Hi. The parameters are: E0 = 1[V/m] radius= 230 r_pml = 10*radius t_pml = 3*radius lambda = 1000 lambda_min = 1000 lambda_max = 2000 lambda_step = 5 sigma_geom = pi(*radius[nm])^2 S_in = E0^2/(2*Z0_const) Liliana Avalos, also I saw that you have problems with the functions: nrelPoav = nx*emw.relPoavx+ ny*emw.relPoavy+ nz*emw.relPoavz (this one is different from yours) sigma_sc = intop_surf(nrelPoav)/S_in sigma_abs = intop_vol(emw.Qh)/S_in sigma_ext = sigma_sc+sigma_abs Also, it depends of the module that you are using. If you are using the eww, you should substitute ewfd by emw.
shouldn't it be: nrelPoav = abs(nx)*emw.relPoavx+ abs(ny)*emw.relPoavy+ abs(nz)*emw.relPoavz ? suppose you have a large cylinder, with the incident light coming perpendicular to the flat surface, so there would be a lot of transmission. And if the transmission is great enough, the scattering cross section would become negative right if you dont take the absolute values of nx,ny, and ,nz
Thank you Mr. Nuno, honestly speaking this is the most funny comsol tutorial i've ever watched! No offence sir i just feel your accent and your tone are very hilarious and there is a subtle sense of humor in it. Love to watch your video while study, I appreciate your video!
Sir , can you upload more COMSOL videos like these one ? Please do in the same way by choosing a paper and then reproducing the same results .I am new to COMSOL and finding difficulty in finding an error in my simulation . Can u fig it out .Shall I send u my COMSOL file ? Thnx for this tuto With best wishes from India
Hi Nuno, Great Job and nicely explained. Could you please write down the equations appearing after 27:20 in the video ? Also, I could not find the use of scaling factor defined in the global parameters list. Could you please write this expression as well. (At that moment, you did not explain, while writing the expression). Thanks
Brilliant tutorial for green hand learner! I think there might be a mistake of the definition of scattering cross section (SCS). The SCS is actually the product integration of rel poynting vector and surface. It should not be integration of S_x+S_y. An easy way to calculate the scattering cross section is actually to define a square boundary outside nanoparticle and integrate the poynting vector at each surface.
When did you define Poavx etc. for the Poynting vector, my Comsol doesn't recognize the expression. I learned a lot in your video, thanks!. Unfortunately, the nice level of detail stopped at a dead-end at 28 minutes.
Dear Sir/Mam, how to solve the Allen Cahn and Cahn Hilliard equation for 2D and 3D BOTH. What is the exact equation for Allen Cahn and Cahn Hilliard for both 2D and 3D which I can use in COMSOL. And also, what are the parameters?
Hello! thank you very much for the video! I have one question. Why integration over surface of the particle is correct ? In this case we have near-field but not far-field. I thought that we must integrate in the distance where we have the far-field. Thank you.
good question. As far as i know for the calculation of the scattering cross section we need to take an imaginary surface around nanoparticle and calculate the scattered energy by that surface. Could you please explain that dear Nuno de Sousa?
Thanks a lot, this is a very helpful tutorial, how would the setup change if instead of a particle you were measuring against a multilayered sphere of dielectric material? I would assume that you would have to change the surface integration to account for the layers but how does that change the volume integral? Thanks
Sir, can you please put screen shots of parameters , variables and other expressions you wrote on screen, we were unable to see them clearly, thanks in advance
when i added " E0^2/(2*Z0_const)" in last parameter it shows red line . this means its not true value. i am use 5.6 version. please tell me whats correct value.
Hello, I seem to be having trouble getting a full plot of the absorbance cross section. For some reason, when I run the study its only computing it for one parameter value of Lambda and not actually doing the parametric sweep - would anyone know why this is happening? Thank you!
Hello Nuno. This model does not work when I use pure water (relative permittivity = 80) instead of air. Do you know why? I get an error on the stationary solver for undefined value. Thanks
Dear Nuno De Sousa, please tell me how can I find out the Multipole effects and Far-field plots??? Also please tell me that if I want to define the material with 300 nm to 2000nm wavelength range wise real refractive index and extinction co-efficient then how can I define it. Thanks
How can i try scattering cross section about Au nanoparticle? In our case not single particle ( Dimer, Trimer ) and also we should control incidence beam angle.
