Daniel, Rosenberger is a German company with 15000 employees and $6 Billion revenue, and Helmut Reiter is their R&D Director
Helmut Reiter Director RD @ RosenbergerDirector RD
This goes well beyond 100 GHz with plasmons. Here's an interesting article in IEEE Spectrum about how Polariton Technologies Ltd. plans to break the terahertz barrier. (LWLG Inside!!!)