BBO (beta-BaB2O4) is an excellent non-linear crystal for frequency-doubling (SHG) of Visible and Near IR laser light, OPO/OPG/OPA pumped by ultrafast pulses of wavelengths in the Near IR to UV, and sum-frequency mixing (SFM) into the Visible to the deep UV. BBO is one of the few practical crystal for use below 500 nm in SHG and SFM.

The price depends on the specifications and requirements. Contact us with more details.

BBO crystal has broad tunability, high damage threshold, and high efficiency. BBO’s small acceptance angle requires a very good beam quality and its large walkoff results in output beams that are very elliptical or slit-like. Type I is usually much more efficient than type II operation. BBO cannot be used for NCPM (temperature tuned) application. BBO is very good for tunable laser sources, such as ultrafast Ti:Sapphire or dye lasers. And it is also widely used for SHG, 3HG, 4HG, and autocorrelation of femtosecond and picosecond Ti:Sapphire lasers; SHG, 3HG, 4HG, 5HG of YAG lasers at 1064 nm and 1320 nm to yield output of 212-660nm; SHG of tunable dye or solid-state laser sources from 410-750 nm to yield output of 205-375 nm, SFM of dye laser and YAG harmonics to yield output of 189-400 nm; DFM (difference-frequency mixing) from the Visible to the IR range up to over 3000 nm; OPO pumped with SHG or 3HG of YAG or Ti:Sapphire with an output range of 400-3000 ; Intracavity SHG of Argon ion lasers (488, 514 nm) or Copper vapor lasers (510 nm, 578 nm).

Dimension tolerance: (W0.1mm)x(H0.1mm)x(L 0.2/-0.1mm)

Clear aperture: >90%

Scratch/Dig: 10/5

Flatness: < λ/8 @ 633nm

Wavefront distortion: < λ/8 @ 633nm

Parallelism: ≤ 20 arc seconds

Perpendicularity: ≤5 arc minutes

Angle tolerance: ≤0.25

Chamfer: ≤0.2mmx45

Chip: ≤ 0.1mm

Damage threshold: 0.5 GW/cm2 @1064nm,TEM00,10ns,10Hz (AR-coated).

BBO is a negative uniaxial crystal,with ordinary refractive-index(n_o) larger than extraordinary refractive-index(n_e).Both type I and type II phase-matching can be reached by angle-tuning.The phase matching angles of frequency doubling are shown in Fig.2.

Application in Nd:YAG Lasers

BBO is an efficient NLO cyrstal 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 200mW 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 AR-coated BBO crystal. When pumped by the 600 mW SHG output of a mode-locked Nd:YLF laser, 66 mW output at 266 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. Tight focus of laser beam is not recommended by our engineers.

Applications in Tunable Lasers

1. Dye lasers
   Efficient UV output (205nm-310nm) with a SHG efficiency of over 10% at wavelength of ≥206nm was obtained in type I BBO, and 36% conversion efficiency was achieved for a XeC1-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.

Our 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, we can provide as thin as 0.02mm 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 -390nm with pulse energy of 105 mJ(31% SHG efficiency) at 378 nm, and output in the region 244nm-259nm 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 efficienies have been also obtained for the THG and FHG of Ti:Sapphire lasers.

4. Argon Ion and Copper-Vapor lasers
By employing the intracavit 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.