Frequency [GHz]
2
•Antihole position and hole width vary systematically across the 7 F 0 5 D 0 excitation line due to a linear variation in . •Transient hole width in sol-gel glasses shows weaker dependence on ex than the melt glass, indicating weaker crystal field coupling. This may be because the sol-gel glasses are not fully densified. 0 2 A -5 -4 -3 -2 -1 0 1 2 3 4 5 0 Frequency [GHz] Fluorescence 10 sec 30 sec 2 min 5 min 10 min T=1.7K =578nm 800 TEOS Transient and persistent spectral hole burning in Eu 3+ -doped sol-gel produced SiO 2 glass D. M. Boye 1 , T. S. Valdes 1 , J. H. Nolen 1 , A.J. Silversmith 2 , K.S. Brewer 2 , R. E. Anderman 2 and R. S. Meltzer 3 1 Davidson College, Davidson, NC 28036 USA 2 Hamilton College, Clinton, NY 13323 USA 3 University of Georgia, Athens, GA 30602 USA Transient and persistent spectral hole burning (TSHB and PSHB) experiments were performed on Eu 3+ ions in sol-gel SiO 2 glasses with aluminum co-doping. Differences in the hole burning behavior were observed among samples made from two organosilicate precursors that were annealed to a series of final temperatures. All glasses exhibited persistent spectral holes when annealed to 800C but, as the annealing temperature was raised to 1000C, an increasing number of Eu 3+ ions exhibited TSHB with a corresponding decrease in the number showing PSHB behavior. This is consistent with a reduction in metastable configurations with an increased final annealing temperature. The TSHB behavior is similar to that observed for Eu 3+ -doped silicate melt glass. Abstract Conclusions Corresponding author: Dr. Dan Boye Physics Department Davidson College P.O. Box 7133 Davidson, NC 28035- 7133 [email protected] Eu Local Environment Experiment Ingredients: Er(NO 3 ) 3 •6H 2 O Al(NO 3 ) 3 •9H 2 O H 2 O (deionized) C 3 H 6 O HNO 3 Tetraethylorthosilic ate (TEOS) Titanium n-butoxide (TBOT) Reaction - Hydrolysis and condensation - Room temp. - pH 1.5 to 3.5 Gelation - Polymeric gel forms - Supports stress elastically -”Wet” gel - 2 days, 40°C Aging - Solvent escapes - Pore contraction - Shrinkage - 2 days, 60°C Drying - Shrinkage - Cracking - Densification - Pore collapse - 2 days, 90°C Annealing Process time (days) Temperature ( o C) 0 200 400 600 800 1000 0 2 4 6 8 10 Al - network modifier Sili con Oxygen Europium 0 500 1000 1500 2000 2500 3000 3500 570 572 574 576 578 580 582 800TEO S 1.5K Feofilov 800TEO S 2.2K 900TEO S 1.6K 900TM O S 1.4K Excitation Wavelength [nm] Persistent Hole Width [MHz] Transient and Persistent Holes Persistent Hole Behavior Experimental Setup Argon Laser PMT Dye Laser Cryostat with sample @ 77K Monochromator Ammeter Oscillosc ope Computer with Labview software Waveform Synthesize r TEOS TMOS TEM Images for TEOS and TMOS sol-gel precursors All samples annealed to 900°C Type of hole burning depends strongly on the final annealing temperature and weakly on the organosilicate precursor. TEOS TMOS T ann 800°C PSHB only P and T SHB 900°C P and T SHB P and T SHB 1000°C P and T SHB TSHB only • As T ann is raised, the glass becomes denser. •There is less likelihood of photo-induced rearrangement. -2 -1 0 1 2 Frequency [GHz] Fluorescence Transient Holes Persistent Holes 800 TMOS 900 TEOS 75MHz 80MHz 290MHz 540MHz T = 1.65K =578nm The average pore size in the TMOS samples is smaller and there is a narrower range of sizes than in the TEOS samples. Constant fluence experiments show PSHB is 1- photon process. Proposed mechanisms for PSHB: Photo-induced rearrangement of local environment x Photoionization of Eu 3+ x Photo-reduction of Eu 3+ to Eu 2+ Hole burning time dependence 0 5 10 15 20 25 30 35 0 200 400 600 800 1000 0 5 10 15 20 25 30 35 0 2 4 6 8 10 12 Delay Time [ms] % Hole Depth Delay Time [s] % Hole Depth Hole recovery time dependence 0 0.25 0.5 0.75 1 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 Time [s] b a 0.62e -2.5t 0.38e - 24t a) Fluorescence level decreases in time as the hole is burned. The long tail is fit to an exponential with a time constant of 2.5s -1 . b) The fast component has a time constant 10x faster. Fluorescence References S.P. Feofilov, K.S. Hong, R.S. Meltzer, W. Jia and H. Liu, Phys. Rev. B60, 9406 (1999). T.T.Schmidt, R.M. Macfarlane, and S. Volker, Phys. Rev. B50, 15707 (1994). Acknowledgements AJS and DMB thank the NSF for a Research Opportunity Award associated with NSF DMR 9871864. Thanks to H.Y. Fang, currently of Sandia National Laboratories, for performing the TEM and x-ray diffraction work. 565 570 575 580 585 590 5% Al 1000C Fluorescence (arb. units) 7 F 0 5 D 0 excitation Transient Hole Behavior 0 20 40 60 80 100 120 140 160 571 573 575 577 579 581 900 TEO S 1.6K 900 TM O S 1.4 K 1000 TM O S 2K Schmidt et al 75 100 125 150 175 200 Excitation Wavelength [nm] Transient Hole Width [MHz] Antihole position [MHz] Both hole burning and recovery rates indicate: • Fast component – affects 1/3 of ions in first 100ms. • Slow component - ~10 times slower than fast component. • Transient hole burning observed on Eu 3+ sol-gel produced glass for first time. • TSHB mechanism: redistribution of electron population among hyperfine levels. • Combination of PSHB and TSHB observed with the proportion of the two being strongly dependent on the final annealing temperature. • PSHB mechanism: photo-induced rearrangement of local environment. Regions at or near a pore boundary are ripe for metastable configurations having a range of barrier energies. Persistent Hole Profiles Transient and Persistent Hole Profiles
description
Transient and persistent spectral hole burning in Eu 3+ -doped sol-gel produced SiO 2 glass. Transient and Persistent Holes. D. M. Boye 1 , T. S. Valdes 1 , J. H. Nolen 1 , A.J. Silversmith 2 , K.S. Brewer 2 , R. E. Anderman 2 and R. S. Meltzer 3 - PowerPoint PPT Presentation
Transcript of Frequency [GHz]
![Page 1: Frequency [GHz]](https://reader034.fdocuments.us/reader034/viewer/2022051518/56815d71550346895dcb7a09/html5/thumbnails/1.jpg)
•Antihole position and hole width vary systematically across the 7F05D0 excitation line due to a
linear variation in .
•Transient hole width in sol-gel glasses shows weaker dependence on ex than the melt glass,
indicating weaker crystal field coupling. This may be because the sol-gel glasses are not fully densified.
02A
-5 -4 -3 -2 -1 0 1 2 3 4 5
0
Frequency [GHz]
Fluo
resc
ence
10 sec
30 sec
2 min
5 min
10 min
T=1.7K=578nm800 TEOS
Transient and persistent spectral hole burning in Eu3+ -doped sol-gel produced SiO2 glass
D. M. Boye1, T. S. Valdes1, J. H. Nolen1 , A.J. Silversmith2, K.S. Brewer2, R. E. Anderman2 and R. S. Meltzer3
1Davidson College, Davidson, NC 28036 USA2 Hamilton College, Clinton, NY 13323 USA3University of Georgia, Athens, GA 30602 USA
Transient and persistent spectral hole burning (TSHB and PSHB) experiments were performed on Eu3+ ions in sol-gel SiO2 glasses with aluminum co-doping. Differences in the hole burning behavior were observed among samples made from two organosilicate precursors that were annealed to a series of final temperatures. All glasses exhibited persistent spectral holes when annealed to 800C but, as the annealing temperature was raised to 1000C, an increasing number of Eu3+ ions exhibited TSHB with a corresponding decrease in the number showing PSHB behavior. This is consistent with a reduction in metastable configurations with an increased final annealing temperature. The TSHB behavior is similar to that observed for Eu3+-doped silicate melt glass.
