Use of MIE SIMULATOR software

[laurena....@gmail.com]

Hi,

I'm working on a scattering problem caused by bacteria during optical density measurement with spectrophotometers.
I would like to know if your software (Mie simulator) is based on only single scattering or if it includes multiple scattering?

Do you know some articles that explain the phenomenon Mie without going into details of mathematics calculations?

Thanks you for your help,

Best regards,

Laurena

[Janaka]

Hi Laurena,

Thank you for your interest in our software. Mie Simulator GUI considers multiple scattering. Its "Concentration / Volume Fraction" input panel allows users to input either concentration or volume fraction. You can find more details in the documentation.

Mie Simulator GUI documentation can be found here
https://github.com/VirtualPhotonics/MieSimulatorGui/wiki

The Mie theory or the Mie solution to Maxwell's equation describes the scattering of light by spherical particles. I would suggest you look for articles that discuss "light scattering by spherical particles" to understand the concepts. If you want to know more about Mie, read "The Mie Theory Basics and Applications" edited by Hergert Wolfram and Thomas Wriedt

Best Regards
Janaka

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[cchu...@gmail.com]

Hi,

I am working with your simulator within the framework of a project about spectrophotometers.

I would like to be sure that with your simulator “Mie simulator GUI v1.0.5”, we cannot get the phase function for a mix of spheres with sizes and numbers defined.
Could you confirm this? So, I’m working with the following formulae. Do you agree with it?

 

If we suppose a mix of beads with a number and size distribution function n(a), the equation of phase function is written :

with  being the angle between the diffused light and the incident light, and  being the scattering section for a.

The scattering coefficient  is equal to:

 .

In the case of a mix of beads defined in size and number, we can write:

With a being the different sizes considered, and n_a the number of beads of each size.

It leads for the phase function to :

 

Thanks for your help,

Best regards,

Claire

Le jeudi 25 janvier 2018 20:37:44 UTC+1, Janaka R a écrit :

Hi Laurena,

Thank you for your interest in our software. Mie Simulator GUI considers multiple scattering. Its "Concentration / Volume Fraction" input panel allows users to input either concentration or volume fraction. You can find more details in the documentation.

Mie Simulator GUI documentation can be found here
https://github.com/VirtualPhotonics/MieSimulatorGui/wiki

The Mie theory or the Mie solution to Maxwell's equation describes the scattering of light by spherical particles. I would suggest you look for articles that discuss "light scattering by spherical particles" to understand the concepts. If you want to know more about Mie, read "The Mie Theory Basics and Applications" edited by Hergert Wolfram and Thomas Wriedt

Best Regards
Janaka

On Thu, Jan 25, 2018 at 1:58 AM, <laurena....@gmail.com> wrote:

Hi,

I'm working on a scattering problem caused by bacteria during optical density measurement with spectrophotometers.
I would like to know if your software (Mie simulator) is based on only single scattering or if it includes multiple scattering?

Do you know some articles that explain the phenomenon Mie without going into details of mathematics calculations?

Thanks you for your help,

Best regards,

Laurena

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[Janaka]

Hi Claire,

Our Mie Simulator GUI provides the correct phase function for a mix of scatterers. See attached excel worksheet.
If you use your formulae properly, you should get correct results.
Could you share your incorrect data with us?

Best Regards

Janaka

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[cchu...@gmail.com]

Hi Janaka,

Thanks a lot for your very fast answer ! We obtain the same results than you. However, we find that it's a pity that we cannot enter the sizes of several spheres on your simulator. In fact, lots of researchers like us work with precise sizes.

Best Regards,

Claire

[cchu...@gmail.com]

Hi !

I have another question for you.
Any sphere has an absorption index not equal to zero. And, the phase function changes with this absorption index of the sphere. So, does your simulator take into account the absorption index of the sphere ? If so, where can I see that ?

Thanks a lot for your clarification,

Claire

[Janaka]

Hi Claire,

In your previous email, you mentioned that you want to input precise sphere parameters in polydisperse distribution. This can be done by reading parameters from a file. We will include this capability in our next release (v1.0.6).

