Editing Sapphire (section)

====Equipment windows====
[[File:cermax.jpg|thumb|Cermax [[xenon arc lamp]] with synthetic sapphire output window]]
[[File:Citizen Eco-Drive Titanium Sapphire.jpg|thumb|[[Wristwatch]] with synthetic sapphire watch crystal]]

Synthetic sapphire—also referred to as ''sapphire glass''—is commonly used for small windows, because it is both highly transparent to wavelengths of light between 150&nbsp;nm ([[Ultraviolet|UV]]) and 5500&nbsp;nm ([[Infrared|IR]]) (the visible [[spectrum]] extends about 380&nbsp;nm to 750&nbsp;nm<ref>{{cite book|title = Biology: Concepts and Applications|author = Cecie Starr|publisher = Thomson Brooks/Cole|year = 2005|isbn = 978-0-534-46226-0|url = https://books.google.com/books?id=RtSpGV_Pl_0C&pg=PA94|page=94}}</ref>), and extraordinarily scratch-resistant.<ref>{{cite press release |url=http://www.corning.com/news_center/features/gorillaglasssuccess.aspx | url-status = dead | title = Corning® Gorilla® Glass Now Found On More Than 1.5 Billion Devices: Continuing innovation to fuel future versions, Sapphire not seen as major threat | date = May 2013 | location = Corning, N.Y. |publisher=Corning Incorporated | archive-url = https://web.archive.org/web/20130607071047/http://www.corning.com/news_center/features/gorillaglasssuccess.aspx | archive-date = 7 June 2013}}</ref><ref>{{cite web | url = http://www.cultofmac.com/267068/everything-wanted-know-sapphire-glass-afraid-ask-qa/ | title = Everything You Wanted To Know About Sapphire Glass, But Were Afraid To Ask [Q&A] | first = Luke | last = Dormehl | date = 19 February 2014 | work = Cult of Mac | access-date = 7 October 2014 | archive-date = 11 October 2014 | archive-url = https://web.archive.org/web/20141011070950/http://www.cultofmac.com/267068/everything-wanted-know-sapphire-glass-afraid-ask-qa/ | url-status = live }}</ref>

The key benefits of sapphire windows are:

* Very wide optical transmission band from [[UV]] to [[near infrared]] (0.15–5.5&nbsp;μm)
* Significantly stronger than other optical materials or standard glass windows
* Highly resistant to scratching and abrasion (9 on the [[Mohs scale of mineral hardness]] scale, the third-hardest natural substance next to [[moissanite]] and diamonds)<ref name="Arem-2017" />
* Extremely high melting temperature (2030&nbsp;°C)

[[File:Sapphire boule, Kyropoulos method.jpg|thumb|upright|Single-crystal sapphire boule grown by the [[Kyropoulos method]].<ref>{{cite web | url=http://functmaterials.org.ua/contents/32-1/0 | title="Functional materials", Vol.32, No.1, 2025. &#124; Journal "Functional Materials" }}</ref><ref>{{cite journal |last1=Fang |first1=H.S. |last2=Jin |first2=Z.L. |last3=Zhang |first3=M.J. |last4=Zhang |first4=Z. |last5=Zhao |first5=C.J. |title=Role of internal radiation at the different growth stages of sapphire by Kyropoulos method |journal=International Journal of Heat and Mass Transfer |date=December 2013 |volume=67 |pages=967–973 |doi=10.1016/j.ijheatmasstransfer.2013.08.074 |bibcode=2013IJHMT..67..967F }}</ref> Approximately {{convert|200|mm|in|0}} in diameter, weighing approximately {{cvt|30|kg}}. (A second boule is visible in the background.)]]
Some sapphire-glass windows are made from pure sapphire boules that have been grown in a specific crystal orientation, typically along the optical axis, the ''c''&nbsp;axis, for minimum [[birefringence]] for the application.<ref>{{cite book |last1=Dobrovinskaya |first1=Elena R. |last2=Lytvynov |first2=Leonid A. |last3=Pishchik |first3=Valerian |title=Sapphire |chapter=Properties of Sapphire |series=Micro- and Opto-Electronic Materials, Structures, and Systems |date=2009 |pages=55–176 |doi=10.1007/978-0-387-85695-7_2 |isbn=978-0-387-85694-0 |url=https://www.springer.com/cda/content/document/cda_downloaddocument/9780387856940-c1.pdf |access-date=11 September 2017 |archive-date=15 February 2017 |archive-url=https://web.archive.org/web/20170215163235/http://www.springer.com/cda/content/document/cda_downloaddocument/9780387856940-c1.pdf? |url-status=live }}</ref><ref>{{cite web |title=Crystals – Introduction |url=http://www.quartzpage.de/crs_intro.html |website=The Quartz Page |archive-url=https://web.archive.org/web/20071010190156/http://www.quartzpage.de/crs_intro.html |archive-date=10 October 2007}}</ref>

