Robust and adhesive-free joint of Nd:YAG crystals by femtosecond laser-assisted welding

We demonstrate the laser-assisted yttrium aluminum garnet (YAG) crystal-to-crystal bonding with the shear strength up to 110 MPa. The structure of the fabricated weld is investigated by micro-Raman spectroscopy, scanning electron microscopy and high-resolution transmission electron microscopy. The correlation of Raman peak broadening with the presence of an amorphous phase is reliably established. The formation of the amorphous phase was confirmed by electron microscopy. TEM and HR-TEM have shown that the bonding of crystals is presented by 80-90 nm thick nanoperiodic amorphous nanoplanes interleaved with crystalline regions. The laser-induced weld can withstand a rapid heating to 1000 degrees C by placing the sample in an electric furnace as well as pumping by an 808 nm CW fiber-coupled laser diode with a power density up to 15 kW/cm(2). The obtained results are an essential step to the development of passive cooling technology for high-power solid-state lasers with excellent beam quality.

Automated summary

The laser-assisted yttrium aluminum garnet (YAG) crystal-to-crystal bonding with shear strength up to 110 MPa was investigated using various microscopy techniques. The presence of an amorphous phase, confirmed by electron microscopy, showed a nanoperiodic amorphous nanoplanes structure interleaved with crystalline regions. The results suggest a potential development of passive cooling technology for high-power solid-state lasers.