Even though Alexandrite (Cr3+:BeAl2O4) can be found as natural gemstone, 3photon laser grade alexandrite is artificially grown. Due to toxic properties of beryllium, alexandrite crystals are grown only by few companies worldwide.

Alexandrite crystal has low symmetry and strong birefringence which allows to obtain linearly polarized emission without significant loss in depolarization.

Lasers with alexandrite laser medium do not operate well at room temperature, however they perform significantly better at higher temperatures.

Alexandrite is widely used in medical lasers, mostly in dermatology, because alexandrite lasers have wide tuning range from 700 nm to 860 nm centered around 755 nm and low absorption in water allows to penetrate deeper into the skin.

As supplemental product 3photon can provide standard or custom alexandrite crystal oven in order to keep desired temperatures and ensure the best possible performance of alexandrite crystal.

https://3photon.com/alexandrite-chromium-doped-chrysoberyl/