excited-state maser

excited-state maser

[ek¦sīd·əd ′stāt ′mā·zər]
(physics)
A maser whose amplifying transition has a terminal level that is not appreciably populated at thermal equilibrium for the ambient temperature.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.