Hi Sandrine,

The Excel file is really helpful to create own ZBF file. I have one idea on this topic. Is it possible you add one sample ZBF file including non-zero imaginary profile? That means the phase of beam is not flat. Some users sometimes want to convert a beam profile generated from other EM filed simulator. In this case, they might be confused how do they think the imaginary part of ZBF file.

Here is an update to the Excel file with non-zero imaginary profile. 

Do not hesitate if you have any comments. (I have updated the original post)

Here is a new update to the excel file. 
In the Pivot_Table tab, there are now 3 columns.

• Column I calculates the EX Intensity = Exr^2+Exi^2
• Column J calculates the EX Phase.
• Column K calculate the EX Irradiance = EX Intensity / pixel area

The Irradiance and phase are displayed by OpticStudio.

I have updated the original post.

Hi Sandrine,

I did laser characterization, which gave me the information about laser beam waist, divergence angle, and Rayleigh in x and y separately; however I didn’t have any Ex values at all!  Does it mean I cannot define my own .ZBF? 

In this case, what can I do to define initial beam in order to use POP analysis?

Thanks,

Ying

Hi Ying

I think that with those values you can define directly your beam in POP using Gaussian Size + Angle:

You have the divergence angle so that can be entered in Angle X and Angle Y.

Then using the Rayleigh length, the distance from the surface to the waist and the waist for the beam, you can estimate Size X and Size Y using: 

Then you can enter these values.

You can then check the properties of your pilot beam (best fit gaussian beam) in the ribbon to see if it fits your calculation. You will need to separate X and Y.

Let us know if that helps.

Hi Sandrine, 

Thanks for your suggestion, I even included M2 value that I got from laser characterization, which really makes full use of all the information that I could get.

one question here: below the laser port 1 and laser port 2 are symmetrical , how to differentiate them if they are the surface that I will define the beam? The gaussian size and angle are the same, or maybe the angle is negative VS. positive?

Thanks,

Ying

Hello Ying

Yes you are correct, I think there can be an ambiguity in the definition here. You can check what is chosen by the software in the ribbon below POP. It indicates the best bit gaussian beam and so you will see the position from the gaussian beam. Let me know if that helps.

Would you like to create a case so we can have a look at your values?

Hello Sandrine,

I built a very simple system as shown below to test it:

It looks like if we switch +/- sign of the angle, it can differentiate these two situations :-)

This is cool …

Regards,

Ying

OK thank you for sharing! I hadn’t realized it.

Dear Sandrine,

Thank you for sharing the information! I would like to ask the following:

1. What is the Rayleigh distance? I assume it is the Rayleigh range if the beam is close to Gaussian. In the case of arbitrary beam shape, is it defined as (beam_aperture^2)/(2*wavelength) - wavelength/8?
2. If one wants to calculate fiber coupling efficiency at the end, how re and se are supposed to be set?
3. You wrote “If polarized, followed by 2*nx*ny Ey values.” When we set ispol as 0, are all Ey values considered as the same as Ex values or considers as null (zeros)?

Regards,

Jiang

Hi Ying

I think that with those values you can define directly your beam in POP using Gaussian Size + Angle:

You have the divergence angle so that can be entered in Angle X and Angle Y.

Then using the Rayleigh length, the distance from the surface to the waist and the waist for the beam, you can estimate Size X and Size Y using: 

Then you can enter these values.

You can then check the properties of your pilot beam (best fit gaussian beam) in the ribbon to see if it fits your calculation. You will need to separate X and Y.

 

Let us know if that helps.

Dear Sandrine,

Could you please give me help material to read about how Zemax transforms the “Gaussian size+angle” settings into the beam profile? I am really puzzled because it seems to me that those settings still lack of phase information. Then how does Zemax calculate the beam propagation?

Regards,

Jiang

Hi Sandrine, The excel file is very useful. I am trying to use it to create a pilot beam based on Bessel beam. Since this is my first time using your file, Did you mean to say “column G was the zbf beam file”? because column E in the ZBF tab is index_y and has no information on the Gaussian beam you created. Thanks in advance!

Hi @Driss.Touahri ! Yes you are right. Column G. I will update my post. Thank you for your feedback!

Thanks for confirming Sandrine! Have a wonderful day!