Reading. Read closely the text; divide it into several logical parts and think of a suitable headline for each part:
Read closely the text; divide it into several logical parts and think of a suitable headline for each part:
LASERS Lasers (Light Amplification by Stimulated Emission of Radiation) are devices which amplify light and produce beams of light which are very intense, directional, and pure in colour. They can be solid state, gas, semiconductor, or liquid. When lasers were invented in 1960, some people thought they could be used as 'death rays'. In the 1980s, the United States experimented with lasers as a defence against nuclear missiles. Nowadays, they are used to identify targets. Butapartfrom military uses, they have many applications in engineering, communications, medicine, and the arts. In engineering, powerful laser beams can be focused on a small area. These beams can heat, melt, or vaporize material in a very precise way. They can be used for drilling diamonds, cutting complex shapes in materials from plastics to steel, for spot welding and for surfacing techniques, such as hardening aircraft engine turbine blades. Laser beams can also be used to measure and align structures. Lasers are ideal for communications in space. Laser light can travel long distances without losing signal strength. Lasers can also be used for information recording and reading. In medicine laser beams can treat damaged tissue in a fraction of a second without harming healthy tissue. They can be used in very precise eye operations. In the arts, lasers can provide fantastic displays of light. Pop concerts are often accompanied by laser displays.
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