Large LBO crystal growth at 2 kg-level

The growth of large size and high quality LBO crystal is always the research hotspot in nonlinear optical crystal field. In order to obtain large size LBO crystal, it is very important to explore a suitable region in a good flux system. The suitable region for LBO crystal growth in the Li2O–B2O3–MoO3 ternary system was investigated by the viscosity measurement. LBO crystal, up to 160×150×77 mm3 in size and 1988 g in weight, was successfully grown by seeding in [011] direction. The LBO single crystal processed was of high quality. Optical homogeneity reached 3.8×10−6 cm−1, transmittance was more than 90% from 200 nm to 380 nm and the laser-induced surface damage threshold was 11.2 GW/cm2 (λ=1064 nm, τ=7.5 ns).

► Suitable region for large LBO crystal growth was investigated.
► Bulk LBO single crystal with weight close to 2 kg was successfully obtained.
► The LBO crystal was proved to possess high quality.
► Elements with 100×100 mm2 aperture of high power Nd-lasers may be provided for THG.