5D 'Eternity Crystal' Stores 360 TB of Data for Billions of Years

No mention of how this works..

It's called "birefringence":

> The recently developed 5D optical storage technique uses birefringence as an extra degree of freedom – the property of a medium whereby its refractive index varies depending on the polarization and direction of incident light. Birefringence generated by the orientation and size of optical nano-gratings offers two extra dimensions, providing much higher storage capacities.

from https://www.5dmemorycrystal.com/technology

Any information on how much it cost to do this? There’s also no mention of how the data is being read, at least not by this source.