Nd:YAG laser#Applications

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Nd:YAG lasers are optically pumped using a flashtube or laser diodes. These are one of the most common types of laser, and are used for many different applications.

Nd:YAG lasers typically emit light with a wavelength of 1064 nm, in the infrared.{{cite book | first =Amnon | last =Yariv | year =1989 | title = Quantum Electronics| edition =3rd | publisher =Wiley | isbn =978-0-471-60997-1|pages=208–11}} However, there are also transitions near 946, 1120, 1320, and 1440 nm. Nd:YAG lasers operate in both pulsed and continuous mode. Pulsed Nd:YAG lasers are typically operated in the so-called Q-switching mode: An optical switch is inserted in the laser cavity waiting for a maximum population inversion in the neodymium ions before it opens. Then the light wave can run through the cavity, depopulating the excited laser medium at maximum population inversion. In this Q-switched mode, output powers of 250 megawatts and pulse durations of 10 to 25 nanoseconds have been achieved.Walter Koechner (1965) Solid-state laser engineering, Springer-Verlag, p. 507 The high-intensity pulses may be efficiently frequency doubled to generate laser light at 532 nm, or higher harmonics at 355, 266 and 213 nm.

Nd:YAG absorbs mostly in the bands between 730–760 nm and 790–820 nm. At low current densities krypton flashlamps have higher output in those bands than do the more common xenon lamps, which produce more light at around 900 nm. The former are therefore more efficient for pumping Nd:YAG lasers.Koechner §6.1.1, pp. 251–64.

The amount of the neodymium dopant in the material varies according to its use. For continuous wave output, the doping is significantly lower than for pulsed lasers. The lightly doped CW rods can be optically distinguished by being less colored, almost white, while higher-doped rods are pink-purplish.{{Citation needed|date=February 2021}}

Other common host materials for neodymium are: YLF (yttrium lithium fluoride, 1047 and 1053 nm), YVO₄ (yttrium orthovanadate, 1064 nm), and glass. A particular host material is chosen in order to obtain a desired combination of optical, mechanical, and thermal properties. Nd:YAG lasers and variants are pumped either by flashtubes, continuous gas discharge lamps, or near-infrared laser diodes (DPSS lasers). Prestabilized laser (PSL) types of Nd:YAG lasers have proved to be particularly useful in providing the main beams for gravitational wave interferometers such as LIGO, VIRGO, GEO600 and TAMA.{{Citation needed|date=February 2021}}

Image:Posterior capsular opacification on retroillumination.jpg photograph of posterior capsular opacification visible a few months after implantation of intraocular lens in eye, seen on retroillumination]]

