A wavelength separation multilayer for Yb:YAG laser

A wavelength separation multilayer with high reflectivity at 1 030 nm and high transmittance at 940 and 980 nm was obtained by optimizing the film stack, such as inserting matching layers, tuning the periodic thickness with the help of thin film design software. The Fabry-Perot configuration was adopted to increase the transmitiance of pass-band. This applicable sample multilayer was carried out by dual ion beam sputtering on BK7 glass. The testing result shows that transmittances of 97.73% and 93.63% are obtained at 940 nm and 980 nm, respectively. A laser induced damage threshold (LIDT) of 35 J/cm2 (1 064 nm, 12 ns) of the separation film is characterized with self-made testing facility. 