| Autor: |
Margueron, Samuel H., Clarke, David R. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 5/1/2007, Vol. 101 Issue 9, p094902, 8p, 3 Diagrams, 5 Charts, 8 Graphs |
| Abstrakt: |
The polarization dependence of the optical absorption and R-line emission of a Cr3+-doped sapphire single crystal have been characterized. The absorption bands, U(4T2) and Y(4T1), as well as the R-line emission are determined to be dipole-like transitions associated with three incoherent dipoles oriented along the sapphire principal crystallographic axes (a,m,c). From measurements using the Muller method, it is found that the polarization of the R lines does not depend on either the polarization of the incident excitation or its wavelength. The σ emission is also an order of magnitude stronger than π emission. The R2-R1 peak separation and the ratio of the R2/R1 peak areas are found to be dependent on both the polarization and the stress directions. Stress in the basal plane breaks the symmetry of α polarization with the R2/R1 ratio increasing along the stress direction and decreasing in the perpendicular direction in the basal plane. The π emission also decreases with stress in the basal plane. However, in both polarizations the ratio R2/R1 does not depend on stress applied along the c axis. The value of the R2/R1 peak area ratio can be understood in terms of a piezoelectric-like effect on the dipole transition. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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