The Physics
An encyclopedia of scientific essays

Power of a Laser Pointer

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World Book. Chicago: World Book, Inc, 2003: 85. "Continuous-wave lasers range from less than 1/1,000 of a watt to more than 10,000 watt" 1 mW
The New Book of Popular Science, Volume 6. Danbury, Connecticut: Grolier, 2002: 342. "The lasers used in entertainment generally fall into two classes depending on their power: 10- to 20-watt lasers are used in sky shows, and lower powered lasers in the 500-milliwatt to a 2-watt range are used in indoor shows; 2 mW
What You Should Know When Buying a Laser Pointer. DeHarpporte Trading Company. "As a result, almost all pointers are rated at just less than 5 mW INPUT (Class IIIa) in order to achieve maximum brightness while meeting FDA requirements."; 5 mW
Barat, Ken Can I Use a Laser Pointer Safely? The Health Physics Society. "Visible laser pointers operating with 1-5 mW power are Class 3a and can be hazardous if viewed even for a very short time." 1-5 mW

The two most significant qualities of a laser pointer are that it emits only one color of light and spreads over a long and narrow distance. A laser point is monochromatic because it has waves with a limited range of wavelengths. However, if a laser point consists of many narrow color bands, then it can emit more than one color. These two qualities categorize the laser pointer as coherent light. By coherent light, the waves of the laser are organized in phases. These waves travel in one direction and step after the previous.

There are a variety of lasers. A laser pointer is a solid-state laser. This kind of laser travels through a medium made of a solid matter such as glass or crystals. The structure of a laser pointer is fairly simple. It consists of three main parts. One of the main parts provides the source of energy. The source of energy carries the electric current. The second structure is the medium where the laser light travels through. It absorbs the emitted light and releases it. The third structure is called the optical cavity-the closure of the medium. The optical cavity serves as a reflector for the light in the medium.

Some lasers are the size of a football field yet, some are the size of your finger or even smaller. The laser pointer is approximately the size of your finger. It is considered a toy to the majority of the population. It is amusing to aim it at a person's forehead as a target. However, it is used differently by the military. A soldier may aim it at their targeted enemy not for amusement but for terminal purposes. A laser pointer detector is then used after the beam is aimed. When the beam is detected, the targeted enemy will be automatically killed by a bullet or some type of weapon. Another use can be for households. The accuracy of the straight beam from a laser pointer can be used to align furniture in a house. It can also be used for construction purposes.

The laser pointer comes in two colors-red and green. Many children enjoy flashing a laser point at all directions without knowing the precautions and damages it may cause. The green light is more damaging to the eye because it has a wavelength of 533 nm and a high frequency of 1064 nm. The red light has a weaker effect coming in 670 nm, 650 nm, and 635 nm. The frequency of the red light is lower. The power of laser points vary from 1-5 mW. The human eye is most sensitive to a beam of 5 mW. The green light exceeds the power of 5 mW. The laser pointer has become so hazardous to the human eye that sometimes insurance is needed along the purchase of the laser pointer.

Looking directly at the beam of a laser pointer can cause temporary blinding that flashes, headaches, afterimages or glare. It is recommended that no one should look directly at a laser pointer or have it pointed at a person. The beam should also not be aimed at a highly reflective surface such as crystal, glass or mirror. An object of such entertaining can be equally or more dangerous.

Amy Ly -- 2003