variations d’indice de réfraction athermiques dans les
TRANSCRIPT
JNCO - Optique Grenoble 2007
- MIL
JNCO – Optique Grenoble 2007, 3-5 juin 2007
Variations d’indice de réfraction athermiques dans les systèmes laser solides
fortement pompés
R. Moncorgé, J.L. Doualan, P. CamyCentre Interdisciplinaire de Recherches Ions et Lasers (CIRIL-MIL)
UMR 6637 CEA-CNRS-ENSICAEN, Université de Caen, [email protected] ; website: www.ganil.fr/ciril/
O. N. Eremeykin, O. L. AntipovInstitute of Applied Physics of the Russian Academy of science,
46 Ulyanov Street, Nizhny Novgorod 603950, Russia
JNCO - Optique Grenoble 2007
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Contexte
INTAS program 03-4893 (laser systems based on Nd3+, Yb3+
and Cr3+ doped materials)
Inst. Appl. Phys. Nizhny-Novgorod (O.Antipov) Stepanov Inst.(E.Ivakin), Int. Laser Center (N.Kuleshov) MinskGPI Moscow (I.Shcherbakov) Imperial College of London (Damzen)
JNCO - Optique Grenoble 2007
- MIL Réseaux holographiques dynamiquesinduits par laser: réseaux de phase (dispersif)
ou réseaux de gain ?
M1 E2
M2 E4
E1
E4
E3
Nd:YAG
PC-mirror
Flash, Diode Pumping
Self-organized laser systemsbased on strongly pumped rare-earth doped laser materials
Eremeykin, Antipov, Damzen, Opt. Lett. 2004 Sillard, Brignon, Huignard, IEEE J.Q.E.1998
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Catunda et al, Appl. Opt. 1986, Weaver, Payne, Phys. Rev. B 1989 → Cr3+
Powell, Payne et al, Phys. Rev. B + Opt. Lett. 1990 → Nd3+
PexcLR Nf απχ Δ=Δ 22πσλχ 4/,Im gaexcNn Δ=ΔPhase contributionAbs/Gain contribution
excN number of excited active ions
322 +
=nfL
Lorentz local correction factor
PαΔ polarizabilityvariationga,σΔ Abs./Gain
cross-section
Réseaux holographiques dynamiquesinduits par laser: réseaux de phase (dispersif)
ou réseaux de gain ?
JNCO - Optique Grenoble 2007
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Passilly et al, JOSA B 2004 + Opt. Com. 2006 → Cr3+
Margerie, Moncorgé, Phys. Rev. B 2006 → Nd3+
PexcLR Nf απχ Δ=Δ 22πσλχ 4/,Im gaexcNn Δ=ΔPhase contributionAbs/Gain contribution
excN number of excited active ions
322 +
=nfL
Lorentz local correction factor
PαΔ polarizabilityvariationga,σΔ Abs./Gain
cross-section
Réseaux holographiques dynamiquesinduits par laser: réseaux de phase (dispersif)
ou réseaux de gain ?
