Re: [MPB-discuss] About the lightcone and projected slab mode
Dear Prof.Steven, Thank you for your instant reply. I am sorry that I can't understand you. I know sent the supercell with no defect to calculate slab mode. But how to project it to the waveguide direction? Just a large supercell is enough? why? Could you please talk into it a little bit more in details? Professor, I know you are busy. If you have no time, Could you please be so kind to forward this question to one of your student who can answer me? Your instant reply will be greatly appreciated. On Nov 15, 2007 1:08 PM, Steven G. Johnson <[EMAIL PROTECTED]> wrote: > The easiest way to project the slab modes for a line defect is just to use > a large supercell with no defect. > > > On Thu, 15 Nov 2007, Ryan Hao wrote: > > Dear Prof.Steven and others, > > Thank you for your answer. > > But my question is how to set the K path in calculating and > > projecting the slab mode? > > You known, projecting the slab mode needs to scan the full area > > of Brillouin zone, then project to the waveguide direction. > > > > > > Below is my code, Could you please have a look and tell me whether it > > is correct or not (I think there may something wrong in setting the > > reciprocal lattice and k path ): > > (define-param kymin 0) > > (define-param kymax 0.57735) > > (define-param k-interp 20) > > (define (do-stuff k k-hi k-inc) > > (if (<= k k-hi) > > (begin > > > > (set! k-points (interpolate k-interp (list (lattice->reciprocal > > (vector3 k kymin 0)) > > (lattice->reciprocal (vector3 k kymax 0) > > (run-zeven ) > > (do-stuff (+ k k-inc) k-hi k-inc) > > ))) > > (do-stuff 0 0.5 0.1) > > > > > > Best wishes > > Ryan > > > > > > On Mar 28, 2007 2:20 AM, Steven G. Johnson <[EMAIL PROTECTED]> wrote: > >> On Tue, 13 Mar 2007, Ryan Hao wrote: > >>> In the case of line defect waveguide in photonic crystal slab,I succeed > >>> in caculating the waveguide mode with MPB.but there still something > >>> left:I must find way to project the band strucure of the regular lattice > >>> of the slab(slab mode) and the lightcone?You can see in the below > >>> picture,the blue line represent for the lightcone,and the green line > >>> represent for slab mode. > >> > >> Projecting the light cone (for a uniform substrate/superstrate) is easy -- > >> it is just the kmag output column divided by the substrate index. > >> > >> For projecting the modes of the unperturbed slab, the easiest thing to do > >> is to use the same computational cell as your line-defect waveguide, but > >> without the defect. (In fact, you can use a smaller supercell if you > >> want, as long as you plot the slab bands for several values of ky from 0 > >> to 0.5, where y is the direction perpendicular to your waveguide, assuming > >> a rectilinear supercell.) > >> > >> Cordially, > >> Steven G. Johnson > >> > >> ___ > >> mpb-discuss mailing list > >> mpb-discuss@ab-initio.mit.edu > >> http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss > >> > > > > > > > > -- > > === > > > > Best wishes > > > > Yours, > > Ryan Hao > > > > ___ > > mpb-discuss mailing list > > mpb-discuss@ab-initio.mit.edu > > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss > > > > ___ > mpb-discuss mailing list > mpb-discuss@ab-initio.mit.edu > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss > -- === Best wishes Yours, Ryan Hao Wuhan National Laboratory for Optoelectronics College of Optoelectronic Science and Engineering, Huazhong University of Science & Technology, Wuhan, 430074, P.R.CHINA Phone: 86-027-87792242-809(O) Mobile: Fax: ___ mpb-discuss mailing list mpb-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss
Re: [MPB-discuss] About the lightcone and projected slab mode
The easiest way to project the slab modes for a line defect is just to use a large supercell with no defect. On Thu, 15 Nov 2007, Ryan Hao wrote: > Dear Prof.Steven and others, > Thank you for your answer. > But my question is how to set the K path in calculating and > projecting the slab mode? > You known, projecting the slab mode needs to scan the full area > of Brillouin zone, then project to the waveguide direction. > > > Below is my code, Could you please have a look and tell me whether it > is correct or not (I think there may something wrong in setting the > reciprocal lattice and k path ): > (define-param kymin 0) > (define-param kymax 0.57735) > (define-param k-interp 20) > (define (do-stuff k k-hi k-inc) > (if (<= k k-hi) > (begin > > (set! k-points (interpolate k-interp (list (lattice->reciprocal > (vector3 k kymin 0)) > (lattice->reciprocal (vector3 k kymax 0) > (run-zeven ) > (do-stuff (+ k k-inc) k-hi k-inc) > ))) > (do-stuff 0 0.5 0.1) > > > Best wishes > Ryan > > > On Mar 28, 2007 2:20 AM, Steven G. Johnson <[EMAIL PROTECTED]> wrote: >> On Tue, 13 Mar 2007, Ryan Hao wrote: >>> In the case of line defect waveguide in photonic crystal slab,I succeed >>> in caculating the waveguide mode with MPB.but there still something >>> left:I must find way to project the band strucure of the regular lattice >>> of the slab(slab mode) and the lightcone?You can see in the below >>> picture,the blue line represent for the lightcone,and the green line >>> represent for slab mode. >> >> Projecting the light cone (for a uniform substrate/superstrate) is easy -- >> it is just the kmag output column