> [...] This is possible by multiplexing the storage in the spectral domain.
> "It means that we can store many different images at the same place in the diamond by using a laser of a slightly different color to store different information into different atoms in the same microscopic spots," said Delord, a postdoctoral research associate at CCNY. "If this method can be applied to other materials or at room temperature, it could find its way to computing applications requiring high-capacity storage." [...]
> "What we did was control the electrical charge of these color centers very precisely using a narrow-band laser and cryogenic conditions," explained Delord. "This new approach allowed us to essentially write and read tiny bits of data at a much finer level than previously possible, down to a single atom."
"Reversible optical data storage below the diffraction limit" (2023) https://www.nature.com/articles/s41565-023-01542-9