Nd:YAG lasers are used in ophthalmology to correct posterior capsular opacification,{{Cite journal|last1=Findl|first1=Oliver|last2=Buehl|first2=Wolf|last3=Bauer|first3=Peter|last4=Sycha|first4=Thomas|date=2010-02-17|title=Interventions for preventing posterior capsule opacification|journal=The Cochrane Database of Systematic Reviews|issue=2|pages=CD003738|doi=10.1002/14651858.CD003738.pub3|issn=1469-493X|pmid=20166069|pmc=10658648}} after cataract surgery, for peripheral iridotomy in patients with chronic{{Cite journal|last1=Dias-Santos|first1=Arnaldo|last2=Ferreira|first2=Joana|last3=Abegão Pinto|first3=Luís|last4=Domingues|first4=Isabel|last5=Silva|first5=José Pedro|last6=Cunha|first6=João Paulo|last7=Reina|first7=Maria|date=April 2015|title=Phacoemulsification versus peripheral iridotomy in the management of chronic primary angle closure: long-term follow-up|url=https://pubmed.ncbi.nlm.nih.gov/24728533/|journal=International Ophthalmology|volume=35|issue=2|pages=173–178|doi=10.1007/s10792-014-9926-8|issn=1573-2630|pmid=24728533|hdl=10400.17/2093|s2cid=14929770|hdl-access=free}} and acute angle-closure glaucoma,{{Cite journal|last=Saunders|first=D. C.|date=September 1990|title=Acute closed-angle glaucoma and Nd-YAG laser iridotomy|journal=The British Journal of Ophthalmology|volume=74|issue=9|pages=523–525|doi=10.1136/bjo.74.9.523|issn=0007-1161|pmc=1042198|pmid=2393642}} where it has largely superseded surgical iridectomy,{{Cite journal|last1=Rivera|first1=A. H.|last2=Brown|first2=R. H.|last3=Anderson|first3=D. R.|date=September 1985|title=Laser iridotomy vs surgical iridectomy. Have the indications changed?|url=https://pubmed.ncbi.nlm.nih.gov/4038128/|journal=Archives of Ophthalmology|volume=103|issue=9|pages=1350–1354|doi=10.1001/archopht.1985.01050090102042|issn=0003-9950|pmid=4038128}} for the treatment of vitreous eye floaters,{{cite journal|vauthors=Kokavec J, Wu Z, Sherwin JC, Ang AJ, Ang GS |date=2017|title=Nd:YAG laser vitreolysis versus pars plana vitrectomy for vitreous floaters|journal=Cochrane Database Syst Rev|volume=2017|issue=6|pages=CD011676|doi=10.1002/14651858.CD011676.pub2|pmc=6481890|pmid=28570745}} for pan-retinal photocoagulation in the treatment of proliferative diabetic retinopathy,{{Cite journal|last1=Moutray|first1=Tanya|last2=Evans|first2=Jennifer R.|last3=Lois|first3=Noemi|last4=Armstrong|first4=David J.|last5=Peto|first5=Tunde|last6=Azuara-Blanco|first6=Augusto|date=2018-03-15|title=Different lasers and techniques for proliferative diabetic retinopathy|journal=The Cochrane Database of Systematic Reviews|volume=2018|issue=3|pages=CD012314|doi=10.1002/14651858.CD012314.pub2|issn=1469-493X|pmc=6494342|pmid=29543992}} and to damage the retina in ophthalmology animal research.{{Cite journal|last1=Kameel Ghaly|first1=Sally|last2=Foad Ghoneim|first2=Dina|last3=Abdelkawi Ahmed|first3=Salwa|last4=Medhat Abdel-Salam|first4=Ahmed|date=2013|title=Histological Evaluation of Retina after Photo Disruption for Vitreous Humor by Q-Switched Neodymium-Doped Yttrium Aluminium Garnet (Nd:YAG) Laser|journal=Journal of Lasers in Medical Sciences|volume=4|issue=4|pages=190–198|issn=2008-9783|pmc=4282007|pmid=25606329}}

Nd:YAG lasers emitting light at 1064 nm have been the most widely used laser for laser-induced thermotherapy, in which benign or malignant lesions in various organs are ablated by the beam.

In oncology, Nd:YAG lasers can be used to remove skin cancers.{{cite journal | last = Moskalik | first = K |author2=A Kozlov |author3=E Demin |author4=E Boiko | title = The Efficacy of Facial Skin Cancer Treatment with High-Energy Pulsed Neodymium and Nd:YAG Lasers | journal = Photomedicine Laser Surgery | year = 2009 | volume = 27 | issue = 2 | pages = 345–49 | doi = 10.1089/pho.2008.2327 | pmid = 19382838}} They are also used to reduce benign thyroid nodules,{{cite journal |vauthors=Valcavi R, Riganti F, Bertani A, Formisano D, Pacella CM |date=November 2010| title = Percutaneous Laser Ablation of Cold Benign Thyroid Nodules: A 3-Year Follow-Up Study in 122 Patients | journal =Thyroid |volume = 20|issue=11|pages=1253–61| doi = 10.1089/thy.2010.0189 | pmid =20929405}} and to destroy primary and secondary malignant liver lesions.{{cite journal |author1=Pacella CM |author2=Francica G |author3=Di Lascio FM |author4=Arienti V |author5=Antico E |author6=Caspani B |author7=Magnolfi F |author8=Megna AS |author9=Pretolani S |author10=Regine R |author11=Sponza M |author12=Stasi R |date=June 2009| title = Long-term outcome of cirrhotic patients with early hepatocellular carcinoma treated with ultrasound-guided percutaneous laser ablation: a retrospective analysis | journal =Journal of Clinical Oncology | volume = 27|issue=16|pages=2615–21| doi = 10.1200/JCO.2008.19.0082 | pmid =19332729 |s2cid=23374952 |doi-access=free }}{{cite journal |author1=Pompili M |author2=Pacella CM |author3=Francica G |author4=Angelico M |author5=Tisone G |author6=Craboledda P |author7=Nicolardi E |author8=Rapaccini GL |author9=Gasbarrini G . |date=June 2010| title = Percutaneous laser ablation of hepatocellular carcinoma in patients with liver cirrhosis awaiting liver transplantation | journal =European Journal of Radiology | volume = 74|issue=3|pages=e6–e11 |doi= 10.1016/j.ejrad.2009.03.012 | pmid =19345541|hdl=2108/22095 |hdl-access=free }}

