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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]

•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 28035-7133daboye@davidson.edu

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

•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 28035-7133daboye@davidson.edu

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 28035-7133daboye@davidson.edu

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