A team of physicists in the us has created an infrared laser beam at a point in mid air, by focusing a UV laser onto a tiny volume of oxygen molecules.
But what they noticed was that even when they turned the flame off they were still getting a signal - in other words, the laser was breaking up as well as exciting the oxygen.
It's suitable for: oxygen, nitrogen making, dental therapeutic apparatus, instruments and meters, food packaging, laser cutting, and many other industries.