On Feb 20, 2009, at 4:02 AM, cef...@sina.com wrote:
I design a PC waveguide , but the period of waveguide is not equal to the period of crystal .When i calculate the mode of the waveguide , how to set the k-point ?
If the periods are commensurate, then the period should be the least common multiple of the two periods.
If the periods aren't commensurate (i.e. one is not a rational multiple of the other), then you don't really have a "waveguide" because you don't have translational symmetry.
The "k" is only meaningful with respect to the actual period of the structure (if any), which is the least common multiple (if any). "k" comes from periodicity (via Bloch's theorem). See e.g. our book ab- initio.mit.edu/book
Steven _______________________________________________ mpb-discuss mailing list mpb-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss
