Editing Laser pointer (section)

===Blue===
{{Main|Blue laser}}
Blue laser pointers in specific wavelengths such as 473&nbsp;nm usually have the same basic construction as DPSS green lasers. In 2006 many factories began production of blue laser modules for [[optical disc|mass-storage devices]], and these were used in laser pointers too. These were DPSS-type frequency-doubled devices. They most commonly emit a beam at 473&nbsp;nm, which is produced by frequency doubling of 946&nbsp;nm laser radiation from a diode-pumped [[Nd:YAG]] or [[Nd:YVO4]] crystal (Nd-doped crystals usually produce a principal wavelength of 1064&nbsp;nm, but with the proper reflective coating mirrors can be also made to lase at other "higher harmonic" non-principal neodymium wavelengths). For high output power, [[beta barium borate|BBO]] crystals are used as frequency doublers; for lower powers, [[potassium titanyl phosphate|KTP]] is used. The Japanese company [[Nichia]] controlled 80% of the blue-laser-diode market in 2006.<ref>{{cite news| url=https://www.theguardian.com/technology/2006/sep/14/newmedia.media|work=The Guardian|location=London|title=Is the end in sight for Sony's laser blues?|date=14 September 2006|access-date=7 May 2010|first=Jane|last=Qiu|author-link=Jane Qiu}}</ref>

Some vendors are now selling collimated diode blue laser pointers with measured powers exceeding 1,500&nbsp;mW. However, since the claimed power of "laser pointer" products also includes the IR power (in DPSS technology only) still present in the beam (for reasons discussed below), comparisons on the basis of strictly visual-blue components from DPSS-type lasers remain problematic, and the information is often not available. Because of the higher neodymium harmonic used, and the lower efficiency of frequency-doubling conversion, the fraction of IR power converted to 473&nbsp;nm blue laser light in optimally configured DPSS modules is typically 10–13%, about half that typical for green lasers (20–30%).{{citation needed|date=June 2013}}

Lasers emitting a violet light beam at 405&nbsp;nm may be constructed with GaN ([[gallium nitride]]) semiconductors. This is close to ultraviolet, bordering on the very extreme of human vision, and can cause bright blue [[fluorescence]], and thus a blue rather than violet spot, on many white surfaces, including white clothing, white paper, and projection screens, due to the widespread use of [[optical brightener]]s in the manufacture of products intended to appear brilliantly {{nowrap|white{{hsp}}{{mdash}}}}{{hsp}}the brighteners are chemical compounds that absorb light in the violet (and [[ultraviolet]]) region of the [[electromagnetic spectrum]] and re-emit light in the blue region by fluorescence. On ordinary non-fluorescent materials, and also on fog or dust, the color appears as a shade of deep violet that cannot be reproduced on monitors and print. A GaN laser emits 405&nbsp;nm directly without a frequency doubler, eliminating the possibility of accidental [[#Infrared hazards of DPSS laser pointers|dangerous infrared emission]]. These laser diodes are mass-produced for the reading and writing of data in [[Blu-ray]] drives (although the light emitted by the diodes is not blue, but distinctly violet). In mid-to-late 2011, 405&nbsp;nm blue-violet laser diode modules with an optical power of 250&nbsp;mW, based on GaN violet laser diodes made for Blu-ray disc readers, had reached the market from Chinese sources for prices of about US$60 including delivery.<ref>In September 2011, GaN diode laser modules capable of operating at 250mW (or 300mW pulse) with a heatsink were offered on eBay in the Industrial Lasers category at around US$60.</ref>