Fundamental Study on Laser Micro-welding of Glass by Using Spatial Light Modulator

In micro-joining of glass by using an ultra-short pulsed laser, high intensity of laser beam focusing into a micro-spot inside the glass initiates the nonlinear absorption phenomenon, and micro-area inside the glass can be melted locally. However, it is difficult to achieve high joining strength, since molten area is formed by periodic movement of laser energy absorption point in an optical axis. In this study, the improvement method to control molten area formation by using a spatial light modulator (SLM) was discussed in micro-welding of borosilicate glass by a picosecond pulsed laser. SLM can modulate a wavefront shape of laser beam into the desired pattern image, and it can form different molten area shapes from traditional method.