ZrO2-SiO2 coatings for wavelength-selective reflection filter

Using ZrO2 and SiO2 sol as coating materials, a multilayer wavelength-selec tive high reflective (HR) coating was deposited by the way of sol-gel spinn ing technique. A new kind of ZrO2 sol was prepared to lower the layer numbe r and to increase the laser damage threshold of HR filter. The adding of Po lyvinylpyrrolidone (PVP) was added into ZrO2 sol to decrease the porosity a nd then to enhance the refractive index of ZrO2 layer as well as to increas e the coating strength. At the peak position, the reflection more than 98% can be easily achieved with 21 layers. The laser damage threshold was as hi gh as 19.9J/cm(2) (3 ns, 1064 nm).