A dollop of infrared light can greatly improve nanocrystals that convert infrared photons to visible light.

Such crystals are made of sodium yttrium fluoride doped with ions of elements such as thulium, which emit radiation in the visible spectrum. If too much thulium is added to the mix, the luminosity drops.

But Jiangbo Zhao and Dayong Jin at Macquarie University in Sydney, Australia, and their colleagues have discovered that using high levels of infrared light to irradiate the crystals prevents this 'quenching' of the visible light emission and makes the crystals shine 1,000 times brighter.

Nature Nanotechnol. http://dx.doi.org/10.1038/nnano.2013.171 (2013)