It's not dead yet[1] but, yes, it's never quite caught on the way so many of us thought it would back in the 1980s and 90s. The 1987 movie "Innerspace" even re

It's not dead yet[1] but, yes, it's never quite caught on the way so many of us thought it would back in the 1980s and 90s. The 1987 movie "Innerspace" even referred to "photon echo memory chips." Friends of mine worked for years at one of the companies mentioned in the Wiki page but came up just a little short. FWIW, gallium arsenide was also supposed to take over from silicon for CPUs once speeds went above 25-MHz (or so). A senior colleague of mine said, "There are a lot of smart people whose kids's college tuition depend on making silicon a little better every year." And so, it came to pass. GaAs is definitely important but we've got multi-GHz silicon CPUs now. [1] https://www.microsoft.com/en-us/research/project/hsd/ https://www.microsoft.com/en-us/research/project/hsd/ "Project HSD: Holographic Storage Device for the Cloud"