Photoluminescent Microbit Inscripion Inside Dielectric Crystals by Ultrashort Laser Pulses for Archival Applications

Inscription of embedded photoluminescent microbits inside micromechanically positioned bulk natural diamond, LiF and CaF2 crystals was performed in sub-filamentation (geometrical focusing) regime by 525 nm 0.2 ps laser pulses focused 0.65 NA micro-objective as a function pulse energy, exposure inter-layer separation. The resulting were visualized 3D-scanning confocal Raman/photoluminescence microscopy conglomerates photo-induced quasi-molecular color centers tested regarding their spatial resolution thermal stability via high-temperature annealing. Minimal lateral longitudinal microbit separations, enabling robust optical read-out through micromechanical positioning, measured the most promising crystalline material, LiF, 1.5 13 microns, respectively, to be improved information storage capacity more elaborate focusing systems. These findings pave way novel optomechanical memory platforms, utilizing ultrashort-pulse inscription carriers archival memory.