A compound that can transform near-infrared (NIR) light into broadband white light could offer a cheap, efficient means to produce visible light. The light is also exceedingly directional, a desirable quality for devices such as microscopes that require high spatial resolution, or for applications with high throughput, such as projection systems. Illustration of red laser impinging onto the appearing cluster, inducing a glow and the emission of a white-light laser. Courtesy of Nils W. Rosemann. Researchers from the Philipp University of Marburg and Justus Liebig University Giessen designed their compound of tin and sulfur, with a diamondoid-like structure, then coated the scaffolding with organic ligands. When irradiated with NIR laser light, the structure of the compound altered the wavelength of the light through a nonlinear interaction process, producing light at wavelengths that are visible to the human eye. The researchers noted that the warm, white-colored light emitted was very similar to a standard tungsten-halogen light source (2856 K), and can be adjusted based on levels of excitation via the laser. The development could open up new routes for advanced directed illumination technologies, especially since the materials used in this system are inexpensive, readily available and scalable. The research was published in Science (doi: 10.1126/science.aaf6138).