
2017 ◽  
Vol 7 (27) ◽  
pp. 16360-16370 ◽  
Author(s):  
Muhammad Rafique ◽  
Yong Shuai ◽  
He-Ping Tan ◽  
Muhammad Hassan
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Monolayer Graphene ◽  
Alkaline Earth Metal ◽  
First Principles Calculations ◽  
Metal Atoms

In this paper, the structural, electronic, magnetic and optical properties of alkaline earth metal (AEM) atom-doped monolayer graphene are investigated using first-principles calculations.

Electronic and optical properties of monolayer and bilayer graphene

2010 ◽  
Vol 368 (1932) ◽  
pp. 5445-5458 ◽  
Author(s):  
Y. H. Ho ◽  
J. Y. Wu ◽  
Y. H. Chiu ◽  
J. Wang ◽  
M. F. Lin
Keyword(s):  
Optical Properties ◽  
Bilayer Graphene ◽  
Landau Levels ◽  
Optical Measurements ◽  
Monolayer Graphene ◽  
Zero Field ◽  
Electronic And Optical Properties ◽  
Graphene Layers ◽  
Lower Pair ◽  
Dependent Absorption

The electronic and optical properties of monolayer and bilayer graphene are investigated to verify the effects of interlayer interactions and external magnetic field. Monolayer graphene exhibits linear bands in the low-energy region. Then the interlayer interactions in bilayers change these bands into two pairs of parabolic bands, where the lower pair is slightly overlapped and the occupied states are asymmetric with respect to the unoccupied ones. The characteristics of zero-field electronic structures are directly reflected in the Landau levels. In monolayer and bilayer graphene, these levels can be classified into one and two groups, respectively. With respect to the optical transitions between the Landau levels, bilayer graphene possesses much richer spectral features in comparison with monolayers, such as four kinds of absorption channels and double-peaked absorption lines. The explicit wave functions can further elucidate the frequency-dependent absorption rates and the complex optical selection rules. These numerical calculations would be useful in identifying the optical measurements on graphene layers.

scholarly journals An Effort Towards Full Graphene Photodetectors

2020 ◽  
Author(s):  
Farhad Larki ◽  
Yaser Abdi ◽  
Parviz Kameli ◽  
Hadi Salamati
Keyword(s):  
Optical Properties ◽  
Absorption Spectrum ◽  
Device Fabrication ◽  
Monolayer Graphene ◽  
High Quality ◽  
Promising Candidate ◽  
2D System ◽  
Proper Design ◽  
Pros And Cons ◽  
Electro Magnetic

AbstractGraphene as a truly 2-dimensional (2D) system is a promising candidate material for various optoelectronic applications. Implementing graphene as the main building material in ultra-broadband photodetectors has been the center of extensive research due to its unique absorption spectrum which covers most of the electro-magnetic spectra. However, one of the main challenges facing the wide application of pure graphene photodetectors has been the small optical absorption of monolayer graphene. Although novel designs were proposed to overcome this drawback, they often need complicated fabrication processes in order to integrate with the graphene photodetector. In this regard, fabrication of purely graphene photodetectors is a promising approach towards the manufacturing of simple, inexpensive, and high photosensitive devices. The fabrication of full graphene photodetectors (FGPDs) is mainly based on obtaining an optimal technique for the growth of high quality graphene, modification of electronic and optical properties of the graphene, appropriate techniques for transfer of graphene from the grown substrate to the desire position, and a proper design for photodetection. Therefore, the available states of the art techniques for each step of device fabrication, along with their pros and cons, are reviewed and the possible approaches for optimization of FGPDs have been proposed.

scholarly journals Patterning and tuning of electrical and optical properties of graphene by laser induced two-photon oxidation

Nanoscale ◽  
2015 ◽  
Vol 7 (7) ◽  
pp. 2851-2855 ◽  
Author(s):  
Jukka Aumanen ◽  
Andreas Johansson ◽  
Juha Koivistoinen ◽  
Pasi Myllyperkiö ◽  
Mika Pettersson
Keyword(s):  
Optical Properties ◽  
Monolayer Graphene ◽  
Optical Fabrication ◽  
Electrical And Optical Properties ◽  
Two Photon ◽  
Graphene Devices

Laser-induced two-photon oxidation modifies locally the electrical and optical properties of monolayer graphene allowing optical fabrication of all-graphene devices.

scholarly journals Temperature-Dependent Optical Properties of Graphene on Si and SiO2/Si Substrates

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 358
Author(s):  
Sisi Wu ◽  
Lingyu Wan ◽  
Liangmin Wei ◽  
Devki N. Talwar ◽  
Kaiyan He ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Constants ◽  
Near Infrared ◽  
Infrared Region ◽  
Peak Position ◽  
Monolayer Graphene ◽  
Ultraviolet Region ◽  
Si Substrate ◽  
Temperature Dependent ◽  
Si Substrates

Systematic investigations are performed to understand the temperature-dependent optical properties of graphene on Si and SiO2/Si substrates by using a variable angle spectroscopic ellipsometry. The optical constants of graphene have revealed changes with the substrate and temperature. While the optical refractive index (n) of monolayer graphene on Si exhibited clear anomalous dispersions in the visible and near-infrared region (400–1200 nm), the modification is moderate for graphene on SiO2/Si substrate. Two graphene sheets have shown a pronounced absorption in the ultraviolet region with peak position related to the Van Hove singularity in the density of states. By increasing the temperature from 300 K to 500 K, for monolayer graphene on Si, the n value is gradually increased while k decreased. However, the optical constants [n, k] of monolayer graphene on SiO2/Si exhibited unpredictable wave variations. In the wavelength range of 400–1200 nm, an experiential formula of a like-Sellmeier equation is found well suited for describing the dispersions of graphene on Si and SiO2/Si substrates.

Design of objective lens for 200-kV high-resolution electron microscopes

1983 ◽  
Vol 41 ◽  
pp. 314-315
Author(s):  
K. Tsuno ◽  
T. Honda ◽  
Y. Harada ◽  
M. Naruse
Keyword(s):  
Optical Properties ◽  
Computer Technology ◽  
Axial Magnetic Field ◽  
Chromatic Aberration ◽  
Objective Lens ◽  
Resolution Electron ◽  
Correction Of Astigmatism ◽  
Three Stages ◽  
Electron Microscopes ◽  
Stage 1

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.

Optical Properties of HVEM Accelerators

1975 ◽  
Vol 33 ◽  
pp. 180-181
Author(s):  
A. Strojnik ◽  
J.W. Scholl ◽  
V. Bevc
Keyword(s):  
Optical Properties ◽  
Electron Accelerator ◽  
Systematic Investigation ◽  
Electron Source ◽  
High Brightness ◽  
The Past ◽  
Wide Range ◽  
Optical Behavior

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).

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