[Meep-discuss] Transmission flux greater than 1 in the waveguide-cavity-waveguide structure
Hi Steven and all Meep users, I know that this has been discussed in the Meep-discussion mailing list for many times. I searched in the archives and tried almost all the mentioned points there, but still I have this problem.What I want to simulate is the transmission flux of direct coupled cavity-waveguide structure created in 2D square lattice PhC of dielectric rods in air background, as shown schematically bellow: -wg_inО---wg_out--I did exactly the same as the tutorial says. Run two simulations, first with and second without the cavity, but the ratio is greater than 1. I define the flux plane at the end of the output waveguide (one lattice constant away from the pml), and put the Gaussian source at the edge of the pml and pad layer before the input waveguide.I use "run-sources+" and "stop-when-fields-decayed" function to stop the simulation when the field at the center of flux plane decayed by 1e-3.I have attached my .ctl file and. I will be very grateful if some one could help me to solve this problem. Thank you for your time! Best,Taimaz MCQF.ctl Description: Binary data ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
Re: [Meep-discuss] definition of "meep-fields-modal-volume-in-box "
Dear Prof. Steven Johnson and meep users, At each time step, meep calculate modal volume proportional to field profile at that time step. Since at the next time step, field profile is changed thus the modal volume changes. I would like to know how we can obtain the correct value of the this quantity? Regards, Taimaz, Date: Tue, 4 Sep 2012 01:34:26 +0800 From: china_jia...@163.com To: stevenj@gmail.com; meep-discuss@ab-initio.mit.edu Subject: Re: [Meep-discuss] definition of "meep-fields-modal-volume-in-box " Does V is a time average value? or calculate in each step in meep? V = integral (epsilon * |E|^2) / maximum (epsilon * |E|^2) or integral (( integral (epsilon * |E|^2) )/ maximum (epsilon * |E|^2)* dt ) / (delta T), where T= 1/f. which is the calculation in meep? -- At 2012-09-02 05:01:49,"Steven G. Johnson" wrote: On Aug 26, 2012, at 12:33 PM, liu wrote: I have not found the definition of meep-fields-modal-volume-in-box in meep. Can anyone give us the definition? It computes V = integral (epsilon * |E|^2) / maximum (epsilon * |E|^2) in the box. This is a typical definition of modal volume used e.g. for Purcell enhancement (because it appears in the local density of states computed at the point of maximum E energy density, for a resonant mode). Are there any other meep functions that have not descripted in meep Reference ? Plenty. ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
[Meep-discuss] FW: make a triangle in MEEP
Hi Tianyi If you google meep discussion archive you will find more example about the creation of triangular lattice in meep, You should build a rectangular unit cell and put two holes or rods relative to your structure in unit cell. first one in the middle and second one in the coroner of your unit cell , taimaz > Date: Wed, 25 Apr 2012 11:38:02 -0400 > From: ahtan@gmail.com > To: meep-discuss@ab-initio.mit.edu > Subject: [Meep-discuss] make a triangle in MEEP > > Dear All, > > I need to create a triangle as a geometric object in my simulation but > do not know how to do it. > Is there a function for generating a triangle, like "make triangle"? > > Thanks! > > Tianyi > > ___ > meep-discuss mailing list > meep-discuss@ab-initio.mit.edu > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
[Meep-discuss] nonlinear feedback parameter
Dear Meep users and Prof. Steven Johnson, To calculate the nonlinear feedback parameter, as defined in PRE66(2002), I simulte the Guassian source with Meep software and obtain electric field values at the end of the simulation. Using these values at the region of defect and the corresponding data for n (refractive index) and n2(Kerr coefficient), I calculate this parameter, but the obtained result is incorrect. Please, kindly let me know what is my problem or if there is anything else to do.Thanks in advance. ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
[Meep-discuss] nonlinear feedback parameter
Dear meep users and Prof. Steven Johnson, I am interested in nonlinear photonic crystals and I would like to know, is it possible to calculate nonlinear feedback parameter with this software? with great regards, taimaz taim...@hotmail.com ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
[Meep-discuss] question about field unit and chi3 for calculating optical bistability.
