Lasers are concentrated beams of light through a medium of some sort. Used for many modern appkications today. Not a major technological POD.
Here are points of divergence dealing with alternate developments of lasers. All POD entries are sorted as chronologically as possible.
WI: Galiloean/Newtownian Lasers
WI: Laserdisc doesn't have a bad launch
Know of any PODs or POD discussions ? Feel free to add them.