In the early years, they tended to be a bit exotic and unreliable. You had to have a Ph.D. to know how to keep them tweaked up and reliable. Today, however, lasers are dependable enough to be useful in a wealth of technologies. They're not just for Ph.D.s anymore. Radiation, in this case, is another word for electromagnetic energy, which includes light.
Laser light has several properties that make it different from regular light.
First, it is often collimated, which means it travels in a narrow beam for long distances, rather than going off in many directions as regular light does. Laser light is also coherent, which means that the light waves stay synchronized over long distances. And it is monochromatic, of one color. Some laser beams are invisible, producing light in the infrared or ultraviolet wavelengths. A laser can produce a short burst of light or a continuous beam.