Fundamental-frequency-absorbed oxyfluoride glass in a high-power laser

A high-power third-harmonic laser faces challenges in the filtering remnant unconverted fundamental frequency, which is from the frequency converting crystal. In this work, a novel fundamental-frequency-absorbed oxyfluoride glass has been prepared, which provides a possible option to solve the problem. By being doped with Fe²⁺ ion, the glass shows strong absorption property at 1053 nm, and the glass's transmittances at 351 and 1053 nm are stable with changing the laser power or increasing the irradiation times under high-power laser irradiation. Meanwhile, the laser-induced damage threshold of the glass is 12.5  J/cm² at 351 nm, which is two times higher than that of fused silica whose threshold is 6.2  J/cm² in the same testing condition. The glass also exhibits a higher laser-induced damage threshold as well as 36.6  J/cm² at its absorption wavelength of 1053 nm. The results indicate that this glass is promising as a color-separation optic, thus allowing a novel design for the final optics assembly in an inertial confinement fusion laser system.