How would I calculate the reflection and transmission from the particle? I actually performed the same model to observe the scattering from a thin film with a nanohole. The scattering cross section values on the y-axis are in negative. What does it mean? Also on the x-axis it actually does not show the wavelength but some arbitrary numbers. Why is that so?
You've calculated the scattering cross-section of a single silicon particle. Can you please how to calculate the Scattering Cross-section of two Silicon NPs side by side (Dimer)... Should I perform surface integration like you did and then divide by 2*geometric cross-section? Please Help!
Hi. thank you ver much. it was very useful. Would it be possible to measure the scattering of a this sphere with a dipole? I mean instead of plan wave we have a dipole close to this sphere and measure the scatterin cross section.
Meqdad Hassani Hl. That is not a comsol question, it is a scatttering theory problem. Cross sections are only defined for a plane wave because it is a direction measurement. Instead, for a dipole emitter you can compute decay rates.
Hello Sir, I want to ask if I want to couple your model in video with Electrostatic physics study, I mean I want to calculate static electric field (Es) from the Electrostatic study and then substitute by Es in the electromagnetic study. What are the proper steps to kindly couple them. Note(I have nonlinear study so the static electric field will affect my model)
@Nuno de Souza, thanks a lot for the video. I have repeated your work and its really nice. Works perfectly!. However, the absorption cross section values are negative, I guess it has not been important for you, but do you have a suggestion to avoid or manage that negative absorption cross section values?
HI Nuno, your tutorial is very informative\. My problem is a bit different. I have a tube from which nanoparticles are coming in the rate of 635 mol/m3 every second. How can I put this in Comsol. Thanks
Hi, thank you for the tutorial, it helps a lot. I am trying to perform the simulation on Comsol 5.3. I carefully followed the steps you show and got the error: Undefined value found. - Detail: Undefined value found in the equation residual vector. Could you please tell how I can fix this, if you have any idea. Thanks.
Thank you very much for this video. But i have couple of question regarding Scattering Cross section. You calculated Scattering cross section by integrating over the nanoparticle surface. By integrating over the nanoparticle surface we are not considering the Far field calculation. What should i do if i want to calculate scattering cross section in far field domain??
Nuno de Sousa thanks for ur comment. I also want to know how to calculate Extinction cross section for array of any nanoparticle like nanodisc or nanosphere. I know for calculating periodicity we have to introduce floquet boundary condition but i m not be able to calculate Extinction cross section for whole 2-D array
Hello Sir Could you kindly give the expressions for the cross sections (extinction and scattering)? You mentioned about the book by Hoffman. Could you kindly refer to the corresponding equations also for these? Thanks in advance. Saif.
+Saiful Babu Saif Hello. Bohren and Huffman have the expression in the Mie scattering context. If you want directly the expressions you can see the following article: www.comsol.com/paper/mie-scattering-of-electromagnetic-waves-15917 It is very basic but have what you probably need.
Thank you very much Sir with your interesting tutorial. May I ask your help ? I study acoustic scattering through laminate medias. Thank you Mister Nuno.
Thank you Nuno. I find your video very instructive. I just started working with Comsol - following your video everything goes well, until minute 27.40. comsol tells me that emv.relPoavx is an unknown variable. Did I forget to load anything? I am using Comsol with windows and I noticed that also in the formula E0*exp(-i*2*pi/lambda[nm])*z I cannot put the [nm], comsol does not seem to accept it. Do you have an idea how I can proceed? Thx, Ingmari
@@ingmaritietje5489 Sir, By correcting this still I cant't get any result. It shows yellow line rather black after going to second row in the variable defining section. Please help me.
@@Nunodsousa Sir, By correcting this still I cant't get any result. It shows yellow line rather black after going to second row in the variable defining section. Please help me.
Hi, thanks for the video. Could you please write the title and author(s) of the book you cite in several parts of the tutorial? ...I cannot find it... Thanks a lot!
Please Sir I have a question. Why we put the area of the sphere pi*r^2 , should it be 4*pi*r^2? Thanks for the very useful tutorials. Hassan, Nanyang Technological University
Hi. Thanks for your kind tutorial. I can follow your tutorial easily, but in my program, COMSOL show error "NaN or Inf found when solving linear system using SOR."....I don't know why system show this kind of error. And i also want to change the wavelength range to lower wavelength part(300-1500 nm). Could you explain how to change the wavelength range?
