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Absorption intensity analysis of Pr3+: Y3Al5O12
Solid State Communications, Printed in Great Britain.
ABSORPTION
Vol.
74,
No.
1,
INTENSITY
pp.
17-20,
ANALYSIS
1990.
OF
00x3-1098/90$3.00+.00 Pergamon Press
plc
Pr3+: Y3A15012
M.Malinowski, R.Wolski and W.Woliieki Institute of Microelectronics and Optoelectronics ul. Koszykora 75, (Received19 The
intensity
00-662 Warsaw,
Poland
December 1989 by M.Balkanski) studies
of
the
optical
absorption
spectra of Pr3+ ions in Y3A15012 crystal are presented. Oscillator
strengths
of
f-f
Pr3+ transitions,
radiative lifetimes, fluorescence branching ratios, and Ot
intensity parameters
have been
calculated
and the
obtained results are compared witch the data reported for other host materials.
I .T.M.E. the Czochraleki method at room laboratory in Warsaw. The temperature abeorption epectrum, over 13 mm optical path length in the crystal, wa6 recorded by a Beckman WV 5270 spectrophotometer. Hmieeion epectra to the experimental leading the branching ratio0 determonation of ion laser argon were recorded under excitation at X - 488 run. The room temperature abeorption epectrum of the Pr3+: YAG have been agalyeed using the treatment of Judd and 0felt.7 of the etatic In this model coupling between the radiation field and the electronic charge dietribution of ligands, the oecillator etrength f of the electric dipole f-f traneltion of RE3+ is expreesed aa a eum of phenomenological inteneity parametere Rt and reduced matrix 8 lemente of tensor operators Ut of a rank t of the form
Trivalent rare earth lone (RE3+l doped yttrium aluminum garnet, Y3A15012 (YAG) have been exteneively studied during the last decade. Because Nd3+: YAG ie the meet ;uccesful solid &ate it attracted moet laser material attention and much lees ie known about f luoreecence of other RE3+ ions in thie cryetal. The optical spectrum of 2Pr3+: YAG hae been studied since 1963 but only recently a good deal of physical and spectroscopic data of thie magef;ijl are reported in the literature ’ ’ . However, to our knowledge, there has never been a complete of the analysis absorption line intensity of Pr3+: YAG, although eimllar calculations baeed on Judd-Ofelt approach 6D7 been have reporte; gf;t; praaeodymlum In other ho&e. ’ ’ In this study. we have presented calculations absorption inteneity leading to determination of the ot parameter8 that occur in the Judd-Ofelt radiative theory, the excited etate lifetime6 and branching ratios. We found also Interesting to compare our concerning other reeul:e Pr thoae with containing hoets with relation to the structure and point different crystal RH3+ ion. Thie ie ale0 symaetry of 1aser important because of potential applications of Pr3+: YAG cry&ale. crystal of A good quality single Y3A15012: 0.12 at.% Pr3+ was obtained by
f(aJ,bJ’l
8B2mcX - 3(2J+l)h
&1<4f”[dSL]JI t
1 x ’
lUtl 14fn[d’S’L’lJ’>12
(1)
where 5 is the average wavelength of the local field transition and I! ie the correction which for electric dipole transitions ie approximated by (n(h) 2t2) 2/9n(S1 . The spontaneoue emieeion probabilitiee A 17
18
ABSORPTION INTENSITY ANALYSIS OF Pr3+: Y3A150,2
in terms of above oscillator are calculated from
A(aJ,bJ’l
-
gl12Xe2n2
-zX-
f (aJ,bJ’l
strengths
(21
Since the details of this theory, its been precision and draw ;a,ckfo have analysed elsewhere * ’ we have presented here only essential the formulas. Because the 41 wave functions, due to the shielding by the outlying 5s and SP shells, retain much of their free ion character the
Table 1. Measured strengths
and for
calculated Pr
manif old
osci 1 lator
: YAQ
x
SLJ
Vol. 74, No. 1
f
f talc
exp
x 106
tnml
x 106 A
27.56
8.28
470
15.58
12.85
13.6
488
6.83
8.79
9.08
600
6.35
2.46
2.30
1030
0.50
0.69
0.58
1400
5.68
7.81
6.79
1500
14.91
14.88
13.72
1850
5.63
6.45
6.51
2315
1.
