Lasers are known for the monochromatic nature of their light, so much so that you might never have thought there could be such a thing as a white laser. But in the weird world of physics ...

[Jason H. Gao] and [Li-Shiuan Peh] used an infra-red (IR) line laser and the camera on a smartphone. Their prototype cost only $49 since they used a smartphone that was on hand. The article ...