The Theoretical Study of TM Transmittance and Contrast Ratio for Sub-Wavelength Metallic Gratings

2014 ◽  
Vol 575 ◽  
pp. 138-141
Author(s):  
Ren Cheng Jin ◽  
Yang Rui ◽  
Jin Kui Chu ◽  
Ying Jie Zhang
Keyword(s):  
Performance Indicators ◽  
Theoretical Study ◽  
Structural Parameters ◽  
Contrast Ratio ◽  
Fdtd Method ◽  
Slit Width ◽  
Wave Band ◽  
Metallic Gratings ◽  
Difference Time ◽  
Sub Wavelength

According to the requirement of the bionic navigation sensitive wave band of 380nm~520nm for sub-wavelength metallic gratings, in order to achieve performance indicators under the basic structural parameters. Analyzing TM transmittance and contrast ratio is carried out by employing finite-difference time-domain (FDTD) method. The result reveals that height, slit width and dielectric of grating impact TM transmittance and contrast ratio in various extents, and the greatest influence on the TM transmittance and contrast ratio is slit dielectric and slit width respectively.

scholarly journals Tuning Plasmon Induced Reflectance with Hybrid Metasurfaces

Photonics ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 29 ◽  
Author(s):  
Mohsin Habib ◽  
Ekmel Ozbay ◽  
Humeyra Caglayan
Keyword(s):  
Modulation Depth ◽  
Contrast Ratio ◽  
Fdtd Method ◽  
Spectral Contrast ◽  
Design Flexibility ◽  
Different Dimensions ◽  
Control Light ◽  
And Control ◽  
Difference Time ◽  
Total Shift

Electrically tunable metasurfaces with graphene offer design flexibility to efficiently manipulate and control light. These metasurfaces can be used to generate plasmon-induced reflectance (PIR), which can be tuned by electrostatic doping of the graphene layer. We numerically investigated two designs for tunable PIR devices using the finite difference time-domain (FDTD) method. The first design is based on two rectangular antennas of the same size and a disk; in the second design, two parallel rectangular antennas with different dimensions are used. The PIR-effect was achieved by weak hybridization of two bright modes in both devices and tuned by changing the Fermi level of graphene. A total shift of ∼362 nm was observed in the design with the modulation depth of 53% and a spectral contrast ratio of 76%. These tunable PIR devices can be used for tunable enhanced biosensing and switchable systems.

All-optical simultaneous XOR-AND operation using 1-D periodic nonlinear material

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Tanay Chattopadhyay
Keyword(s):  
Contrast Ratio ◽  
Fdtd Method ◽  
Optical Computing ◽  
Material Model ◽  
Nonlinear Material ◽  
Gate Operation ◽  
Nonlinear Materials ◽  
One Dimensional ◽  
All Optical ◽  
Difference Time

Abstract In this paper, an all-optical XOR-AND gate operation has been proposed using one-dimensional periodic nonlinear material model. This structure consists of alternating layers of different nonlinear materials. In this design, we can obtain XOR and AND logical operation simultaneously at the reflected and transmitted port of the periodic structure. Numerical simulation has also been done using the finite-difference-time-domain (FDTD) method. The response time of this switching operation is picoseconds (ps) range order. We find low insertion loss (−3.01 dB), high contrast ratio (14.13 dB) and high extension ratio (10.93 dB) of this device. This design will be useful in future all-optical computing.

A SILVER-COATED SINUSOIDAL SUB-WAVELENGTH STRUCTURE WITH POLARIZATION FEATURE FOR LIGHT EMITTING DIODE

2009 ◽  
Vol 16 (04) ◽  
pp. 631-634 ◽  
Author(s):  
CHENG-HAO KO ◽  
JIAN-SHIAN LIN ◽  
CHANG-TAI CHEN ◽  
NIEN-PO CHEN
Keyword(s):  
Light Emitting Diode ◽  
Red Light ◽  
Fdtd Method ◽  
Dielectric Materials ◽  
Transmission Efficiency ◽  
Light Emitting ◽  
Light Region ◽  
Fluorescence Efficiency ◽  
Difference Time ◽  
Sub Wavelength

A two-dimensional sub-wavelength grating (SWG) is fabricated on light-emitting diodes (LEDs). The SWG is simulated by finite-difference time-domain (FDTD) method. The SWG surface has silver-coated dielectric materials with sinusoidal structures, 175 nm period and 125 m depth of groove. When the incident wave is in the red light region of 600–700nm, the transmission efficiency of TM propagated light will reach 0.82. If this SWG structure is applied in LCD direct backlight module, the lower polarization piece can be replaced and fluorescence efficiency of LED can be improved.

