Research News

Optics: Interfering With Atoms to Clear a Path for Lasers

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Science  19 Jan 1996:
Vol. 271, Issue 5247, pp. 293
DOI: 10.1126/science.271.5247.293


A powerful laser beamed into a gas turns it, in essence, into a lens that either focuses the beam more intensely, until it splinters into filaments and hot spots, or defocuses and weakens it. This phenomenon—a vexing one for researchers and engineers—takes place because the light alters the electronic states of atoms in the medium, changing its refractive index. Now researchers have found a way to forestall this atomic response, allowing the laser to pass through unmolested.