Lutetium aluminium garnet

Lutetium aluminum garnet (commonly abbreviated LuAG, molecular formula Lu3Al5O12) is an inorganic compound with a unique crystal structure primarily known for its use in high-efficiency laser devices.

LuAG has a relatively small lattice constant in comparison to the other rare-earth garnets, which results in a higher density producing a crystal field with narrower linewidths and greater energy level splitting in absorption and emission.

[2] These properties make it an excellent host for active ions such as Yb, Tm, Er, and Ho employed in diode-pumped solid-state lasers.

This high melting temperature, in addition to the lack of availability of lutetium has made this crystal less commonly used than its fellow garnets, despite its favorable physical properties.

[1] Lutetium aluminum garnet is an artificial crystal that can be grown using a technique developed approximately a century ago, the Czochralski growth process.