QPMS README

QPMS is a toolkit for frequency-domain simulations of photonic systems consisting of compact objects (particles) inside a homogeneous medium. Scattering properties of the individual particles are described by their T-matrices (which can be obtained e.g. with the scuff-tmatrix tool from the SCUFF-EM suite).

QPMS handles the multiple scattering of electromagnetic radiation between the particles. The system can consist either of a finite number of particles or an infinite number of periodically arranged lattices (with finite number of particles in a single unit cell).

Features

Finite systems

• Computing multipole excitations and fields (TODO) scattered from nanoparticle clusters illuminated by plane, spherical or cylindrical (TODO) waves.
• Finding eigenmodes.
• Calculating cross sections (TODO).
• Reducing numerical complexity of the computations by exploiting symmetries of the cluster (decomposition to irreducible representations).

Infinite systems (lattices)

• 2D-periodic systems supported. (TODO 1D and 3D.)
• Calculation of transmission and reflection properties (TODO).
• Finding eigenmodes and calculating dispersion relations.
• Calculation of far-field radiation patterns of an excited array (TODO).
• Reducing numerical complexity of the computations by exploiting symmetries of the lattice (decomposition to irreducible representations).

Installation

The package depends on several python modules, a BLAS/LAPACK library with the respective C bindings (incl. the lapacke.h and cblas.h headers; OpenBLAS does have it all and is recommended) and GSL (>= 2.0). The python module dependencies should be installed automatically when running the installation script. If you have a recent enough OS, you can get GSL easily from the repositories; on Debian and derivatives, just run apt-get install libgsl-dev under root. Alternatively, you can get the source and compile it yourself.

You also need a fresh enough version of cmake.

After GSL is installed, you can install qpms to your local python library using::

  cmake .
  make amos
  python3 setup.py install --user

If GSL is not installed the standard library path on your system, you might need to pass it to the installation script using the LIBRARY_PATH and LD_LIBRARY_PATH environment variables.

Special care has often be taken when installing QPMS in cluster environments. Specific installation instructions for Aalto University's Triton cluster can be found in a separate document.

Documentation

Documentation of QPMS is a work in progress. Most of the newer code is documented using doxygen comments. To build the documentation, just run doxygen in the root directory; the documentation will then be found in docs/html/index.html.

Of course, the prerequisite of this is having doxygen installed. If you don't, you will probably find it easily in your OS's repositories. On Debian and derivatives, simply run apt-get install doxygen under root.

Tutorials

• Infinite system (lattice) tutorial
• Finite system tutorial