A: RMS dev-7.7 10-20cm2,
10
10B6
Q6-9.20
B: RMS dev-2.4
-20,,2
B
452
1.36 R2-0.
Q4-
11.78
“4’
12.20
10-20cm2
10e6
n2-0.
, R6-8. 27 10-20cm2
with the measured fluorescence lifetimes which are; xf - 8.8 CIS for 3Pl, 7f - 8.4 ps for
3Po and ~~ -
180 vs for
‘D2 state
In 1% Pr3+: YAG at 300 K. The nonradiative transition probabilities to the next lower lying levelT4are governed by the energy gap law, euggeeting thus more eff lclent nonradiative deexcltation in the case of YAG then LiYP4 crystal. This is probabely also the main reason of the great differences in the observed fluorescence lifetimes in thie two materials. Room temperature emission of Pr3+ ions in YAG , after c.w. 1aser argon excitation at X - 488 nm, is dominated by the very strong fluorescence from the state to the sound 3H4 lD2 excited state. The 3Po emission line intensities were too weak to perform precise measurementa. The experimental values of branching ratios for transitions from the excited ‘D2 state are presented in Table 2 together with the calculated values. observed that It could be
Vol. lh, No. 1
ABSORPTION INTENSITY ANALYSIS OF Pr3+: Y3A150,*
Table
2.
Calculated the
3P1,
ratios Final
radiative
transition
3P0 and ‘D2
P for
the
levels
probabilities
and calculated
Initial
etate
k [nml
3po
A[s%
17689
branching
state lD2
X[nml 0
X[nml
A[& _
-
Ah-‘1 _
P
talc
P
exp
-
2371
0
2739
0
-
lG4
904
1372
953
2373
1470
357
0.07
-
3P4
714
1336
745
14454
1023
146
0.03
0.02
3P3
689
10235
718
0
972
177
0.03
0.03
3P2
632
0
656
0
862
1232
0.24
0.15
3H6
611
6314
633
11709
823
1212
0.24
0.30
Rs
540
37790
557
0
700
62
0.01
0.05
3R4
485
26578
499
610
1854
0.37
0.45
parameter6
Qt
Us
69086 ZR- 10.2
[1O-2o
cm21
laser
crystals.
Pr3+
Material
of
Nd3+
‘2
‘4
‘6
‘2
‘4
‘6
YAL03 ”
2
6
7
1.3
4.7
5.9
LaP3 I3
0.12
1.77
4.78
0.35
2.57
2.5
4.88
8.55
5.25
2.9
8.07
7.32
1.9
2.7
5
12.20
8.27
0.
2.7
5
17.2
LiYF4B ’ ’ O0 YAG ’
YAG for
D2
some Pr3+ and Nd3+ doped
l3
Pr3+:
and measured
3P0
ZR- 11.9
‘2’3
A of
‘D2 emission.
3Pl
Table 3. Intensity
19
0 this
19.8
work
agreement between theory and experiment Thie could be explained in is poor. selective terms of the observed, under laser excitation, multieite luminescence from regular and perturbed Pr3+ ions characterised the different by transition probabilities. compares Table 3. parameters Gt
pe
TR- 198 ps
determined for several Pr3+ and Nd3+ laser hosts. As in the case of Nd3+ ion, the R4 and R6 in LiYP4 and YAG doped
have also similar values for Pr3+. The discrepancies observed for R2 in Nd3+ doped crystals are probabely due to different site synnnetry of Re3+ ion which is S4 in LiYP4 and D2 in YAG. In comparing the fit of Pr3+: YAG with those of other hosts it is seen that Q4 has relatively large value when R6 parameter ia in agreement with this of YA103, concentrated LiYP4 and praseodymium phosphates.” In conclusion, based on the absorption intensity analysis, we have pgsented several spectroscopic data on Pr : YAG. Thie can be useful in further studies of this interesting earth doped rare crystal which could be also an efficient laser material. We wish to thank Dr 2. Frukacz, ITME growing the crystal of Warsaw, for YAG:Pr3+. This work wa8 supported by the CPBR 8.14 program.
20
ABSORPTION INTENSITY ANALYSIS OF Pr3+: Y3A150,2
Vol. 74, No. 1
R8f@rMiCOB.
