Yttrium aluminium garnet

YAG redirects here. For the IATA airport code see Fort Frances Municipal Airport.

Yttrium aluminium garnet (YAG, scintillator.

Gemstone YAG

YAG for a period was used in jewelry as a diamond (50,000 or 100,000) on common polishing laps. YAG has low heat sensitivity.

As a synthetic gemstone YAG has numerous varietal and trade names, as well as a number of misnomers. Synonymous names include:^[1] alexite, amamite, circolite, dia-bud, diamite, diamogem, diamonair, diamone, diamonique, diamonite, diamonte, di'yag, geminair, gemonair, kimberly, Linde simulated diamond, nier-gem, regalair, replique, somerset, triamond, YAIG, and yttrium garnet. It's misnomers include;^[1] synthetic diamond, and synthetic demantoid, for green stones.

Production for the gem trade lapsed after the introduction of synthetic cubic zirconia, with little or no current production.^[1]

Technical-use varieties

Nd:YAG

Main article: Nd:YAG laser

Nd:YVO₄. It can be operated on power levels of up to kilowatts. It can be directly Q-switched with Cr⁴⁺:YAG.

Nd:YAG lases at 1064 nanometers and its best absorption band for pumping is 1 nm wide and located at 807.5 nm. [1]

The dopant concentration in commercially available Nd:YAG usually varies between 0.5-1.4 molar %. Higher dopant concentration is used for pulsed lasers, lower concentration is suitable for continuous wave lasers. Nd:YAG is pinkish-purple, lighter doped rods being less intensely colored than heavier-doped ones. As its absorption spectrum is narrow, the hue will depend on the type of light and will differ between sunlight and artificial light.

Nd:Cr:YAG

YAG doped with solar power satellite system.^[3]

Er:YAG

Main article: Er:YAG laser

blood sugar. The mechanical properties of Er:YAG are essentially the same as Nd:YAG. Er:YAG operates at relatively eye-safe wavelengths (while it hits the lens, it is absorbed in the eye so it does not damage retina), works well at room temperature, and has high slope efficiency. Er:YAG is pale-green colored.

Yb:YAG

laser diodes at 940 or 970 nm.

Yb:YAG is a good substitute for 1064 nm Nd:YAG in high-power applications, and its frequency-doubled 515 nm version can replace the 514 nm argon lasers.

Nd:Ce:YAG

lasing threshold. Usually 1.1-1.4 % of Y atoms are replaced with Nd, and 0.05-0.1% with Ce.

Ho:Cr:Tm:YAG

thulium triple-doped YAG (Ho:Cr:Tm:YAG, or Ho,Cr,Tm:YAG) is an active laser medium material with high efficiency. It lases at 2097 nm and can be pumped by a flashlamp or a laser diode. It is widely used in military, medicine, and meteorology. It operates at relatively eye-safe wavelengths, works well at room temperature, and has high slope efficiency. When pumped by a diode, the 781 nm band is used. Other major pump bands are located between 400 and 800 nm. The dopant levels used are 0.35 atom.% Ho, 5.8 atom.% Tm, and 1.5 at.% Cr. The rods have green color, imparted by chromium(III).

Tm:YAG

Thulium-doped YAG (Tm:YAG) is an active laser medium operating at the relatively eye-safe wavelengh of 2010 nm. It is suitable for being diode-pumped. It can be tuned between 1930-2040 nm. A dual-mode Tm:YAG laser emits two frequencies separated by 1 GHz.

Cr⁴⁺:YAG

dyes. The dopant levels range between 0.5-3 molar %.

It can be used for passive Q-switching the diode or lamp pumped Nd:YAG, Nd:YVO₄, Yb:YAG, and other neodymium and yttrium doped lasers at wavelengths between 1000-1200 nm.

Cr:YAG can be also used for tunable lasers with output adjustable between 1350-1550 nm. It can generate ultrashort (down to femtoseconds range) pulses when pumped at 1064 nm by a Nd:YAG laser.

Cr:YAG was demonstrated in a non-linear optics application as a self-pumped phase-conjugated mirror in a Nd:YAG loop resonator. It provides compensation of both phase and polarization aberrations induced into the loop resonator.

Dy:YAG

K.^[4] The phosphor can be applied directly to the measured surface, or to an end of an optical fiber.

Sm:YAG

Samarium-doped YAG (Sm:YAG) is a temperature-sensitive phosphor similar to Dy:YAG.

Tb:YAG

Terbium-doped YAG (Tb:YAG) is a phosphor used in cathode ray tubes. It emits at yellow-green color, at 544 nm.

Ce:YAG

light-emitting diodes, as a coating on a high-brightness blue InGaN diode, converting part of the blue light into yellow, which then appears as white. Such light however gives suboptimal color fidelity of green and red colors, causing color distortion. The output color is also strongly dependent on temperature and current.

Ce:YAG is also used in some photomultipliers.

Ce:YAG is used in ultraviolet radiation.

Ce:YAG can be further doped with gadolinium.

See also

• Yttrium iron garnet
• Gadolinium gallium garnet
• Nd:YAG laser
• Er:YAG laser

References

1. ^ ^{a b c d e f g h i j k l m n o p q r s} Gemological Institute of America, GIA Gem Reference Guide 1995, ISBN 0-87311-019-6
2. ^ §IIE, Crystalline solid lasers, Z. J. Kiss and R. J. Pressley, Proceedings of the IEEE, 54, #10 (October 1996), pp. 1236–1248.
3. ^ Disk-type Nd/Cr:YAG ceramic lasers pumped by arc-metal-halide-lamp, Taku Saiki, Kazuo Imasaki, Shinji Motokoshi, Chiyoe Yamanaka, Hisanori Fujita, Masahiro Nakatsuka and Yasukazu Izawa, Optics Communications 268, #1 (December 1, 2006), pp. 155–159. DOI 10.1016/j.optcom.2006.07.002.
4. ^ Goss, L.P.; Smith, A.A.; Post, M.E. (1989). "Surface thermometry by laser-induced fluorescence". Review of Scientific Instruments: 3702–3706. doi:10.1063/1.1140478. Retrieved on 2007-03-06.