scholarly journals Investigation on Super-Resolution Focusing Performance of a TE-Polarized Nanoslit-Based Two-Dimensional Lens

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 3
Author(s):  
Yechuan Zhu ◽  
Shun Zhou ◽  
Zhiheng Wang ◽  
Yiting Yu ◽  
Weizheng Yuan ◽  
...  
Keyword(s):  
Focal Length ◽  
Fdtd Method ◽  
Super Resolution ◽  
High Refractive Index ◽  
Diffraction Limit ◽  
Two Dimensional ◽  
Lens Aperture ◽  
Wide Wavelength Range ◽  
Lens Focal Length ◽  
Difference Time

Conventional optics suffer from the diffraction limit. Our recent work has predicted a nanoslit-based two-dimensional (2D) lens with transverse-electric (TE) polarized design that is capable of realizing the super-resolution focusing of light beyond the diffraction limit in the quasi-far field. Furthermore, the super-resolution capability can be kept in a high-refractive-index dielectric over a wide wavelength range from ultraviolet to visible light. Here, we systematically investigate the influence of various factors on the super-resolution focusing performance of the lens. Factors such as lens aperture, focal length and nanoslit length are considered. In particular, the influence of nanoslit length on lens focusing was ignored in the previous reports about nanoslit-based 2D lenses, since nanoslit length was assumed to be infinite. The numerical results using the finite-difference time-domain (FDTD) method demonstrate that the super-resolution focusing capability of a nanoslit-based 2D lens increases with the lens aperture and reduces with the increase of the lens focal length. On the other hand, it is notable that the length of the lens focus is not equal to but smaller than that of the nanoslits. Therefore, in order to achieve a desired focus length, a lens should be designed with longer nanoslits.

Investigation of Contact Conditions During Stamping of a Thin Plate

2020 ◽  
Author(s):  
Harshal Y. Shahare ◽  
Rohan Rajput ◽  
Puneet Tandon
Keyword(s):  
Wave Propagation ◽  
Material Properties ◽  
High Speed ◽  
Fdtd Method ◽  
Propagation Model ◽  
Transmitted Wave ◽  
Two Dimensional ◽  
Contact Conditions ◽  
Simulation Based ◽  
Difference Time

Abstract Stamping is one of the most used manufacturing processes, where real-time monitoring is quite difficult due to high speed of the mechanical press, which leads to deterioration of the accuracy of the products In the present work, a method is developed to model elastic waves propagation in solids to measure contact conditions between die and workpiece during stamping. A two-dimensional model is developed that reduces the wave propagation equations to two-dimensional equations. To simulate the wave propagation inside the die-workpiece model, the finite difference time domain (FDTD) method and modified Yee algorithm has been employed. The numerical stability of the wave propagation model is achieved through courant stability condition, i.e., Courant-Friedrichs-Lewy (CFL) number. Two cases, i.e., flat die-workpiece interface and inclined die-workpiece interface, are investigated in the present work. The elastic wave propagation is simulated with a two-dimension (2D) model of the die and workpiece using reflecting boundary conditions for different material properties. The experimental and simulation-based results of reflected and transmitted wave characteristics are compared for different materials in terms of reflected and transmitted wave height ratio and material properties such as acoustic impedance. It is found that the numerical simulation results are in good agreement with the experimental results.

Two Dimensional Photonic Filter with a Circular Resonant Cavity

2013 ◽  
Vol 712-715 ◽  
pp. 1751-1754
Author(s):  
Zhao Xia Wu ◽  
Yuan Long Shao ◽  
Wen Chao Li ◽  
Er Dan Gu
Keyword(s):  
Dielectric Constant ◽  
Resonant Cavity ◽  
Fdtd Method ◽  
Circular Ring ◽  
Two Dimensional ◽  
Transmission Characteristics ◽  
New Type ◽  
Micro Cavity ◽  
The Impact ◽  
Difference Time

A new type of the two dimensional photonic filter which includes two in-line waveguides and a circular ring resonant cavity is presented in this paper. By using Finite Difference Time Domain (FDTD) method, we calculated and demonstrated the broadband frequency response of the filter and analyzed the impact of changing the dielectric constant of the inner rods on the transmission characteristics of the filter. Compared with the transmission characteristics of a micro-cavity,our numerical results show that such a filter can transmit multiple narrowband signals simultaneously. The number of the passbands of the filter increases with the rings of inner dielectric rods in the cavity. The center wavelength of the passbands can be tuned by adjusting the dielectric constant of the whole rods and inner rods without changing the size of the cavity..

Design Two Dimensional Nanocavity Photonic Crystal Biosensor Detection in Malaria

2018 ◽  
Vol 6 (6) ◽  
pp. 16 ◽  
Author(s):  
Varsha Sharma ◽  
Vijay Laxmi Kalyani
Keyword(s):  
Photonic Crystal ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Fdtd Method ◽  
Expansion Method ◽  
Two Dimensional ◽  
Plane Wave Expansion ◽  
Plane Wave Expansion Method ◽  
Output Terminal ◽  
Difference Time

In this paper we design a two dimensional (2-D) photonic crystal based biosensor implemented by linear waveguide and nanocavity detection in malaria. The bio molecules such as a red blood cell, infected red blood cell, trapped inside the nanocavity cause transmission shift at the output terminal.  The sensing mechanism of biosensor is change in refractive index of analytes. The layout biosensor is consists a linear waveguide with a nanocavity in square symmetry For the proposed photonic based biosensor, the band gap from 2210nm to 1420 nm and input wavelength of 1550nm are used in this design. The simulation results have analysed by using the finite difference time domain (FDTD) method, bandgap calculation is performed using plane wave expansion method.

