Description
A laser by definition is "a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation" (Wikipedia). But what does that mean? When you think about lasers you probably think about a destructive weapon in outer space, or the annoying little red pen your classmate has. But there is so much more to lasers than that!
LASER is an acronym for light amplification by stimulated emission of radiation. It is a form a light, not found naturally. What makes a laser so special are three characteristics, lasers are coherent, monochromatic, and collimated. Lasers are coherent because all of the wavelengths are in phase. This is like a well timed dance group that moves together, and in sync. Lasers are also monochromatic which means that they all have the same wave length, resulting in only one color. Lasers have one pure color that doesn't change when going through a prism because they are monochromatic (refer to figure 1). Finally, lasers are collimated which results in light waves that travel in the same direction and are parallel to each other.
These factors produces a powerful, concentrated beam of light that can travel over great distances. But lasers also can be extremely precise. This characteristics makes lasers an useful tool for modern day science, and a great tool for everyday life.
LASER is an acronym for light amplification by stimulated emission of radiation. It is a form a light, not found naturally. What makes a laser so special are three characteristics, lasers are coherent, monochromatic, and collimated. Lasers are coherent because all of the wavelengths are in phase. This is like a well timed dance group that moves together, and in sync. Lasers are also monochromatic which means that they all have the same wave length, resulting in only one color. Lasers have one pure color that doesn't change when going through a prism because they are monochromatic (refer to figure 1). Finally, lasers are collimated which results in light waves that travel in the same direction and are parallel to each other.
These factors produces a powerful, concentrated beam of light that can travel over great distances. But lasers also can be extremely precise. This characteristics makes lasers an useful tool for modern day science, and a great tool for everyday life.
Laser Classification
There are four classes of lasers, going from not harmful to extremely harmful (refer to figure 2):
Class I - No harmful radiation
Class II - Harmful only if viewed for a long period of time
Class III - Dangerous if exposed to for short periods of time
Class IV - Can blind or burn you even when briefly exposed
Class I - No harmful radiation
Class II - Harmful only if viewed for a long period of time
Class III - Dangerous if exposed to for short periods of time
Class IV - Can blind or burn you even when briefly exposed
Figure 2
Above is a laser classification table.
Above is a laser classification table.
Types of Lasers
The laser can also be classified by its medium, which can be a solid, liquid, gas, or semiconductor:
Solid state lasers - Laser material is distributed in a solid matrix (e.g. ruby)
Gas lasers - Uses gases (e.g. carbon dioxide)
Excimer lasers - Uses reactive gases (e.g. chlorine + fluorine mixed with argon, krypton or xenon)
Dye lasers - Uses organic dyes (e.g. rhodamine 6G)
Semiconductor lasers - Not solid state lasers, is small and uses low power (also called diode lasers)
Solid state lasers - Laser material is distributed in a solid matrix (e.g. ruby)
Gas lasers - Uses gases (e.g. carbon dioxide)
Excimer lasers - Uses reactive gases (e.g. chlorine + fluorine mixed with argon, krypton or xenon)
Dye lasers - Uses organic dyes (e.g. rhodamine 6G)
Semiconductor lasers - Not solid state lasers, is small and uses low power (also called diode lasers)