Graphene Based Polarization-Dependent Terahertz Photodetector

2021 ◽  
Vol 894 ◽  
pp. 13-20
Author(s):  
Yu Zhe Li
Keyword(s):  
Finite Difference Time Domain ◽  
Room Temperature ◽  
Chemical Potential ◽  
Incident Light ◽  
Localized Surface Plasmon ◽  
High Tech ◽  
Polarization Angle ◽  
Terahertz Frequency ◽  
Terahertz Technology ◽  
Difference Time

Terahertz technology can be used in sensing and communication applications. We designed a polarization-sensitive photodetector specially for Terahertz frequency based on cross-shaped graphene sheet. The shaped graphene excites localized surface plasmon which can enhance the absorption of incident light. From the Finite Difference Time Domain Solutions (FDTD), we figured out that transmission of incident light relates to the size of photodetector, polarization angle and physical properties of graphene such as chemical potential and layers. The transmission can be tuned as low as 8.3 ×10-5 when we set the size at 14×6µm and 14×5µm for two different graphene pieces and polarization angle as 0°, at room temperature. This device we designed can absorb Terahertz at a wavelength around 126 µm, which can be used in THz application applied in future high-tech communication or safety inspection.

Three-Dimensional Finite-Difference Time-Domain Method Modeling of Nanowire Optical Probe

2014 ◽  
Vol 602-605 ◽  
pp. 3359-3362
Author(s):  
Chun Li Zhu ◽  
Jing Li
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Incident Light ◽  
Near Field ◽  
Three Dimensional ◽  
Polarization Direction ◽  
Near Field Imaging ◽  
Difference Time ◽  
Field Imaging

In this paper, output near fields of nanowires with different optical and structure configurations are calculated by using the three-dimensional finite-difference time-domain (3D FDTD) method. Then a nanowire with suitable near field distribution is chosen as the probe for scanning dielectric and metal nanogratings. Scanning results show that the resolution in near-field imaging of dielectric nanogratings can be as low as 80nm, and the imaging results are greatly influenced by the polarization direction of the incident light. Compared with dielectric nanogratings, metal nanogratings have significantly enhanced resolutions when the arrangement of gratings is perpendicular to the polarization direction of the incident light due to the enhancement effect of the localized surface plasmons (SPs). Results presented here could offer valuable references for practical applications in near-field imaging with nanowires as optical probes.

Dynamically tunable plasmon-induced transparency effect based on graphene metasurfaces

2021 ◽  
Author(s):  
Shuxian Chen ◽  
Junyi Li ◽  
Zicong Guo ◽  
Li Chen ◽  
Kunhua Wen ◽  
...  
Keyword(s):  
Modulation Depth ◽  
Incident Light ◽  
Polarization Angle ◽  
Refractive Index Sensitivity ◽  
Coupled Mode ◽  
Terahertz Devices ◽  
Index Sensitivity ◽  
Induced Transparency ◽  
Difference Time ◽  
Plasmon Induced Transparency

Abstract Plasmon-induced transparency (PIT) is theoretically explored with a graphene metamaterial using finite-difference time-domain numerical simulations and coupled-mode-theory theoretical analysis. In this work, the proposed structure is consisted of one rectangular cavity and three strips to generate the PIT phenomenon. The PIT window can be regulated dynamically by adjusting the Fermi level of the graphene. Importantly, the modulation depth of the amplitude can reach 90.4%. The refractive index sensitivity of the PIT window is also investigated, and the simulation result shows that a sensitivity of 1.335 THz/RIU is achieved. Additionally, when the polarization angle of the incident light is changed gradually from 0˚ to 90˚, the performances of the structure are greatly affected. Finally, the proposed structure is particularly enlightening for the design of dynamically tuned terahertz devices.

Localized Surface Plasmon Resonance of Single Silver Nano-Hemisphere

2013 ◽  
Vol 818 ◽  
pp. 137-140
Author(s):  
Rui Li ◽  
Kun Liu ◽  
Shi Pan ◽  
Jian Hua Ding
Keyword(s):  
Surface Plasmon Resonance ◽  
Finite Difference ◽  
Surface Plasmon ◽  
Time Domain ◽  
Plasmon Resonance ◽  
Finite Difference Time Domain ◽  
Localized Surface Plasmon Resonance ◽  
Resonance Effect ◽  
Localized Surface Plasmon ◽  
Difference Time

