Tunable plasmonic filter based on graphene-layered waveguide

2018 ◽  
Vol 32 (08) ◽  
pp. 1850110 ◽  
Author(s):  
Yuncai Feng ◽  
Youwen Liu ◽  
Yaoyao Shi ◽  
Jinghua Teng
Keyword(s):  
Finite Difference Time Domain ◽  
Chemical Potential ◽  
Fdtd Method ◽  
Optical Filter ◽  
Monolayer Graphene ◽  
Physical Parameters ◽  
Plasmonic Filter ◽  
Tunable Optical Filter ◽  
Difference Time ◽  
Different Thickness

We propose a tunable band-stop plasmonic filter based on monolayer graphene with different thickness of structure, and the corresponding transmission characteristic is numerically investigated by using finite-difference time-domain (FDTD) method. The results show that the proposed filter can achieve a broad stopband that can be tuned by various physical parameters such as the chemical potential of graphene, the thickness of packing layers and so on. Our studies may be important for designing tunable optical filter, the fabrication of nano-integrated plasmonic circuits and the refractive index sensitive sensors.

Comb-Shaped Graphene Nanoribbon Bandpass Filter

2020 ◽  
Vol 20 (12) ◽  
pp. 7577-7582
Author(s):  
Guangsheng Deng ◽  
Tianxiang Zhao ◽  
Zhiping Yin ◽  
Ying Li ◽  
Jun Yang
Keyword(s):  
Finite Difference Time Domain ◽  
Bandpass Filter ◽  
Chemical Potential ◽  
Graphene Nanoribbon ◽  
Frequency Region ◽  
Monolayer Graphene ◽  
Transmission Spectra ◽  
All Optical ◽  
Graphene Devices ◽  
Difference Time

In this study, a novel comb-shaped graphene nanoribbon wideband bandpass filter for use at midinfrared frequencies is proposed. In addition, numerical investigation was carried outwith finite difference time-domain (FDTD) numerical simulations. The filter includes one graphene nanoribbon (GNR) waveguide laterally coupled to six perpendicular GNRs on each side. With a simple geometric shape, the transmission bandwidth and efficiency of waves within the structure can be tuned by altering the width or length of the GNR teeth. Moreover, the transmission spectra can be easily tuned within a broad frequency region by tuning the chemical potential of the graphene teeth, thanks to the electronic tunability of monolayer graphene. This work offers a promising method for developing ultra-compact tunable graphene devices and for designing integrated all-optical architectures.

scholarly journals From Time-Collocated to Leapfrog Fundamental Schemes for ADI and CDI FDTD Methods

Axioms ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 23
Author(s):  
Eng Leong Tan
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Fdtd Method ◽  
Unconditionally Stable ◽  
Alternating Direction Implicit ◽  
One Dimensional ◽  
Alternating Direction ◽  
Fdtd Methods ◽  
Difference Time

The leapfrog schemes have been developed for unconditionally stable alternating-direction implicit (ADI) finite-difference time-domain (FDTD) method, and recently the complying-divergence implicit (CDI) FDTD method. In this paper, the formulations from time-collocated to leapfrog fundamental schemes are presented for ADI and CDI FDTD methods. For the ADI FDTD method, the time-collocated fundamental schemes are implemented using implicit E-E and E-H update procedures, which comprise simple and concise right-hand sides (RHS) in their update equations. From the fundamental implicit E-H scheme, the leapfrog ADI FDTD method is formulated in conventional form, whose RHS are simplified into the leapfrog fundamental scheme with reduced operations and improved efficiency. For the CDI FDTD method, the time-collocated fundamental scheme is presented based on locally one-dimensional (LOD) FDTD method with complying divergence. The formulations from time-collocated to leapfrog schemes are provided, which result in the leapfrog fundamental scheme for CDI FDTD method. Based on their fundamental forms, further insights are given into the relations of leapfrog fundamental schemes for ADI and CDI FDTD methods. The time-collocated fundamental schemes require considerably fewer operations than all conventional ADI, LOD and leapfrog ADI FDTD methods, while the leapfrog fundamental schemes for ADI and CDI FDTD methods constitute the most efficient implicit FDTD schemes to date.