Abstract
Conclusions
Corresponding author:Dr. Dan BoyePhysics Department Davidson CollegeP.O. Box 7133 Davidson, NC [email protected]
Eu Local Environment
Experiment
Ingredients:Er(NO3)3•6H2OAl(NO3)3•9H2OH2O (deionized)C3H6OHNO3
Tetraethylorthosilicate (TEOS)Titanium n-butoxide (TBOT)
Reaction- Hydrolysis and
condensation- Room temp.- pH 1.5 to 3.5
Gelation- Polymeric gel forms- Supports stress
elastically-”Wet” gel- 2 days, 40°C
Aging- Solvent escapes- Pore contraction- Shrinkage- 2 days, 60°C
Drying- Shrinkage- Cracking- Densification- Pore collapse- 2 days, 90°C
Annealing Process
time (days)
Tem
pera
ture
(o C)
0
200
400
600
800
1000
0 2 4 6 8 10
Al - network modifier
SiliconOxygen
Europium
0
500
1000
1500
2000
2500
3000
3500
570 572 574 576 578 580 582
800TEOS 1.5K Feofilov800TEOS 2.2K900TEOS 1.6K900TMOS 1.4K
Excitation Wavelength [nm]
Pers
iste
nt H
ole
Wid
th [M
Hz]
Transient and Persistent Holes
Persistent Hole Behavior
Experimental Setup
Argon Laser
PMT
Dye LaserCryostat with sample @ 77K
Monochromator
Ammeter
OscilloscopeComputer withLabview software
WaveformSynthesizer
TEOS
TMOS
TEM Images for TEOS and TMOS sol-gel precursors All samples annealed to 900°C
Type of hole burning depends strongly on the final annealing temperature and weakly on the organosilicate precursor.
TEOS TMOSTann
800°C PSHB only P and T SHB
900°C P and T SHB P and T SHB
1000°C P and T SHB TSHB only
•As Tann is raised, the glass becomes denser.
•There is less likelihood of photo-induced rearrangement.
-2 -1 0 1 2
Frequency [GHz]
Fluo
resc
ence
Transient Holes
Persistent Holes
800 TMOS
900 TEOS
75MHz
80MHz
290MHz
540MHz
T = 1.65K=578nm
The average pore size in the TMOS samples is smaller and there is a narrower range of sizes than in the TEOS samples.
Constant fluence experiments show PSHB is 1-photon process.
Proposed mechanisms for PSHB:
Photo-induced rearrangement of local environment
x Photoionization of Eu3+
x Photo-reduction of Eu3+ to Eu2+
Hole burning time dependence
05
101520253035
0 200 400 600 800 1000
0
5
10
15
20
25
30
35
0 2 4 6 8 10 12
Delay Time [ms]
% H
ole
Dep
th
Delay Time [s]
% H
ole
Dep
th
Hole recovery time dependence
0
0.25
0.5
0.75
1
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
Time [s]
b
a
0.62e-2.5t
0.38e-24t
a) Fluorescence level decreases in time as the hole is burned. The long tail is fit to an exponential with a time constant of 2.5s-1.
b) The fast component has a time constant 10x faster.
Fluo
resc
ence
References S.P. Feofilov, K.S. Hong, R.S. Meltzer, W. Jia and H. Liu, Phys. Rev. B60, 9406 (1999).
T.T.Schmidt, R.M. Macfarlane, and S. Volker, Phys. Rev. B50, 15707 (1994).
AcknowledgementsAJS and DMB thank the NSF for a Research Opportunity Award associated with NSF DMR 9871864.
Thanks to H.Y. Fang, currently of Sandia National Laboratories, for performing the TEM and x-ray diffraction work.
565 570 575 580 585 590
5% Al 1000C
Fluo
resc
ence
(arb
. uni
ts)
7F05D0 excitation
Transient Hole Behavior
0
20
40
60
80
100
120
140
160
571 573 575 577 579 581
900 TEOS 1.6K
900 TMOS 1.4 K
1000 TMOS 2K
Schmidt et al
75
100
125
150
175
200
Excitation Wavelength [nm]
Tra
nsie
nt H
ole
Wid
th [M
Hz]
Ant
ihol
e po
sitio
n [M
Hz]
Both hole burning and recovery rates indicate:• Fast component – affects 1/3 of ions in first 100ms.• Slow component - ~10 times slower than fast component.
• Transient hole burning observed on Eu 3+ sol-gel produced glass for first time.
• TSHB mechanism: redistribution of electron population among hyperfine levels.
