FDTD Study of the Surface Waves Detection in Apertureless Scanning Near-Field Microscopy

2008 ◽  
Author(s):  
G. Parent ◽  
S. Fumeron ◽  
D. Lacroix
Keyword(s):  
Surface Waves ◽  
Near Field ◽  
Fdtd Method ◽  
Three Dimensional ◽  
Far Field ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Experimental Tool ◽  
Field Transformation ◽  
Difference Time

Recent studies have shown the importance of surface waves in heat transfer near interfaces. The scanning near field optical microscopy (SNOM) provides an experimental tool to investigate the thermal electromagnetic field near surfaces. In this work, we present a three dimensional model of SNOM devices. This model is based on the finite-difference-time domain (FDTD) method associated to a near to far field transformation. Near field and far field scattered by a silicon tetrahedral tip and by a pecfectly conducting one are presented and discussed.

scholarly journals Roughness effect on the efficiency of dimer antenna based biosensor

2012 ◽  
Vol 1 (2) ◽  
pp. 41 ◽  
Author(s):  
D. Barchiesi ◽  
S. Kessentini
Keyword(s):  
Surface Roughness ◽  
Near Field ◽  
Three Dimensional ◽  
Biological Molecules ◽  
Far Field ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Roughness Effect ◽  
Highly Sensitive ◽  
Local Plasmon

The fabrication process of nanodevices is continually improved. However, most of the nanodevices, such as biosensors present rough surfaces with mean roughness of some nanometers even if the deposition rate of material is more controlled. The effect of roughness on performance of biosensors was fully addressed for plane biosensors and gratings, but rarely addressed for biosensors based on Local Plasmon Resonance. The purpose of this paper is to evaluate numerically the influence of nanometric roughness on the efficiency of a dimer nano-biosensor (two levels of roughness are considered). Therefore, we propose a general numerical method, that can be applied to any other nanometric shape, to take into account the roughness in a three dimensional model. The study focuses on both the far-field, which corresponds to the experimental detected data, and the near-field, responsible for exciting and then detecting biological molecules. The results suggest that the biosensor efficiency is highly sensitive to the surface roughness. The roughness can produce important shifts of the extinction efficiency peak and a decrease of its amplitude resulting from changes in the distribution of near-field and absorbed electric field intensities.

Modification to time domain near-field to far-field transformation for FDTD method

1997 ◽  
Vol 33 (25) ◽  
pp. 2132
Author(s):  
A. Giannopoulos ◽  
B.S. Randhawa ◽  
J.M. Tealby ◽  
A.C. Marvin
Keyword(s):  
Time Domain ◽  
Near Field ◽  
Fdtd Method ◽  
Far Field ◽  
Field Transformation

Effect of the Molecular Weight and Density of Ambient Gas on Shock Wave in Laser-Assisted Nanostructuring

2008 ◽  
Author(s):  
Liying Guo ◽  
Xinwei Wang
Keyword(s):  
Shock Wave ◽  
Molecular Weight ◽  
Near Field ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Shock Wave Formation ◽  
Ambient Gas ◽  
Dynamics Simulations ◽  
Lower Ratio

This paper presents the results from molecular dynamics simulations that are performed to explore the properties of the shock wave during laser-assisted near field surface nanostructuring. A quasi-three dimensional model is constructed to study systems consisting of over 2 million atoms. This work includes studies on the velocity as well as pressure evolution of shock wave front with respect to different solid/gas molecular mass ratios and different ambient gas densities. The limitation on shock wave formation under the same laser fluence is also investigated. The results show that lower ratio of the solid/gas molecular weight weakens the strength of the shock wave during the nanostructuring process. Additionally, the formation and attenuation of the shock wave under different ambient gas conditions is studied in substantial detail.

scholarly journals Structural design of a broadband spiral nanoantenna for solar energy collection

2020 ◽  
Vol 34 (11) ◽  
pp. 2050122
Author(s):  
Na Li ◽  
Zhichao Xu ◽  
Jin Zhang ◽  
Fanji Jin
Keyword(s):  
Solar Energy ◽  
Near Field ◽  
Three Dimensional ◽  
Far Field ◽  
Archimedean Spiral ◽  
Field Patterns ◽  
Solar Energy Harvesting ◽  
Linearly Polarized ◽  
Incident Waves ◽  
Difference Time

In this research, a new design of spiral nanoantenna for solar energy harvesting was proposed and analyzed by using three-dimensional finite difference time-domain method. The structure of the proposed nanoantenna consisted of two Archimedean spiral arms integrated on a supporting substrate layer. The analysis included the radiation efficiencies, polarization, near-field characteristics and far-field patterns. The new nanoantenna considers the polarized characteristics of sunlight and has high total radiation efficiency of 74.49% within the broad wavelength range from 400 to 1600 nm, which are both superior to those of previously proposed linear antennas. Moreover, the same order of electric enhancement factor at the spiral gap was also obtained for different linearly polarized incident waves. Furthermore, the far-field characteristics of the proposed nanoantenna were studied for wide-angle reception.

Calculation of ground motion in a three-dimensional model of the 1966 Parkfield earthquake

1976 ◽  
Vol 66 (2) ◽  
pp. 405-423
Author(s):  
N. A. Levy ◽  
A. K. Mal
Keyword(s):  
Surface Waves ◽  
Ground Motion ◽  
Near Field ◽  
Three Dimensional ◽  
Vertical Component ◽  
Elastic Half Space ◽  
The Body ◽  
Body Waves ◽  
Three Dimensional Model ◽  
Ground Displacements

abstract Near-field ground displacements are calculated from an earthquake source in a homogeneous, elastic half-space. An analytical formulation of the problem is presented that requires no physical approximations except at the source. A model of the source is constructed by retaining the essential kinematic character of the faulting process. A computer program is developed to calculate ground motion from an assumed model of the 1966 Parkfield, California earthquake. Favorable agreement is obtained between the theoretically computed ground displacements and those derived from the recorded accelerations. The relative contributions of the body waves and surface waves to the displacement field are examined. The results indicate that a significant portion of near-field motion may consist of surface waves, especially in the vertical component of the ground motion.

scholarly journals Numerical Analysis of Ridged-Circular Nanoaperture for Near-Field Optical Disk

ISRN Optics ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Toshiaki Kitamura
Keyword(s):  
Phase Change ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Near Field ◽  
Fdtd Method ◽  
Three Dimensional ◽  
Free Electrons ◽  
Metallic Material ◽  
Motion Equations ◽  
Difference Time

A ridged-circular nanoaperture is investigated through three-dimensional (finite-difference time-domain) FDTD method. The motion equations of free electrons are inserted to analyze a metallic material. The electromagnetic field distributions of optical near-field around the aperture are investigated. The phase change disk illuminated by a near-field optical light through a ridged-circular nanoaperture is also analyzed. The far-field scattering patterns from the phase change disk and the crosstalk characteristics between plural marks are studied.

Three-Dimensional Model for Virtual Surgical Simulation, during Complex Skull Base Surgery and Aneurysm Surgery

Skull Base ◽  
2008 ◽  
Vol 18 (S 01) ◽  
Author(s):  
Akio Morita ◽  
Toshikazu Kimura ◽  
Shigeo Sora ◽  
Kengo Nishimura ◽  
Hisayuki Sugiyama ◽  
...  
Keyword(s):  
Skull Base ◽  
Surgical Simulation ◽  
Skull Base Surgery ◽  
Three Dimensional ◽  
Aneurysm Surgery ◽  
Dimensional Model ◽  
Three Dimensional Model
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