Dear Mekawy, Thank you very much for this wonderful video. If I am not wrong, then this is for the TM mode bandgap. How can we calculate the TE mode bandgap? Thanks in advances.
@@sinaybehera8008 Dear Sinay. Under the settings of Electromagnetic Waves, Frequency domain (ewfd) tab, please choose solve for: out of plane. I believe there is a long discussion in the comments section between other colleagues and me about how to set this up. Please have a look into that.
Hi Ahmed Mekawy, I plotted graph for k = 0 to 3 in X axis. And I want Gamma to X, X to M , M to gamma instead of 0,1,2,3 how to do that in COmsol Multiphysics?
This is so cool! Today is exactly two years since I got into this area. I began to learn Comsol with the help of these videos from the respected Ahmed. And two years later, when I opened the video again, I surprisingly found out that the author's office is on the same floor as mine.
Hi Ahmad, thank you so very much. I really found this video helpful and educating too. Please i have a little issue, i don’t know if i could get a guide about going on to simulate the array structure, applying excitation at one side and getting response at another end so as to see the transmission characteristics.
Hi Muhammad, yes that should be straight forward. please search for "Plasmonic Wire Grating (RF) " you will find a tutorial on COMSOL. I may be able to upload something similar in future, but not sure when.
10:07 I'm gonna publish a paper can you tell me how to change x axis in graph from 0 to 3 into M to M ( M to Gamma to X to M) it is number i want in M TO M format
what should it be? if you agree on the point X (0,pi/a), then a similar point Y above the Gamma point has coordinates (pi/a,0), so the M point has the coordinates (pi/a,pi/a). We have the M point in 2D crystals. also you can check the book "photonic crystal: molding flow of light".
@@keke301 I see. in COMSOL you can always choose your unit cell as square. This might contain other inclusions from the neighboring cells in the hexagonal lattice. you can also define X,M,Gamma points. I may add another video about Hexagonal lattice soon.
Ahmed Mekkawy Also I have a question about the TE mode and TM mode. If I need both these two modes of band diagram, how can I set up in COMSOL? Thank you.
Hi Ahmed that was very nice video thank you. I was wondering when does the periodic condition break down in the simulation. If you have elements that are approaching the size of the fiber then is it still a valid solution?
Hi Omar. Thank you. The periodic condition never breaks down, it just tells you that your medium is periodic. I do not get what do you mean by elements?
Hi Ahmed. it was very helpful and informative tutorial. I try to plot bandgap of mass-spring chain and it makes me crazy. do you have any magic advice?!
I followed your tutorial step by step. It worked just like yours for out-of-plane vectors. When I changed to in-plane vector, the comsol gave me doggy results. Any idea?
please check the discussion between me and Keke in the comments. You should find the answer there. Basically, you can play with three parameters. firsy try change the option "search for eigenfrequency around" try make it 1e5 for example. Also select eigenfrequency with larger real part
Thank you Ahmed. It's a nice video. I have a small query, If I want to simulate seismic metamaterial, which Physics I have to chose? Will solid mechanics module with eigenfrequency study will work? Kindly help.
Hello, thanks for such videos. I need to know about 3D hexagonal array of holes simulation and find dispersion. Sir, i need to know how we take kx,ky and kz.if possible please share your email. thanks.
Hello Ahmed, you've searched for eigenvalues around 0 Hz here for out of plane vectors, and for in plane vectors you've suggested searching for eigenvalues around 1e5 Hz in the comments, what is the logic behind what frequency we search for eigenvalues? And what is the significance of choosing eigenvalues closest in absolute value to eigenfrequency with largest real part?
dear sir, first thank you for your discussion. What should be changed in Band-Gap Analysis of a Photonic Crystal to obtain a photonic diagram for the in-plane electric field (TE modes) because changing just out-of-plane to in-of-plane in Electric field components solved for a section doesn't work. Please help me out.
Thank you very much, I revised it for Lumerical users If you are going to get a band diagram like Lumerical or RSoft photonic software, please set kx and ky as follows kx= if( k
Thanks to ur contents. By the way, I would like to ask a question. I've tried several times to mesh (sequence type : physics-controlled mesh).but I dont have any idea why cant I get rid off from error edge 1. I have a same problem. Is there any solution?
