Laser | Wikipedia audio article
Channel: wikipedia tts
Date: 2018-12-08

This is an audio version of the Wikipedia Article:
Laser


00:01:30 1 Fundamentals
00:03:02 1.1 Terminology
00:04:47 2 Design
00:06:14 3 Laser physics
00:06:31 3.1 Stimulated emission
00:08:57 3.2 Gain medium and cavity
00:12:16 3.3 The light emitted
00:15:09 3.4 Quantum vs. classical emission processes
00:15:53 4 Continuous and pulsed modes of operation
00:16:46 4.1 Continuous wave operation
00:18:16 4.2 Pulsed operation
00:20:05 4.2.1 Q-switching
00:20:51 4.2.2 Mode-locking
00:22:16 4.2.3 Pulsed pumping
00:23:13 5 History
00:23:21 5.1 Foundations
00:24:32 5.2 Maser
00:26:31 5.3 Laser
00:30:54 5.4 Recent innovations
00:32:25 6 Types and operating principles
00:32:35 6.1 Gas lasers
00:34:38 6.1.1 Chemical lasers
00:35:23 6.1.2 Excimer lasers
00:36:51 6.2 Solid-state lasers
00:40:05 6.3 Fiber lasers
00:41:53 6.4 Photonic crystal lasers
00:42:18 6.5 Semiconductor lasers
00:46:10 6.6 Dye lasers
00:46:51 6.7 Free-electron lasers
00:47:36 6.8 Exotic media
00:49:57 7 Uses
00:52:30 7.1 In medicine
00:53:49 7.2 As weapons
00:56:46 7.3 Hobbies
00:57:39 7.4 Examples by power
00:58:42 8 Safety



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SUMMARY
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A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term "laser" originated as an acronym for "light amplification by stimulated emission of radiation".  The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow.
A laser differs from other sources of light in that it emits light coherently. Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances (collimation), enabling applications such as laser pointers and lidar. Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum, i.e., they can emit a single color of light. Alternatively, temporal  coherence can be used to produce pulses of light with a broad spectrum but durations as short as a femtosecond ("ultrashort pulses").
Lasers are used in optical disk drives, laser printers, barcode scanners, DNA sequencing instruments, fiber-optic and free-space optical communication, laser surgery and skin treatments, cutting and welding materials, military and law enforcement devices for marking targets and measuring range and speed, and in laser lighting displays for entertainment.