Amplified spontaneous emission
- Amplified spontaneous emission
Amplified spontaneous emission (ASE) or superluminescence is light, produced by spontaneous emission, that has been optically amplified by the process of stimulated emission in a gain medium.
Origins and problems
ASE is produced when a laser gain medium is pumped to produce a population inversion. Feedback of the ASE by the laser's optical cavity may produce laser operation if the lasing threshold is reached. Excess ASE is an unwanted effect in lasers, since it limits the maximum gain that can be achieved in the gain medium. ASE creates serious problems in any laser with high gain and/or large size. In this case, a mechanism to absorb or extract the incoherent ASE must be provided, otherwise the excitation of the gain medium will be depleted by the incoherent ASE rather than by the desired coherent laser radiation. ASE is especially problematic in lasers with short and wide optical cavities, such as disk lasers (active mirrors). [cite journal| author=D.Kouznetsov| coauthors=J.F.Bisson, K.Takaichi, K.Ueda| title=Single-mode solid-state laser with short wide unstable cavity| url=http://josab.osa.org/abstract.cfm?id=84730| journal=JOSAB| volume=22| issue=8| pages=1605–1619| year=2005| doi=10.1364/JOSAB.22.001605] .]
ASE in disk lasers: Controversy
According to some publications, at the
power scaling of disk lasers, the round-trip gain should be reduced [cite journal| author=D. Kouznetsov|coauthors= J.F. Bisson, J. Dong, and K. Ueda| title=Surface loss limit of the power scaling of a thin-disk laser| journal=JOSAB| volume=23| issue=6| pages=1074–1082| year=2006| url=http://josab.osa.org/abstract.cfm?id=90157| accessdate=2007-01-26| doi=10.1364/JOSAB.23.001074; [http://www.ils.uec.ac.jp/~dima/disk.pdf] ] , which means hardening of requirement on the background loss. Other colleagues think, the existing disk lasers work far from such a limit, and the power scaling can be achieved without modification of existing laser materials [cite journal| author=A. Giesen| coauthors=H. Hügel, A. Voss, K. Wittig, U. Brauch and H. Opower| title=Scalable concept for diode-pumped high-power solid-state lasers| year=1994
url=http://www.springerlink.com/content/n7350870q8q57324/?p=c874af0585094717b13bb41e3fc548da&pi=0
journal=Applied Physics B|volume=58| issue=5| pages=365–372| doi=10.1007/BF01081875] .
References
ee also
*maser
*disk laser
Wikimedia Foundation.
2010.
Look at other dictionaries:
Self-Amplified Stimulated-Emission — Self Amplified Spontaneous (or Stimulated) Emission (SASE) is a process within a Free electron laser (FEL) by which a laser beam is created by the high energy electron beam. The lasing starts up from the random microbunching (i.e., shot noise) on … Wikipedia
Induced gamma emission — In physics, induced gamma emission (IGE) refers to the process of fluorescent emission of gamma rays from excited nuclei, usually involving a specific nuclear isomer. It is analogous to conventional fluorescence, which is defined to be the… … Wikipedia
Optical amplifier — An optical amplifier is a device that amplifies an optical signal directly, without the need to first convert it to an electrical signal. An optical amplifier may be thought of as a laser without an optical cavity, or one in which feedback from… … Wikipedia
Astrophysical maser — An astrophysical maser is a naturally occurring source of stimulated spectral line emission, typically in the microwave portion of the electromagnetic spectrum. This emission may arise in molecular clouds, comets, planetary atmospheres, stellar… … Wikipedia
Laser construction — A laser is constructed from three principal parts:*An energy source (usually referred to as the pump or pump source ), *A gain medium or laser medium , and *Two or more mirrors that form an optical resonator . Pump sourceThe pump source is the… … Wikipedia
European x-ray free electron laser — The European x ray free electron laser (XFEL) is a planned European project in strong connection with the DESY research center in Hamburg. [cite web |title=XFEL|url=http://xfel.desy.de/ |format= |accessdate=2007 12 20] . A free electron laser… … Wikipedia
Disk laser — Not to be confused with Laserdisc. Fig.1. An optically pumped disk laser (active mirror). A disk laser or active mirror (Fig.1.) is a type of solid state laser characterized by a heat sink and laser output that are realized on opposite sides of a … Wikipedia
ASE — can stand for: Institutions *Academia de Studii Economice (the Economic Sciences Academy) in Bucharest, Romania *Admiralty Signal Establishment, a defense research organization in the UK *Advanced Semiconductor Engineering, a Taiwanese… … Wikipedia
Laser — Laserlicht; Laserstrahl; köhärentes Licht * * * La|ser 〈[ lɛızə(r)] od. [le:zə(r)] m. 3; Phys.〉 eine von außen angeregte, gleichzeitige Strahlungsemission vieler Atome, wobei die höchsten bekannten Energiedichten je Flächeneinheit erreicht werden … Universal-Lexikon
Optical parametric amplifier — An optical parametric amplifier, abbreviated OPA, is a laser light source that emits light of variable wavelengths by an optical parametric amplification process. Contents 1 Optical parametric generation (OPG) 2 Optical parametric amplification… … Wikipedia
