Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences), now is manufactured and marketed by CASTECH Inc. The high-quality crystal boule is steadily available from CASTECH, who holds specialized proprietary techniques (flux-method) of the BBO crystal growth.
Application in Nd:YAG Lasers:
       BBO is an efficient NLO crystal for the second, third and fourth harmonic generation of Nd:YAG  lasers, and the best NLO crystal for the fifth harmonic generation at 213nm. Conversion efficiencies of more than 70% for SHG, 60% for THG and 50% for 4HG, and 200 mW output at 213 nm (5HG) have been obtained, respectively.
   BBO is also an efficient crystal for the intracavity SHG of high power Nd:YAG lasers. For the intracavity SHG of an acousto-optic Q-switched Nd:YAG laser, more than 15 W average power at 532 nm was generated in a CASTECH AR-coated BBO crystal. When it is pumped by the 600 mW SHG output of a mode-locked Nd:YLF laser, 66 mW output at 263 nm was produced from a Brewster-angle-cut BBO in an external enhanced resonant cavity.
   Because of a small acceptance angle and large walk-off, good laser beam quality (small divergence, good mode condition, etc.) is the key for BBO to obtain high conversion efficiency. Tightly focusing of laser beam is not recommended by CASTECH' s engineers.

Applications in Tunable Lasers:
1. Dye lasers
Efficient UV output (205nm - 310 nm) with a SHG efficiency of over 10% at wavelength of ≥206 nm was obtained in type I BBO, and 36% conversion efficiency was achieved for a XeCl-laser pumped Dye laser with power 150KW which is about 4-6 times higher than that in ADP. The shortest SHG wavelength of 204.97 nm with efficiency of about 1% has been generated.
CASTECH's BBO is widely used in the Dye lasers. With type I sum-frequency of 780 - 950 nm and 248.5 nm (SHG output of 495 nm dye laser) in BBO, the shortest UV outputs ranging from 188.9nm to 197 nm and the pulse energy of  95 mJ at 193 nm and 8 mJ at 189 nm have been obtained, respectively.

2. Ultrafast Pulse Laser

Frequency-doubling and -tripling of ultrashort-pulse lasers are the applications in which BBO shows superior properties to KDP and ADP crystals. Now, CASTECH can provide as thin as 0.005mm BBO for this purpose. A laser pulse as short as 10 fs can be efficiently frequency-doubled with a thin BBO, in terms of both phase-velocity and group-velocity matching.

3. Ti:Sapphire and Alexandrite lasers
UV output in the region 360nm - 390 nm with pulse energy of 105 mJ (31% SHG efficiency) at 378 nm, and output in the region 244nm - 259 nm with 7.5 mJ (24% mixing efficiency) have been obtained for type I SHG and THG of an Alexandrite laser in BBO crystal.

More than 50% of SHG conversion efficiency in a Ti:Sapphire laser has been obtained. High conversion efficiencies have been also obtained for the THG and FHG of Ti:Sapphire lasers.

4.  Argon Ion and Copper-Vapor lasers
By employing the intracavity frequency-doubling technique in an Argon Ion laser with all lines output power of 2W, maximum 33 mW at 250.4 nm and thirty-six lines of deep UV wavelengths ranging from 228.9 nm to 257.2 nm were generated in a Brewster-angle-cut BBO crystal.
Up to 230 mW average power in the UV at 255.3 nm with maximum 8.9% conversion efficiency was achieved for the SHG of a Copper-Vapor laser at 510.6 nm.
Note:
      •   BBO has a low susceptibility to the moisture. Users are advised to provide dry conditions for both application and preservation of BBO.
      •   BBO is relatively soft and therefore requires precautions to protect its polished surfaces.
      •   When angle adjusting is necessary, please keep in mind that the acceptance angle of BBO is small.
      •   CASTECH engineers can select and design the best crystal, based on the main parameters of your laser, such as energy per pulse, pulse width and repetition rate for a pulsed laser, power for a cw laser, laser beam diameter, mode condition,divergence, wavelength tuning range, etc.
      •   For thin crystals, CASTECH can provide free holders for you.