A program for calculating photonic band structures, Green's functions and transmission/relfection coefficients using a non-orthogonal FDTD method. A.J. Ward, J.B. Pendry.

Title of program: ONYX Version 2.1
Catalogue identifier: ADLU
Ref. in CPC: 128(2000)590
Distribution format: tar gzip file
Operating system: UNIX V3.2D-1 (Rev. 41)
High speed store required: 23MK words
Number of bits in a word: 32
Number of lines in distributed program, including test data, etc: 13192
Programming language used: Fortran
Computer: Digital Alpha 250

Other versions of this program:

 Cat. Id.  Title                             Ref. in CPC
 ADIJ      ONYX                               112(1998)23                    

Nature of physical problem:
Efficient calculation of either photonic dispersion relationships, Green's functions or transmission and reflection coefficients for photons in complex dielectric structures.

Method of solution
A discretisation of Maxwell's equations in both the space and time domains which leads to finite difference equations connecting the electric and magnetic fields at one time step to those at the next. After using these equations to find the response in the time domain to a particular initial set of fields, we perform a Fourier transform to obtain the response in the frequency domain. From this we can easily extract dispersion relationship information, or alternatively, by setting the initial fields to be a delta function, we can obtain the Green's function for the system under consideration. In addition, by projecting onto a complete basis set of plane waves we can find the transmission and reflection matrices for the scattering system.

Restrictions on the complexity of the problem
The complexity of the dielectric structure that the method can be applied to is limited only by the computer time and memory available. Both time and memory requirements scale linearly with the system size. One restriction on the method is that the dielectric permittivity and magnetic permeability must both be independent of frequency. This means it cannot treat some problems, typically those involving metals.

Typical running time
Highly dependent on the system under consideration. For the test transmission calculation given, 120 seconds on a Digital Alpha 250 workstation.

Unusual features of the program
Option to work with non-orthogonal co-ordinate systems.