Danielmsysr in "Laser@" ed. Levine and A.J. DeMaria (Marcel Dekker, Inc. N.Y. and Baael 1976)
1. H.G. A.K.
P.1
2. E.Y. O.M.Stafsudd and Wow. D.R.Johnston. J.Chem.Phye. 39, 786 (1963). 3. E.Antic-Fidancev, M.Lemaitre-Blalee and P.Caro, Inorg.Chim. Acts 139, 281 (1987). 4 O.L.Malta, E.Antlc-Fidancev, M.Lemaitre-Blaiae, J.Dexpert-Ghye Chem.Phys.Lett. and B.Pirlou, 183, 557 (1986). 5. J.B.Gruber, M.E.Hills, R.M.Macfarlane C.A.Morrison and G.A.Turner, Chem.Phys. 139, 24 (1989). 6. B.R.Judd, Phys.Rev. 187, 750 (1962). 7. G.S.Ofelt, J.Chem.Phys. 37, 511 (1962) 8. C.A.Morrieon and R.P.Leavitt in "Handbook on the Physic6 and Chemistry of Rare Earth" vol 5.
ed. K.A.Gschneidner Jr and L,!Eyring (North-HollandPubl.Co 1982) e.461 9. M.Malinowski, R.Wolski and W.Wolifiski J.Lumln.35, 1 (1986). 10. J.L.Adam, W.A.Sibley, and D.R.Gabbe, J.Lumin.33, 391 (1985). 11. M.J.Weber, J.Chem.Phys. 48, 4774 (1968). 12. M.J.Wsber, T.E.Varltlmos and B.H. Matsinger, Phy8.Rev.B 9, 47 (1973). 13. W.F.Krupke, Phys.REv, 145, 325 (1966). Laser 14. H.P.Jenssen, "Phonon Assisted Transitions and Energy Transfer in RE Laser Cry&ale" Crystal Physics Lab. Tech.Rep. No 16, MIT, Cambridge, Mass. 1971 15. M.Mallnowskl, Proc. 1st Int.SymP. on Rare Earth Spectroscopy, WrocZaw. ed. B.Je*owska-Trzebiatowska, J.Legendziewicz and W.Str?k (World Scientific Publ.Co Singapore 1985) P.348
ABSORPTION
Vol.
74,
No.
1,
INTENSITY
pp.
17-20,
ANALYSIS
1990.
OF
00x3-1098/90$3.00+.00 Pergamon Press
plc
Pr3+: Y3A15012
M.Malinowski, R.Wolski and W.Woliieki Institute of Microelectronics and Optoelectronics ul. Koszykora 75, (Received19 The
intensity
00-662 Warsaw,
Poland
December 1989 by M.Balkanski) studies
of
the
optical
absorption
spectra of Pr3+ ions in Y3A15012 crystal are presented. Oscillator
strengths
of
f-f
Pr3+ transitions,
radiative lifetimes, fluorescence branching ratios, and Ot
intensity parameters
have been
calculated
and the
obtained results are compared witch the data reported for other host materials.
I .T.M.E. the Czochraleki method at room laboratory in Warsaw. The temperature abeorption epectrum, over 13 mm optical path length in the crystal, wa6 recorded by a Beckman WV 5270 spectrophotometer. Hmieeion epectra to the experimental leading the branching ratio0 determonation of ion laser argon were recorded under excitation at X - 488 run. The room temperature abeorption epectrum of the Pr3+: YAG have been agalyeed using the treatment of Judd and 0felt.7 of the etatic In this model coupling between the radiation field and the electronic charge dietribution of ligands, the oecillator etrength f of the electric dipole f-f traneltion of RE3+ is expreesed aa a eum of phenomenological inteneity parametere Rt and reduced matrix 8 lemente of tensor operators Ut of a rank t of the form
Trivalent rare earth lone (RE3+l doped yttrium aluminum garnet, Y3A15012 (YAG) have been exteneively studied during the last decade. Because Nd3+: YAG ie the meet ;uccesful solid &ate it attracted moet laser material attention and much lees ie known about f luoreecence of other RE3+ ions in thie cryetal. The optical spectrum of 2Pr3+: YAG hae been studied since 1963 but only recently a good deal of physical and spectroscopic data of thie magef;ijl are reported in the literature ’ ’ . However, to our knowledge, there has never been a complete of the analysis absorption line intensity of Pr3+: