is was an optical disc technology that was a bit denser than dvds but not that much. Of course density is a function of the pit size and the imprinting pattern and it turns out that the
pattern for imprinting blue ray disks makes a wonderful (Eli is tempted
to say idea) stamp for visible light collection because of the good
match to the wavelength of visible light. Technical details can be found at Extreme Tech. Folks at Northwestern have used this to raise the efficiency of solar cells by 20% or a bit more. FWIW, they used Police Story 3 for their stamp. Somebunny wanted it out of the house
As IEEE Spectrum points out, the stamping technology is already available, and with the death of Blue Ray or at least its moribund status up for sale cheap. The destructive creativity of the market at work.