To treat benign prostatic hyperplasia (BPH), Nd:YAG lasers can be used for laser prostate surgery—a form of transurethral resection of the prostate.{{Cite journal|last1=Sun|first1=Feng|last2=Sun|first2=Xincheng|last3=Shi|first3=Qinglu|last4=Zhai|first4=Yuzhang|date=December 2018|title=Transurethral procedures in the treatment of benign prostatic hyperplasia: A systematic review and meta-analysis of effectiveness and complications|journal=Medicine|volume=97|issue=51|pages=e13360|doi=10.1097/MD.0000000000013360|issn=1536-5964|pmc=6320039|pmid=30572440}}{{Cite journal|last1=Costello|first1=A. J.|last2=Johnson|first2=D. E.|last3=Bolton|first3=D. M.|date=1992|title=Nd:YAG laser ablation of the prostate as a treatment for benign prostatic hypertrophy|url=https://pubmed.ncbi.nlm.nih.gov/1374142/|journal=Lasers in Surgery and Medicine|volume=12|issue=2|pages=121–124|doi=10.1002/lsm.1900120202|issn=0196-8092|pmid=1374142|s2cid=39538383}}

These lasers are also used extensively in the field of cosmetic medicine for laser hair removal and the treatment of minor vascular defects such as spider veins on the face and legs. Nd:YAG lasers are also used to treat venous lake lip lesions.{{Cite journal|pmc = 2957073|year = 2010|last1 = Azevedo|first1 = L. H|title = Venous Lake of the Lips Treated Using Photocoagulation with High-Intensity Diode Laser|journal = Photomedicine and Laser Surgery|volume = 28|issue = 2|pages = 263–265|last2 = Galletta|first2 = V. C|last3 = De Paula Eduardo|first3 = C|last4 = Migliari|first4 = D. A|pmid = 19811083|doi = 10.1089/pho.2009.2564}} Recently Nd:YAG lasers have been used for treating dissecting cellulitis of the scalp, a rare skin disease.{{cite journal |author1=Krasner BD |author2=Hamzavi FH |author3=Murakawa GJ |author4=Hamzavi IH |date=August 2006| title = Dissecting cellulitis treated with the long-pulsed Nd:YAG laser. | journal =Dermatologic Surgery | issue=8|pages=1039–44 |pmid=16918566 | doi=10.1111/j.1524-4725.2006.32227.x | volume=32|s2cid=31317584 }}

Using hysteroscopy the Nd:YAG laser has been used for removal of uterine septa within the inside of the uterus.{{cite journal |vauthors=Yang J, Yin TL, Xu WM, Xia LB, Li AB, Hu J |title=Reproductive outcome of septate uterus after hysteroscopic treatment with neodymium:YAG laser |journal=Photomedicine Laser Surgery | pmid=17069494 | year=2006 | volume=24 | issue=5 | page=625 | doi=10.1089/pho.2006.24.625}}

In podiatry, the Nd:YAG laser is being used to treat onychomycosis, which is fungus infection of the toenail.{{cite journal|last1=Ledon|first1=Jennifer A.|last2=Savas|first2=Jessica|last3=Franca|first3=Katlein|last4=Chacon|first4=Anna|last5=Nouri|first5=Keyvan|title=Laser and light therapy for onychomycosis: a systematic review|journal=Lasers in Medical Science|year=2012|issn=0268-8921|doi=10.1007/s10103-012-1232-y|pmid=23179307|volume=29|issue=2|pages=823–29|s2cid=7950300}} The merits of laser treatment of these infections are not yet clear, and research is being done to establish effectiveness.{{cite journal |journal=Podiatry Today |title=Laser care for onychomycosis: can it be effective? |volume=23 |issue=5 |date=May 2010|url=http://www.podiatrytoday.com/laser-care-for-onychomycosis-can-it-be-effective |pages=54–59 |first1=John |last1=Mozena |first2=Brent |last2=Haverstock}}{{cite journal |journal=Podiatry Today |title=Emerging concepts in treating onychomycosis |volume=22 |issue=10 |date=October 2009 |pages=46–51 |first1=John D. |last1=Mozena |first2=Joshua P. |last2=Mitnick|url=http://www.podiatrytoday.com/emerging-concepts-in-treating-onychomycosis}}