YAG, although eimllar calculations baeed on Judd-Ofelt approach 6D7 been have reporte; gf;t; praaeodymlum In other ho&e. ’ ’ In this study. we have presented calculations absorption inteneity leading to determination of the ot parameter8 that occur in the Judd-Ofelt radiative theory, the excited etate lifetime6 and branching ratios. We found also Interesting to compare our concerning other reeul:e Pr thoae with containing hoets with relation to the structure and point different crystal RH3+ ion. Thie ie ale0 symaetry of 1aser important because of potential applications of Pr3+: YAG cry&ale. crystal of A good quality single Y3A15012: 0.12 at.% Pr3+ was obtained by
f(aJ,bJ’l
8B2mcX - 3(2J+l)h
&1<4f”[dSL]JI t
1 x ’
lUtl 14fn[d’S’L’lJ’>12
(1)
where 5 is the average wavelength of the local field transition and I! ie the correction which for electric dipole transitions ie approximated by (n(h) 2t2) 2/9n(S1 . The spontaneoue emieeion probabilitiee A 17
18
ABSORPTION INTENSITY ANALYSIS OF Pr3+: Y3A150,2
in terms of above oscillator are calculated from
A(aJ,bJ’l
-
gl12Xe2n2
-zX-
f (aJ,bJ’l
strengths
(21
Since the details of this theory, its been precision and draw ;a,ckfo have analysed elsewhere * ’ we have presented here only essential the formulas. Because the 41 wave functions, due to the shielding by the outlying 5s and SP shells, retain much of their free ion character the
Table 1. Measured strengths
and for
calculated Pr
manif old
osci 1 lator
: YAQ
x
SLJ
Vol. 74, No. 1
f
f talc
exp
x 106
tnml
x 106 A
27.56
8.28
470
15.58
12.85
13.6
488
6.83
8.79
9.08
600
6.35
2.46
2.30
1030
0.50
0.69
0.58
1400
5.68
7.81
6.79
1500
14.91
14.88
13.72
1850
5.63
6.45
6.51
2315
1.
A: RMS dev-7.7 10-20cm2,
10
10B6
Q6-9.20
B: RMS dev-2.4
-20,,2
B
452
1.36 R2-0.
Q4-
11.78
“4’
12.20
10-20cm2
10e6
n2-0.
, R6-8. 27 10-20cm2
with the measured fluorescence lifetimes which are; xf - 8.8 CIS for 3Pl, 7f - 8.4 ps for
3Po and ~~ -
180 vs for
‘D2 state
In 1% Pr3+: YAG at 300 K. The nonradiative transition probabilities to the next lower lying levelT4are governed by the energy gap law, euggeeting thus more eff lclent nonradiative deexcltation in the case of YAG then LiYP4 crystal. This is probabely also the main reason of the great differences in the observed fluorescence lifetimes in thie two materials. Room temperature emission of Pr3+ ions in YAG , after c.w. 1aser argon excitation at X - 488 nm, is dominated by the very strong fluorescence from the state to the sound 3H4 lD2 excited state. The 3Po emission line intensities were too weak to perform precise measurementa. The experimental values of branching ratios for transitions from the excited ‘D2 state are presented in Table 2 together with the calculated values. observed that It could be
Vol. lh, No. 1
ABSORPTION INTENSITY ANALYSIS OF Pr3+: Y3A150,*
Table
2.
Calculated the
3P1,
ratios Final
radiative
transition
3P0 and ‘D2
P for
the
levels
probabilities
and calculated
Initial
etate
k [nml
3po
A[s%
17689
branching
state lD2
X[nml 0
X[nml
A[& _
-
Ah-‘1 _
P
talc
P
exp
-
2371
0
2739
0
-
lG4
904
1372
953
2373
1470
357
0.07
-
3P4
714
1336
745
14454
1023
146
0.03
0.02
3P3
689
10235
718
0
972
177
0.03
0.03
3P2
632
0
656
0
862
1232
0.24
0.15
3H6
611
6314
633
11709
823
1212
0.24
0.30
Rs
540
37790
557
0
700
62
0.01
0.05
3R4
485
26578
499
610
1854
0.37
0.45
parameter6
Qt
Us
69086 ZR- 10.2
[1O-2o
cm21
laser
crystals.
