Now, a US team has created thousands of the molecules by merging electrons with their antimatter equivalent: positrons.
The discovery, reported in the journal Nature, is a key step in the creation of ultrapowerful lasers known as gamma-ray annihilation lasers.
"The difference in the power available from a gamma-ray laser compared to a normal laser is the same as the difference between a nuclear explosion and a chemical explosion," said Dr David Cassidy of the University of California, Riverside, and one of the authors of the paper.
"It would have an incredibly high power density."
As a result, there is a huge interest in the technology from the military as well as energy researchers who believe the lasers could be used to kick-start nuclear fusion in a reactor.
--Jonathan Fildes, BBC, on first steps towards Star Wars laser guns