Hello Iam trying to find bandgap for a 1 dimensional photonic crystal.(bragg reflector structure) I have many doubts in simulating the structure..
1.As Iam dealing with a 1 dimensional structure,how can I specify my lattice vectors such that the structure repeats just in 1 direction.(i.e if crystal strucutre is periodic in x has to repeat in x but not in y and z).. If I specify no-size in y or z direction it doesn't consider y at all but I have to specify a length in that direction without the lattice repeating... Attached is the code that Iam using. Please help me Thanks Hyma Yalamanchili ----- Original Message ----- From: "F.S.F. Brossard" <[email protected]> Date: Saturday, December 13, 2008 8:06 pm Subject: Re: [MPB-discuss] To: Hyma Yalamanchili <[email protected]> > Hi Hyma, > > MPB does some internal dielectric averaging between boundaries so > that your structure look more realistic. It also means you probably > don't need such high resolution. For me, I rarely had to use a > resolution beyond 16 in x and y for all bandgap calculations. I > didn't see a significant difference with higher res (except a few > %). Also, you can lower your supercell size in z to 8, even for low > index material such as yours. > Howevever, you should increase your k-interp to 8 at least to make > sure you get a reasonably accurate bandgap. > Last advice: there is no need to calculate all points of the > reduced Brillouin zone to calculate the bandgap of a simple > triangular lattice with circular air-holes, at least for TE-like > modes (I have rarely looked at TM-like modes). In this last case, > just look at the K and M points of your first and second bands and > also at the intersection between the light cone and the G-K and G-M > directions. > Hope this helps, > > Frederic > > On Dec 12 2008, Hyma Yalamanchili wrote: > > >Hi Frederic > > > >Attached is the control file which Iam using.. > > > >Thank u so much for your reply. > >I hope my problem gets resolved > > > >Hyma > > > >----- Original Message ----- > >From: Frederic Brossard <[email protected]> > >Date: Friday, December 12, 2008 1:13 pm > >Subject: Re: [MPB-discuss] efield vs. dpwr, field definition --> > follow>up on old thread > >To: Hyma Yalamanchili <[email protected]> > >Cc: [email protected] > > > >> Hi Hyma, > >> > >> Could you please let us know your control file? otherwise, it is > >> difficult to know why it takes so much time without asking you a > >> lot of > >> questions first. > >> > >> Thanks, > >> > >> Frederic > >> > >> Frederic Brossard > >> Researcher > >> Cavendish Laboratory > >> J J Thomson Avenue > >> Cambridge CB3 0HE > >> > >> > >> > >> Hyma Yalamanchili wrote: > >> > Hii > >> > > >> > Iam in the initial stages of learning MPB tool. > >> > My work is mainly focused on band gap tuning. > >> > I tried to change the radius every time before I simulate and > >> find the > >> > band gap but as Iam dealing with 3-D structures,its consuming > a > >> lot of > >> > time like 4 to 5 hrs for each simulation to run. > >> > Can anybody suggest me a method to find the radius of the > >> triangular> lattice photonic crystal for a particular band gap > >> using some kind of a > >> > loop??? > >> > > >> > > >> > Thanks, > >> > hyma > >> > > >> > ----- Original Message ----- > >> > From: "Steven G. Johnson" <[email protected]> > >> > Date: Thursday, December 4, 2008 12:01 pm > >> > Subject: Re: [MPB-discuss] efield vs. dpwr, field definition --> > >> > follow up on old thread > >> > To: [email protected] > >> > > >> > > >> >> Your k point is wrong, for one thing. Maybe you're not > looking > >> at > >> >> a > >> >> band underneath the light line. > >> >> > >> >> Look at the line-defect.ctl example file included with MPB. > >> >> > >> >> Alternatively, you may find it easier to rearrange things > into > >> an > >> >> orthogonal supercell. See: > >> >> > >> >> http://article.gmane.org/gmane.comp.science.photonic-bands/1376 > >> >> http://article.gmane.org/gmane.comp.science.photonic-bands/1213 > >> >> > >> >> Steven (with a v) > >> >> > >> >> On Dec 4, 2008, at 12:10 AM, Chad Husko wrote: > >> >> > >> >> > >> >>> Stephen, > >> >>> I spent a little more time with the fields and have some > follow > >> >>> > >> >> up > >> >> > >> >>> questions (on the bottom). > >> >>> > >> >>> First, some answers to yours. I will be using the proper > >> >>> > >> >> definition > >> >> > >> >>> of the effective area as you suggest. I am sure that there > is > >> an > >> >>> > >> >> Ex > >> >> > >> >>> field. The propagation direction is x of the PhCWG. z is the > > >> >>> vertical super cell and y is the direction of sqrt(3)*a of > the > >> >>> > >> >> air > >> >> > >> >>> holes. Attached is the CTL file. > >> >>> > >> >> _______________________________________________ > >> >> mpb-discuss mailing list > >> >> [email protected] > >> >> http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss > >> >> > >> >> > >> > > >> > _______________________________________________ > >> > mpb-discuss mailing list > >> > [email protected] > >> > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss > >> > > >> > > > > -- > Dr Frederic Brossard > Researcher > Hitachi Cambridge Laboratory > Cavendish Laboratory > J J Thomson Avenue > Cambridge CB3 0HE > > > > >
aln6.ctl
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