Patent GB-1111857-A (GB)
Title: Improvements in or relating to laserable materials
IPC: C03C4/00
Filed: 1965-10-12
Abstract: A glass laser material consists of a silicate glass containing 0-10 mol. per cent of a divalent metal oxide selected from the group consisting of Sn, Ba, Zn, Cd and Pb, 18-25 weight per cent of an alkali metal oxide selected from the group consisting of Li, Na and mixtures thereof, 5-23 weight per cent potassium oxide, 0.01-30 weight per cent of a lanthanide or actinide activator, e.g. Ce3+, Pr3+, Nd3+, Sm2+, Sm3+, Eu2+, Eu3+, Tb3+, Dy3+, Ho3+, En3+, Tm3+, Yb3+, U3+, the balance being essentially silicate and the whole being uncontaminated with material causing light absorption at 1.06 microns wavelength. Constituents which may be present are e.g. 0-4 weight per cent La2O3, Bi2O3, 0-3 weight per cent Al2O3, B2O3, and Sb2O3. Mention is also made of the use of MgO or CaO as the divalent metal oxide and of the effect of employing Cs2O or Rb2O.  Specific glass compositions are, by weight per cent:  .SiO2.68.1.62.0.67.1 .Na2O.7.2.6.0.7.2 .K2O.10.9.18.0.10.9 .BaO.4.8.3.0.4.8 .Sb2O3.1.0.1.0.1.0 .Al2O3.1.5.2.0.1.5 .ZnO.1.5.2.0.1.5 .Nd2O3.5.0.5.0.5.0 .Li2O.-.1.0.1.0 For each composition there is given the fluorescent life time, the thermal coefficient, the refractive index at various wavelengths and the relationships between viscosity and temperature. The glass may be prepared by heating in air in a platinum or ceramic crucible at 1200-1450 DEG  C. with stirring until clear, holding at 1000-1200 DEG  C. for one hour, and then casting and annealing.  The glass has a long fluorescent life time, thus increasing the energy which can be stored in the excited material and hence the power output for a pulsed laser, while retaining a low viscosity.  Radiation occurs, using neodymium, on transitions from a 4F3/2 energy state to either 4I13/2, 4I11/2 or 4I9/2 states, these latter states each being split.ALSO:A glass laser material consists of a silicate glass containing 0-10 mol. per cent of a divalent metal oxide selected from the group consisting of Sn, Ba, Zn, Cd and Pb, 18-25 weight per cent of an alkali metal oxide selected from the group consisting of Li, Na and mixtures thereof, 5-23 weight per cent potassium oxide, 0.01-30 weight per cent of a lanthanide or actinide activator, e.g. Ce3+, Pr3+, Nd3+ Sm2+, Sm3+, Eu2+, Eu3+, Tb3+ Dy3+, Ho3+, En3+, Tm3+, Yb3+, U3+, the balance being essentially silicate and the whole being uncontaminated with material causing light absorption at 1.06 microns wavelength. Constituents which may be present are, e.g. 0-4 weight per cent La2O3, Bi2O3, 0-3 weight per cen Al2O3, B2O3, and Sb2O3. Mention is also made of the use of MgO or CaO as the divalent metal oxide and of the effect of employing Cs2O or Rb2O.  Specific glass compositions are, by weight per cent:  .SiO2.68.1.62.0.67.1 .Na2O.7.2.6.0.7.2 .K2O.10.9.18.0.10.9 .BaO.4.8.3.0.4.8 .Sb2O3.1.0.1.0.1.0 .Al2O3.1.5.2.0.1.5 .ZnO.1.5.2.0.1.5 .Nd2O3.5.0.5.0.5.0 .Li2O.-.1.0.1.0  For each composition there is given the fluorescent life time, the thermal coefficient, the refractive index at various wavelengths and the relationships between viscosity and temperature. The glass may be prepared by heating in air in a platinum or ceramic crucible at 1200-1450 DEG  C. with stirring until clear, holding at 1000-1200 DEG C. for one hour, and then casting and annealing.  The glass has a long fluorescent life time, thus increasing the energy which can be stored in the excited material and hence the power output for a pulsed laser, while retaining a low viscosity.  Radiation occurs, using neodymium, on transitions from a 4F 3/2 energy state to either 4I 13/2 , 4I 11/2 or 4I 9/2 states, these latter states each being split.