JNCO - Optique Grenoble 2007
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Large non-thermal refraction index
variations (Δn>10-6)
observed in Nd3+:YAG underdiode and flash pumping
Antipov et alIEEE J. Q.E. 39 (2003)
JNCO - Optique Grenoble 2007
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Refraction index variationsdue to
populations of metastablelevels
4F3/2, 2P3/2, 4D3/2, 2F(2)5/2
5d
4f
E cm-1
26000 2P3/2
4F3/2
4I11/2 4I9/2
2F(2)5/2
0
2100
11500 12500
4D3/2
4G7/2 19000
28000
38000
54000
59000
62500
52000
70000
61000
43000
68000
46000
4F5/2 2H9/2
4G11/2 4G9/2
Laser1.06µm
Flashpump
Diode808nm
)2(2 F
2F(2)5/2
4f25d
4f3but
Case of Nd:YAG
JNCO - Optique Grenoble 2007
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5d
4f
E cm-1
26000 2P3/2
4F3/2
4I11/2 4I9/2
2F(2)5/2
0
2100
11500 12500
4D3/2
4G7/2 19000
28000
38000
54000
59000
62500
52000
70000
61000
43000
68000
46000
4F5/2 2H9/2
4G11/2 4G9/2
)2(2 F
2F(2)5/2
Refractive index changes Δnof purely dispersive origin
associated withvariations of polarizabilities Δαp
of the ions in theirground- and excited energy levels
due to the existence of strong
(electric-dipole allowed)4f3 ↔ 4f25d
absorption bands
Case of Nd:YAG
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Outline
Result of theoretical and experimental study in the case of Nd3+:YAG and Comparison with interferometric and 4-wave mixing
Contribution of Ligand to Metal Charge Transfer (LMCT) in the case of Yb3+:YAG
Study of other Yb3+ doped laser crystals: GGG, KGW, KYW, YVO4
Summary and conclusion
JNCO - Optique Grenoble 2007
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)()()( ννν gex nnn −=Δ
exLP N
nf
n )(2
)( 2
νπ
να Δ=Δ
Changes of refractive index Δn and polarizability Δαp associated with 4f3 →4f25d
absorption bands
5d
4f
E cm-1
26000 2P3/2
4F3/2
4I11/2 4I9/2
2F(2)5/2
0
2100
11500 12500
4D3/2
4G7/2 19000
28000
38000
54000
59000
62500
52000
70000
61000
43000
68000
46000
4F5/2 2H9/2
4G11/2 4G9/2
)2(2 F
2F(2)5/2
4f25d
4f3
( )∫∞
−
−=Δ
0 222 ''
)'()'(2
)( ννν
νσνσπ
ν dPNn gesaex
( ) 2
',,
22
'0
2
' 32 '9
22')'(ifpidfii
pii D
nn
chd ΨΨ
+=∫ ν
επννσ
Margerie, Moncorgé, Phys. Rev. B74 (2006)
Clausius-Mosotti
JNCO - Optique Grenoble 2007
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0 5000 10000 15000 20000 25000 300000,0
5,0x10-5
1,0x10-4
1,5x10-4
2,0x10-4
Δn(4I9/2)Δn(4F3/2)
Laser wavelength of 1.064 µm
Δn (4F3/2-4I9/2)
Δn
Wavenumber (cm-1)
Nex=1020cm-3
exNxnmn 25107.1)1064( −≈Δ
0 20000 40000 60000 80000 100000 120000 140000
-1,0x10-3
-5,0x10-4
0,0
5,0x10-4
1,0x10-3
Δn(4I9/2)
Δn(4F3/2)
Δn (4F3/2-4I9/2)
Δn
Wavenumber (cm-1)
Nex=1020cm-3
Refractive index changesdue to population of metastable 4F3/2
(Δα4F-4I (1064 nm) ≈ 1.6 x 10-26 cm3)Margerie, Moncorgé, Phys. Rev. B74 (2006)
JNCO - Optique Grenoble 2007
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exPL Nfn
n )2( 2 απΔ=Δ
Comparison with literature data
Antipov: IEEE J. QE 39 (2003)910; Powell: Opt. Lett. 14 (1989)1204
Δα4F-4I (514 nm) ≈ 2.5 x 10-26 cm3Powell 1989: 4-waves mixing at 514nm
Δα4F-4I (514 nm) ≈ 4.9 x 10-26 cm3
Δα4F-4I (633 nm) ≈ 2.0 x 10-26 cm3
Δα4F-4I (1064 nm) ≈ 1.6 x 10-26 cm3
Δα2F(2)-4I (633 nm) ≈ 10-25 cm3
Antipov 2003: Pump-probe transientinterferometry (pump at 808 nm, probe at633 nm)
Δα4F-4I (633 nm) ≈ 4.0 x 10-26 cm3
Estimation at 1064 nm:
Δα4F-4I (1064 nm) ≈ 3.3 x 10-26 cm3
Δα2F(2)-4I (633 nm) ≈ 1.5 x 10-25 cm3
(modified according to our own data)
Results ofcalculations
Experimental dataand estimates
JNCO - Optique Grenoble 2007
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exPL Nfn
n )2( 2 απΔ=Δ
Comparison with literature data
Δα4F-4I (514 nm) ≈ 2.5 x 10-26 cm2Powell 1989: 4-waves mixing at 514nm
Δα4F-4I (514 nm) ≈ 4.9 x 10-26 cm2
Δα4F-4I (633 nm) ≈ 2.0 x 10-26 cm2
Δα4F-4I (1064 nm) ≈ 1.6 x 10-26 cm2
Δα2F(2)-4I (633 nm) ≈ 10-25 cm2
Antipov 2003: Pump-probe transientinterferometry (pump at 808 nm, probe at633 nm)
Δα4F-4I (633 nm) ≈ 4.0 x 10-26 cm2
Estimation at 1064 nm:
Δα4F-4I (1064 nm) ≈ 3.3 x 10-26 cm2
Δα2F(2)-4I (633 nm) ≈ 1.5 x 10-25 cm2
Results ofcalculations
Experimental dataand estimates
Calculated values a factor 2 smaller ?
