Barium borate, known for its chemical formula β-BaB2O4 or BBO, is a versatile material utilized in various optical applications due to its unique properties. It is recognized as an exceptional non-linear optical (NLO) crystal, which is prized for its broad transparency range and phase matching capabilities. This allows BBO to be extensively used in the frequency-doubling (SHG) of visible and near-infrared laser light, enhancing the performance of optical parametric oscillators (OPOs), optical parametric generators (OPGs), and optical parametric amplifiers (OPAs).
BBO crystals are particularly favored for their high non-linear coefficient, which is a significant factor in laser technology. They are also noted for their high damage threshold, making them suitable for high-power laser applications, and their excellent optical homogeneity, which contributes to the quality of laser beams they are involved in generating.
One of the key uses of BBO is in the generation of higher harmonics, ranging from the second to the fifth, in popular laser systems such as Ti:Sapphire, Yb:KGW/KYW, and in Pockels cells, which are electro-optical modulators that utilize the Pockels effect to modulate light . These applications take advantage of BBO’s ability to handle high average powers and high peak powers, which are crucial in industrial laser systems.
Furthermore, BBO crystals are also used in sum-frequency mixing (SFM) to extend the wavelength coverage into the visible to deep ultraviolet range. This capability is vital for applications requiring a broad spectrum of laser light.
In summary, barium borate’s optical properties make it an invaluable material in the field of nonlinear optics, with applications spanning from scientific research to industrial laser systems, where its ability to manipulate and enhance laser light is highly sought after