Physicist Have Created A New Form Of Light That Can Interact Like Atoms | IFLScience

http://www.iflscience.com/physics/physicist-have-created-a-new-form-of-light-that-can-interact-like-atoms/
American researchers have been able to create a three-photon bound state that represents a completely new form of light.
As reported in Science, the researchers have been looking at complex interactions between photons for years. They obtained a two-photon state in 2013.