• Combination of PSHB and TSHB observed with the proportion of the two being strongly dependent on the final annealing temperature.
• PSHB mechanism: photo-induced rearrangement of local environment. Regions at or near a pore boundary are ripe for metastable configurations having a range of barrier energies.
Persistent Hole Profiles
Transient and Persistent Hole Profiles
![Page 2: Frequency [GHz]](https://reader034.fdocuments.us/reader034/viewer/2022051518/56815d71550346895dcb7a09/html5/thumbnails/2.jpg)
•Antihole position and hole width vary systematically across the 7F0 5D0 excitation line due to a linear variation in .
•Transient hole width in sol-gel glasses shows weaker dependence on ex than the melt glass, indicating weaker crystal field coupling. This may be because the sol-gel glasses are not fully densified.
02A
-5 -4 -3 -2 -1 0 1 2 3 4 5
0
Frequency [GHz]
Fluo
resc
ence
10 sec
30 sec
2 min
5 min
10 min
T=1.7K=578nm800 TEOS
Transient and persistent spectral hole burning in Eu3+ -doped sol-gel produced SiO2 glass
D. M. Boye1, T. S. Valdes1, J. H. Nolen1 , A.J. Silversmith2, K.S. Brewer2, R. E. Anderman2 and R. S. Meltzer3
1Davidson College, Davidson, NC 28036 USA2 Hamilton College, Clinton, NY 13323 USA3University of Georgia, Athens, GA 30602 USA
Transient and persistent spectral hole burning (TSHB and PSHB) experiments were performed on Eu3+ ions in sol-gel SiO2 glasses with aluminum co-doping. Differences in the hole burning behavior were observed among samples made from two organosilicate precursors that were annealed to a series of final temperatures. All glasses exhibited persistent spectral holes when annealed to 800C but, as the annealing temperature was raised to 1000C, an increasing number of Eu3+ ions exhibited TSHB with a corresponding decrease in the number showing PSHB behavior. This is consistent with a reduction in metastable configurations with an increased final annealing temperature. The TSHB behavior is similar to that observed for Eu3+-doped silicate melt glass.
Abstract
Conclusions
Corresponding author:Dr. Dan BoyePhysics Department Davidson CollegeP.O. Box 7133 Davidson, NC [email protected]
Eu Local Environment
Experiment
Ingredients:Er(NO3)3•6H2OAl(NO3)3•9H2OH2O (deionized)C3H6OHNO3 Tetraethylorthosilicate (TEOS)Titanium n-butoxide (TBOT)
Reaction- Hydrolysis and
condensation- Room temp.- pH 1.5 to 3.5
Gelation- Polymeric gel forms- Supports stress
elastically-”Wet” gel- 2 days, 40°C
Aging- Solvent escapes- Pore contraction- Shrinkage- 2 days, 60°C
Drying- Shrinkage- Cracking- Densification- Pore collapse- 2 days, 90°C
Annealing Process
time (days)
Tem
pera
ture
(o C)
0
200
400
600
800
1000
0 2 4 6 8 10
Al - network modifier
SiliconOxygen
Europium
0
500
1000
1500
2000
2500
3000
3500
570 572 574 576 578 580 582
800TEOS 1.5K Feofilov800TEOS 2.2K900TEOS 1.6K900TMOS 1.4K
Excitation Wavelength [nm]
Pers
iste
nt H
ole
Wid
th [M
Hz]
Transient and Persistent Holes
Persistent Hole Behavior
Experimental Setup
Argon Laser
PMT
Dye LaserCryostat with sample @ 77K
Monochromator
Ammeter
OscilloscopeComputer withLabview software
WaveformSynthesizer
TEOS
TMOS
TEM Images for TEOS and TMOS sol-gel precursors All samples annealed to 900°C
Type of hole burning depends strongly on the final annealing temperature and weakly on the organosilicate precursor.
TEOS TMOSTann
800°C PSHB only P and T SHB
900°C P and T SHB P and T SHB
1000°C P and T SHB TSHB only
•As Tann is raised, the glass becomes denser.
•There is less likelihood of photo-induced rearrangement.
-2 -1 0 1 2
Frequency [GHz]
Fluo
resc
ence
Transient Holes
Persistent Holes
800 TMOS
900 TEOS
75MHz
80MHz
290MHz
540MHz
T = 1.65K=578nm
The average pore size in the TMOS samples is smaller and there is a narrower range of sizes than in the TEOS samples.
