FDTD simulation of near-field scattering pattern of a surface crack in plate-like structures for optimal inspection angle determination

2021 ◽  
Author(s):  
Tzuyang Yu
Keyword(s):  
Surface Crack ◽  
Near Field ◽  
Fdtd Simulation ◽  
Scattering Pattern

scholarly journals Broadband Plasmonic Nanopolarizer Based on Different Surface Plasmon Resonance Modes in a Silver Nanorod

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 447
Author(s):  
Junxi Zhang ◽  
Lei Hu ◽  
Zhijia Hu ◽  
Yongqing Wei ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Electric Fields ◽  
Near Infrared ◽  
Near Field ◽  
Resonant Cavity ◽  
Transverse Magnetic ◽  
Wave Mode ◽  
Fdtd Simulation ◽  
Nanophotonic Devices ◽  
Resonance Modes ◽  
Polarization Characteristics

Conventional polarizers including sheet, wire-grid, prism, and Brewster-angle type polarizers are not easily integrated with photonic circuits. Polarizing elements on the nanoscale are indispensable for integrated all-optical nanophotonic devices. Here, we propose a plasmonic nanopolarizer based on a silver nanorod. The polarization characteristics result from the excitation of different resonance modes of localized surface plasmons (LSPs) at different wavelengths. Furthermore, the polarization characteristics in near field regions have been demonstrated by the electric field distribution of the nanorod based on finite-difference time-domain (FDTD) simulation, indicating a strong local resonant cavity with a standing wave mode for transverse electric (TE) polarization and weak electric fields distributed for transverse magnetic (TM) polarization. The nanopolarizer can efficiently work in the near field region, exhibiting a nanopolarization effect. In addition, very high extinction ratios and extremely low insertion losses can be achieved. Particularly, the nanopolarizer can work in a broadband from visible to near-infrared wavelengths, which can be tuned by changing the aspect ratio of the nanorod. The plasmonic nanopolarizer is a promising candidate for potential applications in the integration of nanophotonic devices and circuits.

Plasmonic Lithography

2004 ◽  
Author(s):  
W. Srituravanich ◽  
N. Fang ◽  
C. Sun ◽  
S. Durant ◽  
M. Ambati ◽  
...  
Keyword(s):  
Surface Plasmons ◽  
Ion Beam ◽  
Near Field ◽  
Diffraction Limit ◽  
Fdtd Simulation ◽  
Hole Array ◽  
Exposure Test ◽  
Spacer Layer ◽  
Bull's Eye ◽  
Sub Wavelength

As the next-generation technology moves below 100 nm mark, the need arises for a capability of manipulation and positioning of light on the scale of tens of nanometers. Plasmonic optics opens the door to operate beyond the diffraction limit by placing a sub-wavelength aperture in an opaque metal sheet. Recent experimental works [1] demonstrated that a giant transmission efficiency (>15%) can be achieved by exciting the surface plasmons with artificially displaced arrays of sub-wavelength holes. Moreover the effectively short modal wavelength of surface plasmons opens up the possibility to overcome the diffraction limit in the near-field lithography. This shows promise in a revolutionary high throughput and high density optical lithography. In this paper, we demonstrate the feasibility of near-field nanolithography by exciting surface plasmon on nanostructures perforated on metal film. Plasmonic masks of hole arrays and “bull’s eye” structures (single hole surrounded by concentric ring grating) [2] are fabricated using Focused Ion Beam (FIB). A special index matching spacer layer is then deposited onto the masks to ensure high transmissivity. Consequently, an I-line negative photoresist is spun on the top of spacer layer in order to obtain the exposure results. A FDTD simulation study has been conducted to predict the near field profile [3] of the designed plasmonic masks. Our preliminary exposure test using these hole-array masks demonstrated 170 nm period dot array patterns, well beyond the resolution limit of conventional lithography using near-UV wavelength. Furthermore, the exposure result obtained from the bull’s eye structures indicated the characteristics of periodicity and polarization dependence, which confirmed the contribution of surface plasmons.

scholarly journals Design and Optimization of Plasmon Resonance Sensor Based on Micro–Nano Symmetrical Localized Surface

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 841
Author(s):  
Fengyu Yin ◽  
Jin Liu ◽  
Haima Yang ◽  
Aleksey Kudreyko ◽  
Bo Huang
Keyword(s):  
Refractive Index ◽  
Plasmon Resonance ◽  
Incident Angle ◽  
Near Field ◽  
Measurement Techniques ◽  
Fdtd Simulation ◽  
Localized Surface Plasmon ◽  
Small Scale ◽  
Surface Plasma Resonance ◽  
Resonance Sensor

Surface Plasma resonance (SPR) sensors combined with biological receptors are widely used in biosensors. Due to limitations of measurement techniques, small-scale, low accuracy, and sensitivity to the refractive index of solution in traditional SPR prism sensor arise. As a consequence, it is difficult to launch commercial production of SPR sensors. The theory of localized surface plasmon resonance (LSPR) developed based on SPR theory has stronger coupling ability to near-field photons. Based on the LSPR sensing theory, we propose a submicron-sized golden-disk and graphene composite structure. By varying the thickness and diameter of the array disk, the performance of the LSPR sensor can be optimized. A graphene layer sandwiched between the golden-disk and the silver film can prevent the latter from oxidizing. Symmetrical design enables high-low concentration of dual-channel distributed sensing. As the fixed light source, we use a 632.8-nm laser. A golden nano-disk with 45 nm thickness and 70 nm radius is designed, using a finite difference time domain (FDTD) simulation system. When the incident angle is 42°, the figure of merit (FOM) reaches 8826, and the measurable refractive index range reaches 0.2317.

