When ordering a nonlinear optical crystal, crystal orientation (or crystal cut) and size have to be known. The orientation is solely determined by the nonlinear optical process. For example, for type I frequency-doubling of 1064nm, BBO is cut at θ = 22.8^o and Φ = 0^o. Where:θ is the polar angle between the optical axis and the propagation direction, Φ is the azimuthal angle between the projection of propagation direction onto the XY plane and the X axis. If you are uncertain about the required crystal orientation please contact us for advice.