Pr3+
Material
of
Nd3+
‘2
‘4
‘6
‘2
‘4
‘6
YAL03 ”
2
6
7
1.3
4.7
5.9
LaP3 I3
0.12
1.77
4.78
0.35
2.57
2.5
4.88
8.55
5.25
2.9
8.07
7.32
1.9
2.7
5
12.20
8.27
0.
2.7
5
17.2
LiYF4B ’ ’ O0 YAG ’
YAG for
D2
some Pr3+ and Nd3+ doped
l3
Pr3+:
and measured
3P0
ZR- 11.9
‘2’3
A of
‘D2 emission.
3Pl
Table 3. Intensity
19
0 this
19.8
work
agreement between theory and experiment Thie could be explained in is poor. selective terms of the observed, under laser excitation, multieite luminescence from regular and perturbed Pr3+ ions characterised the different by transition probabilities. compares Table 3. parameters Gt
pe
TR- 198 ps
determined for several Pr3+ and Nd3+ laser hosts. As in the case of Nd3+ ion, the R4 and R6 in LiYP4 and YAG doped
have also similar values for Pr3+. The discrepancies observed for R2 in Nd3+ doped crystals are probabely due to different site synnnetry of Re3+ ion which is S4 in LiYP4 and D2 in YAG. In comparing the fit of Pr3+: YAG with those of other hosts it is seen that Q4 has relatively large value when R6 parameter ia in agreement with this of YA103, concentrated LiYP4 and praseodymium phosphates.” In conclusion, based on the absorption intensity analysis, we have pgsented several spectroscopic data on Pr : YAG. Thie can be useful in further studies of this interesting earth doped rare crystal which could be also an efficient laser material. We wish to thank Dr 2. Frukacz, ITME growing the crystal of Warsaw, for YAG:Pr3+. This work wa8 supported by the CPBR 8.14 program.
20
ABSORPTION INTENSITY ANALYSIS OF Pr3+: Y3A150,2
Vol. 74, No. 1
R8f@rMiCOB.
Danielmsysr in "Laser@" ed. Levine and A.J. DeMaria (Marcel Dekker, Inc. N.Y. and Baael 1976)
1. H.G. A.K.
P.1
2. E.Y. O.M.Stafsudd and Wow. D.R.Johnston. J.Chem.Phye. 39, 786 (1963). 3. E.Antic-Fidancev, M.Lemaitre-Blalee and P.Caro, Inorg.Chim. Acts 139, 281 (1987). 4 O.L.Malta, E.Antlc-Fidancev, M.Lemaitre-Blaiae, J.Dexpert-Ghye Chem.Phys.Lett. and B.Pirlou, 183, 557 (1986). 5. J.B.Gruber, M.E.Hills, R.M.Macfarlane C.A.Morrison and G.A.Turner, Chem.Phys. 139, 24 (1989). 6. B.R.Judd, Phys.Rev. 187, 750 (1962). 7. G.S.Ofelt, J.Chem.Phys. 37, 511 (1962) 8. C.A.Morrieon and R.P.Leavitt in "Handbook on the Physic6 and Chemistry of Rare Earth" vol 5.
ed. K.A.Gschneidner Jr and L,!Eyring (North-HollandPubl.Co 1982) e.461 9. M.Malinowski, R.Wolski and W.Wolifiski J.Lumln.35, 1 (1986). 10. J.L.Adam, W.A.Sibley, and D.R.Gabbe, J.Lumin.33, 391 (1985). 11. M.J.Weber, J.Chem.Phys. 48, 4774 (1968). 12. M.J.Wsber, T.E.Varltlmos and B.H. Matsinger, Phy8.Rev.B 9, 47 (1973). 13. W.F.Krupke, Phys.REv, 145, 325 (1966). Laser 14. H.P.Jenssen, "Phonon Assisted Transitions and Energy Transfer in RE Laser Cry&ale" Crystal Physics Lab. Tech.Rep. No 16, MIT, Cambridge, Mass. 1971 15. M.Mallnowskl, Proc. 1st Int.SymP. on Rare Earth Spectroscopy, WrocZaw. ed. B.Je*owska-Trzebiatowska, J.Legendziewicz and W.Str?k (World Scientific Publ.Co Singapore 1985) P.348