I’m trying to understand, given the wide array of current laser applications:
- Which applications actually require laser characteristics, as opposed to just use lasers because they are the most practical/efficient source of light with characteristics not unique to lasers
- What alternatives exist, or may exist, to lasers for applications that don’t require laser characteristics
My key assumption here is that the essential characteristic of a laser is that it produces temporally coherent light. Often, but not necessarily, lasers produce light with two other useful characteristics:
But these convenient characteristics can be produced using non-lasers. For example, LEDs produce monochromatic light. And lenses can take diffuse light and produce a beam collimated to near the diffraction limit, right?
If this is the case, then the only applications that require lasers are those that depend on interferometry, and that’s pretty much just holography and measurement, right? All of the other applications – directed energy, medical therapies, optical discs, optronics – could be accomplished with non-coherent collimated and/or monochromatic light, right?
Presumably lasers are used in these cases only because they are currently the most efficient or practical way of producing light with those characteristics. But now I am wondering: What other technologies could supersede lasers in practice (and efficiency) for applications that require light with high energy, collimation, and/or monochromaticity?