A complex refractive index is often used to accommodate the light propagation in absorbing spheres.  However, the previous version that only considers real refractive index, does not support absorption. So, you will not get correct results for absorbing spheres. Recently, we changed the sphere refractive index from a real value to a complex value in our code to help one of our internal collaborators. This modification will be included in the next release.

Our plan is to release the next version before April. 

 

Best Regards

Janaka

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[cchu...@gmail.com]

Hi Janaka,

Thank you for your fast answer. We look forward to test your next version !

Best regards,

Claire 

[Janaka]

Hi Claire,

We have released a new version of our Mie Simulator GUI during this weekend.
It will allow you to input a custom sphere data file in the polydisperse distribution.

You can download the latest version here:

https://github.com/VirtualPhotonics/MieSimulatorGUI/wiki/Downloads

The format of a sample data file is given here:
https://github.com/VirtualPhotonics/MieSimulatorGUI/wiki/Mie-Simulator-GUI-Sample-Infiles

If you have any questions, feel free to contact.

Best Regards

Janaka

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[Karthik Sasihithlu]

Dear Janaka,

Thanks for making this cool simulator available to all.

A follow up question to what Laurena has asked regarding multiple scattering:  is there any limitation in this code ? For example, do you expect the code to give accurate scattering parameters when you have dense concentration (fill factor >0.7) of spherical particles?  Any limitation to the size of the particles that can be adopted?  Multiple scattering between spherical particles can be carried out either multipole expansion techniques or ray tracing method - can we find details in some source as to what technique you have adopted in this code?  This will give a good picture of what the limitations are.  I tried finding in your wiki if there is some documentation regarding how these scattering parameters are calculated but I couldn't find any.

Also, I noticed that the thickness of the matrix film where the spherical particles are embedded is not a parameter in the simulation. Only the number density/volume fraction is.   If you have absorbing spherical particles, wouldn't the thickness of film/matrix  come into picture (for normal incidence, higher the thickness -> more the number of absorbing particles along the initial path of light).   If you have a thin film ,  and a thick film with the same number density of particles ; wouldn't the multiple scattering solutions be different for these two cases ?

Thanks!

Karthik

On Friday, January 26, 2018 at 1:07:44 AM UTC+5:30 janak...@gmail.com wrote:

Hi Laurena,

Thank you for your interest in our software. Mie Simulator GUI considers multiple scattering. Its "Concentration / Volume Fraction" input panel allows users to input either concentration or volume fraction. You can find more details in the documentation.

Mie Simulator GUI documentation can be found here
https://github.com/VirtualPhotonics/MieSimulatorGui/wiki

The Mie theory or the Mie solution to Maxwell's equation describes the scattering of light by spherical particles. I would suggest you look for articles that discuss "light scattering by spherical particles" to understand the concepts. If you want to know more about Mie, read "The Mie Theory Basics and Applications" edited by Hergert Wolfram and Thomas Wriedt

Best Regards
Janaka

On Thu, Jan 25, 2018 at 1:58 AM, <laurena....@gmail.com> wrote:

Hi,

I'm working on a scattering problem caused by bacteria during optical density measurement with spectrophotometers.
I would like to know if your software (Mie simulator) is based on only single scattering or if it includes multiple scattering?

Do you know some articles that explain the phenomenon Mie without going into details of mathematics calculations?

Thanks you for your help,

Best regards,

Laurena

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[Janaka R]

Hi Karthik,

Sorry for the delay.

Our tool is based on well known Mie calculation algorithms. I have added references to our main page and wiki page.  

You will find answers to most of your questions in these references.

  - van de Hulst's Light Scattering by Small Particles (1957) book

  - Bohren and Huffman's Absorption and Scattering of Light by Small Particles, (1983) book, 

  - Maetzler's research report 

  - Scott Prahl's 'Mie Basics' web pages. 

  - Gélébart et al's Pure and Applied Optics , 5 (1996) paper. 

  - Steve L. Jacques's Phys. Med & Bio. 58 (2013) review paper

higher the thickness -> more the number of absorbing particles along the initial path of light 

Yes, but to keep the same number density in a thin film, you need to spread the scatterers in a larger area 

and illuminate the "whole area" with a plane wave.

Remember, Mie calculations are based on "plane wave" incident upon spherical scatterers. 

Best regards

Janaka