Hi, Thank you very much for this video. I am new to comsol. I was tryinh to reproduce the result, but got stuck while adding the variables under component1, as it says "unknown variable emw.relPoavx". Please help. TIA :)
Diego Rativa thank you for reply! I am trying to get the scattering cross section vs scattering angles. Do you have any idea how I can get this plot? thanks once again
Normally, a cross section is integrated over all scattering angles, so it doesn't make sense a scattering angle-dependence of the scattering cross section.
On the other hand, if you are looking for the scattering cross section vs the incident angle of the Electric Field, you should have two options. 1. Keep the electric field at the same direction (as this video) and rotate the cylinder in different angles (x,y) (in the case of an incident unpolarized light, you have to average both the X and Y axes), 2. or rotating the electric field.
I have done simulation for one particle( sphere) with different permeability and frequencies. Now I need to do it for multiple particles( 4 particles). I am thinking to draw 4 particles but have problem to define the infinite element layer and the domains. Don't know how to do that. This is the first time I am using COMSOL.
Hello i want to get the evanescent light images of the nano-particle.. light scattered from nano-particle and i want its evanescent images...can i do like this simulations in comsol???? Kindly give your any social media contact info to contact with you regards: Kaleem
+Scientific_Mind Bohren and Huffman www.amazon.com/Absorption-Scattering-Light-Small-Particles/dp/0471293407 But if you want a short resume of the equations you can see the following paper: www.comsol.com/paper/mie-scattering-of-electromagnetic-waves-15917
+Nuno de Sousa Thanks for the links. It's very helpful. We are currently doing research work on Nanoantennas using Comsol, and we're undergrads. Can I connect with you on some platform? It'd be of immense help to us if you do. Thanks a lot for the video though. Moreover, we saw that you used Relative Permittivity of Silicon as a constant of 12.25 for the whole frequency range. Is it really constant throughout the whole range or is it an assumption?? Thanks a lot again. Cheers
+Scientific_Mind Hi. The Silicon have a constant permittivity between the 1000 and 2000nm. It is a real number (doesn't absorve in this range). It is the used value in the paper that I cite. Also you can see the refractive index of different materials here: refractiveindex.info
+Nuno de Sousa Thanks, for clearing that up. :) If I wanted to calculate the near-field enhancements of a spherical dimer pair in the gap in middle, or suppose the near field enhancement for a single Ag/Au nano-particle.. How can I do that? can you please suggest? My goal is to calculate the Near-Field enhancement of various structures (Bow-tie, Dimer, DIpole). I can do the geometry modeling, but don't know how to post-process the data. (I can use material index from Johnson & Christy by interpolation).
hello sir i m very thank full to you for this beautiful modal .... kindly send me expressions for variables as i can not see these expression s... thanks again
Reading what you are typing is very hard or impossible. For next lessons, please make sure the poor reader can read what you typed. We don't have eagle eyes.
OMG his comment at 20:35! This guy's sense of humor in midst of tutorial makes this really great to watch and learn.
Hi.
The parameters are:
E0 = 1[V/m]
radius= 230
r_pml = 10*radius
t_pml = 3*radius
lambda = 1000
lambda_min = 1000
lambda_max = 2000
lambda_step = 5
sigma_geom = pi(*radius[nm])^2
S_in = E0^2/(2*Z0_const)
Liliana Avalos, also I saw that you have problems with the functions:
nrelPoav = nx*emw.relPoavx+ ny*emw.relPoavy+ nz*emw.relPoavz (this one is different from yours)
sigma_sc = intop_surf(nrelPoav)/S_in
sigma_abs = intop_vol(emw.Qh)/S_in
sigma_ext = sigma_sc+sigma_abs
Also, it depends of the module that you are using. If you are using the eww, you should substitute ewfd by emw.
