Searching for the paper mentioned in the article turned up this: http://www.orc.soton.ac.uk/fileadmin/downloads/5D_Data_Storage_by_Ultrafast_Laser_Nanostructuri

Searching for the paper mentioned in the article turned up this: http://www.orc.soton.ac.uk/fileadmin/downloads/5D_Data_Storage_by_Ultrafast_Laser_Nanostructuring_in_Glass.pdf http://www.orc.soton.ac.uk/fileadmin/downloads/5D_Data_Stora... The five dimensions are in the first paragraph: More recently self - assembled nanogratings produced by ultrafast laser writing in glass were proposed for the polarization multiplexed optical memory, where the information encodi ng would be realized by means of two birefringence parameters, i.e. the slow axis orientation (4th dimension) and strength of retardance (5th dimension), in addition to three spatial coordinates [3,4] .