Metallic Ellipsoidal Array – Film for Enhancing Transmission via Plasmonic Coupling

2014 ◽  
Vol 548-549 ◽  
pp. 393-396
Author(s):  
Ying Hu ◽  
Gui Qiang Liu ◽  
Xiang Nan Zhang ◽  
Yuan Hao Chen ◽  
Zheng Jie Cai ◽  
...  
Keyword(s):  
Slow Light ◽  
Fdtd Method ◽  
Three Dimensional ◽  
Metal Structure ◽  
Transparent Conductors ◽  
Long Wavelength ◽  
Highly Sensitive ◽  
Highly Sensitive Sensors ◽  
Difference Time ◽  
Sub Wavelength

In this paper, a novel metal structure that integrates double continuous Au films and double aligned gold (Au) non-close-packed ellipsoidal nanoparticle arrays is proposed. The optical features of this structure are simulated by using the three-dimensional finite-difference time-domain (3D-FDTD) method. Bimodal plasmonic resonances with the highest transmission up to 74% and 66% (corresponding to the short and long-wavelength, respectively) are achieved. This proposed structure with sub-wavelength size may provide fascinating applications in optoelectronic devices such as transparent conductors and conductive devices, slow light devices, highly sensitive sensors.

Assessment of specific absorption rate reduction in human head using metamaterial

2014 ◽  
Vol 21 (1) ◽  
pp. 79-85 ◽  
Author(s):  
Mohammad Rashed Iqbal Faruque ◽  
Mohammad Tariqul Islam ◽  
Nik Abdullah Nik Mohamed
Keyword(s):  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Structural Parameters ◽  
Fdtd Method ◽  
Human Head ◽  
Ring Resonators ◽  
Specific Absorption ◽  
Difference Time ◽  
Communication Equipment ◽  
Insight Into

AbstractIn this paper, the specific absorption rate (SAR) reduction in human head with metamaterial attachment is calculated. The finite-difference time-domain (FDTD) method has been used to evaluate the SAR in an anatomically correct model of the human head. We designed the double-negative metamaterials by placing periodic array arrangement of split ring resonators (SRRs). By properly designing and tuning the structural parameters of SRRS, the effective medium parameters can be made negative at 900 and 1800 MHz band, as presented in this paper. Experimental results show that, with presence of resonators, SAR reduction in the human head is achievable. These results can provide useful insight into the design of safety-compliant mobile communication equipment.

scholarly journals Tunable Mid-Infrared Graphene Plasmonic Cross-Shaped Resonator for Demultiplexing Application

2020 ◽  
Vol 10 (3) ◽  
pp. 1193 ◽  
Author(s):  
Somayyeh Asgari ◽  
Tapio Fabritius
Keyword(s):  
Fdtd Method ◽  
Three Dimensional ◽  
Single Mode ◽  
Transmission Spectra ◽  
Mid Infrared ◽  
Coupled Mode ◽  
Light Waves ◽  
Dimensional Parameters ◽  
Difference Time ◽  
Sub Wavelength

In this study, a tunable graphene plasmonic filter and a two-channel demultiplexer are proposed, simulated, and analyzed in the mid-infrared (MIR) region. We discuss the optical transmission spectra of the proposed cross-shaped resonator and the two-channel demultiplexer. The transmission spectra of the proposed MIR resonator are tunable by change of its dimensional parameters and the Fermi energy of the graphene. Our proposed structures have a single mode in the wavelength range of 5–12 µm. The minimum full width at half maximum (FWHM) and the maximum transmission ratio of the proposed resonator respectively reached 220 nm and 55%. Simulations are performed by use of three-dimensional finite-difference time-domain (3D-FDTD) method. Coupled mode theory (CMT) is used to investigate the structure theoretically. The numerical and the theoretical results are in good agreement. The performance of the proposed two-channel demultiplexer is investigated based on its crosstalk. The minimum value of crosstalk reaches −48.30 dB. Our proposed structures are capable of providing sub-wavelength confinement of light waves, useful in applications in MIR region.

scholarly journals A Plasmonic Chip-Scale Refractive Index Sensor Design Based on Multiple Fano Resonances

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3181 ◽  
Author(s):  
Kunhua Wen ◽  
Li Chen ◽  
Jinyun Zhou ◽  
Liang Lei ◽  
Yihong Fang
Keyword(s):  
Refractive Index ◽  
Fdtd Method ◽  
High Sensitivity ◽  
Refractive Index Sensor ◽  
Fano Resonances ◽  
Metal Insulator Metal ◽  
High Figure ◽  
On Chip ◽  
Difference Time ◽  
Sub Wavelength

In this paper, multiple Fano resonances preferred in the refractive index sensing area are achieved based on sub-wavelength metal-insulator-metal (MIM) waveguides. Two slot cavities, which are placed between or above the MIM waveguides, can support the bright modes or the dark modes, respectively. Owing to the mode interferences, dual Fano resonances with obvious asymmetrical spectral responses are achieved. High sensitivity and high figure of merit are investigated by using the finite-difference time-domain (FDTD) method. In view of the development of chip-scale integrated photonics, two extra slot cavities are successively added to the structure, and consequently, three and four ultra-sharp Fano peaks with considerable performances are obtained, respectively. It is believed that this proposed structure can find important applications in the on-chip optical sensing and optical communication areas.

