Nonlinear absorption properties of new cobalt-doped transparent glass ceramics

Absorption saturation as well as bleaching relaxation of (4)A(2) --> T-4(1) (F-4) transition of tetrahedrally coordinated Co2+ ion in magnesium-aluminum and magnesium-gallium-aluminum glass ceramics prepared under different conditions were studied. Ground state absorption cross sections at the wavelength of 1.54 mm were estimated. The level of unsaturable losses was observed to be proportional to the cobalt concentration in the raw materials. The difference spectrum of stimulated emission and excited state absorption under excitation in the (4)A(2) --> T-4(1) (P-4) transition of the tetrahedral Co ion was derived and analyzed.