AUTHOR=Okuno Tatsuya , Shimotsuma Yasuhiko , Shimizu Masahiro , Miura Kiyotaka 

TITLE=Photoinduced self-assembly of nanocrystals inside Al2O3-Lu2O3 glass

JOURNAL=Advanced Optical Technologies

VOLUME=12

YEAR=2023

URL=https://www.frontiersin.org/journals/advanced-optical-technologies/articles/10.3389/aot.2023.1237663

DOI=10.3389/aot.2023.1237663

ISSN=2192-8584

ABSTRACT=<p>The femtosecond laser direct writing technique can allow spatially selective crystallization with suppression of thermal conduction effects. In the case of Al<sub>2</sub>O<sub>3</sub>-R<sub>2</sub>O<sub>3</sub> (R = Y, Dy) glass, the polarization-dependent periodic nanostructure with crystallization is self-assembled, however, the formation mechanism of self-assembled nanocrystals in glass remains to be clarified. We focused on Al<sub>2</sub>O<sub>3</sub>-Lu<sub>2</sub>O<sub>3</sub> glass prepared by a containerless laser melting method and demonstrated the formation of a nanograting with crystallization by femtosecond laser irradiation. Polarized luminescence measurements of the crystallized region by the pulse bursts with a controllable number of pulses reveal that luminescence anisotropy increased at more than 50 pulses in a burst, suggesting the formation of the nanograting. We have also followed the time variation of birefringence by polarized light imaging to evaluate the time scale for the formation of nanogratings with crystallization.</p>