Tunable Negative Refractive Index Metamaterials Based on Thermochromic Oxides

2012 ◽  
Author(s):  
Yimin Xuan ◽  
Jinguo Huang ◽  
Qiang Li
Keyword(s):  
Refractive Index ◽  
Size Dependence ◽  
Negative Refractive Index ◽  
Structural Parameters ◽  
Fdtd Method ◽  
Wavelength Region ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Tunable Metamaterial ◽  
Difference Time

A tunable metamaterial is proposed by combining a thermochromic oxide with a fishnet structure. The reflection and transmission coefficients are calculated by finite-difference time-domain (FDTD) method. Then the effective electromagnetic parameters of the metamaterial are retrieved on the basis of these data. The results reveal that an effective negative refractive index is obtained by this proposed structure. Furthermore, the wavelength region with negative refractive index can be self-regulated by simply tuning the temperature, which is of importance to extend the applications of negative refractive index materials. The effects of structural sizes on the negative refractive index are discussed in detail. The size-dependence indicates that wavelength region with negative refractive index can be designed to locate at the desired position by dexterously tailoring the structural parameters.

scholarly journals Broadband Absorption Tailoring of SiO2/Cu/ITO Arrays Based on Hybrid Coupled Resonance Mode

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 852 ◽  
Author(s):  
Jiqing Lian ◽  
Dawei Zhang ◽  
Ruijin Hong ◽  
Tingzhen Yan ◽  
Taiguo Lv ◽  
...  
Keyword(s):  
Near Infrared ◽  
Broad Band ◽  
Fdtd Method ◽  
Local Surface Plasmon Resonance ◽  
Cross Sectional ◽  
Broadband Absorption ◽  
Gap Resonance ◽  
Optical Applications ◽  
Difference Time ◽  
Sub Wavelength

Sub-wavelength artificial photonic structures can be introduced to tailor and modulate the spectrum of materials, thus expanding the optical applications of these materials. On the basis of SiO2/Cu/ITO arrays, a hybrid coupled resonance (HCR) mechanism, including the epsilon-near-zero (ENZ) mode of ITO, local surface plasmon resonance (LSPR) mode and the microstructural gap resonance (GR) mode, was proposed and researched by systematically regulating the array period and layer thickness. The optical absorptions of the arrays were simulated under different conditions by the finite-difference time-domain (FDTD) method. ITO films were prepared and characterized to verify the existence of ENZ mode and Mie theory was used to describe the LSPR mode. The cross-sectional electric field distribution was analyzed while SiO2/Cu/ITO multilayers were also fabricated, of which absorption was measured and calculated by Macleod simulation to prove the existence of GR and LSPR mode. Finally, the broad-band tailoring of optical absorption peaks from 673 nm to 1873 nm with the intensities from 1.8 to 0.41 was realized, which expands the applications of ITO-based plasmonic metamaterials in the near infrared (NIR) region.

Tunable Negative Refractive Index Metamaterials Based on Thermochromic Oxides

2013 ◽  
Vol 135 (9) ◽  
Author(s):  
Yimin Xuan ◽  
Jinguo Huang ◽  
Qiang Li
Keyword(s):  
Refractive Index ◽  
Size Dependence ◽  
Negative Refractive Index ◽  
Structural Parameters ◽  
Fdtd Method ◽  
Wavelength Region ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Tunable Metamaterial ◽  
Difference Time

A tunable metamaterial is proposed by combining a thermochromic oxide with a fishnet structure. The reflection and transmission coefficients are calculated by finite-difference time-domain (FDTD) method. The effective electromagnetic parameters of the metamaterial are retrieved on the basis of these data. The results reveal that an effective negative refractive index is obtained by this proposed structure and the wavelength region with negative refractive index can be self-regulated by simply tuning the temperature, which is of importance to extend the applications of negative refractive index materials. The effects of structural sizes on the negative refractive index are discussed. The size-dependence indicates that the wavelength range in which the apparent refractive index is negative can be tuned to be located at the desired position by dexterously tailoring the structural parameters.

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