Study on Efficient Second Harmonic Generation of 1.55-μm Femtosecond Laser with BBO Crystal

摘要

β-BaB2O4 (BBO) crystal is one of the negative uniaxial crystals and it is generally used for second harmonic generation (SHG) excited by femtosecond lasers. However, the interaction length is limited by the walk off effect and the efficiency of the SHG is not enough to combine with weak power laser sources. In this study, two BBO crystals were set at inverse direction (inversed layered), for the purpose of negating the walk off effect. The efficiency of the SHG from the inversed layered BBO crystals was 3 times stronger than using a single crystal and two times stronger than using forward layered crystals.