Laser stands for Light Amplification by the Simulated Emission or Radiation. Lasers beams are rays of light of great intensity and absolute purity. Unlike other ordinary rays of light, laser beams exist at a single wavelength and can be reflected by carefully positioned mirrors so that the beam does not spread out. Lasers are also coherent meaning that when the light emerges from its source, the beams are almost parallel.
Lasers are usually thought of as being futuristic: only used in science or as part of something in 'outer space', but lasers are everywhere nowadays. They are used to communicate, to determine how far away things are, like distances between planets, are able to record and retrieve information and sometimes they are used in defence weapons. Laser discs reproduce high quality music and in grocery stores they are used to read the codes on purchases. Also, lasers not only fix machines but the human body as well: because the pinpoint beam of a laser can focus precisely on a target and make highly delicate incisions, lasers have drastically changed modern medicine and surgery.
The surgical laser is an intense beam of light capable of removing unwanted tissue from the body. It can be delivered through a hand-held device, a microscope or an endoscope, which is a long, thin flexible tube that allows the physician to see inside the body.
I believe Lasers have made a large contribution to society in the world of today. They help people with medical problems that years ago would have meant that the person died. They have helped scientists around the world to gain knowledge of the universe that we live in. Without Lasers we would not be the people we are today.