Title :
Nd:YAG quantum efficiency and related radiative properties
Author :
Devor, D.P. ; DeShazer, L.G. ; Pastor, R.C.
Author_Institution :
Hughes Res. Lab., Malibu, CA, USA
fDate :
8/1/1989 12:00:00 AM
Abstract :
Measured quantum efficiencies of ten different Nd:YAG crystals show a variation from 0.47 to 0.87. In phototropic crystals, the quantum efficiency can be degraded by color center formation or improved by bleaching. Color center bleaching occurs by oxidation, using a high-temperature reactive atmosphere process to control crystal defects related to hydroxyl impurities. Ion-ion and ion-lattice interaction effects are examined for further evidence of Nd3+ fluorescence quenching centers. Fluorescence rates, nonequivalent crystal field (NCF) effects, line broadening, Nd+3 lattice-defect interactions, and their temperature dependences are studied. Nd3+ site perturbations occur in all crystal samples. Five NCF Nd3+ sites show 6 cm-1 site-to-site Stark level shifts at liquid helium temperatures. Smaller scale shifts are characteristic of particular samples. While the crystals examined show individual differences, only hydroxyl-related coloration provides specific evidence of quenching centers
Keywords :
Stark effect; colour centres; crystal field interactions; fluorescence; garnets; luminescence of inorganic solids; neodymium; quantum optics; radiation quenching; solid lasers; spectral line breadth; spectral line shift; yttrium compounds; Nd3+ fluorescence quenching centers; Nd3+ site perturbations; YAG:Nd crystals; YAl5O12:Nd; color center formation; colour centre bleaching; crystal defects; high-temperature reactive atmosphere process; hydroxyl impurities; hydroxyl-related coloration; ion-ion interaction effects; ion-lattice interaction effects; line broadening; nonequivalent crystal field; oxidation; phototropic crystals; quantum efficiency; quenching centers; site-to-site Stark level shifts; temperature dependences; Atmosphere; Atmospheric measurements; Bleaching; Color; Crystals; Degradation; Fluorescence; Neodymium; Oxidation; Process control;
Journal_Title :
Quantum Electronics, IEEE Journal of