Constant fluence experiments show PSHB is 1-photon process.
Proposed mechanisms for PSHB:
Photo-induced rearrangement of local environment
x Photoionization of Eu3+
x Photo-reduction of Eu3+ to Eu2+
Hole burning time dependence
05
101520253035
0 200 400 600 800 1000
0
5
1 0
1 5
2 0
2 5
3 0
3 5
0 2 4 6 8 1 0 1 2
Delay Time [ms]
% H
ole
Dep
th
Delay Time [s]
% H
ole
Dep
th
Hole recovery time dependence
0
0.25
0.5
0.75
1
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
Time [s]
b
a
0.62e-2.5t
0.38e-24t
a) Fluorescence level decreases in time as the hole is burned. The long tail is fit to an exponential with a time constant of 2.5s-1.
b) The fast component has a time constant 10x faster.
Fluo
resc
ence
ReferencesS.P. Feofilov, K.S. Hong, R.S. Meltzer, W. Jia and H. Liu, Phys. Rev. B60, 9406 (1999).
T.T.Schmidt, R.M. Macfarlane, and S. Volker, Phys. Rev. B50, 15707 (1994).
AcknowledgementsAJS and DMB thank the NSF for a Research Opportunity Award associated with NSF DMR 9871864.
Thanks to H.Y. Fang, currently of Sandia National Laboratories, for performing the TEM and x-ray diffraction work.
565 570 575 580 585 590
5% Al 1000C
Fluo
resc
ence
(arb
. uni
ts)
7F0 5D0 excitation
Transient Hole Behavior
0
20
40
60
80
100
120
140
160
571 573 575 577 579 581
900 TEOS 1.6K
900 TMOS 1.4 K
1000 TMOS 2K
Schmidt et al
75
100
125
150
175
200
Excitation Wavelength [nm]
Tra
nsie
nt H
ole
Wid
th [M
Hz]
Ant
ihol
e po
sitio
n [M
Hz]
Both hole burning and recovery rates indicate:• Fast component – affects 1/3 of ions in first 100ms.• Slow component - ~10 times slower than fast component.
• Transient hole burning observed on Eu 3+ sol-gel produced glass for first time.
• TSHB mechanism: redistribution of electron population among hyperfine levels.
• Combination of PSHB and TSHB observed with the proportion of the two being strongly dependent on the final annealing temperature.
• PSHB mechanism: photo-induced rearrangement of local environment. Regions at or near a pore boundary are ripe for metastable configurations having a range of barrier energies.
Persistent Hole Profiles
Transient and Persistent Hole Profiles
•Antihole position and hole width vary systematically across the 7F0 5D0 excitation line due to a linear variation in .
•Transient hole width in sol-gel glasses shows weaker dependence on ex than the melt glass, indicating weaker crystal field coupling. This may be because the sol-gel glasses are not fully densified.
02A
•Antihole position and hole width vary systematically across the 7F0 5D0 excitation line due to a linear variation in .
•Transient hole width in sol-gel glasses shows weaker dependence on ex than the melt glass, indicating weaker crystal field coupling. This may be because the sol-gel glasses are not fully densified.
02A
-5 -4 -3 -2 -1 0 1 2 3 4 5
0
Frequency [GHz]
Fluo
resc
ence
10 sec
30 sec
2 min
5 min
10 min
T=1.7K=578nm800 TEOS
-5 -4 -3 -2 -1 0 1 2 3 4 5
0
Frequency [GHz]
Fluo
resc
ence
10 sec
30 sec
2 min
5 min
10 min
T=1.7K=578nm800 TEOS
Transient and persistent spectral hole burning in Eu3+ -doped sol-gel produced SiO2 glass
D. M. Boye1, T. S. Valdes1, J. H. Nolen1 , A.J. Silversmith2, K.S. Brewer2, R. E. Anderman2 and R. S. Meltzer3
1Davidson College, Davidson, NC 28036 USA2 Hamilton College, Clinton, NY 13323 USA3University of Georgia, Athens, GA 30602 USA
Transient and persistent spectral hole burning (TSHB and PSHB) experiments were performed on Eu3+ ions in sol-gel SiO2 glasses with aluminum co-doping. Differences in the hole burning behavior were observed among samples made from two organosilicate precursors that were annealed to a series of final temperatures. All glasses exhibited persistent spectral holes when annealed to 800C but, as the annealing temperature was raised to 1000C, an increasing number of Eu3+ ions exhibited TSHB with a corresponding decrease in the number showing PSHB behavior. This is consistent with a reduction in metastable configurations with an increased final annealing temperature. The TSHB behavior is similar to that observed for Eu3+-doped silicate melt glass.