Nd:YAG dental lasers have been used for the removal of dental caries as an alternative to drill therapy, although evidence supporting its use is of low quality.{{Cite journal|last1=Montedori|first1=Alessandro|last2=Abraha|first2=Iosief|last3=Orso|first3=Massimiliano|last4=D'Errico|first4=Potito Giuseppe|last5=Pagano|first5=Stefano|last6=Lombardo|first6=Guido|date=2016-09-26|title=Lasers for caries removal in deciduous and permanent teeth|journal=The Cochrane Database of Systematic Reviews|volume=2016|issue=9 |pages=CD010229|doi=10.1002/14651858.CD010229.pub2|issn=1469-493X|pmc=6457657|pmid=27666123}} They have also been used for soft tissue surgeries in the oral cavity, such as gingivectomy,{{Cite journal|last=Cortes|first=M.|date=April 1999|title=Nd:YAG laser-assisted gingivectomy, bleaching, and porcelain laminates, Part 2|url=https://pubmed.ncbi.nlm.nih.gov/10765801/|journal=Dentistry Today|volume=18|issue=4|pages=52–55|issn=8750-2186|pmid=10765801}}{{Cite journal|last1=De Benedittis|first1=Michele|last2=Petruzzi|first2=Massimo|last3=Pastore|first3=Luca|last4=Inchingolo|first4=Francesco|last5=Serpico|first5=Rosario|date=February 2007|title=Nd:YAG laser for gingivectomy in Sturge-Weber syndrome|url=https://pubmed.ncbi.nlm.nih.gov/17236940/|journal=Journal of Oral and Maxillofacial Surgery|volume=65|issue=2|pages=314–316|doi=10.1016/j.joms.2006.05.011|issn=0278-2391|pmid=17236940}} periodontal sulcular debridement,David M. Harris, Robert H. Gregg, Delwin K. McCarthy, Leigh E. Colby, Lloyd V. Tilt, "Sulcular debridement with pulsed Nd:YAG," Proc. SPIE 4610, Lasers in Dentistry VIII, (3 June 2002); doi: 10.1117/12.469328 LANAP,{{Cite journal|last1=Yukna|first1=Raymond A.|last2=Carr|first2=Ronald L.|last3=Evans|first3=Gerald H.|date=December 2007|title=Histologic evaluation of an Nd:YAG laser-assisted new attachment procedure in humans|url=https://pubmed.ncbi.nlm.nih.gov/18092452/|journal=The International Journal of Periodontics & Restorative Dentistry|volume=27|issue=6|pages=577–587|issn=0198-7569|pmid=18092452}} and pulpotomy.{{Cite journal|last1=De Coster|first1=Peter|last2=Rajasekharan|first2=Sivaprakash|last3=Martens|first3=Luc|date=November 2013|title=Laser-assisted pulpotomy in primary teeth: a systematic review|url=https://pubmed.ncbi.nlm.nih.gov/23171469/|journal=International Journal of Paediatric Dentistry|volume=23|issue=6|pages=389–399|doi=10.1111/ipd.12014|issn=1365-263X|pmid=23171469}} Nd:YAG dental lasers have also been shown to be effective at treating and preventing dental hypersensitivity,{{Cite journal|last1=Rezazadeh|first1=Fahimeh|last2=Dehghanian|first2=Paria|last3=Jafarpour|first3=Dana|date=2019|title=Laser Effects on the Prevention and Treatment of Dentinal Hypersensitivity: A Systematic Review|journal=Journal of Lasers in Medical Sciences|volume=10|issue=1|pages=1–11|doi=10.15171/jlms.2019.01|issn=2008-9783|pmc=6499583|pmid=31360362}} as an adjunct for periodontal instrumentation,{{Cite journal|last1=Roncati|first1=Marisa|last2=Gariffo|first2=Annalisa|date=April 2014|title=Systematic review of the adjunctive use of diode and Nd:YAG lasers for nonsurgical periodontal instrumentation|url=https://pubmed.ncbi.nlm.nih.gov/24697584/|journal=Photomedicine and Laser Surgery|volume=32|issue=4|pages=186–197|doi=10.1089/pho.2013.3695|issn=1557-8550|pmid=24697584}} and for the treatment of recurrent aphthous stomatitis.{{Cite journal|last1=Suter|first1=Valerie G. A.|last2=Sjölund|first2=Sophia|last3=Bornstein|first3=Michael M.|date=May 2017|title=Effect of laser on pain relief and wound healing of recurrent aphthous stomatitis: a systematic review|url=https://pubmed.ncbi.nlm.nih.gov/28345122/|journal=Lasers in Medical Science|volume=32|issue=4|pages=953–963|doi=10.1007/s10103-017-2184-z|issn=1435-604X|pmid=28345122|s2cid=3853214}}

