Editing Laser pointer (section)

===Green===
[[File:Greenlasertrails.jpg|thumb|Trails by a 15 mW green laser pointer in a time exposure of a living room at night]]
Green laser pointers<ref>[http://www.repairfaq.org/sam/laserpic/glpdpics.htm Sam's Laser FAQ: Dissection of Green Laser Pointer] {{Webarchive|url=https://web.archive.org/web/20130522190301/http://www.repairfaq.org/sam/laserpic/glpdpics.htm |date=22 May 2013 }}. repairfaq.org</ref> appeared on the market around 2000 and are the most common type of DPSS lasers (also called ''diode-pumped solid-state frequency-doubled'', DPSSFD). They are more complex than standard red laser pointers, because [[laser diode]]s are not commonly available in this wavelength range. The green light is generated through a multi-step process, usually beginning with a high-power (typically 100–300&nbsp;mW) [[infrared]] [[aluminium gallium arsenide]] (AlGaAs) laser diode operating at 808&nbsp;nm. The 808&nbsp;nm light [[laser pumping|pumps]] a neodymium doped crystal, usually [[Nd:YVO4|neodymium-doped yttrium orthovanadate]] (Nd:YVO<sub>4</sub>) or [[yttrium aluminium garnet#Nd:YAG|neodymium-doped yttrium aluminium garnet]] (Nd:YAG), or, less commonly, [[neodymium-doped yttrium lithium fluoride]] (Nd:YLF)), which lases deeper in the infrared at 1064&nbsp;nm. This lasing action is due to an electronic transition in the fluorescent [[neodymium]] ion, Nd(III), which is present in all of these crystals.

Some green lasers operate in pulse or quasi-continuous wave (QCW) mode to reduce cooling problems and prolong battery life.

An announcement in 2009<ref>[https://arstechnica.com/science/news/2009/07/green-diode-lasers-a-big-breakthrough-for-laser-display-tech.ars Green diode lasers a big breakthrough for laser-display tech] (i-micronews.com via arstechnica.com).</ref> of a direct green laser (which does not require doubling) promises much higher efficiencies and could foster the development of new color video projectors.

In 2012, [[Nichia]]<ref>[http://www.nichia.co.jp/en/product/laser.html LASER Diode-NICHIA CORPORATION]. nichia.co.jp</ref> and [[OSRAM]]<ref>[http://www.osram-os.com/osram_os/en/products/product-catalog/laser-diodes/visible-laser/green-laser/index.jsp Green Laser, Visible Laser – OSRAM Opto Semiconductors]. osram-os.com</ref> developed and manufactured merchant high-power green laser diodes (515/520&nbsp;nm), which can emit green laser directly.

Because even a low-powered green laser is visible at night through [[Rayleigh scattering]] from air molecules, this type of pointer is used by astronomers to easily point out stars and constellations. Green laser pointers can come in a variety of different output powers. The 5&nbsp;mW green laser pointers (classes II and IIIa) are the safest to use, and anything more powerful is usually not necessary for pointing purposes, since the beam is still visible in dark lighting conditions.