I need to have a telecentric lens at terahertz spectral range (wavelength of 500 to 900 um). According to the documentations, the best material in this range is ZEONEX E48R. However, in ZEMAX, in the catalogue of E48R (and the whole ZEON.AGF catalogue materials) the maximum available wavelength is 1.6um. It is strange to me, since I have seen in numerous documentations that this specific material is used in ZEMAX in terahertz spectral ranges.
I have two questions in this regard:
Am I looking at the wrong catalogue or do I need to download or update this catalogue myself? If that, where should I find the related data or documentation for it?
Also is there some other material that I could use instead of ZEONEX E48R that is supportive of terahertz spectral range? How can I find its related parameters to add for ZEMAX catalogues?
Thanks a lot in advance for your time.