Nd:YAG lasers are used in manufacturing for engraving, etching, or marking a variety of metals and plastics, or for metal surface enhancement processes like laser peening.[https://www.academia.edu/6125762/Studies_on_laser_peening_of_spring_steel_for_automotive_applications Studies on laser peening of spring steel for automotive applications | Ranganathan Kandasamy - Academia.edu] They are extensively used in manufacturing for cutting and welding steel, semiconductors and various alloys. For automotive applications (cutting and welding steel) the power levels are typically 1–5 kW. Super alloy drilling (for gas turbine parts) typically uses pulsed Nd:YAG lasers (millisecond pulses, not Q-switched). Nd:YAG lasers are also employed to make subsurface markings in transparent materials such as glass or acrylic glass and in white and transparent polycarbonate for identity documents. Lasers of up to 2 kW are used for selective laser melting of metals in additive layered manufacturing. In aerospace applications, they can be used to drill cooling holes for enhanced air flow/heat exhaust efficiency.{{Citation needed|date=November 2012}}

Nd:YAG lasers are also used in the non-conventional rapid prototyping process laser engineered net shaping (LENS).

Laser peening typically uses a high energy (10 to 40 joule) 10 to 30 nanosecond pulse. The laser beam is focused down to a few millimeters in diameter to deposit gigawatts of power on the surface of a part. Laser peening is unlike other manufacturing processes in that it neither heats nor adds material; it is a mechanical process of cold working the metallic component to impart compressive residual stresses. Laser peening is widely used in gas-fired turbine engines in both aerospace and power generation to increase strength and improve resistance to damage and metal fatigue.{{cite web |url=http://www.lsptechnologies.com/why-laser-peen.php |website=LSP Technologies |title=How laser peening works |accessdate=2022-12-24}}

Nd:YAG lasers can be used for flow visualization techniques in fluid dynamics (for example particle image velocimetry or laser-induced fluorescence).{{cite journal |title=Rapid in-vitro physiologic flow experimentation using rapid prototyping and particle image velocimetry |first=Gilbert N. |last=Palafox|author2=Wicker, Ryan B. |author3= Elkins, Christopher J. |journal=2003 Summer Bioengineering Conference |year=2003 |page=419 |url=http://www.tulane.edu/~sbc2003/pdfdocs/0419.PDF | access-date=2007-10-10}}

Nd:YAG lasers are frequently used to build optical tweezers for biological applications. This is because Nd:YAG lasers mostly emit at a wavelength of 1064 nm. Biological samples have a low absorption coefficient at this wavelength, as biological samples are usually mostly made up of water.

{{cite journal |author1=D. J. Stevenson |author2=T. K. Lake |author3=B. Agate |author4=V. Gárcés-Chávez |author5=K. Dholakia |author6=F. Gunn-Moore |date=2006-10-16 |title=Optically guided neuronal growth at near infrared wavelengths |journal=Optics Express |pmid=19529370 |volume=14 |issue=21 |pmc=2869025 |pages=9786–93 |doi=10.1364/OE.14.009786 |url=http://www.opticsinfobase.org/viewmedia.cfm?uri=oe-14-21-9786&seq=0|bibcode = 2006OExpr..14.9786S }} As such, using an Nd:YAG laser minimizes the damage to the biological sample being studied.