JNCO - Optique Grenoble 2007
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exPL Nfn
n )2( 2 απΔ=Δ
Comparison with literature data
Δα4F-4I (514 nm) ≈ 2.5 x 10-26 cm2Powell 1989: 4-waves mixing at 514nm
Δα4F-4I (514 nm) ≈ 4.9 x 10-26 cm2
Δα4F-4I (633 nm) ≈ 2.0 x 10-26 cm2
Δα4F-4I (1064 nm) ≈ 1.6 x 10-26 cm2
Δα2F(2)-4I (633 nm) ≈ 10-25 cm2
Antipov 2003: Pump-probe transientinterferometry (pump at 808 nm, probe at633 nm)
Δα4F-4I (633 nm) ≈ 4.0 x 10-26 cm2
Estimation at 1064 nm:
Δα4F-4I (1064 nm) ≈ 3.3 x 10-26 cm2
Δα2F(2)-4I (633 nm) ≈ 1.5 x 10-25 cm2
Results ofcalculations
Experimental dataand estimates
Additional contribution: Charge Transfer (CT) ?
JNCO - Optique Grenoble 2007
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Position (Jorgensen)
)]()(.[30000 32 +− −≈ NdOE LMCTgsa χχ
2.3)( 2 ≈−Oχ 2.1)( 3 ≈+Ndχ
)167(60000 1 nmcmE LMCTgsa
−≈
Reorganisationof electronic cloud around
excited ion
Ligand → Metal Charge Transfer (LMCT) O2-→Nd3+ in Nd:YAG
5d
4f
E cm-1
26000 2P3/2
4F3/2
4I11/2 4I9/2
2F(2)5/2
0
2100
11500 12500
4D3/2
4G7/2 19000
28000
38000
54000
59000
62500
52000
70000
61000
43000
68000
46000
4F5/2 2H9/2
4G11/2 4G9/2
)2(2 F
2F(2)5/2
4f3
4f25d
CT
JNCO - Optique Grenoble 2007
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Outline
Result of theoretical and experimental study in the case of Nd3+:YAG and Comparison with interferometric and 4-wave mixing
Contribution of Ligand to Metal Charge Transfer (LMCT) in the case of Yb3+:YAG
Study of other Yb3+ doped laser crystals: GGG, KGW, KYW, YVO4
Summary and conclusion
JNCO - Optique Grenoble 2007
- MIL Case of Yb:YAG: large refractive index variation under 940 nm diode pumping !
