Lightning Optical Corporation proposes to develop the materials refinement and crystal growth of Tm and Ho doped scheelite fluoride crystals for diode-pumped 2 µm solid state laser systems. After months of refinement and optimization of the commercial growth of Nd:LiYF4 at Lightning Optical, it is our desire to test the versatility of our proprietary growth techniques with other fluoride-based laser host materials. A systematic optimization of the parameters utilized in the Czochralski growth of Tm and Ho doped scheelite isomorphs, such as LiLuF4 and LiGdF4, is proposed here in hopes of leading to 2 µm laser materials that have superior performance to those materials currently being used. Preliminary laser results indicate that this is indeed the case. We are proposing to grow and spectroscopically evaluate eight boules with preselected Tm and Ho dopant densities that should produce efficient 2 µm laser operation. Once these materials become commercially available, alternative solid state laser sources operating in the 2µm region can be marketed. Since preliminary data supports claims that fluoride hosts, such as LiLuF4, can be more efficient than those currently being packaged for various NASA programs (LiYF4), we believe that a steady, reliable source of these materials will improve NASA's 2 µm wind lidar technologies. Commercial Applications:If the goals of this research are achieved, LiYF4 isomorph materials doped with Tm and Ho will be commercially available for the first time for various 2 µm laser systems. These 2µm lasers have applications in military countermeasures, minimally invasive surgical techniques, and as pump sources for nonlinear materials, such as OPO's. Wind shear lidar and differential absorption lidar applications exist for both commercial products and for researchers at NASA.
