Semihumid gels as matrices for laser media

摘要

Laser dyes were trapped in SiO$-2$/ xerogel host matrices to obtain a solid state dye laser. The evolution of the mechanical properties of two kinds of matrices, 'classic' and 'sono' gels, was followed during drying. A new impregnation process was performed on these xerogels: impregnation with a 'sono' sol. The influence of this treatment on certain physical and mechanical properties of the resulting impregnated gels was studied. The results indicate that impregnation substantially improves hardness, elastic modulus and fracture stress. The samples can then be easily polished to obtain optical quality surfaces and be used in a laser cavity. Moreover, optical properties related to laser emission of these materials such as efficiency, lifetime and longevity are better when the laser dye doped xerogels are impregnated. The organic dye molecule used was sulforhodamine 640, and results were obtained six months after their synthesis, with a pump beam working at a 5 Hz repetition rate with 450 $mu@J/pulse energy level. With the first pump shot on a fixed point of the samples, tunability from 600 to 650 nm, 60 $mu@J threshold, 2600 pump shots lifetime and a 10.5% slope efficiency were achieved using an impregnated 'sono' gel matrix.