Compact, fully programmable photonic circuit operates in free space using only three layers to perform complex calculations

https://www.eurekalert.org/news-releases/1124871

"more data modes processed require more physical layers/ components adding bulk/ losing light energy passing through each component/ scaling difficult... overcome using high-dimensional unitary transformations with just 3 programmable layers... commercially available liquid-crystal spatial light modulator pixelated arrays: each cell independently controlled via software changing light phase... couple single input to up to 7K outputs...  managing quantum computers' high-dimensional states"