Dear meep users and Dr. Steven Johnson, I would like to see optical bistability in 1-D photonic crystal. therefore I have used a paper in this field, http://www.sciencedirect.com/science/article/pii/S0030401802016899. I defined a 1-D photonic crystal which consist of alternative layer of materials with high and low dielectric constant. a Kerr medium is sandwiched symmetrically between two same PCs. then I have defined single-frequency source with trigonometric shape. I have chosen chi3 = (4/3)*3e-8*n^2 for nonlinear material but I really get confused about how to choose the amplitude of my source to see optical bistability. when I am choosing amplitude of my source 1MW I see a noisy output intensity. I have seen previous answer of steven for similar question: http://www.mail-archive.com/meep-discuss@ab-initio.mit.edu/msg00402.html but I still have a few question about what steven have said, 1-is the method steven said work for trigonometric source? 2- which meep flux function should use for measuring the power? 3-for instance if we use (flux-in-box...) or (electric-energy-in-box) , we must calculate it in hole photonic crystal volume or in a limited plane just after the source or at the end of photonic crystal? I am very thankful if you could help me in this field. I desperately need to answer these questions. regards, taimaz, ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
[Meep-discuss] Question about suitable source for calculating optical bistability in nonlinear PCs
Dear meep users and Dr. Steven Johnson, I'd like to know what kind of source we should use for calculating optical bistability in nonlinear photonic crystals. is it possible to use predefined source in meep like gaussian-src or not? and if the answer is yes, how? according to my information we should use single frequency source with an amplitude of the triangular function for calculating O.B. a source like: A(n) Eo exp( 0+i w n dt) which A(n) is a trigonometric function. if we want to use this kind of source we have to use custom-src in meep, but there is a big question. in meep w(frequency) specified in units of (2 *pi* c/a). therefore when we speak about frequency it is usually a number between 0 until 1 in unit of (2 *pi* c/a), for instance we say there is a band gap between w=0.2 (2pic/a) and w=0.4 (2pic/a) frequencies. according to this comments if we use a source like this : A(n) Eo exp( 0+i w n dt) , instead of w, we should put frequency in unit of (2 pi c /a) or we must multiply light velocity and pi number and then put it in above source? The answer to this question is very important to me, I appreciate if someone gives me some information. regards, taimaz taim...@hotmail.com ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
[Meep-discuss] Question about Gaussian source in meep software
Dear meep users and Dr. Steven Johnson, I have two questions regarding the source in meep software, 1- What is the conception of turning on and especially turning off the source? turning on the source , specifies the moment that the Gaussian pulse fully formed and turning off the source ,After a specified time due to the this term: exp( (t − t0)2 / 2w2),pulse tend towards zero. Am i right to expression these concept? 2- exp( − iωt − (t − t0)2 / 2w2) in above Mathematical relationship, w ,represents the pulse width in time domain? and f or (ω = 2 *pi * f ) represent the pulse frequency in time domain ? and at the end, It would be very helpful If Dr. Steven Johnson or the users of meep State that is there any way of viewing the pulses of effluent in the environment or not? Sincerely, Thanks, Taimaz Fathollahi taim...@hotmail.com http://www.facebook.com/tomy.fathollahi ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
[Meep-discuss] Questions about the possibility of calculating surface states by meep or mpb
Dear meep & mpb users In the book of "photonic crystal :modeling the flow of light" by janopoulos and et al. It is written, all calculations are done by software Meep and mpb. In this book, obviously, surface states in one-dimensional and two dimensional photonic crystals has been studied. but in mpb and meep Tutorial,There is no mention of how to calculate the surface states. Would be very helpful if someone can give me information,document etc. about the possibility or the methods of calculating surface states by meep or mpb. regards, Taimaz, http://www.facebook.com/tomy.fathollahi ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
[Meep-discuss] Question about triangular lattice first brillouin zone
Dear meep & mpb users In MPB user tutorial , when it;s described calculation of Photonic band structure of triangular lattice, we see such statement about k-point of irreducible Brillouin zone of a triangular lattice. (set! k-points (list (vector3 0 0 0) ; Gamma (vector3 0 0.5 0); M (vector3 (/ -3) (/ 3) 0) ; K (vector3 0 0 0))); Gamma (set! k-points (interpolate 4 k-points)) as far as I know the Brillouin zone of a triangular lattice is look like a honeycomb the coordinate of its center and edges is characterized by points like Gamma=[0 0] , K=2pi/a*[2/3 0] , M=2pi/a*[1/2 1/(sqrt(3)*2)] I would like to know, is there any one who can show me [-1/3 1/3] point on Brillouin zone? I am get completely confused by the point which have shown in MPB user tutorial. regards, taimaz, ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
