Meaning of optical pumping

op'tical pump'ing

Pronunciation: [key]
— Physics, Optics. Physics,Optics.
  1. a method for increasing the number of atoms or molecules occupying higher energy levels by irradiating them with light of the proper frequencies to raise them to those levels.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.