In the 1960s, physicists showed how light could interact with itself in intriguing ways thanks to a process known as second-harmonic generation. In the right kind of material, two photons of a certain frequency can interact to produce another…
In the 1960s, physicists showed how light could interact with itself in intriguing ways thanks to a process known as second-harmonic generation. In the right kind of material, two photons of a certain frequency can interact to produce another…