In this work, we use 3D finite difference time domain (3D-FDTD) to calculate the plasmon resonance effect for a single silver hemisphere in which the palsmon line shape have distinct peaks when the particles are located on a glass substrate. The dependence of the resonance on hemisphere size and the ratio of height over radius are characterized, and it is found that the surface interface effect played an important role on the plasman resonace effect for a single silver hemisphere.

scholarly journals Study on the Plasmonic Properties of Ag-Coated Spherical Dielectric Nanoparticles by Finite-Difference Time-Domain Calculations

2021 ◽  
Author(s):  
Qing-Wei Sun ◽  
Qi Sun ◽  
Qing-Yu Zhang ◽  
Nan Zhou ◽  
Xi-Na Li
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Electromagnetic Waves ◽  
Incident Light ◽  
Plasmonic Resonance ◽  
Ag Nps ◽  
Zno Nps ◽  
Infrared Band ◽  
Difference Time

Abstract The optical properties of nanostructures are rather important for designing plasmonic devices. In this work, the plasmonic properties of Ag-coated spherical dielectric nanoparticles (NPs), namely, Ag-SiO2-NPs, Ag-ZnO-NPs, and Ag-TiO2-NPs, were studied using a method of finite-difference time-domain calculations. It was found that the Ag-coated dielectric NPs start to exhibit unique plasmonic properties different from Ag-NPs as the thickness of Ag shells is reduced to be less than a critical value, which is basically determined by the penetration depth of light in silver. On the other hand, the core-shell structures of Ag-coated dielectric NPs were found to be of benefit to the plasmonic resonance high-efficiently coupled with the incident light. In the extinction spectra of Ag-coated dielectric NPs with sufficient thin Ag shells, the dipole plasmonic resonance is predominant and exhibits a pronounced red-shift up to infrared band with increasing the NP sizes. In addition to the electromagnetic waves of emission towards the outside, the electromagnetic field in the dielectric NP inside is uniformly enhanced as well and both of dipole and quadrupole plasmonic resonances are identified. The Ag-coated dielectric NPs are suggested to have great potential in the plasmonic devices working in infrared band, such as the light emitters and SERS substrates for biosensing.

scholarly journals Surface Plasmon Resonances in Silver Nanostars

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3821 ◽  
Author(s):  
Faustino Reyes Gómez ◽  
Rafael Rubira ◽  
Sabrina Camacho ◽  
Cibely Martin ◽  
Robson da Silva ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Localized Surface Plasmon ◽  
Surface Plasmon Resonances ◽  
Localized Surface Plasmon Resonances ◽  
Sensing Applications ◽  
Surface Enhanced ◽  
Plasmon Resonances ◽  
Difference Time

The recent development of silver nanostars (Ag-NSs) is promising for improved surface-enhanced sensing and spectroscopy, which may be further exploited if the mechanisms behind the excitation of localized surface plasmon resonances (LSPRs) are identified. Here, we show that LSPRs in Ag-NSs can be obtained with finite-difference time-domain (FDTD) calculations by considering the nanostars as combination of crossed nanorods (Ag-NRs). In particular, we demonstrate that an apparent tail at large wavelengths ( λ ≳ 700 nm) observed in the extinction spectra of Ag-NSs is due to a strong dipolar plasmon resonance, with no need to invoke heterogeneity (different number of arms) effects as is normally done in the literature. Our description also indicates a way to tune the strongest LSPR at desired wavelengths, which is useful for sensing applications.

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.

The Analysis of Ag Nanospheres and Arrays LSPR Phenomena Based on DDA and FDTD Method

2011 ◽  
Vol 110-116 ◽  
pp. 3860-3866
Author(s):  
Wei Zhang ◽  
Cheng Wang ◽  
Wei Zhou ◽  
Zhao Yue ◽  
Guo Hua Liu
Keyword(s):  
Surface Plasmon Resonance ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Localized Surface Plasmon Resonance ◽  
Electric Field Distribution ◽  
Fdtd Method ◽  
Dipole Approximation ◽  
Localized Surface Plasmon ◽  
Difference Time ◽  
Dda Method

The Discrete Dipole Approximation (DDA) method and the Finite Difference Time Domain (FDTD) method are used to analyze silver nanospheres with different radius and the coupling of nanospheres array complementarily. DDA method is used for simulating the extinction spectra of single silver nanosphere and nanospheres array; and the coupling of two nanospheres and their surrounding electric field distribution are simulated by FDTD method. Through these results, we got some important conclusions of nanoparticles’ Localized Surface Plasmon Resonance (LSPR) phenomenon.

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