Hello sir, Thank you for the tutorial. I have a quarry, what is emw.relPoavz?
shouldn't it be:
nrelPoav = abs(nx)*emw.relPoavx+ abs(ny)*emw.relPoavy+ abs(nz)*emw.relPoavz ?
suppose you have a large cylinder, with the incident light coming perpendicular to the flat surface, so there would be a lot of transmission. And if the transmission is great enough, the scattering cross section would become negative right if you dont take the absolute values of nx,ny, and ,nz
Power flow, time average, of the relative fields in the z direction
Thank you Mr. Nuno, honestly speaking this is the most funny comsol tutorial i've ever watched! No offence sir i just feel your accent and your tone are very hilarious and there is a subtle sense of humor in it. Love to watch your video while study, I appreciate your video!
hi , can you see the whole expressions in the video, I was unable to see the video clearly
Sir , can you upload more COMSOL videos like these one ? Please do in the same way by choosing a paper and then reproducing the same results .I am new to COMSOL and finding difficulty in finding an error in my simulation . Can u fig it out .Shall I send u my COMSOL file ?
Thnx for this tuto
With best wishes
from India
Excellent tutorial! I solves Mie sattering problem by boundary integral equation and comparisons with comsol results are necessary.
Hi Nuno,
Great Job and nicely explained. Could you please write down the equations appearing after 27:20 in the video ? Also, I could not find the use of scaling factor defined in the global parameters list. Could you please write this expression as well. (At that moment, you did not explain, while writing the expression). Thanks
Hello. at 28:00 the functions dont recognized in my comsol. Does anyone one how to fix it?
Brilliant tutorial for green hand learner! I think there might be a mistake of the definition of scattering cross section (SCS). The SCS is actually the product integration of rel poynting vector and surface. It should not be integration of S_x+S_y.
An easy way to calculate the scattering cross section is actually to define a square boundary outside nanoparticle and integrate the poynting vector at each surface.
When did you define Poavx etc. for the Poynting vector, my Comsol doesn't recognize the expression. I learned a lot in your video, thanks!. Unfortunately, the nice level of detail stopped at a dead-end at 28 minutes.
Did you find any solution?
No@@heattransfer8003 I haven't returned to the problem
Should the Scattering Boundary Condition applied to the External PML Surface?
Dear Sir/Mam,
how to solve the Allen Cahn and Cahn Hilliard equation for 2D and 3D BOTH.
What is the exact equation for Allen Cahn and Cahn Hilliard for both 2D and 3D which I can use in COMSOL. And also, what are the parameters?
Hello! thank you very much for the video! I have one question. Why integration over surface of the particle is correct ? In this case we have near-field but not far-field. I thought that we must integrate in the distance where we have the far-field. Thank you.
Did you find the answer to this by any chance?
good question. As far as i know for the calculation of the scattering cross section we need to take an imaginary surface around nanoparticle and calculate the scattered energy by that surface. Could you please explain that dear Nuno de Sousa?
Thanks a lot, this is a very helpful tutorial, how would the setup change if instead of a particle you were measuring against a multilayered sphere of dielectric material? I would assume that you would have to change the surface integration to account for the layers but how does that change the volume integral?
Thanks
Can you make tutorial about Simulation effect of harmonic current in copper busbar system in term of the temperature rise?
Sir, can you please put screen shots of parameters , variables and other expressions you wrote on screen, we were unable to see them clearly, thanks in advance
when i added " E0^2/(2*Z0_const)" in last parameter it shows red line . this means its not true value. i am use 5.6 version. please tell me whats correct value.
Hello, I seem to be having trouble getting a full plot of the absorbance cross section. For some reason, when I run the study its only computing it for one parameter value of Lambda and not actually doing the parametric sweep - would anyone know why this is happening? Thank you!
Hello.
I can´t see the parameters .
Could you tell me what they are?
please
At 29.27, can you repeat the parameters added as variables in the comment section
Thanks for this tutorial, Nuno!
Hello Nuno. This model does not work when I use pure water (relative permittivity = 80) instead of air. Do you know why? I get an error on the stationary solver for undefined value. Thanks
Hi, Thanks for this model.
Could you please share the same model but for 2D case and scattering calculation at far field?
any luck with this?
Not yet. Have you tried?
Hi. I did, all the same, like this video. but my result is only on nanoparticle and the rest is blank. what can I do about it?
Dear Nuno De Sousa, please tell me how can I find out the Multipole effects and Far-field plots???
