https://phys.org/news/2018-06-physicists-terahertz-uncover-state-hidden.html

And then it takes a second terahertz light to trigger an ultrafast camera to take images of the state of matter that, when fully understood and tuned, could one day have implications for faster, heat-free, quantum computing, information storage and communication.

The discovery of this new switching scheme and hidden quantum phase was full of conceptual and technical challenges.