Time-evolution of 3D bulk modifications inside hard crystal using single-shot ultrafast-Bessel pulse

Hard crystals like sapphire have proved to be a key element in a vast range of applications including industrial, optical and aerospace research. However, attaining precision in processing them remains an arduous task due to their exceptional tolerance to high pressure and temperature. In this study, we observe the dynamics of structural and morphological changes in bulk sapphire using quantitative optical phase microscopy. The thermo-optic dynamics reveal the process of phase transformation from crystalline to amorphous and the manifestation of void inside bulk single-crystal sapphire. Furthermore, the scanning and transmission electron microscopy indicates the presence of a nano-void of around 100 nm and a thin layer of disoriented crystals at the interface of the amorphous and crystalline inside the bulk sapphire. This study will be beneficial in understanding the light-matter interaction in hard crystals and help in achieving precise control of the high-aspect-ratio volume modifications inside hard photonic crystals.