Also please tell me that if I want to define the material with 300 nm to 2000nm wavelength range wise real refractive index and extinction co-efficient then how can I define it. Thanks
How can i try scattering cross section about Au nanoparticle? In our case not single particle ( Dimer, Trimer ) and also we should control incidence beam angle.
How would I calculate the reflection and transmission from the particle? I actually performed the same model to observe the scattering from a thin film with a nanohole. The scattering cross section values on the y-axis are in negative. What does it mean? Also on the x-axis it actually does not show the wavelength but some arbitrary numbers. Why is that so?
You've calculated the scattering cross-section of a single silicon particle. Can you please how to calculate the Scattering Cross-section of two Silicon NPs side by side (Dimer)...
Should I perform surface integration like you did and then divide by 2*geometric cross-section? Please Help!
Any luck with this?
Nice video. Sir, do you know how to design Fiber bragg grating sensor using COMSOL
I think the scattering BC should be on the external PML surface
Hi. thank you ver much. it was very useful. Would it be possible to measure the scattering of a this sphere with a dipole? I mean instead of plan wave we have a dipole close to this sphere and measure the scatterin cross section.
Meqdad Hassani Hl. That is not a comsol question, it is a scatttering theory problem. Cross sections are only defined for a plane wave because it is a direction measurement. Instead, for a dipole emitter you can compute decay rates.
the parameter: EO^2/(2*ZO_const) give me "unknow parameter". I will be pleased with you help Nuno de Sousa. Thanks you
You should try 0 (zero) and not O.
hi sir would you make a tutorial about ablation by laser to generate nanoparticles . thank you
sir is there any tutorial or any way to measure the brillouin scattering (guided acoustic wave scattering)_in the hollow core fiber
Hello Sir,
I want to ask if I want to couple your model in video with Electrostatic physics study, I mean I want to calculate static electric field (Es) from the Electrostatic study and then substitute by Es in the electromagnetic study. What are the proper steps to kindly couple them. Note(I have nonlinear study so the static electric field will affect my model)
I am trying to give thickness of 10 nm, but comsol says minimum thickness is 68.5 nm
@Nuno de Souza, thanks a lot for the video. I have repeated your work and its really nice. Works perfectly!. However, the absorption cross section values are negative, I guess it has not been important for you, but do you have a suggestion to avoid or manage that negative absorption cross section values?
The complex number in COMSOL is given by z = Re(a)- i*Im(b), I was writing z = Re(a) + i*Im(b). I solved it!.
Can you please explain in detail, how you fixed this problem?
HI Nuno,
your tutorial is very informative\. My problem is a bit different. I have a tube from which nanoparticles are coming in the rate of 635 mol/m3 every second. How can I put this in Comsol. Thanks
Thanks a lot for this tutorial!!! How can I calculate the scattering coefficient at different angles at a fixed wavelength?
Hi, what's the role of scattering boundary conditions in the internal PML boundaries? Is it really needed? Thanks!
hi sir,is it available in comsol to make ablation for solid material to generate nanoparticles? thank you
Hi Sir! I can't see clearly the values thau enter.Can u please send these values
Hi, thank you for the tutorial, it helps a lot. I am trying to perform the simulation on Comsol 5.3. I carefully followed the steps you show and got the error: Undefined value found. - Detail: Undefined value found in the equation residual vector. Could you please tell how I can fix this, if you have any idea. Thanks.
Thank you for the nice video. May I ask, how do you extract the scattering cross section against wavelength graph? Thank you for your time.
Hi, thank you very much for this nice tutorial. How long did the computation take to finish? and what are the specs of your PC?
Thank you very much for this video.
But i have couple of question regarding Scattering Cross section. You calculated Scattering cross section by integrating over the nanoparticle surface. By integrating over the nanoparticle surface we are not considering the Far field calculation. What should i do if i want to calculate scattering cross section in far field domain??
I will put a video explaining how to do it.
Nuno de Sousa thanks for ur comment.
I also want to know how to calculate Extinction cross section for array of any nanoparticle like nanodisc or nanosphere.
I know for calculating periodicity we have to introduce floquet boundary condition but i m not be able to calculate Extinction cross section for whole 2-D array
hello! do you have any video to explain to show how to calculate scatter cs by far field domain? thank you
Hey can u tell me how to model magnetic field lines of a parmanent magnets.
hi can someone please explain to me this definition of scattering cross section? would this work for a metallic NP?
