Two-step welding for opto-mechanical coupling devices using continuous-wave and ultrafast lasers

Opto-mechanical coupling necessitates precision pose adjustment of glass optical components, which requires a soft interlayer between the optical element and metal base. A dual-laser welding technique is presented for glass-solder-metal joining in such devices, combining ultrafast laser welding after continuous-wave (CW) laser soldering. During CW laser soldering, metal surface textures with gradient wettability direct the solder to predefined zones. Subsequent ultrafast laser welding with energy modulation achieves uniform energy deposition at the solder-glass interface, forming a homogeneous weld. Based on the present method, a shear strength of 20.2 MPa and the beam divergence of 0.088° are achieved for the opto-mechanical device.