I Always Wanted To Know:
What is a laser?
Lasers are a key component in everything from supermarket price scanners, DVD players, high speed fiber optic cables and advanced military weapons, but what is a laser? How does it work? The answer may surprise you. A laser, (which stands for Light Amplification by Stimulated Emission of Radiation), is at its most fundamental level, just focused light.
Laser light is different from normal light due to its characteristic focused, intense beam and specific color (or wavelength in technical terms). The light is created, in basic terms, by pumping energy into atoms causing them to emit photons of light. These photons of light are then bounced between mirrors in the laser’s assembly, which causes more photons to be created amplifying the light beam. What makes this process special is that the new photons created share the shame wavelength, phase and polarization which gives lasers their unique characteristics.
All of this may be quite interesting but why is laser light useful?
- Laser light is very focused, producing a very narrow beam allowing for laser pointers in classrooms & laser sights on weapons.
- Laser light is a specific frequency, so precise measurements of surfaces can be made such as in laser mice and DVD players.
- Laser light is highly amplified, so it can cut or burn objects used in industrial laser cutting and engraving.
Are lasers dangerous?
Recent incidents in the news of people using lasers to blind pilots in cockpits of helicopters may have left you wondering if a laser is a dangerous thing to own. Most consumer laser devices are safe, but all lasers sold in the U.S. have a safety ranking system which indicates the class of the laser.
- Class 1 is inherently safe, usually because the light is contained in an enclosure, for example in CD players.
- Class 2 is safe during normal use; the blink reflex of the eye will prevent damage. Usually up to 1 mW power, for example: laser pointers.
- Class 3R (formerly IIIa) lasers are usually up to 5 mW and involve a small risk of eye damage within the time of the blink reflex. Staring into such a beam for several seconds is likely to cause damage to a spot on the retina.
- Class 3B can cause immediate eye damage upon exposure.
- Class 4 lasers can burn skin, and in some cases, even scattered light can cause eye and/or skin damage. Many industrial and scientific lasers are in this class.
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