Flipping on a light whenever we want it is among the simplest, yet most valuable, benefits of modern life. That’s traditionally done by heating metal filaments in light bulbs until they glow a bright white. Now, researchers have come up with a more direct approach, by inventing a new material that converts photons from an infrared (IR) laser into visible light. The laser fires at a clear film of molecules consisting of tin and sulfur atoms arranged in a diamondlike pattern and surrounded by organic groups. The molecules in the film absorb the IR photons and re-emit that energy as higher-energy visible light photons. Much as piles of coins can be exchanged for a few crisp bills, the process uses the energy from many IR photons to produce fewer visible photons. This kind of conversion isn’t new. What is new is that the tin and sulfur film can direct the light into a single beam, the researchers report today in Science. Whereas most older conversion materials send out their visible photons in random directions, this new technique sends that light out in the same direction it came in. That gives it the ability to direct beams of the light in specific places, making the material useful for microscopes and novel projection systems.