Researchers from Japan's National Institutes of Natural Sciences are developing laser igniters that use YAG chips to ignite fuel in an engine, in place of a spark plug.{{cite web |url=http://www.gizmag.com/laser-ignition-spark-plug-alternative/18469/ |title=Laser igniters could spell the end for the humble spark plug |first=Ben |last=Coxworth |date=April 21, 2011 |access-date= March 30, 2012 |work=Gizmag}}{{cite journal |title=Composite, all-ceramics, high-peak power Nd:YAG/Cr⁴⁺:YAG monolithic micro-laser with multiple-beam output for engine ignition |first=Nicolaie |last=Pavel |journal=Optics Express |volume=19 |issue=10 |pages=9378–84 |year=2011 |doi=10.1364/OE.19.009378|bibcode = 2011OExpr..19.9378P |pmid=21643194 |display-authors=etal|doi-access=free }} The lasers use several 800 picosecond long pulses to ignite the fuel, producing faster and more uniform ignition. The researchers say that such igniters could yield better performance and fuel economy, with fewer harmful emissions.

Image:SSY1 Military Surplus Nd-YAG Laser Firing.JPGThe Nd:YAG laser is the most common laser used in laser designators and laser rangefinders.

During the Iran–Iraq War, Iranian soldiers suffered more than 4000 cases of laser eye injury, caused by a variety of Iraqi sources including tank rangefinders. The 1064 nm wavelength of Nd:YAG is thought to be particularly dangerous, as it is invisible and initial exposure is painless.{{Cite web|url=https://fas.org/nuke/guide/iraq/other/laser.htm|title = Anti-Personnel Lasers - Iraq Special Weapons}}

The Chinese ZM-87 blinding laser weapon uses a laser of this type, though only 22 have been produced due to their prohibition by the Convention on Certain Conventional Weapons. North Korea is reported to have used one of these weapons against American helicopters in 2003.{{cite news |last1=Fisher |first1=Franklin |url=https://www.stripes.com/news/u-s-says-apache-copters-were-targeted-by-laser-weapons-near-korean-dmz-1.9753 |title=U.S. says Apache copters were targeted by laser weapons near Korean DMZ |work=Stars and Stripes |date=2003-05-14 |access-date=2016-12-20 }}{{cite web|last=Lister|first=Tim|title=North Korea's military aging but sizeable|url=http://articles.cnn.com/2010-11-24/world/north.korea.capability_1_military-cooperation-massive-military-parade-pyongyang?_s=PM:WORLD|archive-url=https://web.archive.org/web/20101126153445/http://articles.cnn.com/2010-11-24/world/north.korea.capability_1_military-cooperation-massive-military-parade-pyongyang?_s=PM:WORLD|archive-date=2010-11-26|publisher=CNN|access-date=24 December 2010}}

The Nd:YAG may be used in the application of cavity ring-down spectroscopy, which is used to measure the concentration of some light-absorbing substance.{{Cite web |title=Cavity Ring Down Spectroscopy (CRDS) : Atmospheric Chemistry: HIRAC Group |url=https://hirac.leeds.ac.uk/instrumentation/crds/?adlt=strict&toWww=1&redig=94B32D323B514B6F9FFF7240AF79D5AA |access-date=2023-01-04 |website=hirac.leeds.ac.uk}}

{{main|Laser-induced breakdown spectroscopy}}

A range of Nd:YAG lasers are used in analysis of elements in the periodic table. Though the application by itself is fairly new with respect to conventional methods such as XRF or ICP, it has proven to be less time consuming and a cheaper option to test element concentrations. A high-power Nd:YAG laser is focused onto the sample surface to produce plasma. Light from the plasma is captured by spectrometers and the characteristic spectra of each element can be identified, allowing concentrations of elements in the sample to be measured.{{Citation needed|date=February 2021}}

Nd:YAG lasers, mainly via their second and third harmonics, are widely used to excite dye lasers either in the liquidF. P. Schäfer (Ed.), Dye Lasers (Springer-Verlag, Berlin, 1990). or solid state.F. J. Duarte, Tunable Laser Optics (Elsevier-Academic, New York, 2003). They are also used as pump sources for vibronically broadened solid-state lasers such as Cr⁴⁺:YAG or via the second harmonic for pumping Ti:sapphire lasers.