If you structure is different than one shown here, it may require finer mesh or even a custom mesh with different mesh element shape. Without knowing the structure its difficult to suggest anything.
Do you have some video for band structure in a 1D superlattice? I do not if we should use 2D layers and apply "No-Slip" boundary condition in the top (wall) in order to consider aroud Y-direction like infinite and only use floquet periodicity along X boundaries...
Yes, correct. 1D would be much easier. I assume you talk about acoustic wave in that case, right? you can apply the periodic BCs in one dimension (say left and right), and make the other boundary in the top and bottom, choose hard boundary.
@@ahmedmekawy1632 Yes, acoustic wave. I am using linearized Navier stokes because I want to see the dissipation effects by viscosity. Then, in top and bottom, I have to use Hard boundary? But the problem of a hard boundary (i think) is that in want to include dissipation effects due the viscosity. And when we have "rigid wall" next to fluid, the dissipation enhance a lot of in the viscous layer next to the "hard walls" by Konstantinov Effect. But I don't know if that kind of boundary that you are saying, is not precisely like a "hard wall of material" or is just a kind of boundary for do not taking into account continuity in that direction (in this case Y-direection). Could you help me please? No-Slip boundary condition in that direction could not work for see the system like infinite in Y-direction? or what is exactly the way how works that kind of boundary that you are saying: "Hard boundary"? Thank you so much :) Regards.
@@ahmedmekawy1632 hello. Is not better to consider periodicity in top and bottom to see Y-direcction like infinite? I asked it, to other colleague and he told me if I consider hard boundary, is possible to have a reflection. Is that true? I need to simulate oblique incidence. Please help friend.
@@dynamic-audio Yes this is true, unless you have the boundaries in the Y-direction are far away from your thickness, (1 lambda is more than enough). I really do not have experience in acoustics, so this is just from my EM experience.
Hello Sir.. thanks for the help. When I am trying to obtain band diagram of some other model similar to this paper, it is not working. Can you help little bit? Thanks
Dear Ahmed, Thank you so much, it's a helpful video. So, can you share with us the doi of the article that you show in this class? I can found just with ' huang 2011'?
Thanks a lot for this video and the other one on the same topic. Although, I cannot do the same in the case of Acoustic waves. I wish to create a dispersion relation for a unit cell of a chiral auxetic lattice. Can you please help me?
@@ahmedmekawy1632 www.comsol.com/blogs/modeling-phononic-band-gap-materials-and-structures/ this model please let me know if you were able to verify the structure band gap, vibration analysis
Hello. I have the same question. For oblique incidence I decided to use a 2D model with periodicity along Y-direcction and X-direction. But I am not sure if is correct considered periodicity along Y-direction. I decided to include periodicity along Y because my system are slabs in 1D with periodicity X-direction, But Y direction is taken like infinite. The problem or question is: which values are the corrects in Floquet Kx and Ky Vectors in Y-periodicity?. I have put k*cos(theta)*pi/d for Kx and k*sin(theta)*pi/d for Kx. But I have put these values for floquet periodicity along Y-axis and for X-axis. I think it could be a little confusing. I hope you can understand my question and proposal. I mean.... I am not sure how to simulate oblique incidence in a 1D system with slabs. With Normal incidence I dont have problem because 1D simulation give me the same result of the model in 2D approach.
Hello sir, Thank you for this informative video. I am a fresh research scholar began to work in comsol domain. I have small queries. I want to verify some of the research papers simulation result but i am facing some problems. even i tried your same video i didnt get results when i tried myself. kindly provide me your email id so that i can mail you my problem specifically
The expressions are written here again because they were not clear in the video:
kx = if( k
Dear Mekawy, Thank you very much for this wonderful video. If I am not wrong, then this is for the TM mode bandgap. How can we calculate the TE mode bandgap?
Thanks in advances.
@@sinaybehera8008 Dear Sinay.
Under the settings of Electromagnetic Waves, Frequency domain (ewfd) tab, please choose solve for: out of plane. I believe there is a long discussion in the comments section between other colleagues and me about how to set this up. Please have a look into that.