The boules are sliced up into the desired window thickness and finally polished to the desired surface finish. Sapphire optical windows can be polished to a wide range of surface finishes due to its crystal structure and its hardness. The surface finishes of optical windows are normally called out by the scratch-dig specifications in accordance with the globally adopted MIL-O-13830 specification.{{clarify|date=October 2017}}

Sapphire windows are used in both high-pressure and vacuum chambers for [[spectroscopy]], crystals for [[watch]]es, and windows in grocery-store [[barcode scanner]]s, since the material's exceptional hardness and toughness makes it very resistant to scratching.<ref name="Scheel-2003"/>

In 2014 [[Apple Inc.|Apple]] consumed "one-fourth of the world's supply of sapphire to cover the [[iPhone]]'s camera lens and fingerprint reader".<ref>{{Cite news |last=Wakabayashi |first=Daisuke |date=19 November 2014 |title=Inside Apple's Broken Sapphire Factory |language=en-US |work=[[The Wall Street Journal]] |url=https://online.wsj.com/articles/inside-apples-broken-sapphire-factory-1416436043 |access-date=14 December 2021 |archive-date=4 December 2014 |archive-url=https://web.archive.org/web/20141204152117/http://online.wsj.com/articles/inside-apples-broken-sapphire-factory-1416436043 |url-status=live }}</ref>

Several attempts have been made to make sapphire screens for smartphones viable. Apple contracted GT Advanced Technologies, Inc. to manufacture sapphire screens for iPhones, but the venture failed, causing the bankruptcy of GTAT.<ref>{{Cite web |date=14 November 2014 |title=The desperate struggle at the heart of the brutal Apple supply chain |url=http://www.theguardian.com/technology/2014/nov/14/sapphire-gt-advanced--brutal-apple-supply-chain |access-date=14 December 2021 |website=the Guardian |language=en |archive-date=14 December 2021 |archive-url=https://web.archive.org/web/20211214165033/https://www.theguardian.com/technology/2014/nov/14/sapphire-gt-advanced--brutal-apple-supply-chain |url-status=live }}</ref> The [[Kyocera]] Brigadier was the first production smartphone with a sapphire screen.<ref>{{Cite web |last=T. |first=Florin |title=Meet the world's first smartphone with Sapphire Shield display (no, it's not an iPhone) |url=https://www.phonearena.com/news/Meet-the-worlds-first-smartphone-with-Sapphire-Shield-display-no-its-not-an-iPhone_id58847 |access-date=14 December 2021 |website=Phone Arena |date=31 July 2014 |language=en-US |archive-date=14 December 2021 |archive-url=https://web.archive.org/web/20211214165031/https://www.phonearena.com/news/Meet-the-worlds-first-smartphone-with-Sapphire-Shield-display-no-its-not-an-iPhone_id58847 |url-status=live }}</ref>

Sapphire is used for end windows on some high-powered laser tubes, as its wide-band transparency and thermal conductivity allow it to handle very high power densities in the infrared and UV spectrum without degrading due to heating.

One type of [[xenon arc lamp]]{{snd}}originally called the "Cermax" and now known generically as the "ceramic-body xenon lamp"{{snd}}uses sapphire crystal output windows that tolerate higher thermal loads and consequently can provide higher output powers than conventional Xe lamps with pure [[silica]] windows.<ref>{{cite web |url=http://www.perkinelmer.com/cmsresources/Images/44-6529bro_cermaxproductsandspecifications.pdf |title=Cermax® Products and Specifications |publisher=PerkinElmer Optoelectronics |location=Fremont, California, USA |access-date=12 September 2017 |archive-date=12 September 2017 |archive-url=https://web.archive.org/web/20170912233638/http://www.perkinelmer.com/cmsresources/Images/44-6529bro_cermaxproductsandspecifications.pdf |url-status=live }}</ref><ref>{{cite web | url = http://www.excelitas.com/Downloads/Cermax_Eng_Guide.pdf | title = Cermax® Xenon Lamp Engineering Guide | publisher = Excelitas Technologies | access-date = 12 September 2017 | archive-date = 30 August 2014 | archive-url = https://web.archive.org/web/20140830161825/http://excelitas.com/Downloads/Cermax_Eng_Guide.pdf | url-status = live }}</ref>

Sapphire window was used for the [[F-35 Lightning 2]] Electro Optical Targeting System window, due to its high strength.<ref>{{Cite web |url=https://www.lockheedmartin.com/en-us/products/f-35-lightning-ii-eots.html |title=F-35 Electro Optical Targeting System (EOTS) |access-date=12 May 2024 |archive-date=13 May 2024 |archive-url=https://web.archive.org/web/20240513161553/https://www.lockheedmartin.com/en-us/products/f-35-lightning-ii-eots.html |url-status=live }}</ref>
[[File:F-35 EOTS at ILA-2022.jpg | thumb|220x124px | right]]

Along with [[Zirconium dioxide|zirconia]] and [[aluminum oxynitride]], synthetic sapphire is used for shatter-resistant windows in armored vehicles and various military [[body armor]] suits, in association with composites.{{citation needed|date=February 2025}}