Hi Gwendoline

Thanks for your post here on the forum!

As you said correctly you can find POLYCARB in the MISC catalogue, you can check the glass report to see the valid range of the material. Here:

To solve your problem, I would recommend creating a new catalogue based on the original one (misc in your case) and modify the valid wavelength of POLYCARB within your new catalogue to suit your specific needs.

You can modify the wavelength here:

Please consider that you should not change the wavelength too drastically (In this specific case it is okay: 365nm to 363nm), because otherwise the polynomial extrapolation can behave strangely.

You can also find a in-depth Knowledge Base article on “How to add new matrials and glasses in OpticStudio” here:

https://my.zemax.com/en-US/Knowledge-Base/kb-article/?ka=KA-01673

Hope I was able to help

Have a great week,