Hi Ahmed thank you for this Tutorial. I have a doubt....what is the meaning of this expression. I want to understand please can you explain that.
@ahmedmekawy1632 Thank you very much, here I want to change the square to hexagonal lattice, How to set the kx and Ky, thank you very much, Fangcheng
What would these definitions be for a 3D geometry? E.g., what are the definitions kx, ky, and kz? Thanks in advance!
Hi Ahmed, thank you very much for this video. It is very helpful.
Hi Ahmed Mekawy, I plotted graph for k = 0 to 3 in X axis. And I want Gamma to X, X to M , M to gamma instead of 0,1,2,3 how to do that in COmsol Multiphysics?
This is so cool! Today is exactly two years since I got into this area. I began to learn Comsol with the help of these videos from the respected Ahmed. And two years later, when I opened the video again, I surprisingly found out that the author's office is on the same floor as mine.
Hi Ahmad, thank you so very much. I really found this video helpful and educating too. Please i have a little issue, i don’t know if i could get a guide about going on to simulate the array structure, applying excitation at one side and getting response at another end so as to see the transmission characteristics.
Hi Muhammad, yes that should be straight forward. please search for "Plasmonic Wire Grating (RF)
" you will find a tutorial on COMSOL. I may be able to upload something similar in future, but not sure when.
10:07 I'm gonna publish a paper can you tell me how to change x axis in graph from 0 to 3 into M to M ( M to Gamma to X to M) it is number i want in M TO M format
you are so kind. i love you
hello.. can i know how you get that formula of parameter gamma, M and X?
Hi Ahmed thank you very much for this video. can u please design a array of photonic crystal design using COMSOL
My frequency range is [0.01,1.5(MHz)] don't know how to define it
need assistance
I would like to ask about the coordinates of M. Why is it pi/a, what’s this from? Thank you.
what should it be?
if you agree on the point X (0,pi/a), then a similar point Y above the Gamma point has coordinates (pi/a,0), so the M point has the coordinates (pi/a,pi/a). We have the M point in 2D crystals. also you can check the book "photonic crystal: molding flow of light".
Ahmed Mekkawy Thank you. What about the hexagonal condition?
@@keke301 I see. in COMSOL you can always choose your unit cell as square. This might contain other inclusions from the neighboring cells in the hexagonal lattice.
you can also define X,M,Gamma points.
I may add another video about Hexagonal lattice soon.
Ahmed Mekkawy Okay. Thank you so much! Your video is so helpful!
Ahmed Mekkawy Also I have a question about the TE mode and TM mode. If I need both these two modes of band diagram, how can I set up in COMSOL? Thank you.
Hi Ahmed that was very nice video thank you. I was wondering when does the periodic condition break down in the simulation. If you have elements that are approaching the size of the fiber then is it still a valid solution?
Hi Omar. Thank you. The periodic condition never breaks down, it just tells you that your medium is periodic. I do not get what do you mean by elements?
Hi Ahmed. it was very helpful and informative tutorial. I try to plot bandgap of mass-spring chain and it makes me crazy. do you have any magic advice?!
Hi Hassan,
thank you. I am surprised actually that COMSOL can do this. Did you implement it using PDE?
I followed your tutorial step by step. It worked just like yours for out-of-plane vectors. When I changed to in-plane vector, the comsol gave me doggy results. Any idea?
please check the discussion between me and Keke in the comments. You should find the answer there. Basically, you can play with three parameters. firsy try change the option "search for eigenfrequency around" try make it 1e5 for example. Also select eigenfrequency with larger real part
@@ahmedmekawy1632 It works. Much appreciated!
Thank you Ahmed. It's a nice video. I have a small query, If I want to simulate seismic metamaterial, which Physics I have to chose? Will solid mechanics module with eigenfrequency study will work? Kindly help.
yes, I believe Acoustics module (solid mechanics) will work for it.
@@ahmedmekawy1632 Thanks a lot. Does taking finer and finer mesh size changes the eigenfrequency values in that ? Kindly help.
