Micromachines (Jun 2023)

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

  • Sergey Kudryashov,
  • Pavel Danilov,
  • Nikita Smirnov,
  • Evgeny Kuzmin,
  • Alexey Rupasov,
  • Roman Khmelnitsky,
  • George Krasin,
  • Irina Mushkarina,
  • Alexey Gorevoy

DOI
https://doi.org/10.3390/mi14071300
Journal volume & issue
Vol. 14, no. 7
p. 1300

Abstract

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

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