New nonlinear optical LiKB4O7 single crystals: Dispersion of refractive indices

The dispersion of refractive indices has been studied for LiKB4O7 single crystals growth with Czochralsky technique. In spectral range 420-675 nm the refractive indices na > nc > nb and dependencies ni(λ) can be described by monomial Zellmeier formulas. At the room temperature (293 K) nb = 1.521, nc = 1.554, na = 1.562 at λ = 1064 nm, and nb = 1.542, nc = 1.582, na = 1.593 at λ = 532 nm. Estimation of the phase matching conditions for second-harmonic generation (SHG) for radiation of the YAG:Nd laser (λ = 1064 nm) has been performed. We show that SHG in LiKB4O7 crystal can be realized by the phase matching of type I. The bisector of acute angle between optical axes (ϕ ≈ 56°) coincides with crystallographic axis [0 1 0].