Abstract: A core glass and a fiber-optic light guide made from it and a cladding glass are described. The core glass is in the alkali-zinc-silicate system and contains, in Mol % on an oxide basis: 54.5-65, SiO2; 18.5-30, ZnO; 8-20, ? alkali metal oxides; 0.5-3, La2O3; 2-5, ZrO2; 0.02-5, HfO2; 2.02-5, ? ZrO2+HfO2; 0.4-6, BaO; 0-6, SrO; 0-2, MgO; 0-2, CaO; 0.4-6, ? alkaline earth metal oxides; 0.5-3, Li2O, but no more Li2O than 25% of the ? alkali metal oxides; >58.5, ? SiO2+ZrO2+HfO2. A molar ratio of Na2O/K2O is from 1/1.1 to 1/0.3. A molar ratio of ZnO to BaO is greater than 3.5.

Abstract: The opto-ceramics and optical elements of the present invention are transmissive to visible light and/or to infrared radiation. They consist of a crystal combination in which individual crystallites have a cubic structure of the type Y2O3 and are made from In2O3 or a mixture of oxides of the type X2O3 in which X=Y, Lu, Sc, Yb, In, Gd, or La. Also mixtures of X2O3 with oxides having different stoichiometries, such as zirconium and hafnium oxide, are possible, as long as the cubic structure of the opto-ceramic is maintained. The optical elements prepared from the opto-ceramics are particularly suitable for mapping optics, such as objectives having reduced chromatic aberrations, in particular with approximately apochromatic mapping behavior. The optical elements of the present invention may be used in lens systems in combination with lenses of glass, but also with other ceramic lenses.

Abstract: A core glass and a fiber-optic light guide made from it are described. The core glass is in the alkali-zinc-silicate system and contains, in Mol % on an oxide basis: 54.5-65, SiO2; 18.5-30, ZnO; 8-20, ? alkali oxides; 0.5-3, La2O3; 2-5, ZrO2; 0.02-5, HfO2; 2.02-5, ?ZrO2+HfO2; 0.4-6, BaO; 0-6, SrO; 0-2, MgO; 0-2, CaO; 0.4-6, ? alkaline earth oxides; 0.5-3, Li2O, but no more Li2O than 25% of the ? alkali oxides; >58.5, ? SiO2+ZrO2+HfO2. A molar ratio of Na2O/K2O is from 1/1.1 to 1/0.3. A molar ratio of ZnO to BaO is greater than 3.5.

Abstract: The opto-ceramics and optical elements of the present invention are transmissive to visible light and/or to infrared radiation. They consist of a crystal combination in which individual crystallites have a cubic structure of the type Y2O3 and are made from In2O3 or a mixture of oxides of the type X2O3 in which X=Y, Lu, Sc, Yb, In, Gd, or La. Also mixtures of X2O3 with oxides having different stoichiometries, such as zirconium and hafnium oxide, are possible, as long as the cubic structure of the opto-ceramic is maintained. The optical elements prepared from the opto-ceramics are particularly suitable for mapping optics, such as objectives having reduced chromatic aberrations, in particular with approximately apochromatic mapping behavior. The optical elements of the present invention may be used in lens systems in combination with lenses of glass, but also with other ceramic lenses.