The computer program solves Maxwell's equations using a finite-difference time-domain (FDTD) algorithm, where the electric and magnetic field nodes are spatially and temporally staggered over a three-dimensional topography of interest. Version 7 was written for a single processor and has been compiled under Windows XP, Windows Vista, and Linux. The simulation domain may represent periodic, symmetric, or isolated topographies. The algorithm is capable of simulating problems such as scattering from small surface features, surface plasmon couplers, photonic crystals, out-of-plane illumination of grating structures, and transmission through phase-shifting masks.
Illumination can be monochromatic or pulsed and the polarization and incidence angles can be oriented in any direction. Illumination is assumed to be coherent. Monochromatic sources can be constructed with arbitrary amplitude and phase profiles. Matlab scripts are provided to write these source profiles to disk.
TEMPEST parses topography information from an input file. During simulation startup, TEMPEST reads the input file and gives detailed information about any errors encountered. The input geometry is then simulated for a user-specified number of iterations. The topography, field snapshots, and internal simulator state are written to output files during the simulation.
New in Version 7.0:
Version 7.0 of TEMPEST has several extensions from the previous version (version 6.0). PML has been updated to better handle evanescent fields, match discontinuities in refractive index, and to match different material models (so that waveguides may be terminated without reflection). Floquet boundary conditions have been added to enable plane-wave illumination at any angle. Sources can be pulsed, in addition to monochromatic. Floating point precision has been doubled to enable modeling of extremely sub-wavelength features. Matlab scripts enable the modeling of surface plasmon sources and scattered field sources (which enable uniform plane-wave illumination in simulations with PML placed along all edges). Material models for gold and silver in the visible spectrum have been added. Finer grained control over topography placement has been added. Materials can be placed down to the half-cell level so that all boundaries can terminate on the same field component (removing small numerical scattering asymmetries). A few options have disappeared since version 6, including parallel operation and photoresist bleaching.
Version7 was designed to be very flexible so that TEMPEST could be applied to waveguide devices, in addition to photomask scattering. The user has more control over the detailed inner-workings, such as being able to specify material models down to the field component level and placing sources in any field component. The number of output files has been increased so that the user can ascertain the simulator’s internal configuration. The input file language has been extended to accommodate the increased number of options and is more C-like. Increased flexibility comes at the price of larger memory requirements and longer run-times.
Additonally, this version of TEMPEST is tightly integrated with Matlab. Many Matlab scripts are packaged along with the core C++ code both to create input files and process the outputs.
TEMPEST v7 was designed to model surface plasmon and photonic crystal devices, while preserving the functionality required for photomask scattering. It was written in C++ and is tightly linked with Matlab. It uses the ANTLR package (www.antlr.org) to parse input files. During development, TEMPEST was routinely used on Linux (especially RedHat) and Windows XP computers. It has also been run on Windows Vista. Makefiles and compilation notes are included in the release package.
Documentation Included with the Tape:
- A. Wong and T. Pistor, TEMPEST Version 5.0 (UCB/ERL M98/50, August 1998). Available separately for $5.00
Additional Documentation Available:
- A. Wong, TEMPEST Version 4.0 User's Guide (UCB/ERL M95/14, March 1995). Available separately for $5.00
- A. Wong, "Rigorous Three-Dimensional Time-Domain Finite-Difference Electromagnetic Simulation," Ph.D. thesis (UCB/ERL M94/69, September 1994) $5.00.
- A. Wong, "Two-Dimensional Electromagnetic Simulation of Topography Scattering and Diffraction for Optical Lithography," M.S. thesis (UCB/ERL M92/115, October 1992) $5.00.
- K. H. Tadros, "Investigation of Optical Phenomena in Photolithography and Optical Metrology Using Massively Parallel Simulation," M.S. thesis (UCB/ERL M91/72, August 1991) $11.00.