Spatial correlation length below 200 nm in physical optical random number generation.

Random numbers are an essential foundation for quantum simulation, information security and cryptography. A physical random numbers generation based on optical interference patterns created by light scattering in condensed matter random media is investigated to seek the closest possible independent channels. Small optical features of random hotspots created by localized light and high optical resolution capability of scanning probe microscopes were combined to detect extremely close independent optical channels that can be used as source of random numbers. Spatial correlation length (SCL) that dictates the number of independent channels, is observed to have average of 197±8 nm (as small as ~ 154 nm was observed). Such a small SCL demonstrates up to 2 orders of magnitude more available parallel channels in random patterns generated by laser interference in far-field collection (that shows ~2 μm SCL in best configuration).