No abstract

Growth of large beta-barium borate (BBO) crystals of high optical quality has been challenging, even 25 years past its discovery. The best results in terms of size and quality have been demonstrated by means of TSSG (Top Seeded Solution Growth). Nevertheless, the maximum available size of nonlinear optical elements lags behind laser industry requirements. Due to increased size and availability, BBO finally started attracting attention for its favorable Q-switch properties. Yet, two or sometimes three crystals aligned together are still necessary to achieve the lengths often required for these applications. Material quality, in terms of optical perfection and optical absorption, is still questionable in many instances. Limited boule size still dictates relatively high material cost as well. Thorough analysis of the growth behavior of BBO helped us to develop production processes for large boules utilizing TSSG with pulling. High quality nonlinear optical crystal devices and Q-switches up to 40 mm in the z-direction have been enabled. We believe that the above size and quality are currently industry leading.