scholarly journals Butterfly-Inspired 2D Periodic Tapered-Staggered Subwavelength Gratings Designed Based on Finite Difference Time Domain Method

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Houxiao Wang ◽  
Wei Zhou ◽  
Er Ping Li ◽  
Rakesh Ganpat Mote
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Fdtd Method ◽  
Subwavelength Structures ◽  
Surface Reflection ◽  
Subwavelength Gratings ◽  
Difference Time

The butterfly-inspired 2D periodic tapered-staggered subwavelength gratings were developed mainly using finite difference time domain (FDTD) method, assisted by using focused ion beam (FIB) nanoscale machining or fabrication. The periodic subwavelength structures along the ridges of the designed gratings may change the electric field intensity distribution and weaken the surface reflection. The performance of the designed SiO2gratings is similar to that of the corresponding Si gratings (the predicted reflectance can be less than around 5% for the bandwidth ranging from 0.15 μm to 1 μm). Further, the antireflection performance of the designedx-unspaced gratings is better than that of the correspondingx-spaced gratings. Based on the FDTD designs and simulated results, the butterfly-inspired grating structure was fabricated on the silicon wafer using FIB milling, reporting the possibility to fabricate these FDTD-designed subwavelength grating structures.

Application of ADE-FDTD Method in Lossy Lorentz Media

2014 ◽  
Vol 945-949 ◽  
pp. 2486-2489
Author(s):  
Qing Chao Nie ◽  
Bing Kang Chen
Keyword(s):  
Differential Equation ◽  
Wave Propagation ◽  
Finite Difference ◽  
Theoretical Result ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Fdtd Method ◽  
Time Domain Method ◽  
Domain Method ◽  
Difference Time

A finite-difference time-domain method based on the auxiliary differential equation (ADE) technique is used to obtain the formulation of 2-D TM wave propagation in lossy Lorentz media. In the paper, the reflected coefficients calculated by ADE-FDTD method and the exact theoretical result are better agreement.

scholarly journals A Tunable Terahertz Metamaterial Absorber Composed of Hourglass-Shaped Graphene Arrays

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 533 ◽  
Author(s):  
Yunping Qi ◽  
Yu Zhang ◽  
Chuqin Liu ◽  
Ting Zhang ◽  
Baohe Zhang ◽  
...  
Keyword(s):  
Fdtd Method ◽  
Bilayer Graphene ◽  
Metamaterial Absorber ◽  
Dual Band ◽  
Maximum Absorption ◽  
Monolayer Graphene ◽  
Selective Absorption ◽  
Chemical Potentials ◽  
Difference Time ◽  
Absorption Characteristics

In this paper, we demonstrate a tunable periodic hourglass-shaped graphene arrays absorber in the infrared (IR) and terahertz (THz) frequency bands. The effects of graphene geometric parameters, chemical potentials, periods, and incident angles on the pure absorption characteristics are studied by using the Finite Difference Time Domain (FDTD) method. In addition, this paper also analyzes the pure absorption characteristics of bilayer graphene arrays. The simulation results show that the maximum absorption reaches 38.2% for the monolayer graphene structure. Furthermore, comparing the bilayer graphene structure with the monolayer structure under the same conditions shows that the bilayer structure has a tunable dual-band selective absorption effect and has a higher maximum absorption of 41.7%. Moreover, it was found that there are dual-band tunable absorption peaks at 21.6   μ m and 36.3   μ m with the maximum absorption of 41.7% and 11%. The proposed structure is a convenient method which could be used in the design of graphene-based optoelectronic devices, biosensors, and environmental monitors.

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