Linked elsewhere in this thread:
https://www.nobelprize.org/uploads/2023/10/popular-physicspr...
I understand (at an undergrad level) superimposing light waves. But this blows my mind:
At the same time, Ferenc Krausz and his research group in Austria were working on a technique that could select a single pulse – like a carriage being uncoupled from a train and switched to another track. The pulse they succeeded in isolating lasted 650 attoseconds