Plasmonic materials in MEEP

  The aim of this post is to share my experience in incorporating dielectric function of metals such as gold and silver into MEEP (a free finite difference time domain package) code. The incorporation is not an easy task and can be daunting for the first time user. Metals such as gold and silver have both Drude and Lorentz components for the dielectric function. There are many forms of Lorentz-Drude expressions in literature with slight notation differences. I prefer the Lorentz-Drude expression mentioned in Rakic et al., Optical properties of metallic films for vertical-cavity optoelectronic devices, Applied Optics (1998) and Read More …

Charge density in metal nanoparticles at plasmon resonance

It is important to know the magnitude and distribution of electric field near the metallic nanoparticles at plasmon resonance. One can look at the electric field and say whether the plasmon mode is dipolar or higher order mode such as qudrapolar mode. At many times one is also interested to know the surface charge density which makes easier to identify the plasmon mode. One can get the surface charge density by talking the divergence of electric field (near field) either calculated by DDA method or FDTD method [Reference paper]. Below I have calculated the electric field near nanoparticle at plasmon Read More …

Spoof Plasmons / Designer Surface Plasmons

Aim of this article/post: To 1) introduce the concept of Designer surface plasmons or Spoof plasmons and 2) Dispersion relations and Visualization of the fields using MEEP code. (Some of the text/simulations are taken from my paper in the area of DSPs.) Surface Plasmons are electromagnetic waves that travel at the interface of metals such as Ag/Au (follow Lorentz-Drude dielectric model) and a dielectric. Surface plasmons are not expected in perfect electric conductors (PEC’s) as the electric field inside the metal is zero. However, highly localized surface-bound states appear when the PEC is periodically modulated with arrays of sub-wavelength square Read More …

DDSCAT and electric field at plasmon resonance

Discrete Dipole Approximation (DDA) is an important tool in plasmonics research. Using DDA, one can calculate scattering properties of nanoparticles at various wavelengths, polarizations and surrounding medium. The specialty of DDA is that one can calculate scattering properties of irregular shape particles (particles other than spheroids). DDA is based on representing a particle into a set of interacting dipoles and solving their dipole moments such that they are all self-conistent with each other and are linked by far-field and near-field interactions. Once these dipole moments are calculated, they can be used to calculate scattering properties such as scattering efficiency, absorption Read More …

Nmie: Extinction, Scattering and Absorption efficiencies of multilayer nanoparticles

Since 2009, I have been a regular user of Nanohub.org. www.Nanohub.org is a website that provides a platform for online simulation, research and teaching resources. Of interest is the ability to perform simulation online without installing software on your local computer. I envision that this type of cloud computing model will be the future of scientific computing. Developers can use their Rappture toolkit (nice video to learn Rappture toolkit) to write wrappers for codes that are written in Fortran, C or Matlab and enable an easy to use GUI for the executables. There are few tools for Plasmonics on nanohub Read More …

Beamer Themes

One can use Beamer to make high quality presentations using Latex code. To know more about beamer and its capabilities visit here and here. Beamer comes with a set of default templates. However,it has capability to design new themes. Here, I will maintain a list of beamer themes shared by beamer users. If you know any that are not listed below, please let me know and I can add here for the greater good. http://recherche.noiraudes.net/fr/LaTeX.php http://blog.barisione.org/2007-09/torino-a-pretty-theme-for-latex-beamer/ http://www.win.tue.nl/latex/documentation/tuebeamer/tueslides.pdf http://www.shawnlankton.com/2008/02/beamer-and-latex-with-keynote-theme/ http://www.ist.tugraz.at/staff/weiglhofer/misc/tugbeamer/ http://www.guidodiepen.nl/2009/04/latex-beamer-diepen-style/ http://matdat.life.ku.dk/LaTeX/Frederiksberg/examples.html http://win.ua.ac.be/~nschloe/content/ua-beamer-theme http://www.kde.org/kdeslides/ http://latex-my.blogspot.com/2009/10/kde-beamer-themes.html http://www.cert.fr/dcsd/PUBLIS/THESES/sbouveret/francais/LaTeX.html http://win.ua.ac.be/~nschloe/content/ua-beamer-theme http://cameron.bracken.bz/beamer-template https://bitbucket.org/marczellm/beamerports http://latex.simon04.net/

WINSPALL software for surface plasmon resonance experiments

One needs to fit the reflectivity curves obtained in surface plasmon resonance experiments with theoretical models. A free software (for non commercial use) called Winspall exactly does that. According to the developers, WINSPALL is a PC based software which computes the reflectivity of optical multilayer systems. It is based on the Fresnel equations and the matrix formalism. It can be used to analyze surface plasmon experiments. WINSPALL was developed in the Knoll group. WINSPALL is available for use without charge. It may not be reused for commercial purposes. It is available for download here. you can download the software from Read More …

My list of most used packages for ubuntu

To install octave, gnuplot,numpy,scipy,matplotlib,gcc-4.2-base, gfortran sudo apt-get install octave gnuplot \ ipython python-numpy python-scipy \ python-matplotlib wine gcc-4.2-base gfortran-4.2 To install graphics programs: gimp, imagmagick and inkscape sudo apt-get install inkscape gimp imagemagick To install most of the multimedia requirements  sudo apt-get install vlc mozilla-plugin-vlc gstreamer0.10-ffmpeg \ gstreamer0.10-fluendo-mp3 gstreamer0.10-fluendo-mpegdemux \ gstreamer0.10-plugins-ugly gstreamer0.10-plugins-ugly-multiverse \ gstreamer0.10-plugins-bad gstreamer0.10-plugins-bad-multiverse w32codecs To install Microsoft fonts sudo apt-get install msttcorefonts To install latex relates stuff, kile sudo apt-get install texlive kile texlive-latex-extra texlive-xetex lmodern To install utilities: sudo apt-get install subversion unrar kdiff3

Python

I am playing with Python for the first time. The syntax seems to be so natural. So many modules (numpy, scipy and matplotlib) for researchers/scientists. Cannot see any shortcoming at this point. Perhaps need more testing and implementation. Some questions I am looking answers for: Is it faster than Fortran? If not faster, can it do everything Matlab does, such as availability of host of toolboxes?

Resources on Electromagnetics/Plasmonics/Nanophotonics

These are some resources on Electromagnetics/plasmonics/nanophotonics I will maintain a list of free resources on electromagnetics, plasmonics, nanophotonics, optics and other related topics here. If any of you (readers) know any other free resources related to this topic, please let me know and I can add into these lists. Free books: Electromagnetic waves and Antennas by Prof. Sophocles J. Orfanidis Surface plasmons by Smooth and Rough surfaces by Heinz Raether (Note: This book is hosted by Prof. Shalaev’s on Nanophotonics & Metamaterials course website). Photonic Crystals:Molding the Flow of Light by John D. Joannopoulos, Steven G. Johnson, Joshua N. Winn, and Robert D. Meade. This can be downloaded from their Read More …