Optical rotation in the lithium triborate nonlinear crystal

A dual-wavelength polarimetric technique at 633 and 661 nm has been used for the characterization of a nonlinear lithium triborate (LiB₃O₅) nonenantiomorphous biaxial crystal. The mismatch of the crystallographic and optical coordinate systems was taken into account. The optical rotatory power for light propagation along one of the optical axes is ρ = 7.06° mm⁻¹. The gyration tensor component along the bisector between the x and y crystallographic axes has been measured as g₁₂ = 4.31 × 10⁻⁵. Computed values based on the crystalline structure and electronic polarizabilities are in good agreement with those obtained experimentally.