Antipov et al, Opt. Lett. 31 (2006)
0 2 4 6 8 10 12 140.00
0.01
0.02
0.03
0.04
0.05
10%Yb:YAG
1.2 ms 51 ms
time (ms)
inte
nsity
(arb
. uni
t)
ΔαPinterf = (1.9±0.8)x10-26 cm3
at 632.8 nm
Δn ≈ 3.2 to 4.4 x10-6
for a pump fluence of∼ 200mJ/cm2
JNCO - Optique Grenoble 2007
- MIL Ligand → Metal Charge Transfer (LMCT) O2-→Yb3+
LMCT at 10K in YAG:Yb (Van Pieterson J. Lumin. 2000)
émission
excitation)210(47600(max) 1 nmcmE LMCT
gsa−≈
(photo LULI)
JNCO - Optique Grenoble 2007
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5d
4f
E cm-1
2F(2)5/2
0
565
10902
4F7/2612785
1062410327
50000
E(cm-1)
CT
Diode940 nm
laser
5d
Position (Jorgensen)
)]()(.[30000 32 +− −≈ YbOE LMCTgsa χχ
2.3)( 2 ≈−Oχ 62.1)( 3 ≈+Ybχ
)211(47400 1 nmcmE LMCTgsa
−≈
Ligand → Metal Charge Transfer (LMCT) O2-→Yb3+
JNCO - Optique Grenoble 2007
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[ ] [ ]⎥⎦⎤
⎢⎣
⎡−
−−Δ−
=Δ −2222
15
()(101.7)(
υυυυυυα
CT
g
CT
exspectP
ffx
exPL Nfn
n απΔ=Δ 22
147600 −≈ cmCTυ
Energy (cm-1)
50
40
30
20
10
0 2F7/2
2F5/2
CT
210 nm(47600 cm-1)
260 nm ?(38460 cm-1)
110250 −≈Δ cmυ
?, exg ff
JNCO - Optique Grenoble 2007
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5d
4f
E cm-1
2F(2)5/2
0
565
10902
4F7/2612785
1062410327
47500
E(cm-1)
CT
Diode940 nm
laser
1)1025047600( −−≈ cmE LMCTesa
)268( nm
Estimated position
200 250 300 350 4000.0
0.4
0.8
1.2
1.6
Time Delay: 3 μs 220 μs 620 μs
5%Yb:YAG
Wavelength (nm)
Ln(I u/I
p)
Measured ESA spectrum
σesa(265 nm) ≈ 1.1 x 10-18 cm2
ESA
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001.001.0)(1013.12
19
±≈≈ ∫ λλσλ
dxf esaex
Variations de polarisabilité et variations d’indice dues à la bande LMCT ?
approximation: exg ff ≈
326104.2)633( cmxnmspectP
−≈Δα
326102)1030( cmxnmP−≈Δα 6107.2)1030( −≈Δ xnmn
for a pump fluence of ∼200mJ/cm2
326int 10)8.09.1()633( cmxnmerfP
−±≈Δα
JNCO - Optique Grenoble 2007
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Outline
Result of theoretical and experimental study in the case of Nd3+:YAG and Comparison with interferometric and 4-wave mixing
Contribution of Ligand to Metal Charge Transfer (LMCT) in the case of Yb3+:YAG
Study of other Yb3+ doped laser crystals: GGG, KGW, KYW, YVO4
Summary and conclusion
JNCO - Optique Grenoble 2007
- MIL Study of other Yb3+ doped laser crystals:GGG, KGW, KYW and YVO4
0 1 2 3 4 50
5
10
15
10 ms
10%Yb:KGW
380 µs
Inte
nsity
(arb
. uni
t)
Time (ms)
0.0 0.2 0.4 0.6 0.8 1.00
10
20
30
40
50
60
2%Yb:YVO4
288/2=144 µs
Inte
nsity
(arb
. uni
t)
Time (ms)
Ivakin et al, Appl. Phys.B 86 (2007)
Δn ≈ 3 to 4 x 10-6
Δn ≈ 2 to 5 x 10-6
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200 250 300 350 4000
1
2
3
4
ESA x 5
GSA
Yb3+:GGG
Opt
ical
den
sity
, ln(
I u/Ip)
Wavelength (nm)
