Hello,

I've left my OpticStudio laptop at work, but I think several equations are implemented, including Sellmeier, and it is specified for each material in the glass catalog. Each equation is detailed in the Help file by pressing F1.

Usually, they say it in the release note if they made changes to the glass catalog (the section is called Materials & Catalogs):

https://downloads.zemax.com/Zemax-portal/Resources/Downloads/OS_Files/OpticStudio20-3-1_ReleaseNotes_EN.pdf

I hope this helps.

Kind regards

Hi Bella,

David has shared some great notes about using glass catalog glasses. Thanks David! 

For calculating your dispersion profile for a MIL glass, you can use the Universal Plot 1D in OpticStudio. This plot allows you to define an independent variable (wavelength) and a dependent variable (index). The dependent variable is chosen from a list of our available optimization operands. The one you would use is INDX which returns the current index at the surface defined by Surf at the wavelength defined by Wave. 

In the attached file, I have put together a Universal Plot using the above constraints, and matched it to the plot given by our built-in Dispersion Diagram tool. You can see the two match.

The Dispersion Diagram is found under Libraries...Material Analyses but will only accept glass catalog glasses as an input - you cannot enter MIL glasses in that tool. This is why we will need to use Universal Plot in your case. To analyze your material, simply change the material of surface 1 to your MIL glass. The Universal Plot will update with the new data. 

Regarding your question about the typical glasses used for MIL glass fitting, I am discussing this with our developers. I will let you know when I have a response!

Have a great weekend. 

Best,

Allie

Thanks for your answer, David. I should clarify, though. If you look up MIL Number Glasses in the Zemax documentation, you can see how they're described as a refractive index and Abbe number. The example I gave above: 377571. This number shakes out to a refractive index at 588 nm of 1.377 with Abbe number of 57.1. My guess for how Zemax churns this value is it puts a pin in the glass map and tries to find the closest match (this map doesn't even go down to 1.377 for index, but you get the idea):

My guess is that they then use the Sellmeier (or Cauchy, or whatever) fit to that glass's data to estimate what your material will act like at whatever specific wavelength you want to use.

My use case here is that I would like to plot the dispersion curve they're getting from the MIL number from my model, or at least be able to access the refractive index they're assuming for these materials at the wavelengths I'm interested in. Further, I am wondering if using this MIL calculation could potentially differ between Zemax models and glass catalogs because some catalogs might have different materials that correspond to the nearest index of refraction in green + Abbe number.

I'd love to remove some of the guesswork from this problem! Maybe there's a hidden magic button in Zemax to plot this data, there often is.

Thanks,

Bella

Allie, I think I was typing my response at the same time as you! Thank you, that's exactly what I was looking for. Looking forward to learning more about how the glasses are chosen for MIL fitting, but your response will get me what I need for now.

You have a great weekend, and a Happy Halloween,

Bella

Hi Bella,

I hope you had an enjoyable holiday weekend!

I have heard back from our developers. While the code for fitting MIL glasses is proprietary, I can let you know that it was generated based on Schott preferred glasses a few years ago. The MIL fit equation we generated came back with index values at a given lambda within 0.1% of the actual Schott glasses themselves. The fit is not updated with the Schott catalog, so it will be the same between versions and machines. 

Does that answer you question? Let me know if you have any other concerns!

Best,

Allie

Thank you so much, Allie! That's all I needed for now.

Hello Bella, and Allie,

I'm sorry I made a mistake. I thaught MIL was a glass manufacturer... Probably should have read the post twice before going for the weekend.

Thanks to you I've learned new things about glasses!

Thank you, and take care