Abstract
Conclusions
Corresponding author:Dr. Dan BoyePhysics Department Davidson CollegeP.O. Box 7133 Davidson, NC [email protected]
Eu Local Environment
Experiment
Ingredients:Er(NO3)3•6H2OAl(NO3)3•9H2OH2O (deionized)C3H6OHNO3 Tetraethylorthosilicate (TEOS)Titanium n-butoxide (TBOT)
Reaction- Hydrolysis and
condensation- Room temp.- pH 1.5 to 3.5
Gelation- Polymeric gel forms- Supports stress
elastically-”Wet” gel- 2 days, 40°C
Aging- Solvent escapes- Pore contraction- Shrinkage- 2 days, 60°C
Drying- Shrinkage- Cracking- Densification- Pore collapse- 2 days, 90°C
Experiment
Ingredients:Er(NO3)3•6H2OAl(NO3)3•9H2OH2O (deionized)C3H6OHNO3 Tetraethylorthosilicate (TEOS)Titanium n-butoxide (TBOT)
Reaction- Hydrolysis and
condensation- Room temp.- pH 1.5 to 3.5
Gelation- Polymeric gel forms- Supports stress
elastically-”Wet” gel- 2 days, 40°C
Aging- Solvent escapes- Pore contraction- Shrinkage- 2 days, 60°C
Drying- Shrinkage- Cracking- Densification- Pore collapse- 2 days, 90°C
Ingredients:Er(NO3)3•6H2OAl(NO3)3•9H2OH2O (deionized)C3H6OHNO3 Tetraethylorthosilicate (TEOS)Titanium n-butoxide (TBOT)
Reaction- Hydrolysis and
condensation- Room temp.- pH 1.5 to 3.5
Gelation- Polymeric gel forms- Supports stress
elastically-”Wet” gel- 2 days, 40°C
Aging- Solvent escapes- Pore contraction- Shrinkage- 2 days, 60°C
Drying- Shrinkage- Cracking- Densification- Pore collapse- 2 days, 90°C
Annealing Process
time (days)
Tem
pera
ture
(o C)
0
200
400
600
800
1000
0 2 4 6 8 10
Annealing Process
time (days)
Tem
pera
ture
(o C)
0
200
400
600
800
1000
0 2 4 6 8 10
Al - network modifier
SiliconOxygen
EuropiumAl - network modifier
SiliconOxygen
Europium
0
500
1000
1500
2000
2500
3000
3500
570 572 574 576 578 580 582
800TEOS 1.5K Feofilov800TEOS 2.2K900TEOS 1.6K900TMOS 1.4K
Excitation Wavelength [nm]
Pers
iste
nt H
ole
Wid
th [M
Hz]
0
500
1000
1500
2000
2500
3000
3500
570 572 574 576 578 580 582
800TEOS 1.5K Feofilov800TEOS 2.2K900TEOS 1.6K900TMOS 1.4K
Excitation Wavelength [nm]
Pers
iste
nt H
ole
Wid
th [M
Hz]
Transient and Persistent Holes
Persistent Hole Behavior
Experimental Setup
Argon Laser
PMT
Dye LaserCryostat with sample @ 77K
Monochromator
Ammeter
OscilloscopeComputer withLabview software
WaveformSynthesizer
Experimental Setup
Argon Laser
PMT
Dye LaserCryostat with sample @ 77K
Monochromator
Ammeter
OscilloscopeComputer withLabview software
WaveformSynthesizer
TEOS
TMOS
TEM Images for TEOS and TMOS sol-gel precursors All samples annealed to 900°C
TEOS
TMOS
TEM Images for TEOS and TMOS sol-gel precursors All samples annealed to 900°C
TEM Images for TEOS and TMOS sol-gel precursors All samples annealed to 900°C
Type of hole burning depends strongly on the final annealing temperature and weakly on the organosilicate precursor.
