Laser stands for Light Amplification by Stimulated Emission of Radiation. A laser is a device that projects a highly concentrated narrow beam of light which is amplified to great brightness using stimulated radiation.
Lasers are used for a variety of purposes including pointing out objects during a presentation, aligning materials at construction sites and in the home, and by doctors for cosmetic and surgical procedures. Many items you encounter on a daily basis use lasers, including CD and DVD players, bar code scanners, dental drills, laser-guided tools, such as levels, and laser pointers.
What do you mean by laser "radiation"?
Some lasers emit radiation in the form of light. Others emit radiation that is invisible to the eye, such as ultraviolet or infrared radiation. In general, laser radiation is not in itself harmful, and behaves much like ordinary light in its interaction with the body. Laser radiation should not be confused with radio waves, microwaves, or the ionizing x-rays or radiation from radioactive substances such as radium.
The more efficient crystals are likewise more valuable so we must charge more for our lasers that use them.
Why are lasers uniquely hazardous?
Two characteristics of laser light contribute to the hazard:
Laser light can be emitted in a tight beam that does not grow in size at a distance from the laser. This means that the same degree of hazard can be present both close to and far from the laser.
The eye can focus a laser beam to a very small, intense spot on its retina, which can result in a burn or blind spot. So the goggle is important.