ESA spectra of Yb3+:GGG and Yb3+:KGW
275 300 325 350 375 4000.0
0.5
1.0
1.5
ESA
GSA
10%Yb:KGW
Opt
ical
den
sity
, Ln(
I u/Ip)
Wavelength (nm)
JNCO - Optique Grenoble 2007
- MIL CT absorption band in Yb3+:KGW
1410502/72
−≈+= cmesaCT F υυυ
5d
4f
E cm-1
2F(2)5/2
0
565
10902
4F7/2612785
1062410327
41000
E(cm-1)
CT
Diode940 nm
laser
30750 cm-1
(325 nm)
40000 35000 30000 25000
0.0
0.5
1.0
1.5
245 nm
CTabsorption
GSAYb:KGW
Opt
ical
den
sity
, ln(
I uI p)Wavenumbers (cm-1)
+−+ → 65
22
34 , dpf WOYb between mixed
orbitals
JNCO - Optique Grenoble 2007
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1410502/72
−≈+= cmesaCT F υυυ
5d
4f
E cm-1
2F(2)5/2
0
565
10902
4F7/2612785
1062410327
41000
E(cm-1)
CT
Diode940 nm
laser
30750 cm-1
(325 nm)
40000 35000 30000 25000
0.0
0.5
1.0
1.5
245 nm
CTabsorption
GSAYb:KGW
Opt
ical
den
sity
, ln(
I uI p)Wavenumbers (cm-1)
002.0023.0)(1013.12
19
±≈≈ ∫ λλσλ
dxf esaex
Polarizability variation in Yb3+:KGW
JNCO - Optique Grenoble 2007
- MIL Polarizability variation in Yb3+:KGW
[ ] [ ]⎥⎦⎤
⎢⎣
⎡−
−−Δ−
=Δ −2222
15
()(101.7)(
υυυυυυα
CT
g
CT
exspectP
ffx
141050 −≈ cmCTυ
Energy (cm-1)
50
40
30
20
10
0 2F7/2
2F5/2
CT
245 nm(41050 cm-1)
325 nm (30750 cm-1)
110250 −≈Δ cmυ
325102.1)633( cmxnmspectP
−≈Δα
five times larger than in Yb:YAG
exg ff ≈
Ivakin et al, Appl. Phys.B 86 (2007) → 325.,int 10)633( cmnmdifferfP
−≈Δα
JNCO - Optique Grenoble 2007
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Conclusion
Réseaux d’indice de différentes origines:- Réseaux d’absorption/gain- Réseaux de phase (bandes fd and CT)
Cas des matériaux dopés Nd3+: contributions fd (+CT); Réseaux absorption/gain dominant mais contribution de réseaux de phase augmentant non-lineairement avec puissance de pompage – suite à population du metastable2F(2)5/2 (ESA + UC) -
Cas des matériaux dopés Yb3+: contributions CT (+ fd); réseau de phase dominant
JNCO - Optique Grenoble 2007
- MIL Phase or absorption/gain grating ?
pump pump
sondesignal
⎥⎦
⎤⎢⎣
⎡Δ
Δ≈=
ΔΔ
=σ
αυπχχβ
nf
RR PL
gainabs
phR22
/Im
8
0.23 (at 1029 nm) β = 1.1
0.15 (940 nm)β = 18
2
Yb:YAG
0.28 (at 1029 nm)β = 5.5
2.7 (at 1064nm)β = 0.16
16 (980 nm)β = 1
5.9 (à 808 nm) β = 1
103.5
Yb:KGWNd:YAG
)10( 326 cmP−Δα
)10( 220 cmabs−Δσ
)10( 219 cmgain−Δσ
JNCO - Optique Grenoble 2007
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Merci pour votre attention
CIRIL – Materials and Laser InstrumentationWebsite: www.ganil.fr/ciril/; see also: http://cmdo.in2p3.fr
Researchers:• A. Braud (Ass. Prof., Univ.)• P. Camy (Ass. Prof. Univ.)• J.L. Doualan (CNRS)•J. Margerie (Prof. Univ.)• R. Moncorgé (Prof. Univ.) • M. Velazquez (CNRS)
PhD students:• L. Bodiou (CEA)• A. Ferrier (DGA)
MS students:• S. Cheffah• M. Edlinger
Engineer and Technician:• A. Benayad• V. Ménard