SBIlR Phase I: Coherent Blue-Light Converters

This Small Business Innovation Research (SBIR) Phase I project focuses on the implementation of a blue-light converter based on a novel structure of KTiOPO4 (KTP) crystal. It proposes to integrate quasi-phase-matched (QPM) second-harmonic generation (SHG) with 90 degrees phase-matched sum-frequency generation (SFG) in the exclusive partly-periodically-poled KTP crystal. This structure will be used to achieve blue laser through effective third-harmonic generation (THG) from the latest technologies in 1.319 micron Nd:YAG, Nd:YVO4 and other Nd-doped lasers. The proposed blue devices naturally follow our recent demonstrations. They rely on the advantages of a KTP crystal including large second-order nonlinear coefficients and large angular and temperature tolerance. Most importantly, only a KTP crystal can be used in these devices since it can reach 90 degrees -phase-matched SFG from 1.319 micron and 659.5 nm to 439.7 nm. Therefore, the proposed blue devices are simple, highly efficient, highly reliable and low cost. Since the blue-light converter is built from one crystal, it is suitable for intracavity THG similar to intracavity SHG in Verdi and Millennia. Blue-Light Converters can be used in a number of important applications. Some areas of inclusion are health care, photodynamic therapy, spectroscopy with short-temporal and narrow-spectral resolutions, naval communications, nondestructive evaluations, and entertainment.