Lasers are regarded for the monochromatic nature of their gentle, so a lot so that you could hardly ever have believed there could be this kind of a issue as a white laser. But in the weird environment of physics, a large amount of issues that seem to be impossible are not actually, as demonstrated by this grime-low-priced supercontinuum laser.
Of program, we’re not gurus on lasers, and unquestionably not on non-linear optics, so we’ll depend on [Les Wright]’s video below to demonstrate what is going on below. Fundamentally, a “supercontinuum” is just the conversion of a monochromatic resource to a broader spectral bandwidth. It is a non-linear optical procedure which is commonly accomplished with expensive bits of kit, like photonic crystal fibers, which are optical fibers with an array of small air-loaded holes functioning down their lengths. Blast a large-depth monochromatic laser down one particular conclude, and white gentle arrives out the other conclude.
These fibers are of course fantastically highly-priced, so [Les] looked again in the literature and identified that a very simple silica glass one-mode fiber could be applied to develop a supercontinuum. As luck would have it, he experienced been experimenting with telecom fibers just lately, so along with a nitrogen laser he recovered from a Dumpster, he experienced fairly a lot anything he required. The remaining set up employs the UV laser to pump a stilbene dye laser, which shoots a potent pulse of 426 nanometer gentle into about 200 meters of fiber, and generates a stunning supercontinuum made up of mild from 430 nm to 670 nm — really much the whole seen spectrum.
It is wonderful to see projects like this that leverage very low-price, uncomplicated-to-resource gear to take a look at esoteric physics ideas.