KR0000024
KAERI/RR-1841/98
Development of delivery system and excitation technique
for Er:YAG laser
3 1 - 1 1
S U M M A R Y
I. Project Title
Development of delivery system and excitation technique for Er:YAG laser
II. objectives and Importance of the Project
The purpose of this project is development of the excitation system and
optical delivery for Er^YAG laser. The demands for infrared laser which shows
a good water absorption have been increased continuously in the field of
medical area. Because of its efficient absorption by water, Er'-YAG laser is
particularly useful for precise localized tissue ablation. Biological tissue
has a high water content, and this, in the absence of pigment, largely
determines its absorption of light and the Er:YAG laser can be particularly
effective in endoscopic microsurgery. However, because silica is only
transparent within a spectral range of about 0.2 tO 2.3 um, the Er:YAG laser
cannot pass through silica fiber. It has been remained as a hot interest in
medical community.
On the basis of technology achieved in previous long term project of laser
research, we are trying to optimize the excitation and evaluate optical deli
very of Er:YAG laser.
- 4 -
III. Scope and Contents of the Project
- Development of lamp excitation technique
: Optimization research of emission spectrum as a function of electrical
current and fill pressure in Xenon flashlamp.
- Development of lamp excitation system
: geometrical design and fabrication of difussive reflector.
- Research for high conversion efficiency of lamp light to laser
radiation.
: Optimization of gain and loss mechanism in Er:YAG laser
- Investigation of optical delivery of Er:YAG laser
: Optical delivery with an articulated arm
IV. Results and Proposal for Applications
Results
- Fabrication of excitation chamber ( 1 unit)
- Investigation of laser parameters of Er'.YAG laser
( Laser efficiency : 0.3*. Output Energy : 500aJ/pulse at 300//S pulse
width)
- Investigation of optical delivery of Er:YAG laser
(1 unit of articulated arm)
Proposal for Applications
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In this project, the basic system of Er'-YAG laser has been developed.
Therefore, the basic technology from this project will be used in the further
advanced research program for medical applications.
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C O N T E N T S
Chapter 1. Introduction 10
Chapter 2. Flashlamp pumping for Er laser 12
Section 1. Energy level of Er+3 in YAG 12
Section 2. Spectrum of flashlamp 14
Section 3. Flashlamp pumping technique for Er laser 16
Chapter 3. Laser output and its beam delivery 19
Section 1. Experiment for laser output 19
Section 2. Experiment of laser beam delivery 20
Chapter 4. Conclusion 24
Reference 25
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10
12
12
14
3 3 om a(|o|xi % o|7| ^x| 7H^ 16
a||o|*|-ftei % £ 3 £ 4!S 19
ia $\om mm u^ 19
2s s a # ^s 20
f a 5 24
25
- 8 -
l- l- l . #<HH3 313 «-4*^«J 10
2-1-1. Er3* ionSj oflM*l level diagram 12
2-2-1. Er:YAG $]°W$) % ^K* tfl^ ^ -S 13
2-2-2. ^ £ «U3 ^J£ (2900 watt/cm2)6flA^ > ^ ^ ^ ^ - ^ ^ - 5 14
2-2-3. &•& 6 J^ ^ S . (23000 watt/cmzWH2l ^ ^ " ^ ^ - ^ ^ - i 15
2-3-1. ^ f > ^ Sl^Wl^ «UK£ ^ - i 17
2-3-2. *11*^! #&*$ S>4̂ 11 a^a- 18
2-3-3. ^7| | *H*t€ <H^" ^ 1 ^ %<H7] ^ * | 18
3-1-1. Er.YAG B}H*] ^§-^7] ^ - i 19
3-1-2. Er=YAG eflo]^} # ^ ^ J l -^ 19
3-2-1. ^ M ' H ^ ^ ^ ^ Er:YAG j^o]^ ^.^ ^.>g 20
3-2-2. 7 3Hi ^ -n-S- #*1 20
3-2-3. 7 #*1 ^ -H-JE. ̂ * ]5 | 3H*1 ^ 2 f S 22
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M
1-1-1
[1-2]
Water Absorption Spectrum
•a
100000
10000
1000
100
10
1
0.1
0.01
0.001
0.00010
/
I\JI
\ 1\ 1
\ I Er:YAQ laser line
\
1,000 2,000 3,000 4,000 5,0
Wavelength (mn)
1-1-1.
=13000 cm"1
(1.06um, a = l cm"1
2.94 um
Ho:YAG
Er:YAG
= 5 0 cm"1 Nd:YAG
endoscope-f-
- 10 -
Er:YAG « f l W j % § l £ ^ f l
^ o l 0.2um - 2.3um ^ | ? 1 ^2}J£7> #
quartz^. 5 } ^ Sg<>?S. 2.94um EriYAG
ZrF, Sapphire fiber •§•#
30-40*
Er:YAG efl^l^^ ^7l(excitation)
- 11 -
2 g-
2.94um
4/ l3 /2
2-1 -
20}
S1 0
0
3*11 2-1-1. Er3t
•
1
1
ii• v
• „3D
Rt R2 W
I 6/2
I It ,'2
level diagram[3]
Er:YAG
Er
2Hn/2 Er
4-level e
2msH
3 7>xl(Ri, R2,
^ ( ^ <550nm)
Er ^S^. YAG doping £J&-§-
ofl
- 12 -
4I15/2
Er multiphonon r e l a x a t i o n s } ^ 7}^
Er
R2 Er
1.5 um
UV
W
4I13 /2 Er MS.
