Laser Pointers: An Insight

Laser pointers utilize a small laser to draw attention to a certain spot. Though by itself, it is invisible, it becomesPublic concern has been aroused over the last couple of years, since even though laser pointers are designed to be safe, they can be misused very easily.

Flash Back

The first pointers used laser contained helium-neon gas. The laser radiation generated was at 633nm (nanometers) with power out put of maximum 1 mW (milli watt). For such lasers which have less than 1mW power and radiation between 440 and 700 nm, the human eye blink reflux offers adequate protection. These lasers are known as Class 2 laser. Retinal injury can be caused to a person deliberately looks into the beam, overcoming natural reflux.

Following this was the diode lasers which have beams of 690nm with power output pf 5mW. Both are red wavelengths visible to naked eye but the eye sees 633nm brighter than 690nm. This explains the need for higher power for an output equaling that of 633nm laser pointers.

The green laser pointer makes use of frequency doubled Neodymium with a blocked infrared component. The wavelength of this laser pointer is 533nm and it is brighter than the other pointers. Pointers that operate needing 1-5mW power are called as Class 3a lasers and have been proved to be hazardous if viewed for even a short time period. These lasers are required by Food and Drug Administration regulations to be marked as Danger. Class 2 lasers are marked as Caution.

Associated Effects

No user should look at the laser beam directly. The hazards that can occur include:

*Startle effects
*Flash blindness
*Glare
*After images etc.

The law considers pointing laser at people as a criminal misdemeanor and the crime becomes a felony if laser is pointed towards an aircraft. Moreover, in some jurisdictions it is necessary for the purchaser of laser pointer to be above 18 years of age. Also, lasers requiring more than 5mW power should not be used as pointers.

Blue And Green Laser Pointers

Blue and green lasers differ in price. Green laser is less expensive when compared to blue laser. The price difference is mainly due to difference in processes that are used to generate the laser beams, components used and the volume in which they are manufactured.

Both laser beams use diode but they differ in the optical coating of pumped crystals and infrared light producing them. Green laser produces 1064nms infrared light while 946 nm infrared light is given out by the blue beam. Thus blue lasers require a larger pump diode making them more expensive. Green lasers have better visibility and hence are in more demand leading to higher volume of manufacturing. Green lasers are used in astronomy, burning, signaling, pointing and other diverse applications. Thus, the higher the manufacturing volume, the lower is the price.

Laser beams should be used with caution and only for the purpose they are intended.