Ho3+Ñ÷ Tm3+ TÆXØT Y8ÈcÜR Y3Al5O12 +sÇXNË8ý ]kù°ËÑ ¤VRË
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Y3Al5O12&ñ\ ')aTm3+ü< Ho3+s:r_ YUs$ ìrFg<Æ&h :£¤$í`¦¸ %i. Ho3+_5F5
ï
r0Aü< Tm3+_3F2 ïr0A\¦ #l # UV\"f 0lqÒot ©~½Ó¨8+þAFgõ ÔÉrÒo\"f IR t ~½Ó
¨8 +þAFg`¦'a¹1Ï %i. #l Û¼&7àÔ!3, ~½Óئ Û¼&7àÔ!3 x9 ú"îrçß`¦ 8£¤&ñ # +þAFg~½Óئõ&ñ`¦ ì
r$3 %i. ©~½Ó¨8+þAFg_ âĺ Ho3+H STEPõ&ñ`¦, Tm3+H STEPõ ETUs D¥½+Ë)aõ&ñ`¦
5g {9#Qz¤.
PACS numbers: 78
Keywords: Y3Al5O12, Tm3+, Ho3+, ©~½Ó¨8, +þAFg,\-t ²ú
I. "e Â]Ø
Ho3+s:rÉr #Q ¸^(host) Óüt|9\ '÷&#Q 2 µm Â
ÒH_ YUs$ s(5I7→5I8)\¦ {9ܼ. 2 µm ©Ér eye-safe %ò%iܼРYUs$ 6£x6 x \"f @/éßy ׿כ¹ôÇ
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¨ìr [1]. YUs$ *3iç ´òÖ¦`¦ Z}sl 0A # Ho3+ü<
<
Êa Tm3+\¦ 7£xy]jÐ"f 'ôÇ [2]. Tm3+s:rÉr f¨ Ã
º éß&hs H 780 nm ÂÒH_ 3F4 ïr0A\¦ t 9 ¦ Ø
¦§4 s¸×¼ YUs$_ © #30Aü< {9uôÇ. "f 780 nm s¸×¼ YUs$Ð Tm3+_3F4 ïr0AÐ #l
Ho3+_5I7ïr0AÐ_ \-t ²ú`¦ :x # ´òÖ¦&h 2 µm YUs$\¦ %3`¦ ú e. ÕªQ YUs$ s {9
#
QltH Tm3+, Ho3+¿º 7áxÀÓ_ s:r[þts_ \
-t ²ú, \-t ©~½Ó¨8(upconversion),q~½Ó s 1
p
x 4¤¸úôÇ õ&ñ`¦u>)a. sQôÇ © ñ6 xõ&ñ\
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f µ1ÏÒqt H#Q &³©[þt\ @/ôÇ ½¨H@/© Óüt|9 ^ _
Óüto&h :£¤$í`¦sK > ½+É ÷r ëß m z´6 x0px ô
Ç ¦^ YUs$\¦>hµ1Ï HX<¸ @/éßy ׿כ¹ôÇ {9s.
:r ½¨_ @/© Óüt|9 Y3Al5O12(Yttrium Aluminium Garnet, YAG) &ñÉrYUs$ ¸^ Óüt|9Ð"f ¸ú ·ú94R e
ܼ 9 Õª ׿\"f Nd3+ ')a YAG &ñÉr ¦^ YU
∗E-mail: [email protected]
s
$Ð"f ©6 xo÷&#Q V,o s6 x÷&¦ e. YAG\ '
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aTm3+ü< Ho3+_ \-t ïr0AH f¨Ãº x9 +þAFgÛ¼&7àÔ
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3 ìr$3ܼР·ú ú eܼ 9 sp #Q ½¨[þt\ _K µ1Ï
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ð÷&%3 [3, 4]. YAG:Ho3+:Tm3+_ 2 µm YUs$ :£¤$í
Ér Tyminski 1px [5]\ _ # ½¨÷&%3ܼ 9 Falconieri 1px [6]Ér 780 nms¸×¼ YUs$ *3iç\ _ôÇ Z}Ér\-t ï
r0AÐÂÒ' s÷&H +þAFg_ 1lx§4<Æ&h :£¤$í`¦Ð¦ %i
. ÕªQ YAG:Ho3+:Tm3+&ñ_ UV %ò%i\"f IR %ò
%
it µ1ÏÒqt H Fg#30AôÇ %ò%i_ ©~½Ó¨8 x9 ~½Ó
¨8
(down-conversion) +þAFgBj&m7£§Ér ¸ú ·ú9tt ·ú§¦ e
. :r ½¨\"fH Ho3+ü< Tm3+ ')aYAG &ñ
`
¦ 630 nm\"f 660 nm s_ ÒoèYUs$Ð #l # s
M: µ1ÏÒqt H +þAFg:£¤$í`¦¸ %i.
