Temperature Noncritical Phase Matching for Borate Crystals

The borate crystals are often used for laser radiation frequency conversion in visible and ultraviolet (UV) areas via sum-frequency generation (SFG) and near infrared (IR) band via different-frequency generation (DFG). In order to obtain the complete data for all possible frequency conversion processes the presentation was proposed in [1] in the form of diagram for figure of optical merit (FOM: FOM
₂
=(d
_eff
)
²
/(n
₁
n
₂
n
₃
)) with maximum values of the effective nonlinear coefficient d
_eff
along the phase matching directions for every combination of interacting wavelengths. It is also possible to use this diagram for finding interacting wavelengths combinations with noncritical angular and spectral phase matching.