I kinda agree 1THz is considered Far IR at 100um, which is a LOT of bandwidth! From working with folks who did Tunnel Junction mixers, I think it's because thin

I kinda agree 1THz is considered Far IR at 100um, which is a LOT of bandwidth! From working with folks who did Tunnel Junction mixers, I think it's because things start looking particle-like, beyond wave-like at those frequencies. I guess it's actually called EHF up to 300GHz.