Thank you so much dear sir ,,, superb explanation....... can you do it for PbS quantum dot solar cell sir?? kindly please reply me
Hi Eshan, what paper?
@@ahmedmekawy1632 i mean i need help in simulation of solar cell in comsol. can you please help with this?? will really appreciate, thanks
Thank you
what about band gap for fiber Ch
you can check the other video titled "triangular (hexagonal) lattice ..." on the channel
Hello, thanks for such videos. I need to know about 3D hexagonal array of holes simulation and find dispersion. Sir, i need to know how we take kx,ky and kz.if possible please share your email. thanks.
Hi Muhammad, do you mean opals?
tell this expression is correct or wrong : kx=if(k
The expressions are written here again because they were not clear in the video:
kx = if( k
@@ahmedmekawy1632No No I meant I created a new expression could you check? If it is correct or wrong leme know
Hello Ahmed, you've searched for eigenvalues around 0 Hz here for out of plane vectors, and for in plane vectors you've suggested searching for eigenvalues around 1e5 Hz in the comments, what is the logic behind what frequency we search for eigenvalues? And what is the significance of choosing eigenvalues closest in absolute value to eigenfrequency with largest real part?
Do you have any tutorial for case 1D?
Dear Ahmed, Thank you so much ! this was extremely helpful.
dear sir, first thank you for your discussion. What should be changed in Band-Gap Analysis of a Photonic Crystal to obtain a photonic diagram for the in-plane electric field (TE modes) because changing just out-of-plane to in-of-plane in Electric field components solved for a section doesn't work. Please help me out.
Did you figure it out? if you know, Can you teach me? please..
Thank you very much, I revised it for Lumerical users If you are going to get a band diagram like Lumerical or RSoft photonic software, please set kx and ky as follows
kx= if( k
Excellent demo! Thanks a lot...Could you explain for 1D structures as well?
Thanks to ur contents. By the way, I would like to ask a question. I've tried several times to mesh (sequence type : physics-controlled mesh).but I dont have any idea why cant I get rid off from error edge 1. I have a same problem. Is there any solution?
If you structure is different than one shown here, it may require finer mesh or even a custom mesh with different mesh element shape. Without knowing the structure its difficult to suggest anything.
Could you please upload a tutorial to plot wavelength vs reflectance for this photonic crystal.
if one of the materials depends on the wavelength how can we calculate the dispersion curve?
اما صدقت لقيت حد عربي بيشرح ... يطلع الشرح انجليزي طيب ليه بس
nice video, it was really helpful! i have a question, do you know how to put the direction letters on the x axis instead of the numbers?
please, could you help me to trace the time response of a photonic structure
Can we know even and odd modes in TE and TM polarization in the bandsolve tool of software?
Could you please demonstrate SPR fiber optic sensor simulation using comsol ?
How to calculate equi frequency or iso-frequency contour using comsol
Do you have some video for band structure in a 1D superlattice? I do not if we should use 2D layers and apply "No-Slip" boundary condition in the top (wall) in order to consider aroud Y-direction like infinite and only use floquet periodicity along X boundaries...
Yes, correct. 1D would be much easier. I assume you talk about acoustic wave in that case, right? you can apply the periodic BCs in one dimension (say left and right), and make the other boundary in the top and bottom, choose hard boundary.
@@ahmedmekawy1632 Yes, acoustic wave. I am using linearized Navier stokes because I want to see the dissipation effects by viscosity. Then, in top and bottom, I have to use Hard boundary? But the problem of a hard boundary (i think) is that in want to include dissipation effects due the viscosity. And when we have "rigid wall" next to fluid, the dissipation enhance a lot of in the viscous layer next to the "hard walls" by Konstantinov Effect.
But I don't know if that kind of boundary that you are saying, is not precisely like a "hard wall of material" or is just a kind of boundary for do not taking into account continuity in that direction (in this case Y-direection). Could you help me please? No-Slip boundary condition in that direction could not work for see the system like infinite in Y-direction? or what is exactly the way how works that kind of boundary that you are saying: "Hard boundary"?
Thank you so much :) Regards.
