Combining high-repetition femtosecond laser inscription with silica glass materials, researchers came up with a palm-size 5D medium that can store up to 500 TB. In addition to the three spatial dimensions, researchers also use solitons and the strength of retardance of the nanolamellar structures etched with the lasers as fourth and fifth dimensions, respectively.
https://www.notebookcheck.net/Researchers-demonstrate-palm-size-5D-silica-glass-storage-medium-with-500-TB-capacity.576683.0.html