This is a good suggestion.  Currently we can only do it through making our own catalog by saving the suited glasses, but this is really time consuming. It will be great if Zemax can add in the feature to choose the glass with certain transmission percentage over current wavelength setting.

I made this same suggestion a couple years back, and am upvoting it again here.

Hey everyone,

Let me give some color on why this is implemented the way it is.

Each glass already contains minimum and maximum wavelength data, and OpticStudio will not choose a glass outside of the desired wavelength range of the system.

Now transmission is a function of the absorption of the glass and the thickness, so a thin amount of a glass that is starting to absorb may be successfully used, where a thicker piece would not. The correct place for a constraint like that is in the merit function. The Glass Substitution template is a binary decision-maker and runs before the optimization starts: glasses are either in or out. For decisions that are based on what-happens-if, use the merit function. In this case, a single CODA operand can return the transmission of a ray, and you can set a lower limit on this in the merit function.

This way, a glass that is within the allowable range but is starting to absorb can still be used, if the overall transmission is acceptable. 

Thank you for the response! That does make sense to approach it that way.

I would like to respond to your one comment about OpticStudio not picking glasses that are outside the wavelength range of the system. How is this determined? For example Ohara Glass S-BAH28 has a range of 0.40465-2.32542 microns although that data shows it transmitting down to 0.38 microns (58% @ 10mm thickness). If the wavelength range of my system was 0.400-0.700 microns Opticstudio wouldn't pick this glass even though it would certainly work at 0.400.

Hey Nate,

Every glass contains these two data fields



These are tested against the wavelengths entered in the Wavelength Editor and glasses outside of the range required are mot available for substitution. Manufacturers usually set these limits as being where they have measured the dispersion or other data over, rather than an absolute transmission though.



The transmission through 25mm is >70% throughout the allowable range, so my guess is that Ohara set the limits where they are based on the available dispersion data. You should check with Ohara to be sure though. There may also be damage issues as well: that absorbed energy has to go somewhere.