@@ahmedmekawy1632 hello. Is not better to consider periodicity in top and bottom to see Y-direcction like infinite? I asked it, to other colleague and he told me if I consider hard boundary, is possible to have a reflection. Is that true? I need to simulate oblique incidence. Please help friend.
@@dynamic-audio Yes this is true, unless you have the boundaries in the Y-direction are far away from your thickness, (1 lambda is more than enough). I really do not have experience in acoustics, so this is just from my EM experience.
Sir can you suggest papers how you have calculated kx and ky floquet condition. So that i can calculate it for 1D and 3D case. Thank you.
Hi, please check any book like molding flow of the light.
Hello Sir.. thanks for the help.
When I am trying to obtain band diagram of some other model similar to this paper, it is not working. Can you help little bit? Thanks
please type your question here.
Dear Ahmed, Thank you so much, it's a helpful video. So, can you share with us the doi of the article that you show in this class? I can found just with ' huang 2011'?
Dear Davila, Thank you. Please find the DOI: doi.org/10.1038/nmat3030
Hi Ahmed
How can the PCF photonic crystal fiber structure be optimized for loss or dispersion?
Please reply or help with guidance, thank you
Hi Ahmed. I did not work on that in fact, but I plan to post a video on it.
@@ahmedmekawy1632 I hope you can help me in this process, I have been stuck in it for months
Thanks a lot for this video and the other one on the same topic. Although, I cannot do the same in the case of Acoustic waves. I wish to create a dispersion relation for a unit cell of a chiral auxetic lattice. Can you please help me?
Hi, Diptangshu,
I am not really familiar with this kind of lattices. Is it periodic still? if so, I think this method works for any kind of waves.
Dear Ahmed, is it possible to share the simulation file with me?
Hi Fatemeh, yes. I can send via email, or any other method. please let me know how
Hello, were you able to verify the results using a frequency domain analysis for an array of this cell just like the blog of comsol ?
Hello, what COMSOL blog?
@@ahmedmekawy1632 www.comsol.com/blogs/modeling-phononic-band-gap-materials-and-structures/
this model
please let me know if you were able to verify the structure band gap, vibration analysis
nice video， thanks a lot
Hello，i want to ask you about how to calculate the kx and ky.
Hi, you can calculate the reciprocal lattice vectors, using the relation in the video. Is this your question?
sir can you please tell me how to simulate an optical logic gates based on photonic crystal? and also this video was really helpful.
Hi, you can use a numeric port. I believe there are tutorials out there on App Exchange on COMSOL website
@@ahmedmekawy1632 okay sir, Thank you.
Hi Ahmed, thank you for your video. It helps a lot. I can't clearly see the if statement. Could you please write here?
Hi Xuzhi. Please find it below:
kx = if(k
@@ahmedmekawy1632 Really appreciate
Hi, your expression for plotting the photonic band diagram is not clear. Could you write again? Something like ewfd.....
@@xuzhihe2521 ewfd.freq*a/c_const
Thanks alot, how can I simulate pc slabs in 1D
Hello. I have the same question. For oblique incidence I decided to use a 2D model with periodicity along Y-direcction and X-direction. But I am not sure if is correct considered periodicity along Y-direction. I decided to include periodicity along Y because my system are slabs in 1D with periodicity X-direction, But Y direction is taken like infinite.
The problem or question is: which values are the corrects in Floquet Kx and Ky Vectors in Y-periodicity?. I have put k*cos(theta)*pi/d for Kx and k*sin(theta)*pi/d for Kx. But I have put these values for floquet periodicity along Y-axis and for X-axis. I think it could be a little confusing. I hope you can understand my question and proposal. I mean.... I am not sure how to simulate oblique incidence in a 1D system with slabs. With Normal incidence I dont have problem because 1D simulation give me the same result of the model in 2D approach.
Hi Saf, please see my contact in the "about" section on my channel.
Hello sir, Thank you for this informative video. I am a fresh research scholar began to work in comsol domain. I have small queries. I want to verify some of the research papers simulation result but i am facing some problems. even i tried your same video i didnt get results when i tried myself. kindly provide me your email id so that i can mail you my problem specifically