II. ÷mÇ ]Mö
YAG &ñ\ ')aTm3+ü< Ho3+_ 0lx¸H yy 5.9 mol%ü< 1.5 mol%s. ìrFg<Æ&h 8£¤&ñÉr¸¿º 10 K\"f s
ÀÒ#Q&. #lFg"é¶Ér Nd:YAG `OÛ¼ YUs$_ ]j 2 ¸
o(532 nm)Ð *3iç # %3Ér © Òoè YUs$
\
¦s6 x %i. 6 x)a ÒoèH DCMܼÐ"f © #30AH 630 nm\"f 660 nms 9 `OÛ¼ ;¤Ér 5 nsÅÒlH 10 Hzs -231-
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ªaË> 1. ©~½Ó¨8 ¸+þA, (a) ETU ¸+þA (b) STEP
¸+þA. ÕªaË>\"f ÏãTÉr z´Ér #l Fg\ _ôÇ #l\¦,
H z´Ér ©~½Ó¨8 +þAFg ~½Óئ`¦, ÓütÉr q~½Ó
s\¦ ·p. ÕªaË> (a)_ &hÉr © ñs¢-a õ&ñ`¦
·p.
%
3. Òoè YUs$_ K©¸H 0.002 nm &ñ¸s. r«Ñ
\
{9)a YUs$ cÉr `OÛ¼ \-t 10 mJs%3ܼ 9 ú§4 E$ݼРfâ`¦ 1 mm s ÷&> # r«Ñ\¦ :
xõ > %i. r«Ñ\"f µ1ÏÒqtôÇ +þAFgÉr E$ݼР¸ 75 cm éßÒoo ©u\ Ð?/ éßÒoo ©u_ ئ½¨\ ÂÒÃÌ÷&
#
Q eH PMT\"f 7£x;¤÷&%3. éßÒoo ©u_ {9½¨ x9 Ø
¦½¨_ _þtaÅ@`¦ 200 m \P#Q +þAFgÛ¼&7àÔ!3 K©¸ 570 nm\"f 0.22 nm ÷&> %i. PMT\"f :r ñH 300 MHznt_O ¸z´ÐÛ¼ïáÔ\¦5g (ÉÓ'\ {9§4÷&
#
Q %o x9 l2¤÷&%3.
III. +sÇÊÝ õmÍ ÀXØ8ý
"
f:r\"f /åLôÇ כ %!3 Ho3+ü< (¢¸H) Tm3+s '
)
aYAG &ñ_ +þAFg:£¤$íÉrtFKt #Q |ÃÐ[þt\ _ K
½¨÷&%3. s[þt_ õ\¦ 7áx½+Ë rFg\"f
&
hü@ %ò%is_ #QÖ¼ ïr0A\¦ #l 8¸ ¸¿º ©
~
½Ó¨8 +þAFg:£¤$í`¦?/%3. :r ½¨\"f¸ ©~½Ó
¨8
+þAFg`¦'a¹1Ï %iܼ 9 ©~½Ó¨8Ér Ho3+ü< Tm3+ '
)aÓüt|9\"f +þAFg:£¤$í_ ÅÒכ¹ôÇ &³©e`¦ ·ú ú e.
©~½Ó¨8`¦ [O"î H {9ìøÍ&h ¿º ¸4Sq`¦ ÕªaË> 1\ ³ð r
%i. ÕªaË> 1\"f (a)H ETU(energy transfer upcon- version)õ&ñ`¦ (b)H STEPõ&ñ(sequential two-photon excitation process)`¦·p.
