Density of optical states in rolled-up photonic crystals and quasi crystals

Abstract

We describe the local density of optical states (LDOS) and the density of optical states (DOS) in three dimensional (3D) finite size rolled-up photonic crystals and quasi crystals calculated using optimized code based on finite difference time domain (FDTD) techniques. Because the Bloch–Floquet theorem is not used in these calculations, the code can be applied to any dielectric structures that lack discrete translational symmetry, making it ideal for experimentally fabricated structures that are finite in size and include defects. Our software can be used for either LDOS or DOS calculations, is parallelized using standard message passing interface (MPI) protocols, and is freely available at www.fpspackage.com. Program summaryProgram title: FPSCatalogue identifier: AFBP_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AFBP_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: GNU GPL v3No. of lines in distributed program, including test data, etc.: 118342No. of bytes in distributed program, including test data, etc.: 2385803Distribution format: tar.gzProgramming language:C++.Computer: PCs and distributed memory machines.Operating system: Linux, Unix.Has the code been vectorised or parallelized?: Parallelized using message passing interface.RAM: Depending on the problem; gigabytes.Classification: 10.External routines: Minimum: MPI; [1] fftw3; [2] optional: hdf5-tools. [3]Nature of problem: The aim of FPS is providing a fast and easy to use package for studying local density of optical states and density of optical states in arbitrary shaped finite size photonic structures.Solution method: Parallel finite difference time domain method.Restrictions: The post processing codes are not parallelized. At least two processes should be used for the calculations.Unusual features: FPS provides non-experts in computational physics an intuitive tool to obtain local density of optical states and density of optical states calculations. Inserting parameters that define the geometry and the spectrums of interest into a “txt” or “h5” file are all a user needs to do.Additional comments: The package includes a tutorial describing the package and its installation, using an example.Running time: It was found that the average time to compute a single LDOS was 21 minutes. Runtime in general depends on mesh size and the number of points that local density of optical states should be calculated.