SBIR/STTR Phase I: Ytterbium-Doped Stoichiometric Lithium Niobate for Self-Frequency Conversion Lasers

This Small Business Innovative Research (SBIR) Phase I project will demonstrate the potential of new sources of laser radiation based on ytterbium (Yb) doped stoichiometric lithium niobate (SLN) crystals. The Yb-doped SLN crystal will serve as both the laser and nonlinear frequency converter to enable the production of a broad range of wavelengths in a simple, compact device. As an active lasing ion, Yb has the advantages of efficient diode pumping, low thermal loading, and minimal reabsorption of laser radiation. This laser radiation can be converted to various wavelengths of interest via nonlinear optical effects that are intrinsic to lithium niobate. Recent developments in quasi-phase matching techniques in lithium niobate have increased both the efficiency and range of wavelengths that can be generated by nonlinear optical frequency conversion. The use of stoichiometric lithium niobate over conventional congruent lithium niobate leads to greater ease in fabrication of quasi-phase matched structures via electric field poling, and higher power handling capabilities. The combined advantages of Yb lasing, quasi-phase matched frequency conversion, and fabrication and power handling of SLN in one single crystal will enable the realization of new sources of laser radiation at wavelengths not currently available. This will make possible new lasers characterized by lightweight, compact construction, efficient operation, and spectral versatility. Commercial applications include the development of eye safe lasers for non-laboratory environments such as range finders, laser surveying and mapping, and pollution monitoring. Significant medical applications also may exist.