www.gusucode.com > FDTD计算二维光子带隙的程序 > FDTD计算二维光子带隙的程序/247787/EffectiveIndex.m
function N=EffectiveIndex(t,m) %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Electromagnetic Finite-Difference Time-Domain % % Version 1.20, Release 1 % % % % (C) Copyright 2005 % % Sharif University of Technology % % School of Electrical Engineering % % All Rights Reserved % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% global Mode TE TM NormalizedFrequency LatticeCnt global eC mC eF mF w=2*pi*NormalizedFrequency/LatticeCnt; nf=sqrt(eF*mF); nc=sqrt(eC*mC); ky1=0; ky=w*sqrt((nf^2+nc^2)/2); while abs(ky-ky1)>1e-8 ky1=real(ky); if Mode==TE ky=2*atan(w*sqrt(nf^2-nc^2-(ky/w)^2)/ky*(mF/mC))/t+pi*m/t; else ky=2*atan(w*sqrt(nf^2-nc^2-(ky/w)^2)/ky*(eF/eC))/t+pi*m/t; end end N=sqrt(nf^2-(ky/w)^2);