Neologism include "laser" (1960) from Light Amplification by Stimulated Emission of Radiation, "robotics" (1941), "agitprop" (1930). The term "neologism" is first attested in English in 1772, borrowed from French "néologisme" (1734). A proponent of a new word or doctrine may be called a neologist. Neologists might study cultural and ethnic vernacular. The term "neologism" has a broader meaning that includes not only "an entirely new lexical item" but also an existing word whose meaning has been altered. Sometimes, the latter process is called "semantic shifting", or "semantic extension". Neologisms are distinct from a person's "idiolect", one's unique patterns of vocabulary, grammar,
Stimulated emission difference in energies between the two states as a photon. The photon will have frequency "ν" and energy "hν", given by: where "h" is Planck's constant. Alternatively, if the excited-state atom is perturbed by an electric field of frequency "ν", it may emit an additional photon of the same frequency and in phase, thus augmenting the external field, leaving the atom in the lower energy state. This process is known as stimulated emission. In a group of such atoms, if the number of atoms in the excited state is given by "N", the rate at which stimulated emission occurs is