Don't know if anyone posted this, but I did a random search for "terahertz computer".

I found 2 interesting things:
https://extremetech.com/extreme/...
https://sciencedaily.com/releases/...

So DARPA actually built a terahertz chip and some people in the middle east have developed tech for a light based chip.

I don't know about you, but I so WANT a terahertz capable CPU.