Discussion Forum

Posted: 1 decade ago 11.01.2014, 16:11 GMT-5

Ali, 1) all material parameters can be functions, e.g. functions of frequency 2) you can perform a frequency domain study using the frequency range of interest It is all in the documentation. Cheers Edgar -- Edgar J. Kaiser emPhys Physical Technology http://www.emphys.com

Posted: 1 decade ago 11.01.2014, 23:25 GMT-5

[QUOTE] Hello dear. I'm a student of physics. The topic of my thesis is about Optical Filters. I use the COMSOL Multiphysics v. 4.3 for simulation. So I work with RF module. I have designed an array of Optical Nano Antenna (ONAT) . The ONAT is made of Aluminum. I have two problems: 1) When I want to add Aluminum to the ONAT sample, in Material Contents box > Refractive Index row , the values of Refractive Index and Refractive Index imaginary part is undetermined and I must fill it with a number. But we know the refractive index of Aluminum is different for different wavelengths. What should I do with this problem when I use white light (a spectrum of different frequencies)? 2) The incident light is continuous spectrum from 350 nm to 2300 nm, (like light of sun) but I can't define this wavelength range. Can you help me? Thanks in Advance. (( M. A. Managheb )) my E-mail address: managheb2014@gmail.com [/QUOTE] Hi Ali COMSOL (RF module-Frequency domain) will help your problem. It solves for frequency range. Coming to refractive index, you can import the (n, k) values either in um or nm range via Interpolation method. This can be done under Global definitions --> Functions. After this say for example define parameters (under global definitions) for lambda = 800[nm]. Then you have to define frequency = c_const/lambda. Later in Study, you can do parametric sweep for parameter "lambda". Thats it. Now you can do for wavelength range you required. For getting n, k values there are lot websites where you can download the data.

Posted: 1 decade ago 12.01.2014, 07:02 GMT-5

Dear Vasanthan but when i would to define 100 frequencies in ((frequency domain)) for each frequency we should insert specific number for refractive index (n and k). but i heard that with interpolation we can define this. ( t and f(t) that t for frequncy and f(t) for refractive index) . but i can't recal this function ( = interpolation) in material properties ! what should i do?

Posted: 1 decade ago 12.01.2014, 21:59 GMT-5

HI Ali After importing n, k values via Interpolation, you have to define them. After that, define the material properties (epsilon-r). It is given by er = (n-jk)^2. So with respect to Interpolation definitions, you have to define it as er= (n(lambda)-j*k(lambda))^2. This "lambda" is the parameter you have define initially in Parameters (under Global definitions). You can give your own name too other than comsol constants. This is must so that you can run the simulation without an error or for many wavelengths. COMSOL documentation will give you clear idea about this.

Posted: 1 decade ago 13.01.2014, 07:14 GMT-5

Hi dear Vasanthan thanks alot for your Insightfull answer. but as you said : COMSOL documentation will give you clear idea about this. how can i found this in comsol documentation?

Posted: 1 decade ago 13.01.2014, 23:03 GMT-5

You can find COMSOL manual and as well as COMSOL videos gallery for source of this. http://www.comsol.com/video/browse/electromagnetics If you had installed comsol in your PC, then Reference manual is automatically installed (pdf as well HTML version)