Clarification of fast metal sphere movement in glass

In this study, metal spheres were implanted into glass by continuous-wave (CW) laser illumination, which manipulated the metal sphere inside the glass. The spheres moved at approximately 100 mm/s, which is 100 times faster compared to conventional movement. The movement mechanism was clarified by in situ, cross-sectional, and microscopic observations. With a high laser power density, the metal spheres moved fast with plasma emission, and their trajectory contained fine iron particles. The temperatures of the metal sphere with slow (<0.1 mm/s) and fast (>1 mm/s) speeds were 1,900 and 2,900 K, respectively.