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Hello,

I am currently modeling a dynamic zoom system constituted of two liquid lens and a lens with a fixed focal length. The goal of this system is to change the size of the gaussian laser beam entering the zoom by a magnification factor in the range e0.2,0.6], so it can be flexible between each change of magnification. 

My problem is the following: I want to measure the magnification in order to be sure that the system can actually work for different magnifications. I had two ideas so far.

The first one is to measure the magnification of the system using the operand PMAG inside the merit function. But it is valid only in the case of a paraxial system. Using a gaussian beam I am not sure that this is the best way to measure the correct magnification.

My second thought was to measure the size of the gaussian beam waist at the entrance of the system, then at the exit and finally do the division (exit/entrance) inside the merit function. However I didn’t find such operand in order to measure the waist size…

I excluded the paraxial gaussian beam data analysis solution because I have to check that the system works for many magnifications.

What would you suggest in order to achieve this calculation correctly ?

I am looking forward for your answer.

Best regards.

Hello everyone,

In order to be more precise in my question, I want to show you the design I did.

The magnification that I wanted to reach was -0.5, focal f1= -291mm, focal f2=138mm, focal f3=80mm. distance between the first and second lens=100mm, distance between the second and third lens=295mm.

First, I modelled the system with paraxial lenses only (capture1). I also set a gaussian beam illumination. As you can see, the system works pretty well, and gives a magnification of -0.509.

However, when I try the same thing but adding 2 optotunes (liquid lenses), the magnification of ~ -0.5 cannot be reached (capture2)! I don’t know if I did something wrong in the setting of the gaussian beam, or if it is the use of adaptative surfaces that can set the whole system out of paraxial condition for the operand PMAG to work correctly…

What would you change in order to reach a good magnification?

Hi Marie,

I’d use GBPS to get the Gaussian beam size on the two surfaces, and then use DIVI to divide one by the other to get magnification.

  • Mark

 

Hi Mark,

I just tried this, but it looks like the operation gives the same result as the magnification calculation with PMAG…

(see capture)

Do you think adaptative surfaces have a strange behaviors when using paraxial operands with it?

Best regards,

Marie.

Hello again,

I finally found my mistake: I didn’t set the correct radius of curvature in order to get the good focal. That is why the system was not working.

Thank you for your help!

 

Glad you got it fixed!

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