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Ray optics-light scattering

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Hello All,

I am trying to find the way to calculate the scattering cross section or diffuse coefficient for glass surface with hexagonally packed micro lenses.
In other words, I just need estimate the light scattering of such a surface.

I try to use Ray Optics Module since my lenses (10um in diameter) much smaller then wavelength (400um-800um).
I have built the 3D model and got 3D distribution of light rays.
How can I calculate the amount of rays whose intencity remain the same (red rays on pic. 2)?

Please, let me know if someone know another method of light scattering estimation.


10 Replies Last Post Dec 17, 2015, 2:13 a.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 9 years ago Dec 2, 2015, 2:01 a.m. EST
Hi

I'm not sure that is the right approach, as if you are in the THz region with far infrared radiation in the sub mm range, the interaction with sub-wavelength patterns in the ten um range would make diffraction effects, that are better modeled with the RF physics. But if you have non coherent illumination and a large wavelength spread I'm not sure how you can average out all those results to get a global scattering coefficient.

--
Good luck
Ivar
Hi I'm not sure that is the right approach, as if you are in the THz region with far infrared radiation in the sub mm range, the interaction with sub-wavelength patterns in the ten um range would make diffraction effects, that are better modeled with the RF physics. But if you have non coherent illumination and a large wavelength spread I'm not sure how you can average out all those results to get a global scattering coefficient. -- Good luck Ivar

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Posted: 9 years ago Dec 2, 2015, 2:44 a.m. EST
Ivar Thank you for replying

I am very sorry for misleading you. I've made a mistake in my problem explanation.
Actually the wavelength ranges between 400nm to 800nm (visual light) and diameter of lenses is 10um.

Thank you!
Ivar Thank you for replying I am very sorry for misleading you. I've made a mistake in my problem explanation. Actually the wavelength ranges between 400nm to 800nm (visual light) and diameter of lenses is 10um. Thank you!

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 9 years ago Dec 2, 2015, 3:13 a.m. EST
Hi

well I wondered about that :) in that case cannot you just analyze a "section" (one lenslet region) and duplicate that ?

--
Good luck
Ivar
Hi well I wondered about that :) in that case cannot you just analyze a "section" (one lenslet region) and duplicate that ? -- Good luck Ivar

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Posted: 9 years ago Dec 2, 2015, 3:52 a.m. EST
Yes, I have tried to model just 1 unit cell using RF physics but because of the size difference I had to use too fine mash and always got the error message about lack of the memory:(

That's why I've decided to use ray physics. But I don't know how to get numerical results.
I think, a good way for scattering estimation is calculating the ratio of total amount of rays to rays whose intensity and direction remain the same.
How can I calculate the amount of rays whose intensity remains the same?

Thank you!
Yes, I have tried to model just 1 unit cell using RF physics but because of the size difference I had to use too fine mash and always got the error message about lack of the memory:( That's why I've decided to use ray physics. But I don't know how to get numerical results. I think, a good way for scattering estimation is calculating the ratio of total amount of rays to rays whose intensity and direction remain the same. How can I calculate the amount of rays whose intensity remains the same? Thank you!

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Posted: 9 years ago Dec 7, 2015, 12:51 a.m. EST
Did anyone work with similar problem? How can I calculate the amount of rays whose intensity remains the same?

Thank you!
Did anyone work with similar problem? How can I calculate the amount of rays whose intensity remains the same? Thank you!

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 9 years ago Dec 7, 2015, 2:01 a.m. EST
Hi

isn't this the same as saying, if one have a flux, of given properties, traversing a Boundary, then one get the total flux by integrating the flux (boundary density) over the full Boundary, possibly also by integrating over some other property (i.e. wavelength) to get the full contribution.
So if you now want to limit the flux variation region with respect to some particular property "I0" you integrate the flux, over you Boundary, but bounded by your limits (i.e. lower_limit < I0 < upper limit) via for example a Boolean expression.

--
Good luck
Ivar
Hi isn't this the same as saying, if one have a flux, of given properties, traversing a Boundary, then one get the total flux by integrating the flux (boundary density) over the full Boundary, possibly also by integrating over some other property (i.e. wavelength) to get the full contribution. So if you now want to limit the flux variation region with respect to some particular property "I0" you integrate the flux, over you Boundary, but bounded by your limits (i.e. lower_limit < I0 < upper limit) via for example a Boolean expression. -- Good luck Ivar

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Posted: 9 years ago Dec 10, 2015, 9:27 p.m. EST
Ivar Thank you for replying!

I will try to implement what you said.

Have a good day
Ivar Thank you for replying! I will try to implement what you said. Have a good day

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Posted: 9 years ago Dec 12, 2015, 7:36 a.m. EST
Hello Ivar

I have some doubt. If I have solve the problem which involves light in visible range (400-700 [nm]) and interaction with lens having dimensions (in micron). So how someone can solve the problem of focusing through lens and other related problem in Wave optics or RF module because in this case meshing would become a huge issue.
Hello Ivar I have some doubt. If I have solve the problem which involves light in visible range (400-700 [nm]) and interaction with lens having dimensions (in micron). So how someone can solve the problem of focusing through lens and other related problem in Wave optics or RF module because in this case meshing would become a huge issue.

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Posted: 9 years ago Dec 17, 2015, 2:04 a.m. EST
Hello, Abhishek Kumar

I could be wrong, but i think the example of modeling Czerny-Turner Monochromator would be helpful for you. (www.comsol.com/model/czerny-turner-monochromator-19061)
Hello, Abhishek Kumar I could be wrong, but i think the example of modeling Czerny-Turner Monochromator would be helpful for you. (http://www.comsol.com/model/czerny-turner-monochromator-19061)

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Posted: 9 years ago Dec 17, 2015, 2:13 a.m. EST

Hi

isn't this the same as saying, if one have a flux, of given properties, traversing a Boundary, then one get the total flux by integrating the flux (boundary density) over the full Boundary, possibly also by integrating over some other property (i.e. wavelength) to get the full contribution.
So if you now want to limit the flux variation region with respect to some particular property "I0" you integrate the flux, over you Boundary, but bounded by your limits (i.e. lower_limit < I0 < upper limit) via for example a Boolean expression.

--
Good luck
Ivar


Hello Ivar

I am new in Ray optics and have some difficulties with integration in this module. Could you please recommend or give me appropriate simple example.

Thank you alot

[QUOTE] Hi isn't this the same as saying, if one have a flux, of given properties, traversing a Boundary, then one get the total flux by integrating the flux (boundary density) over the full Boundary, possibly also by integrating over some other property (i.e. wavelength) to get the full contribution. So if you now want to limit the flux variation region with respect to some particular property "I0" you integrate the flux, over you Boundary, but bounded by your limits (i.e. lower_limit < I0 < upper limit) via for example a Boolean expression. -- Good luck Ivar [/QUOTE] Hello Ivar I am new in Ray optics and have some difficulties with integration in this module. Could you please recommend or give me appropriate simple example. Thank you alot

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