Chromium Doped Yttrium Aluminum Garnet Crystal (Cr4+:YAG)

Cr4+:YAG is an excellent crystal for passive Q switching of Nd:YAG, other Nd and Yb doped lasers, in the wavelength range from 800 nm to 1200 nm. Because of its chemical stability, durability, good thermal conductivity and high damage threshold (> 500 MW/cm2) and being easy to be operated, it can replace traditional LiF, Dye and color centers which are commonly used as passive Q-switching materials. Cr4+:YAG is also an useful lasing material, with output from 1350 nm to 1600 nm(tunable).

CASTECH provides Cr4+:YAG with Cr4+doping level from 0.5mol% to 3mol%. The size could be from 2×2mm2 to 14×14mm2 with length from 0.1mm to 12mm. We can control the initial transmission from 1% to 99% according to customers’ requirements.

Basic Properties of Cr4+:YAG

Crystal Structure Cubic Garnet
Dopant Level 0.5 mol% ~ 3 mol%
Hardness 8.5
Damage Threshold > 500 MW/cm2
Refractive Index 1.82 @ 1064 nm


The preliminary experiments of CASTECH’s Cr4+:YAG showed that the pulse width of passively Q-switched lasers could be as short as 5ns for diode pumped Nd:YAG lasers and repetition rate as high as 10kHz for diode pumped Nd:YVO4 lasers. Furthermore, an efficient green output @ 532nm, and UV output @ 355nm and 266nm were generated, after a subsequent intracavity SHG in KTP or LBO, THG and 4HG in LBO and BBO for diode pumped and passive Q-switched Nd: YAG and Nd: YVO4 lasers.

Cr4+:YAG is also a laser crystal with tunable output from 1.35μm to 1.6μm. It can generate ultrashort pulse laser (to fs pulsed) when pumped by Nd: YAG laser at 1.064μm.


When ordering Cr4+:YAG crystal, Please specify the size, initial transmission and coatings. For further information, please contact CASTECH.

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