Follow section removed, since its covered in laser applications:
These properties have many uses in science and technology. (Please list some here as links.) Alternative light sources with all these properties are typically weak and cumbersome.Lasers are widely used by the armed forces in many applications. Lasers can be set to specific, pre-determined frequencies to correspond with a bomb or missile's tracking system. Because the frequency can be set to a range not normally found in natural light settings it is easy for a homing device to find and home in on the signal. Also, lasers can be mounted to weapons and collumated to line up properly with the barrel for targeting purposes. This is especially useful in night combat environments. Some lasers are not in the visable spectrum, and can only be seen using devices that can see infrared, allowing easy targeting for users utilizing night vision devices.
-- DrBob