Rapid growth of large LBO crystals for non-liner optical applications

Lithium Borate (LBO) crystals have become essential for frequency conversion in the laser industry, boasting one of the largest commercial markets among non-linear crystals. There is a need in a growth method producing large boules of high-quality material at a competitive price. Traditional growth methods have posed challenges such as lengthy growth times of several months per boule and issues with crystal quality including flux inclusions, striations. We have developed a novel rapid growth process for large LBO boules suitable for mass production. Building upon the Top-Seeded Solution Growth (TSSG) method, our process achieves unparalleled growth rates, exceeding those reported in literature by 10 times. We have demonstrated growth rates up to 10 mm/day, reducing the growth cycle for a typical 2-3 kg LBO boule from several months to just a couple of weeks. Crucially, our accelerated growth conditions have not compromised crystal quality. As-grown boules exhibit superior morphology and higher optical quality compared to conventionally grown crystals. They are entirely free from striations and inclusions also demonstrating record low optical absorption of ~ 0.5 ppm/cm at 1064 nm.