TEOS TMOSTann
800°C PSHB only P and T SHB
900°C P and T SHB P and T SHB
1000°C P and T SHB TSHB only
TEOS TMOSTann
800°C PSHB only P and T SHB
900°C P and T SHB P and T SHB
1000°C P and T SHB TSHB only
•As Tann is raised, the glass becomes denser.
•There is less likelihood of photo-induced rearrangement.
-2 -1 0 1 2
Frequency [GHz]
Fluo
resc
ence
Transient Holes
Persistent Holes
800 TMOS
900 TEOS
75MHz
80MHz
290MHz
540MHz
T = 1.65K=578nm
-2 -1 0 1 2
Frequency [GHz]
Fluo
resc
ence
Transient Holes
Persistent Holes
800 TMOS
900 TEOS
75MHz
80MHz
290MHz
540MHz
T = 1.65K=578nm
The average pore size in the TMOS samples is smaller and there is a narrower range of sizes than in the TEOS samples.
Constant fluence experiments show PSHB is 1-photon process.
Proposed mechanisms for PSHB:
Photo-induced rearrangement of local environment
x Photoionization of Eu3+
x Photo-reduction of Eu3+ to Eu2+
Hole burning time dependence
05
101520253035
0 200 400 600 800 1000
0
5
1 0
1 5
2 0
2 5
3 0
3 5
0 2 4 6 8 1 0 1 2
Delay Time [ms]
% H
ole
Dep
th
Delay Time [s]
% H
ole
Dep
th
Hole recovery time dependence
05
101520253035
0 200 400 600 800 1000
0
5
1 0
1 5
2 0
2 5
3 0
3 5
0 2 4 6 8 1 0 1 2
Delay Time [ms]
% H
ole
Dep
th
Delay Time [s]
% H
ole
Dep
th
Hole recovery time dependence
0
0.25
0.5
0.75
1
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
Time [s]
b
a
0.62e-2.5t
0.38e-24t
a) Fluorescence level decreases in time as the hole is burned. The long tail is fit to an exponential with a time constant of 2.5s-1.
b) The fast component has a time constant 10x faster.
Fluo
resc
ence
0
0.25
0.5
0.75
1
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
Time [s]
b
a
0.62e-2.5t
0.38e-24t
a) Fluorescence level decreases in time as the hole is burned. The long tail is fit to an exponential with a time constant of 2.5s-1.
b) The fast component has a time constant 10x faster.
Fluo
resc
ence
ReferencesS.P. Feofilov, K.S. Hong, R.S. Meltzer, W. Jia and H. Liu, Phys. Rev. B60, 9406 (1999).
T.T.Schmidt, R.M. Macfarlane, and S. Volker, Phys. Rev. B50, 15707 (1994).
AcknowledgementsAJS and DMB thank the NSF for a Research Opportunity Award associated with NSF DMR 9871864.
Thanks to H.Y. Fang, currently of Sandia National Laboratories, for performing the TEM and x-ray diffraction work.
565 570 575 580 585 590
5% Al 1000C
Fluo
resc
ence
(arb
. uni
ts)
7F0 5D0 excitation
Transient Hole Behavior
0
20
40
60
80
100
120
140
160
571 573 575 577 579 581
900 TEOS 1.6K
900 TMOS 1.4 K
1000 TMOS 2K
Schmidt et al
75
100
125
150
175
200
0
20
40
60
80
100
120
140
160
571 573 575 577 579 581
900 TEOS 1.6K
900 TMOS 1.4 K
1000 TMOS 2K
Schmidt et al
75
100
125
150
175
200
Excitation Wavelength [nm]
Tra
nsie
nt H
ole
Wid
th [M
Hz]
Ant
ihol
e po
sitio
n [M
Hz]
Both hole burning and recovery rates indicate:• Fast component – affects 1/3 of ions in first 100ms.• Slow component - ~10 times slower than fast component.
• Transient hole burning observed on Eu 3+ sol-gel produced glass for first time.
• TSHB mechanism: redistribution of electron population among hyperfine levels.
• Combination of PSHB and TSHB observed with the proportion of the two being strongly dependent on the final annealing temperature.
• PSHB mechanism: photo-induced rearrangement of local environment. Regions at or near a pore boundary are ripe for metastable configurations having a range of barrier energies.
Persistent Hole Profiles
Transient and Persistent Hole Profiles