Hello Sir
Could you kindly give the expressions for the cross sections (extinction and scattering)? You mentioned about the book by Hoffman. Could you kindly refer to the corresponding equations also for these?
Thanks in advance.
Saif.
+Saiful Babu Saif
Hello. Bohren and Huffman have the expression in the Mie scattering context. If you want directly the expressions you can see the following article:
www.comsol.com/paper/mie-scattering-of-electromagnetic-waves-15917
It is very basic but have what you probably need.
Hi Luis. Which parameters do you need? The video is in 1440p, so in principle you should see them.
hi Nuno thanks for such a nice video, alas if we can see the video,
Hello, can any one support me with the variables written at the end, i can not see it. thanks in advance
merci pour ce video j'ai une question, comment tracer les trois section efficaces en fonction des longueur d'ondes?
Thank you very much Sir with your interesting tutorial. May I ask your help ? I study acoustic scattering through laminate medias.
Thank you Mister Nuno.
Make tutorial of nanorods geometry please
Thanks mate. This was really helpful!
Thank you Nuno. I find your video very instructive. I just started working with Comsol - following your video everything goes well, until minute 27.40. comsol tells me that emv.relPoavx is an unknown variable. Did I forget to load anything? I am using Comsol with windows and I noticed that also in the formula E0*exp(-i*2*pi/lambda[nm])*z I cannot put the [nm], comsol does not seem to accept it. Do you have an idea how I can proceed? Thx, Ingmari
emv.relPoavx should be emw.relPoavx.
Comsol is independent of the operating system.
I will try to put the model somewhere, and you can download it.
Nuno de Sousa It worked after I corrected the typo and put the right name for Electromagnetic Waves, Frequency Domain 2. Thanks.
@@ingmaritietje5489 Sir, By correcting this still I cant't get any result. It shows yellow line rather black after going to second row in the variable defining section. Please help me.
@@Nunodsousa Sir, By correcting this still I cant't get any result. It shows yellow line rather black after going to second row in the variable defining section. Please help me.
@@Nunodsousa (nx*emw.relPoavx + ny*emw.relPoavy + nz*emw.relPoavz) sir, I had used this still i got error.
Hi, thanks for the video. Could you please write the title and author(s) of the book you cite in several parts of the tutorial? ...I cannot find it...
Thanks a lot!
Matt Brown
For this video I used the Bohren and Huffman book: ""onlinelibrary.wiley.com/book/10.1002/9783527618156
Nuno de Sousa Thanks man!
Please Sir I have a question. Why we put the area of the sphere pi*r^2 , should it be 4*pi*r^2? Thanks for the very useful tutorials.
Hassan,
Nanyang Technological University
Mohamed Hassan geometrical cross section
mohammad have you simmulated this tutorial again?
Thank You for this tutorial. Thank you very much.
sir what is name of cement material in comsol
Hi. Thanks for your kind tutorial. I can follow your tutorial easily, but in my program, COMSOL show error "NaN or Inf found when solving linear system using SOR."....I don't know why system show this kind of error. And i also want to change the wavelength range to lower wavelength part(300-1500 nm). Could you explain how to change the wavelength range?
Hey, were you able to extend the model to lower wavelengths?
Hello Sir , I am unable to see the expression for Geometric Cross Section and Scattering Factor while defining Parameter...... Please help me.
+Sai Ganesh
Hello.
The geometric Cross section is the exposed area, that in this problem is pi*radius^2.
S_in = E0^2/(2*Z0_const)
Thank u so much sir :)
Wow. So great tutorial !! thanks for teaching : )
I expect more Comsol tutorial made by You. ^^/
Hello Sir, Can you show me a tutorial on thermal radiation,So that it can help in my project...
Hi,
Thank you very much for this video. I am new to comsol. I was tryinh to reproduce the result, but got stuck while adding the variables under component1, as it says "unknown variable emw.relPoavx". Please help.
TIA :)
Prabodh Pandey do you solve he problem? I also meet some troubles when i wanna reproduce the results by myself?
I also meet the same result during variable declaration.
I try to use Comsol Multiphysics 5 .4 to repeat your results, but it did not work.
Hello when i change wavelength from 1000 nm to 2000 nm TO 400 to 1400 [nm] and radius from 230nm to 500 nm ,it is not working why???