Õ
ªaË>\"f ETU õ&ñÉr#lFg\ _K ÅÒ>(donor) s
:rõ ~ÃÎ>(acceptor) s:rs {©I 0\"f 2 ©IÐ # l
)a. ~ÃÎ> s:rÉrq~½Ó ;sõ&ñ`¦5g ׿çß©I
1 ©I ÷& ÅÒ> s:r_ 2→0 sü< ~ÃÎ> s:r_ 1→3s_ © ñs¢-a(cross relaxation)ܼР~ÃÎ> s:rÉr
#
l©I 3s ÷&#Q #l \-t Ð H 3→0 s\ _ ô
Ç ©~½Ó¨8 +þAFgs µ1ÏÒqtôÇ. s õ&ñ\"f ÅÒ> s:r
Õ
ªaË> 2. (a) Tm3+ü< Ho3+s:r_ \-t ïr0A¸. (b) Ho3+(5F5) ïr0Aü< Tm3+(3F2,3F3) ïr0A ÂÒH`¦ SX@/ôÇ Õ
ªaË>.
É
r +þAFgs èY>(fluorescence quenching))a. ÅÒ> s:r õ
~ÃÎ> s:rÉr ìøÍ×¼r 1lx{9ôÇ 7áxÀÓ_ s:r{9 9כ¹H \O Ü
¼ ¿º s:rs ]XK e#Q 9 {©I\"f_ # l
(0→2) \-tü< © ñs¢-aõ&ñ\"f \-t çßs {9 u
# ôÇ. ÕªaË> 1(b)H STEP õ&ñ\"f #l Fg\ _K s:rs {©I 0\"f 2 ©IÐ #l(ground state absorption, GSA))aÊê q~½Ó s õ&ñ`¦5g s:r[þt s
B>h ©I(intermediate state) 1Ð Ä»t|¨c M: 1lxr\ {9
)a¢¸ ÉrFg\ _K 8 Z}Ér 3 ©IÐ #l(excited state absorption, ESA)÷&¦ 3→0 s\ _ôÇ ©~½Ó¨8 +þ
AFg`¦ ~½ÓئôÇ. ETU õ&ñ\ _ôÇ 3→0 ©~½Ó¨8 +þAFg _ rçß1lxÉr ¸2£§ rçß(rise time)õ yûZ rçß(decay time)ܼРsÀÒ#Qt 9 *3iç ïr0A 1, ׿çßïr0A 2 x9 ~½Óئ ï
r0A 3_ ú"îrçß\ _>rôÇ. STEP õ&ñ\"fH éß{9 s
:rs ¿º Fg\¦ 1lxr\ f¨Ãº # {9#QټР©~½Ó
¨8
+þAFg_ ú"îrçßÉr f]X #l\ _ôÇ 3 ïr0A_ ú"î r
çßõ °ú .
Õ
ªaË> 2H Tm3+ x9 Ho3+_ \-t ïr0A¸s. :r
½¨\"fH Òoè YUs$Ð 630∼660 nm(15150∼15870 cm−1) %ò%i_ Tm3+_3F2 ïr0Aü< Ho3+_ 5F5 ïr0A\¦
#
l %i. ÕªaË> 2(b)\ Tm3+_ 3F2 ïr0Aü< Ho3+_
5F5 ïr0A\¦ ©[jy ?/%3ܼ 9, Ho3+(5F5) ïr0AH 15457∼15744 cm−1 (635.16∼646.96 nm), Tm3+(3F2,
3F3) ïr0AH 14659∼15438 cm−1(647.75∼682.17 nm) #3 0A\ 0Au ¦ e. ÕªaË> 3Ér Ho3+(5F5)ü< Tm3+(3F2)
ï
r0A\¦ yy 636.8 nmü< 648.7 nm YUs$Ð #l %i
`
¦M: ~½Óئ H +þAFgÛ¼&7àÔ!3s. ÕªaË>\"f 750 nm\
"
f 860 nmt ~½Ó¨8 +þAFg ü@\¸ 350 nm\"f 580 nmt #l ©Ð ©s ÂúªÉr ©~½Ó¨8 +þAFg`¦'a
¹
1Ͻ+É Ãº e. A\"f Kt y +þAFg\ @/6£x÷&H sH
³
ð 1\ ³ðr÷&#Q e. Tm3+\¦#l %i`¦M: µ1ÏÒqtôÇ +þA
Õ
ªaË> 3. 10 K\"f 8£¤&ñôÇ YAG:Tm3+:Ho3+_ +þ
AFg ~½Óئ Û¼&7àÔ!3. ÕªaË>(a), (b) x9 (c)\"f 0AH Tm3+_ 3F2 ïr0A (648. 7 nm)\¦ #l %i`¦ M: ~½Óئ Û
¼&7àÔ!3s¦ AH Ho3+_ 5F5 ïr0A (636.8 nm)\¦
#
l %i`¦M: ~½Óئۼ&7àÔ!3s. y xß¼\ K{© H
s\¦ÕªaË>\ ³ðr %i.
