Hello Benoit,

OpticStudio generates refractive indices within the range based on manufacturer data by using, in this case, the Sellmeier I formula. Using the formula outside the range provided by the manufacturer runs the risk of missing refractive index behavior that occurs at higher wavelengths.

The best option is to contact the manufacturer directly and ask if there is data for your desired wavelenght range. If so, they might give it to you in one or more formats, possibly including tabulated index data by wavelength, or possibly by an updated formula. Alternatively, you might find the data for this material on the internet or somewhere else. Whichever format you receive the data in, you will be able to add into the materials catalog as a new material. Here is the link to an article that explains adding new materials into OpticStudio:

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

Another option you may use is to simply alter the wavelength limits. You would need to rename and resave the catalog to a convenient name, by pressing “Save Catalog As” and picking a new name, and then you would be able to change any of the material properties, including the wavelength limits. This is straightforward to implement, but risky, and I wouldn’t recommend it.

Best,

Berta