Hydrothermal Shelling Synthesis of B_NaYF4 Microparticles

Abstract

This thesis paper covers my research on the shelling of ytterbium (Yb3+) doped B_NaYF4 for application as a radiation balanced microlaser. In general, laser designs rely on either flash pumping or a custom diode. Both of these methods produce a significant amount of energy in the form of heat and therefore require a reliable cooling system. Radiation balanced microlasers have been proven to operate reliably without an external cooling system using what’s referred to as laser refrigeration. This results in both high beam quality and high efficiency. One particular synthetic material proven capable of use in laser refrigeration and lasing is called B_NaYF4. It is made using Sodium, Yttrium, Fluoride, and sometimes a ligand. It’s hexagonal crystal structure combined with proper lanthanide doping can allow for anti-stokes luminescence and laser refrigeration. Therefore, it holds its place in use of this specific laser type. However, getting a properly doped and shelled B_NaYF4 that is capable of both laser refrigeration and lasing is quite difficult. Although these two phenomena have been produced and proven individually, getting a B_NaYF4 sample that is capable of both at the same time is far more difficult. This thesis also hopes to discuss and review our attempts to improve current methods of producing these doped B_NaYF4 samples capable of lasing, our encountered problems and solutions, and what it all means for the technology.