Photoluminescence of the transition metal-oxygen charge transfer absorption band of yttrium aluminum garnet
EMSL Project ID
30092
Abstract
The identification of impurities within Nd:YAG laser crystals is of vital importance to improvement of laser performance. Literature identifies the 256nm absorption band observed in YAG as the result of an iron impurity-oxygen charge transfer process. Ultra-violet solarization and oxidation heat treatments indicate that this absorption band is probably the result of a multi-valence transition metal coupling with oxygen ions. However, recent results from neutron activation analysis and glow discharge mass spectroscopy indicate that the transition metal may not be iron. Analysis indicates that iridium metal could be responsible for the appearance of the charge transfer band. This seems logical as Czochralski-grown YAG involves the use of an iridium crucible during the crystal growth process. This is backed by literature indicating that no 256nm absorption band is found in growth processes that do not utilize an iridium crucible. The purpose of this study is to measure the resulting photoluminescence emitted from the excitation of the 256nm absorption peak in Czochralski-grown undoped YAG, Nd:YAG, and Ce:YAG single crystals. Photoluminescence from these samples will then be used to determine the defect energy levels associated with this complex. This study could potentially lead to the reassignment of the source of the 256nm absorption peak, which could help crystal-growth technicians lower the impurity-ion concentration in grown crystal improving laser performance.
EMSL resources are required for this experiment as no suitable spectrometer can be found at Washington State University. Also, Washington State University does not possess a light source capable of pumping the 256nm absorption band in question.
Project Details
Project type
Limited Scope
Start Date
2008-05-05
End Date
2008-07-05
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members