When a red laser pointer is 100 meters distant, its beam is 100 times larger and appears as bright as a 100-watt light bulb from 3 feet away. The pointer would be as brilliant as a quarter moon viewed from an airplane 40,000 feet in the air, assuming no clouds or smog. A laser pointer's beam can reach up to 5 miles.
Laser pointers are used in science labs around the world because of their small size and low cost. They are also popular with photographers who use them as spotlights. Laser pointers are ideal for this purpose because of their narrow beam that produces a large concentrated area of light.
Laser pointers were first sold by Sigma Instruments, a division of JVC, in 1992. Since then they have become very affordable, starting at $20 for a single-emitter model. There are now more than 20 different types of lasers in the market, each designed for a specific application.
The most common type of laser pointer is the semiconductor diode laser. It consists of two parts: a glass envelope containing the active medium and a mirror called a prism, and a package lid attached to the glass envelope. When electricity is applied to the diode, it emits a beam of light.
Prismatic laser pointers spread out into a fan shape when not being pointed directly at something. This is useful when trying to illuminate a large area from a relatively small device.
The average red laser pointer is around 5 milliwatts, and a good one has a tight enough beam to hit the moon—though it would be scattered out across a vast portion of the surface when it arrived. The atmosphere would distort and absorb part of the light, but most of it would make it. A powerful green laser could reach the moon, but it would be very expensive as well as dangerous to operate.
The laser light reflected off objects back to Earth follows a straight line from its source until it hits something. If this something is another object with a clear flat surface, then the reflected light will simply follow this new path and no damage will be done. However, if the reflecting surface is curved or has a hole in it, then the reflected light will also follow this new path—but now inside the material, which will heat up due to the absorption of light energy—thus causing damage.
Lasers on land, at least less than 100 meters away from a building or vehicle, can cause damage to glass by focusing onto a small area for a long time. This is called "window washing" and is usually done by tourists with poor technique to create a visual effect. Avoid doing this!
Lasers used for signaling work by flashlight-like devices because they are more powerful than ordinary lights and can thus reach farther. These are often called "pointer lasers" or "beacons".
How far can the laser be seen? Crimson Trace is equipped with the most powerful beam permitted by law, a Class IIIa visible light diode. The laser is extremely visible for several hundred yards at night, in low light, even inside. The dot may be seen from up to 15 yards distant in good sunshine. In heavy foliage, it can be seen from 30 to 50 yards.
Where is it mounted? The laser is attached to the barrel of the gun using two screws and a metal bracket. It can be removed as easily as it was installed.
What happens if there is an accident? If the trigger is pulled, the laser will activate automatically and send a strong pulse of light into the sky. This should not cause any problems unless you get close to the vehicle's battery source. Then you might want to move away quickly, because it could start a fire.
Why do we need lasers? Laser lighting has many advantages over traditional lamps: it provides better visibility at night, it can clearly mark hazardous areas such as road borders or other obstacles, it can be used as a warning signal (flashing lights), and it can illuminate objects which would otherwise be hidden in darkness.
Lasers also have some important disadvantages: they are expensive, they require constant maintenance, and they consume much electricity.
But maybe the most important advantage of lasers is that they allow us to see even in total darkness.
Newegg.com offers a High Power, 30 Miles Range, 532nm Green Laser Pointer Light, Lazer Pen, Visible Beam. That's enough power for small animals at range, but not close-up.
The maximum output power of this lasing device is 1 W, so it is capable of cutting paper, thin plastic, and cloth. However, the beam is visible to the human eye even at distances greater than 100 m, so it should not be used within six feet of someone's face.
Laser pointers are useful for displaying information on a screen or paper, but they can also be dangerous if not handled properly. Be sure to use caution when working with lasers, especially if you are trying to see something very small and distant.
Also note that high-powered lasers can cause blindness if they hit your retina. If you're going to use a laser pointer, make sure that you wear protective eyewear.