Nanostructuring With Scanning Probe Microscope Tip Irradiated With Femtosecond Laser

2002 ◽  
Author(s):  
Anant Chimmalgi ◽  
Taeyoul Choi ◽  
Costas P. Grigoropoulos
Keyword(s):  
Femtosecond Laser ◽  
Data Storage ◽  
Near Field ◽  
Laser System ◽  
Ambient Air ◽  
Femtosecond Laser Pulses ◽  
Scanning Probe Microscope ◽  
Scanning Probe ◽  
Fdtd Simulation ◽  
Probe Microscope

Nanostructures, which have characteristic dimensions that are difficult to achieve by conventional optical lithography techniques, are finding ever-increasing applications in a variety of fields. High resolution, reliability and throughput fabrication of these nanostructures is essential if applications incorporating nanodevices are to gain widespread acceptance. Owing to the minimal thermal and mechanical damage, ultra-short pulsed laser radiation has been shown to be effective for precision material processing and surface micro-modification. In this work, nanostructuring based on local field enhancement in the near field of a Scanning Probe Microscope (SPM) probe tip irradiated with femtosecond laser pulses has been studied. High spatial resolution (~10–12nm), flexibility in the choice of the substrate material and possibility of massive integration of the tips make this method highly attractive for nanomodification. We report results of nanostructuring of gold thin film utilizing an 800nm femtosecond laser system in conjunction with a commercial SPM in ambient air. Further, Finite Difference Time Domain (FDTD) simulation results for the spatial distribution of the laser field intensity beneath the tip are presented. Potential applications of this method include nanolithography, nanodeposition, high-density data storage, as well as various biotechnology related applications.

Simulation of Electromagnetic Field Distribution at a Nanowire Probe for Near Field Scanning Optical Microscopy

2008 ◽  
Author(s):  
Nathan P. Malcolm ◽  
Alex J. Heltzel ◽  
Li Shi ◽  
John R. Howell
Keyword(s):  
Optical Microscopy ◽  
Signal To Noise Ratio ◽  
Near Field ◽  
Three Dimensional ◽  
Field Enhancement ◽  
Fdtd Simulation ◽  
Plasmonic Nanoparticle ◽  
Excitation Laser ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

This work studies a new design of a near field scanning optical microscopy (NSOM) probe based on a ZnO nanowire sub-wavelength waveguide terminated with a plasmonic gold nanoparticle. Three-dimensional finite difference time domain (FDTD) simulation is used to visualize light guiding in the nanowire and near field coupling between the plasmonic nanoparticle and the substrate. The simulation results reveal local field enhancement at the gap between the nanoparticle and a gold substrate when the nanowire axis is tilted from the substrate normal by a small angle. The enhancement occurs only along the cross section plane that is parallel to the polarization of the excitation laser beam. The regime of field enhancement is much smaller than the diameter of the 100 nm plasmonic particle, making the nanowire probe well suited for NSOM with superior spatial resolution and signal to noise ratio compared to the state of the art.

scholarly journals Preparation and characteristic analysis of nanofacula array

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lina Shao ◽  
Xin Tian ◽  
Shengxiang Ji ◽  
Hongda Wang ◽  
Yan Shi
Keyword(s):  
Metal Film ◽  
Near Field ◽  
Super Resolution ◽  
Microlens Array ◽  
High Energy ◽  
Fdtd Simulation ◽  
Characteristic Analysis ◽  
Central Wavelength ◽  
Lift Off ◽  
Array Fabrication

AbstractThe development of nanofacula array is an effective methods to improve the performance of Near-field Scanning Optical Microscopy (NSOM) and achieve high-throughput array scanning. The nanofacula array is realized by preparing metal nanopore array through the "two etching-one development" method of double-layer resists and the negative lift-off process after metal film coating. The shading property of metal film plays important rules in nanofacula array fabrication. We investigate the shading coefficient of three kinds of metal films (gold–palladium alloy (Au/Pd), platinum (Pt), chromium (Cr)) under different coating times, and 3.5 min Au/Pd film is determined as the candidate of the nanofacula array fabrication for its lower thickness (about 23 nm) and higher shading coefficient (≥ 90%). The nanofacula array is obtained by irradiating with white light (central wavelength of 500 nm) through the metal nanopore array (250/450 nm pore diameter, 2 μm pore spacing and 7 μm group spacing). Moreover, the finite difference and time domain (FDTD) simulation proves that the combination of nanopore array and microlens array achieves high-energy focused nanofacula array, which shows a 3.2 times enhancement of electric field. It provides a new idea for NSOM to realize fast super-resolution focusing facula array.

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