Disorder is the new order

摘要

Optical frequency converters are widely used to generate coherent light at frequencies at which laser light is unavailable. Standard devices can have a very high efficiency (close to 100%), but they employ pure, sizeable -- and hence expensive -- nonlinear single crystals, and require careful adjustments. On page 374 of this issue, Baudrier-Raybaut et al. show that efficient optical frequency conversion can be achieved in disordered polycrystal-line materials, which are, by contrast, rather cheap tofabricate and require hardly any control. This finding is likely to mark a significant step towards large-scale applications of nonlinear optics in everyday life.