Light Amplification by Stimulated Emission of Radiation (LASER)
A Light Amplification by Stimulated Emission of Radiation (LASER) is a device designed to concentrate light into a narrow and coherent beam. Laser light is distinct from the random and incoherent light emitted by atoms. Typically, atoms emit light in random directions, creating incoherent light. In contrast, coherent light travels in a well-defined direction.
Creating coherent light with a laser involves using specific atoms or molecules in the right environment to emit light at precise times and directions. Various materials, such as gases, liquids, crystals, or other substances, can be employed to construct lasers. These materials are excited within a cavity, raising their energy levels. Reflective surfaces in the cavity reflect and build up energy. Stimulated emission, a process where photons with matching frequencies and phases are emitted, occurs. This leads to a chain reaction, releasing atoms and generating coherent light.
History
The first laser was introduced in 1960, and today, lasers come in various sizes, from tiny ones comparable to a grain of sand to large ones found in buildings. Despite their size differences, most lasers produce thin light beams that can maintain their size and direction over considerable distances.
Application of Light Amplification by Stimulated Emission of Radiation (LASER)
Lasers have diverse applications. In modern medicine, they are major for procedures like Laser-Assisted in Situ Keratomileusis (LASIK) eye surgery. They are also integral to manufacturing, construction processes, military applications, and scientific research. Laser printers are widely used for professional document printing, and lasers play a key role in Compact Disc (CD) and Digital Video Disc (DVD) players.
