New materials for highly efficient acoustooptical operation of high power laser radiation

Summary form only given. The optical (refractive indices, piezooptic coefficients, optical damage thresholds and the transmission spectra) and the elastic properties of the α-BaB₂O₄, β-BaB₂O₄, Li₂B₄O₇ and CsLiB₆O₁₀ crystals are investigated. It is shown that these crystals possess wide range of transparency (∼0.2 - 3 μm) and high level of the optical damage threshold (e.g. for Li₂B₄O₇ it is 32.2 GW/cm²). The components of the elastic matrix C_mn of these crystals are calculated on the basis of the ultrasonic velocity measurements. The photoelastic coefficients of the borate crystals are calculated on the basis of piezooptical coefficients measured with interferometric technique. Using the determined values of the refractive, elastic and photoelastic tensor components, we have calculated the values of the acoustooptic figure of merit M₂ for these crystals. The acoustooptical figure of merit of α-BaB₂O₄ and LiB₄O₇ crystals achieve value M₂ = 243.4 × 10^-15 s³/kg and M₂ = 2.57 × 10^-15 s³/kg at the interaction with the slowest ultrasonic waves ν = 933.5 m/s and ν = 3173 m/s, respectively. The acoustooptical modulators on the base of α-BaB₂O₄ and LiB₄O₇ crystals have been constructed and performance characteristics have been obtained experimentally.