Limit Of Phase Only Approach In Micro–Lens Design

2012 ◽  
Author(s):  
Ali Jebelli ◽  
Ruzairi Abdul Rahim ◽  
Seyed H. Kazemi
Keyword(s):  
Focal Length ◽  
Fdtd Method ◽  
Absorbing Boundary Conditions ◽  
Lens Design ◽  
Diffractive Optical Elements ◽  
Absorbing Boundary ◽  
Optical Elements ◽  
Perfect Matched Layer ◽  
Difference Time ◽  
Micro Lens

Phase only approach (POA) is generally used to analyze diffractive optical elements (DOEs) such as micro–lenses. We used 3–D finite difference time domain (FDTD) method with perfect matched layer (PML) absorbing boundary conditions to test several micro–lenses that were designed based on phase only approach to evaluate the accuracy of this approach. It is shown that if the focal length is greater than 80λ and 25λ for 2π and 4π phase resets, respectively, the error in the main lobe diffraction efficiency will be less than 10%. Key words: Phase only approach (POA); diffractive optical elements (DOEs); micro–lens

scholarly journals Electromagnetic Imaging of Two-Dimensional Geometries by Multipulse Interference Using the Inverse FDTD Method

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Naoki Okada ◽  
James B. Cole
Keyword(s):  
Fdtd Method ◽  
Simple Calculation ◽  
The Body ◽  
Two Dimensional ◽  
Multiple Objects ◽  
Incident Wavelength ◽  
Electromagnetic Imaging ◽  
Imaging Results ◽  
Phase Interference ◽  
Difference Time

The size, shape, and location of unknown objects in the ground and in the body can be estimated by an electromagnetic imaging technique. An imaging approach to clear detection of two-dimensional geometries is proposed in this paper. Based on the inverse finite-difference time-domain (FDTD) method, a phase interference technique using multidirectional pulses is employed. The advantage of the proposed method is that it can clearly reconstruct the geometry in a simple calculation. Sample imaging results are demonstrated. The analysis of the FDTD results shows that the detectable object size is limited by the incident wavelength and the measurement spacing and illustrates the detectability of multiple objects.

Wavelet-Based FDTD and High Resolution Spectral Estimation for Calculation of Band Structures in Two-Dimensional Phononic Crystals

2014 ◽  
Vol 575 ◽  
pp. 108-114
Author(s):  
Zhi Zhong Yan
Keyword(s):  
High Resolution ◽  
Spectral Estimation ◽  
Phononic Crystal ◽  
Fdtd Method ◽  
Phononic Crystals ◽  
Two Dimensional ◽  
Band Structures ◽  
Time Stepping ◽  
Long Time ◽  
Difference Time

This paper discusses the wavelet-based Finite Difference Time Domain (FDTD) method and high resolution spectral estimation with a specific problem of sound wave propagation through phononic crystals. If the band structures of a phononic crystal are calculated by the traditional FDTD method combined with the fast Fourier transform (FFT), good estimation of the eigenfrequencies can only be ensured by the postprocessing of sufficiently long time series generated by a large number of FDTD iterations. In this paper, a postprocessing method based on the high-resolution spectral estimation via the Yule-Walker method is proposed to overcome the difficulty. Numerical simulation results for two-dimensional phononic crystal show that, the wavelet-based FDTD method improves the efficiency of the time stepping algorithm, and high resolution spectral estimation shows the advantages over the classic FFT-based postprocessing.

scholarly journals 2D Anisotropic Photonic Crystals of Hollow Semiconductor Nanorod with Liquid Crystals

2013 ◽  
Vol 394 ◽  
pp. 38-44
Author(s):  
Filiz Karaomerlioglu ◽  
Sevket Simsek ◽  
Amirullah M. Mamedov ◽  
Ekmel Ozbay
Keyword(s):  
Optical Properties ◽  
Photonic Crystals ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Light Wave ◽  
Fdtd Method ◽  
Two Dimensional ◽  
Plane Wave Expansion ◽  
Control Light ◽  
Difference Time

Photonic crystals (PCs) have many applications in order to control light-wave propagation. A novel type of two-dimensional anisotropic PC is investigated band gap and optical properties as a hollow semiconductor nanorod with nematicliquid crystals (LC). The PC structure composed of an anisotropic nematicLC in semiconductor square hollow nanorod is designed using the plane wave expansion (PWE) method and finite-difference time-domain (FDTD) method. It has been used 5CB (4-pentyl-4`-cyanobiphenyl) as LC core, and Tellurium (Te) as square hollow nanorod material.The PC with hollow Tenanorod with nematicLC is compared with the PC with solid Tenanorodand the PC with hollow Tenanorod.

scholarly journals ADE-FDTD method for study of two-dimensional electromagnetic wave propagation in lossy lorentz medium

2020 ◽  
Vol 309 ◽  
pp. 01002
Author(s):  
Bingkang Chen
Keyword(s):  
Electromagnetic Wave ◽  
Plane Electromagnetic Wave ◽  
Fdtd Method ◽  
Two Dimensional ◽  
One Dimensional ◽  
Coefficient Of Reflection ◽  
Difference Formula ◽  
Medium Layer ◽  
The Difference ◽  
Difference Time

In order to study the reflection of electromagnetic wave in Lorentz medium layer, the finite difference time domain method of auxiliary differential equation (ADE-FDTD) is used to derive the difference formula of two-dimensional TM wave propagating in lossy Lorentz medium, and the reflection coefficient of reflection field is calculated in one-dimensional case. The calculated reflection coefficients coincide very well, which shows that the derived propagation formula of two-dimensional TM wave in lossy Lorentz medium is correct. In addition, the reflection of plane electromagnetic wave by infinite high Lorentz medium layer is also simulated. The results show that the reflection of plane electromagnetic wave by Lorentz dispersive medium layer is correct.

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