Through detailed quantum calculations, the presence of classical discrete breathers and, subsequently, a two-phonon bound state (TPBS) or quantum breather (QB) state have already been shown in nonlinear photonic materials such as ferroelectrics. The latter was done in a periodic boundary condition in terms of the variations of TPBS parameters against impurity that is related to nonlinearity. Metamaterials are also nonlinear optical materials for applications as a split-ring-resonator (SRR) in antenna arrays. By using a Klein-Gordon approach, first multi-solitons and classical breathers are shown. For QBs, by using a periodic boundary condition, the variation of the TPBS parameters with coupling within the SRR elements is observed. Finally, in a non-periodic boundary condition approach, the temporal evolution of the number of quanta is shown eventually in order to derive the critical time of redistribution of quanta that is proportional to the QB's lifetime in femtoseconds, which also shows variation with coupling in the SRR system.

This article describes the design of a laser setup excited by 3 He(n,p) 3 H reaction products and intended for investigations of the laser characteristics of 3 He mixtures with metal vapors or other gases at temperatures up to 800°C. This setup could also be used to study the effect of the medium heating on the characteristics of nuclear-pumped gas lasers.

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Quasi-cw stimulated emission of ~ 10 ms pulses at the wavelengths A = 1.59 and 2.45 um of the chlorine atom was detected when mixtures of He, Ne, and Ar with CC1 4 , CHCI3, CF 2 C1 2 , and C 2 F 3 C1 3 were excited by uranium fission fragments. Stimulated emission of the k = 2.45 (im line under nuclear pumping conditions at high pressures was observed for the first time. The maximum energy parameters (output radiation power 130 W, efficiency about 0.2%) were achieved for the 1.59 um line in a mixture of the He: Ne: CC1 4 = 25 000:25 000:1 composition at a pressure of 2 bar. The minimum lasing threshold for this line corresponded to a thermal neutron flux of 2x 10 13 cm" 2 s" 1 . S P Mel'nikov, V V Porkhaev Russian