Einstein's coefficient of stimulated emission

Einstein's coefficient of stimulated emission

[¦īn‚stīnz ‚kō·ə¦fish·ənt əv ¦stim·yə‚lād·əd ə′mish·ən] (atomic physics) Proportionality constant governing the rate at which atoms or molecules pass from an upper energy state to a lower one by stimulated emission of radiation, equal to the number of such transitions per second divided by the product of energy of the radiation inducing the transition per unit volume per unit wave number and the number of atoms in the upper state.