1. Fluorescence of Samarium Ions in Strontium Bismuth Borate Glasses
Lucas Elliott
Mark S. Boley, P. K. Babu, Saisudha B. Mallur

2. Overview Introduction Experimentation Results Summary
The importance and uses of rare earth doped glasses
Explanation of fluorescence
Experimentation
Samples
Laser excitation and fluorescence measurements
Origin analysis
Results
Summary

3. Rare Earth Doped Glasses
Promising in many industrial and research applications
Including:
Windows
Camera lenses
Lasers
Waveguides
Optical Fibers
Research focuses on glasses doped with Sm3+

4. Host Glass
Borate glasses are used as the host material for the samarium ions
This experiment uses strontium bismuth borate glass
These were bismuth borate glasses
A portion of borate is replaced with equal parts strontium
This replacement occurred in 5 mol percentage increments

5. Fluorescence
Luminescence is a general term to describe the emission which can be excited in various ways.
Photoluminescence relates to excitation by photons.
Fluorescence is a type of photoluminescence characterized by an exponential afterglow when excitation is removed.
The emitted photon energy is generally lower than that of excitation.

6. Fluorescence of Sm3+ Ions
Emits a strong reddish orange light
This fluorescence is due to transitions from the 4G5/2 state
Two of these transitions are especially important:
4G5/26H7/2 is an electric dipole (ED) transition
4G5/26H9/2 is a magnetic dipole (MD) transition

7. Term Symbols
Expressions used in the previous slides, such as 4G5/2, are known as term symbols.
These symbols are of the of the form 2S+1LJ.
L indicates the total orbital angular momentum.
Letters S,P,D,F,G, and H corresponds to 0,1,2,3,4, and 5.
The superscript term refers the terms multiplicity, where S is the total spin quantum number.
The subscript term is given by J = L+S, L+S-1,…,L-S.

8. Dipole Transitions
The transition corresponding to the electric dipole (ED) is very sensitive to environmental changes of the Sm3+ ions.
However, the magnetic dipole (MD) transition is not sensitive to these changes surrounding the ions.
The ratio of the area under these spectral peaks shows the distortion of symmetry of these rare earth ions.
Therefore, it points to structural changes within the glass matrix.

9. Samples The experiment uses four samples.
Formula: xSrO : (69-x) B2O3: 30 Bi2O3: 1.0 Sm2O3
Each of samples was prepared using the melt quench technique.
Sample 1
X=0
Sample 2
X=5
Sample 3
X=10
Sample 4
X=15

10. Excitation Three excitation wavelengths:
405.0 nm
457.9 nm
488.0 nm
457.9 and nm laser lines were obtained using an Ar ion laser
405.0 was obtained with a diode laser.

11. Ar ion laser Located in CH 524
More powerful of the two lasers used in this experiment
Data collected using LabVIEW software

12. Diode Laser Located in CH 109 Less powerful
Similar configuration as the Ar ion laser with fewer filters

13. Experimental Methods
Emission spectra was measured for each sample using each excitation wavelength.
Spectra was collected across a range of 500 to 750 nm.
The corresponding spectrometer and PC recorded the data in an Excel file.
This data was then transferred to the program Origin.
The emission spectra was decomposed by fitting with Gaussian curves.

14. Experimental Methods
The emissions are the result of Stark split transitions.
Therefore, the area of the Gaussian curves were added to obtain the area under each transition peak.
Finally, these areas were used to obtain the ED/MD ratio.
This ratio shows the symmetry of the rare earth ions in the glass matrix.

15. 405.0 nm
Sample 1
Sample 2
Sample 3
Sample 4

16. 405.0 nm

17. 457.9 nm
Sample 1
Sample 2
Sample 3
Sample 4

18. 457.9 nm

19. 488.0 nm
Sample 1
Sample 2
Sample 3
Sample 4

20. 488.0 nm

21. ED/MD
Sample
405.0 nm
457.9 nm
488.0 nm 1
2.227 ± 0.035
1.714 ± 0.036
1.795 ± 0.067 2
2.208 ± 0.033
1.617 ± 0.036
1.736 ± 0.069 3
2.172 ±0.089
1.628 ±
1.316 ± 0.059 4
2.163 ± 0.089
1.824 ± 0.034
2.150 ± 0.023

22. Results
For the nm excitation, the ED/MD ratio decreases before increasing drastically.
This excitation wavelength has the largest variance of the ED/MD ratio as concentration changes.

23. Results
For the nm excitation the ED/MD ratio decreases initially, then increases with increased concentration.

24. Results
For the nm excitation, the ED/MD ratio remains constant as the concentration of SrO increases.
The highest ED/MD ratio is for nm excitation
This implies that this excitation wavelength is an efficient wavelength for increased fluorescence intensity.

25. Summary The importance and uses of rare earth doped glasses
Explanation of fluorescence
Samples
Laser excitation and fluorescence measurements
Origin analysis
Results