³
ð 1. ÕªaË> 2_ ©~½Ó¨8 x9 ~½Ó¨8_ y +þAFg\
@
/6£x÷&H s.
A Tm3+ 1D2→3H6 F Tm3+ 1D2→3H5
B Ho3+ 5G4→5I8 G1 Ho3+ 5F4→5I8
C Ho3+ 5G5→5I8 G2 Ho3+ 5S2→5I8
D Tm3+ 1D2→3H4 J Ho3+ 5S2→3H5
E Tm3+ 1G4→3H6 K Tm3+ 3F4→3H6
F
gÉr Tm3+÷rëß m Ho3++þAFg(G1, G2, J)¸ í<Ê÷&
HX< sH Tm3+\"f Ho3+Ð_ \-t ²ú`¦ _pôÇ
. ðøÍtÐ Ho3+\¦ #l %i`¦M: Ho3+ +þAFg÷r ëß
m \-t ²ú\ _ôÇ Tm3++þAFg(A, K)¸ 'a¹1Ï)a
. #l"f Tm3+_ A, K sü< Ho3+_ G1, G2, J s
H Ho3+(5F5)ü< Tm3+(3F2) ïr0A ׿#Qn\¦#l 8
¸ +þAFgs µ1ÏÒqt H âĺs.
Õ
ªaË> 4HÕªaË> 3\ ³ðr)ay +þAFg`¦¸m'aA "f Ò
oè YUs$_ ©`¦ or& 8£¤&ñôÇ #l Û¼&7àÔ!3 s
. D, E, F +þAFg\ @/ôÇ #l Û¼&7àÔ!3ÉrÕªaË> 4(a)ü<
°
ú s Tm3+(3F2) ïr0Aëß z¤. Bü< C+þAFg_ #l Û¼
&
7àÔ!3Ér ÕªaË> 4(c)ü< °ú s Ho3+_ 5F5 ïr0Aëß Û¼&7àÔ
!
3\ èß. Õªo¦ A, G1, G2, J, K +þAFg_ #l Û¼
&
7àÔ!3(ÕªaË> 4(b))Ér Tm3+ü< Ho3+s_ \-t ²ú M
:ëH\ Tm3+(3F2)ü< Ho3+(5F5) ïr0A #l Û¼&7àÔ!3
\
¸¿º'a¹1Ï)a.
~
½Óئ Û¼&7àÔ!3õ #l Û¼&7àÔ!3_ õÐÂÒ' y +þA F
g_ ~½Óئ õ&ñõ \-t ²ú õ&ñ`¦ ìr$3 # ÕªaË>
5\ ³ðr %i. ©~½Ó¨8+þAFg [jl\ @/ôÇ {9 YUs
Õ
ªaË> 4. 10 K\"f 8£¤&ñôÇ +þAFg_ #l Û¼&7àÔ!3.
(a) Tm3+ 1D2→3H4 s\ K{© H D +þAFg_ #l Û
¼&7àÔ!3. (b) Tm3+ 3F4→3H6 s\ K{© H K +þ
AFg_ #l Û¼&7àÔ!3. (C) Ho3+ 5G4→5I8 s\ K
{© H B +þAFg_ #l Û¼&7àÔ!3.