I am also looking for the same, and showing error when give for study...
Did anyone here get an answer?
How can I calculate scattering cross section for a 2D cylinder?
have you had any luck with this?
Instead the surface of the sphere (in this video) for the Poynting vector integration, you may select the surface of the Cylinder.
Diego Rativa thank you for reply! I am trying to get the scattering cross section vs scattering angles. Do you have any idea how I can get this plot? thanks once again
Normally, a cross section is integrated over all scattering angles, so it doesn't make sense a scattering angle-dependence of the scattering cross section.
On the other hand, if you are looking for the scattering cross section vs the incident angle of the Electric Field, you should have two options. 1. Keep the electric field at the same direction (as this video) and rotate the cylinder in different angles (x,y) (in the case of an incident unpolarized light, you have to average both the X and Y axes), 2. or rotating the electric field.
Hi, When I try to replace the nanosphere with a hollow nanotube I get an error that "Cannot find any cartesian regions". Any ideas?
change to cylindrical coordinates instead of cartesian ones
Great one, very helpful! Thanks!
How can I model Geometry for multiple particle by COMSOL?
You can use matlab.
There are some tutorials in the comsol webpage.
Thanks for your response. but I need to do it by COMSOL. How can I do the geometry?
You must draw each particle individually. If you have many particles it can be painful and it is not so easy to control.
I have done simulation for one particle( sphere) with different permeability and frequencies. Now I need to do it for multiple particles( 4 particles). I am thinking to draw 4 particles but have problem to define the infinite element layer and the domains. Don't know how to do that. This is the first time I am using COMSOL.
Hello i want to get the evanescent light images of the nano-particle.. light scattered from nano-particle and i want its evanescent images...can i do like this simulations in comsol???? Kindly give your any social media contact info to contact with you regards:
Kaleem
What is the name of the book (ch4 & 5) for review? thanks.
Bohren & Hoffman
Actually it is Huffman
Can you please mention the name of the Book you suggested (Chap 4 and 5)? I couldn't catch the name properly.
+Scientific_Mind Bohren and Huffman
www.amazon.com/Absorption-Scattering-Light-Small-Particles/dp/0471293407
But if you want a short resume of the equations you can see the following paper:
www.comsol.com/paper/mie-scattering-of-electromagnetic-waves-15917
+Nuno de Sousa Thanks for the links. It's very helpful. We are currently doing research work on Nanoantennas using Comsol, and we're undergrads. Can I connect with you on some platform? It'd be of immense help to us if you do. Thanks a lot for the video though.
Moreover, we saw that you used Relative Permittivity of Silicon as a constant of 12.25 for the whole frequency range. Is it really constant throughout the whole range or is it an assumption?? Thanks a lot again. Cheers
+Scientific_Mind
Hi.
The Silicon have a constant permittivity between the 1000 and 2000nm. It is a real number (doesn't absorve in this range). It is the used value in the paper that I cite. Also you can see the refractive index of different materials here: refractiveindex.info
+Nuno de Sousa Thanks, for clearing that up. :) If I wanted to calculate the near-field enhancements of a spherical dimer pair in the gap in middle, or suppose the near field enhancement for a single Ag/Au nano-particle.. How can I do that? can you please suggest?
My goal is to calculate the Near-Field enhancement of various structures (Bow-tie, Dimer, DIpole). I can do the geometry modeling, but don't know how to post-process the data. (I can use material index from Johnson & Christy by interpolation).
If we change the shape of particle from sphere to cubic, then we cannot simulate it
何佑哲 Doesn't simulate or the result doesn't make sense?
+Nuno de Sousa Can I email some question about COMSOL to you
+Nuno de Sousa hi
hello sir i m very thank full to you for this beautiful modal .... kindly send me expressions for variables as i can not see these expression s... thanks again
screen font is too small to read
Does somebody try to put water instead of air?
Hi Angel, did you make this simulation with water? When I use relative permitttivity = 80.2 the simulation does not work.
what you type is barely visible!!
hi, can i get your email to ask you some question? thank you
Thank you very much!
Thx
Reading what you are typing is very hard or impossible. For next lessons, please make sure the poor reader can read what you typed. We don't have eagle eyes.
Everything was fine until the final plot. LOL. Thanks anyway.
Thank you so much!!!!