divided by the substrate index. >> >> For projecting the modes of the unperturbed slab, the easiest thing to do >> is to use the same computational cell as your line-defect waveguide, but >> without the defect. (In fact, you can use a smaller supercell if you >> want, as long as you plot the slab bands for several values of ky from 0 >> to 0.5, where y is the direction perpendicular to your waveguide, assuming >> a rectilinear supercell.) >> >> Cordially, >> Steven G. Johnson >> >> ___ >> mpb-discuss mailing list >> mpb-discuss@ab-initio.mit.edu >> http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss >> > > > > -- > === > > Best wishes > > Yours, > Ryan Hao > > ___ > mpb-discuss mailing list > mpb-discuss@ab-initio.mit.edu > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss > ___ mpb-discuss mailing list mpb-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss
Re: [MPB-discuss] About the lightcone and projected slab mode
Dear Prof.Steven and others, Thank you for your answer. But my question is how to set the K path in calculating and projecting the slab mode? You known, projecting the slab mode needs to scan the full area of Brillouin zone, then project to the waveguide direction. Below is my code, Could you please have a look and tell me whether it is correct or not (I think there may something wrong in setting the reciprocal lattice and k path ): (define-param kymin 0) (define-param kymax 0.57735) (define-param k-interp 20) (define (do-stuff k k-hi k-inc) (if (<= k k-hi) (begin (set! k-points (interpolate k-interp (list (lattice->reciprocal (vector3 k kymin 0)) (lattice->reciprocal (vector3 k kymax 0) (run-zeven ) (do-stuff (+ k k-inc) k-hi k-inc) ))) (do-stuff 0 0.5 0.1) Best wishes Ryan On Mar 28, 2007 2:20 AM, Steven G. Johnson <[EMAIL PROTECTED]> wrote: > On Tue, 13 Mar 2007, Ryan Hao wrote: > > In the case of line defect waveguide in photonic crystal slab,I succeed > > in caculating the waveguide mode with MPB.but there still something > > left:I must find way to project the band strucure of the regular lattice > > of the slab(slab mode) and the lightcone?You can see in the below > > picture,the blue line represent for the lightcone,and the green line > > represent for slab mode. > > Projecting the light cone (for a uniform substrate/superstrate) is easy -- > it is just the kmag output column divided by the substrate index. > > For projecting the modes of the unperturbed slab, the easiest thing to do > is to use the same computational cell as your line-defect waveguide, but > without the defect. (In fact, you can use a smaller supercell if you > want, as long as you plot the slab bands for several values of ky from 0 > to 0.5, where y is the direction perpendicular to your waveguide, assuming > a rectilinear supercell.) > > Cordially, > Steven G. Johnson > > ___ > mpb-discuss mailing list > mpb-discuss@ab-initio.mit.edu > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss > -- === Best wishes Yours, Ryan Hao ___ mpb-discuss mailing list mpb-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss
[MPB-discuss] Fwd: question
-- Forwarded message -- From: maryam saberi <[EMAIL PROTECTED]> Date: Nov 14, 2007 2:15 PM Subject: Re: [MPB-discuss] question To: nate lipkowitz <[EMAIL PROTECTED]> Hi Thank you very much for your help. I also want to simulate a core-shell fcc structure ( core with dielectric constant epsilon1 + shell with dielectric constant epsilon2) by mpb, but I don't know how to define dielectric constant of spheres(core+shell). I think that I should use of a Step Function, but I can't define it in program. In addition, how can I define and run the program along a special direction, for example [1 1 1]. On 11/13/07, nate lipkowitz <[EMAIL PROTECTED]> wrote: > hi, this is what i use. as steven notes in the manual (which you > should have read) the fcc unit cell has an edge length of sqrt(2) > times the diameter of your spheres, so you need to take that factor > into account if you convert the freqs output by mpb to real frequency > units. > > anyway here is the ctl file.. cheers: > > > (set! num-bands 10) > (set! default-material (make dielectric (index 3.9))) > (set! resolution 16) > (set! mesh-size 5) > > > > (set! geometry-lattice > (make lattice > (basis1 0 1 1) > (basis2 1 0 1) > (basis3 1 1 0) > (basis-size (sqrt 0.5) (sqrt 0.5) (sqrt 0.5)) > (size 1 1 1) > ) > ) > > (set! geometry > (list > (make sphere > (center 0 0 0) > (radius (/ (sqrt 0.5) 2)) > (material > (make dielectric > (index 1.0) > ) > ) > ) > ) > ) > > > (set! k-points > (interpolate 4 > (list > (vector3 0 0.5 0.5); X > (vector3 0 0.625 0.375); U > (vector3 0 0.5 0) ; L > (vector3 0 0 0); Gamma > (vector3 0 0.5 0.5); X > (vector3 0.25 0.75 0.5); W > (vector3 0.375 0.75 0.375) ; K > ) > ) > ) > > (run) > > > > > maryam saberi <[EMAIL PROTECTED]> wrote: > > > Hello > > I' d like simulate a fcc inverse opal structure with Mit Photonic Bands > > package, but I don't know how to write it's program. > > Please help me. > > thanks > > > > > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > nate lipkowitz > 416 823 8057 > [EMAIL PROTECTED] > > ___ > mpb-discuss mailing list > mpb-discuss@ab-initio.mit.edu > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss > ___ mpb-discuss mailing list mpb-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss
