OPTICAL CHARACTERIZATION OF PERTURBED SITES AND C3i SITES IN RARE EARTH DOPED OXIDE CRYSTALS

Dr. Gregory Reinemer
Idaho State University
Department of Physics

Oxide crystals have long been successfully employed as a host lattice for the trivalent rare earth ions (R3+) that are used as the active ions in many laser processes.  In this capacity, oxides are generally mechanically robust and thermally stable at the temperatures necessary for good laser operation.  More recently, R3+ doped oxides are being employed in research to develop spatial-spectral holography techniques for high-speed, high-bandwidth optical signal processing device applications such as optical correlators, optical routers, optical memory, and optical computers.

Poor crystal quality has direct consequences for laser efficiency and longevity, including overheating, darkening, and mechanical breakdown.  For optical signal processing applications, the demand for high bandwidth within an extremely narrow transition line requires that no defect transitions fall under the inhomogeneous broadening of the main line.  No crystal is perfect, however and a few defects can always be found in even the most carefully grown crystals – some defects may actually be intrinsic to the growth process!  

In this talk, I will present results of work I did to characterize point defects in two R3+ doped crystals – R3+:YAG and R3+:Y2O3.  Using a combination of absorption, fluorescence, and angle dependent Zeeman spectroscopy, I was able to isolate and identify a previously unobserved point defect in the YAG and Y2O3 cubic lattices that may be intrinsic to the methods employed by nearly all commercial crystal growers.