For many applications, the infrared light is frequency-doubled or -tripled using nonlinear optical materials such as lithium triborate to obtain visible (532 nm, green) or ultraviolet light.{{Cite book|last=Paschotta|first=Rüdiger|title=Field Guide to Lasers |chapter=Frequency Doubling |date=2008-01-15|chapter-url=https://www.spiedigitallibrary.org/ebooks/FG/Field-Guide-to-Lasers/110/Frequency-Doubling/10.1117/3.767474.p110?SSO=1|volume=FG12|doi=10.1117/3.767474.p110|isbn=9780819478269}} Cesium lithium borate generates the 4th and 5th harmonics of the Nd:YAG 1064 nm fundamental wavelength.{{Cite journal|last1=Komatsu|first1=R.|last2=Sugawara|first2=T.|last3=Sassa|first3=K.|last4=Sarukura|first4=N.|last5=Liu|first5=Z.|last6=Izumida|first6=S.|last7=Segawa|first7=Y.|last8=Uda|first8=S.|last9=Fukuda|first9=T.|last10=Yamanouchi|first10=K.|date=1997-06-30|title=Growth and ultraviolet application of Li2B4O7 crystals: Generation of the fourth and fifth harmonics of Nd:Y3Al5O12 lasers|url=https://aip.scitation.org/doi/10.1063/1.119210|journal=Applied Physics Letters|volume=70|issue=26|pages=3492–3494|doi=10.1063/1.119210|bibcode=1997ApPhL..70.3492K|issn=0003-6951|url-access=subscription}} A green laser pointer is a frequency doubled Nd:YVO₄ diode-pumped solid state laser (DPSS laser).{{Cite web|title=Green Lasers|url=https://www.optotronics.com/green-lasers.php|access-date=2021-05-05|website=www.optotronics.com}} Nd:YAG can be also made to lase at its non-principal wavelength. The line at 946 nm is typically employed in "blue laser pointer" DPSS lasers, where it is doubled to 473 nm.{{Cite web|title=Nd:YAG laser|url=http://www.scientificlib.com/en/Physics/Laser/NdYAGLaser.html|access-date=2021-05-05|website=www.scientificlib.com}}{{Cite journal|last1=Fan|first1=T. Y.|last2=Byer|first2=R. L.|date=1987-10-01|title=Continuous-wave operation of a room-temperature, diode-laser-pumped, 946-nm Nd:YAG laser|url=https://pubmed.ncbi.nlm.nih.gov/19741880/|journal=Optics Letters|volume=12|issue=10|pages=809–811|doi=10.1364/ol.12.000809|issn=0146-9592|pmid=19741880|bibcode=1987OptL...12..809F}}{{Cite web|last=Keiderling|first=Tim|date=2013|title=Chem 542 Techniques of Optical Spectroscopy in Analytical Chemistry|url=http://www2.chem.uic.edu/tak/chem52413/|access-date=2021-05-05|website=www2.chem.uic.edu|at=http://www2.chem.uic.edu/tak/chem52413/notes3/notes3b-13sol.pdf}}

• Formula: Y₃Al₅O₁₂
• Molecular weight: 596.7
• Crystal structure: Cubic
• Hardness: 8–8.5 (Mohs){{cite encyclopedia |title=YAG Lasers |url=https://www.rp-photonics.com/yag_lasers.html |encyclopedia=Encyclopedia of Laser Physics and Technology |publisher=RP Photonics |first=Rüdiger |last=Paschotta |access-date=2018-01-16}}
• Melting point: 1970 °C (3540 °F)
• Density: 4.55 g/cm³

• Formula: Y_2.97Nd_0.03Al₅O₁₂
• Weight of Nd: 0.725%
• Atoms of Nd per unit volume: 1.38×10²⁰ /cm³
• Charge state of Nd: 3⁺
• Emission wavelength: 1064 nm
• Transition: ⁴F_3/2 → ⁴I_11/2
• Duration of fluorescence: 230 μs
• Thermal conductivity: 0.14 W·cm⁻¹·K⁻¹
• Specific heat capacity: 0.59 J·g⁻¹·K⁻¹
• Thermal expansion: 6.9×10⁻⁶ K⁻¹
• dn/dT: 7.3×10⁻⁶ K⁻¹
• Young's modulus: 3.17×10⁴ K·g/mm⁻²
• Poisson's ratio: 0.25
• Resistance to thermal shock: 790 W·m⁻¹

{{reflist|30em}}

• {{cite book | first = Anthony E.|last=Siegman|year=1986|title=Lasers| url = https://archive.org/details/lasers0000sieg| url-access = registration|publisher=University Science Books|isbn= 978-0-935702-11-8}}
• {{cite book | first=Walter | last=Koechner | year = 1988 | title=Solid-State Laser Engineering | edition =2nd | publisher=Springer-Verlag | isbn=978-3-540-18747-9}}

{{Solid-state laser}}

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