A couple of years ago in a Q&A for The Creators Project they asked me:
“What fantasy piece of technology would you like to see invented?”
“A simple knob that connects to any source of light, so it slows down the speed of the light. Even down to zero, like a lightsaber.”
I always dreamed about the endless possibilities if such a magical thing was ever feasible. And I recently discovered that it is happening! In the last story of this podcast from Radiolab (min. 45),
Danish physicist Lene Hau explains how she has been able to slow down a beam of light, passing it through an ultra-cold cloud of sodium atoms. She has also been able to transform the form of light into matter, recording the shape of the light pulse with a laser. This light copy (or light metadata) can be stored, and the light form re-created in another place and time.
Collection of sunsets
Cold-cloud photo camera