Ca 4GdO(BO 3) 3 (GdCOB) single crystal is a new nonlinear optical crystal whi ch was discovere d in recent years.It has a large effective nonlinear optical coefficient,a high damage threshold,good chemical and physica...Ca 4GdO(BO 3) 3 (GdCOB) single crystal is a new nonlinear optical crystal whi ch was discovere d in recent years.It has a large effective nonlinear optical coefficient,a high damage threshold,good chemical and physical properties and insensitivity to moi sture.Its moderate birefringence is favorable for phase matching.These propertie s make it possible to obtain frequency doubling laser of 1.064μm.By doping,it may be a excellent self frequency doubling crystal.Transparent single crystals GdCOB as needle were grown by the flux method. Chemical compounds Gd 2O 3,CaCO 3,B 2O 3 and H 3BO 3 were used as starti ng materials.By many experiments,with different ratio,it is proper to mix the st arting materials according to the reaction Gd 2O 3+8CaCO 3+6H 3BO 3=2 Ca 4 G dO(BO 3) 3+8CO 2+9H 2O.PbO was used as the main flux ,adding moderate PbF 2 , and B 2O 3.B 2O 3 also can be used as initial compounds and it is also a goo d solvent,but at high temperature,it has heavy viscousness.The crystals grown fr om B 2O 3 commonly has inclusion,so we used H 3BO 3 instead of B 2O 3.At t he same time,we considered that at high temperature H 3BO 3 will be decomposed and evaporated,which would make the initial composition change.When proper B 2 O 3 was added,it not noly can be used as solvent,but also can stabilize solvent component.The melt was contained in a platinum crucible.After holding the melt 1200℃ for 24h,it was cooled at a rate of 0.5℃ per hour.Single crystals GdCOB were obtained.With microscope,we observed the crystals have defects such as inc lusion and bubbles,which are related to rapid cooling,imperfect melt transport a nd unstable temperature.展开更多
文摘Ca 4GdO(BO 3) 3 (GdCOB) single crystal is a new nonlinear optical crystal whi ch was discovere d in recent years.It has a large effective nonlinear optical coefficient,a high damage threshold,good chemical and physical properties and insensitivity to moi sture.Its moderate birefringence is favorable for phase matching.These propertie s make it possible to obtain frequency doubling laser of 1.064μm.By doping,it may be a excellent self frequency doubling crystal.Transparent single crystals GdCOB as needle were grown by the flux method. Chemical compounds Gd 2O 3,CaCO 3,B 2O 3 and H 3BO 3 were used as starti ng materials.By many experiments,with different ratio,it is proper to mix the st arting materials according to the reaction Gd 2O 3+8CaCO 3+6H 3BO 3=2 Ca 4 G dO(BO 3) 3+8CO 2+9H 2O.PbO was used as the main flux ,adding moderate PbF 2 , and B 2O 3.B 2O 3 also can be used as initial compounds and it is also a goo d solvent,but at high temperature,it has heavy viscousness.The crystals grown fr om B 2O 3 commonly has inclusion,so we used H 3BO 3 instead of B 2O 3.At t he same time,we considered that at high temperature H 3BO 3 will be decomposed and evaporated,which would make the initial composition change.When proper B 2 O 3 was added,it not noly can be used as solvent,but also can stabilize solvent component.The melt was contained in a platinum crucible.After holding the melt 1200℃ for 24h,it was cooled at a rate of 0.5℃ per hour.Single crystals GdCOB were obtained.With microscope,we observed the crystals have defects such as inc lusion and bubbles,which are related to rapid cooling,imperfect melt transport a nd unstable temperature.
