07-10-2017, 09:50 AM
A laser is a device that emits light through an optical amplification process based on the stimulated emission of electromagnetic radiation. The term "laser" originated as an acronym for "amplification of light by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on the theoretical work of Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other light sources in that it emits light coherently. Spatial coherence allows a laser to be focused to a tight spot, allowing applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to remain narrow over long distances (collimation), allowing applications such as laser pointers. Lasers can also have a high temporal coherence, which allows them to emit light with a very narrow spectrum, that is, they can emit a single colour of light. Temporal coherence can be used to produce pulses of light as short as a femtosecond.
Among its many applications, lasers are used in optical disk drives, laser printers and barcode scanners; DNA sequencing instruments, fiber optic optical communication and free space; laser surgery and skin treatments; cutting and welding materials; military and law enforcement devices to mark targets and measure range and speed; and laser lighting displays in entertainment.
In science, lasers are used in many ways, including:
• A wide variety of interferometric techniques
• Raman spectroscopy
• Laser-induced rupture spectroscopy
• Atmospheric remote sensing
• Investigation of phenomena of non-linear optics
• Holographic techniques that employ lasers also contribute to a number of measurement techniques.
• Laser lidar technology (LIght raDAR) has application in geology, seismology, remote sensing and atmospheric physics.
• Lasers have been used aboard spacecraft such as the Cassini-Huygens mission.
• In astronomy, lasers have been used to create artificial laser guide stars, used as reference objects for adaptive optics telescopes.
Among its many applications, lasers are used in optical disk drives, laser printers and barcode scanners; DNA sequencing instruments, fiber optic optical communication and free space; laser surgery and skin treatments; cutting and welding materials; military and law enforcement devices to mark targets and measure range and speed; and laser lighting displays in entertainment.
In science, lasers are used in many ways, including:
• A wide variety of interferometric techniques
• Raman spectroscopy
• Laser-induced rupture spectroscopy
• Atmospheric remote sensing
• Investigation of phenomena of non-linear optics
• Holographic techniques that employ lasers also contribute to a number of measurement techniques.
• Laser lidar technology (LIght raDAR) has application in geology, seismology, remote sensing and atmospheric physics.
• Lasers have been used aboard spacecraft such as the Cassini-Huygens mission.
• In astronomy, lasers have been used to create artificial laser guide stars, used as reference objects for adaptive optics telescopes.