The Er3+: Y2O3 Ceramic System
Aug 20, 2012
from 10:00 AM to 11:30 AM
|Where||ENGR. IV Bldg., Faraday Room 67-124|
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Advisor: Oscar M. Stafsudd
Optical quality ceramics have numerous advantages over single-crystal and glass hosts. General mechanical robustness in extreme conditions, the ability to engineer doping profiles and tailor the laser gain media and, depending on the material system chosen, higher thermal conductivity of these materials are some of the qualities that attract the attention of researchers working on high-powered lasers. Ceramic laser gain media can also be made in large volumes much like glass laser media. This allows the engineer to leverage cheap flash-pumping methods to generate very high powers for military and scientific purposes.
The work reported here spans many topics that, when taken together, present a full evaluation of a laser material. We have experimentally ascertained thus far the refractive indices of varying doping levels of active ion erbium in poly-crystalline yttria and the materials' stress-optic behavior. Spectroscopic data such as absorption and emission spectra in the near and mid infra-red regions, and the calculated cross-sections are also reported. Multiphonon studies were also completed; the data provides vital information on the dominant phonon frequency and the radiative lifetimes.
Energy transfer amongst the erbium ions and upconversion behaviour is also analysed. The theoretical work provided includes an up-to-date Judd-Ofelt analysis of the ion-host system.
Abhijeet Joshi received his B.S. and M.S. degree in Electrical Engineering from University of California, Los Angeles, in 2006 and 2010 respectively.
He is currently working toward his Ph.D. degree in the Electrical Engineering Department at UCLA. His research interests are widely spread from novel laser devices and characterization of laser gain media to basic semiconductor research.