Abstract: A method for producing stimulated emission of gamma radiation comprising: 1] providing at least first and second gamma-radiation sources, both sources being in recoil-free first-excited nuclear levels and the second source being in resonance with the first source and the gamma radiation from the first source being incident on the second source, 2] during the lifetime of its excited state, abruptly moving the first source through a distance equal to ½ the wavelength of the radiation emitted therefrom, thereby inducing a ?-phase-shift gamma radiation transparency in the second source whereby the ?-phase-shifted gamma radiation stimulates the excited nuclear resonant state of the second source to emit gamma radiation.

Abstract: Disclosed is a material for a magneto-optical element, which is made of magnetic garnet single crystals being wide in a band width in a 1310 nm band and thereby being capable of coping with the wavelength multiplex communication at the wavelength band, and a Faraday rotator using the same. The material for a magneto-optical element is made of a magnetic garnet having a composition formula expressed by R.sub.3-y-x Sm.sub.y Bi.sub.x Fe.sub.5 O.sub.12, where R is one kind of rare earth elements including yttrium (Y), and "x" and "y" are constants defined by 0.3.ltoreq.x.ltoreq.1.9 and 0.4.ltoreq.y.ltoreq.2.7, the magnetic garnet being formed on a non-magnetic substrate by liquid-phase epitaxial growth. R is preferably one of Y, La, Sm and Lu. The Faraday rotator, which is used in a wavelength range of from 1250 to 1370 nm, is formed by superposing a film A made of LPE magnetic garnet single crystals expressed by a composition formula of R1.sub.3-x Bi.sub.x Fe.sub.5-z Z.sub.z O.sub.

Abstract: A laser having a gaseous mixture including carbon dioxide as the lasing medium, wherein the lasing medium is cooled to a temperature such that the thermal population of the lower energy level of an output lasing transition between a higher energy level and a lower energy level of the carbon dioxide molecule is reduced, and the lasing medium is initially energised to create the population inversion which results in the lasting transition at a rate such that significant thermal population of the lower energy level is avoided.