Interfacial properties of a direct bonded Nd-doped YVO and YVO single crystal

Sugiyama, Akira; Nara, Yasunaga; Wada, Kengo*; Fukuyama, Hiroyasu

Laser crystal bonding of a neodymium-doped yttrium orthovanadate (Nd: YVO) and a non-doped yttrium orthovanadate (YVO) crystal as a cold finger has been demonstrated. Instead of a traditional chemical treatment, a newly developed dry etching process was applied to the preparation for contact of mechanically polished surfaces. In the subsequent heat treatment process, stable heating at 873 K was required to prevent precipitation at the bonded interface. The bonded interface of 3 mm 3 mm was investigated by optical scattering and wavefront distortion measurements. The scattering density around the bonded interface was less than 4.610 /cm and the wavefront distortion caused by the bonded region was assumed to be around 0.04-wave at 633 nm. Additional magnified inspection showed that atoms in the bonded region were well arranged with the same regularity as the bulk crystal. The diffusion coefficient of Nd ions in the YVO crystal was estimated at 2.310 m/sec at 873 K.