4I1 5 / 2 Er 4I9 / 2 Er
"cross-relaxation"
200 3D0 4C0 500 BCO 700 800 900 1000 UiWAVELENGTH (nn-i)
2-2-1 Er:YAG rfl^
- 13 -
Er:YAG
W ̂ cross-relaxat ion
Envolope: Clear fused Quartz, Ismi
Ace Latvjthi 7.€2cmCircuit Parareters: 500V, 100 pF, 100 uHPulse Repetition Rats: 1 HzCoolimj: Convection
WO 900 «00 900
a) Xenon, 390 Torr
ex TH
,1 ,.is
| ! •
1 * *
Bnvelcpe: Clear Pused Quartz, lineBore Diat 6.0tmtec length: 7.62 onCircuit Parameters; SOW, 100 if, 100 titPulio Repetition Rate: 1 nzOoolingt Convection
jJLM0 tOOO
b) Krypton, 700 fcorr.
2-2-2. (2900 watt/cm2
- 14 -
Sin}.
Er:YAG
Xe. Kr
Xe $ Kr
Kr 7 ^
2-2-2^
infrared)
bound - bound
a) Xeatxii 390 Itotr
is..
Circuit Parameters: 1000V, 200 tr, 52 t*Pulee Repetition fiate IHzCoollog: Convection
b) Krypton, 700 "Sorr
2-2-3. (23000 watt/cm2
- 15 -
2-2-3^ ̂ £ <a«l<HM*l ̂ MQ Xe £
continuum radiation^]
&>] Er:YAG ejlol^e^l ^ c J ^ | A S JL3f^olJELS. Xe ^ S
t h $ ^ ^ o f l ^ S . S7W # ¥ 5 ) Xe lampl- A ]~§-«H 3L2f^*l Er:YAG
71
Xe<>l
triggering 2J- simmer current-^ £^.7\] *fecj{ <^^^.o| ojc}. HZ]3. Xe 7f>i-
4 > Kr 7>>sS A}-§-̂ ttfliLc} JL#^1 #AtH ^ ^
^ f *^ "fl7f D| 3L#o| ^c>. « « -a^^5l bore
j i pulsed ^
7\.
- 16 -
3 s-
7K
3-1-2
Er:YAG rod
ZL^J 3-1-1 Er:YAG
Hz S , ̂ - ^ g : 300usec
Er:YAG
3-1-3
0.6
0.5^»*—3
">, 0.4w.
C
lU 0.3Q."5 0.2O
0.1
r
• Output Eneig/• Efficiency
0.5
0.4
oca)0.2 |
0.1
40 60 80 100 120 140
Input Energy (J)
plot
3-1-2 Er.YAG
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570
0.45* 600V &.M ^>r
dynamic stable
l .
Er:YAG 2.94um o |H
quartzS.
cfl power,
. chalcogenide[4] *£ silver halide
2.3 um
-frss.
700
g-800
1400^300
° 100
0
!
.11y
*̂
y
L
'1//|Itaw-I24SJtb^
i - 4 - -1
0 200 400 GOO 900 1000input Energy (mJ)
H^l 3-2-1 Er:YAG
- 20 -
99% % • 93% 95%
70%
- 10%
3-2-2 fe
^ ^ 3-2-32}
3 0 0
2 5 0
CJ 200
3" 150
1 0 0
50
150 180 210 240 270 3 0 0
3-2-3 7
- 22 -
Endblock#
jacket^ 4 ^ 2 3 |
Xenon
600 volt $i^.HS. ̂ cfl 600
^^^-^r «^ 350usec
\%
2.94um iNlol^^ ^ ^ ^ ^ ^ # 7
7
- 24 -
SUSS
[1] Iain D. Miller, The Erbium laser Gains a Role in Cosmetic Surgery,
Biophotonics International, May/June, p38 (1997).
[2] Klaus vogler and Max Rein, Improved Erbium laser Parameters,
Biophotonics International, Nov./Dec.,p40 (1996).
[3] M.Lukac, S. cencic, and K. Nemes, Influence of direc and cross-relaxation
pumping processes on the output energy and thermal load of an Er:YAG
laser, Appl. Opt. 32, No. 36, 7399 (1993).
[4] Q.G. Antipenko, et. al., Use of a Er;YAG laser with a chalcogenide fiber
waveguide in laser surgery, Quant. Electr. 25 (5), 498 (1995).
- 25 -
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BIBLIOGRAPHIC INFORMATION SHEET
Performing Org.
Report No.
Sponsoring org.
Report No.
Standard Report
No.INIS Subject Code
KAERI/
Title/Subtitle
Development of delivery system and excitation technique forEr:YAG laser
Project Manager and Dept. Kwang-Suk Kim (Opto-mechatronics team)
Researcher and Dept.Cheol-Jung Kim(Opto-mechatronics team)
Min-Suk Kim(Opto-mechatronics team)
Pub.Place Taejon Pub. Org. KAERI Pub.Date 1998.12.
Page 25 P. 111. and Tab. Yes(0 ), No( Size 26 Cm
Note'98 Basic Research Project
Classified Open(O ),Outside( ) Class Report Type Research Report
Sponsoring Org. Ministry of Science and Technology Contract No
Abstract(About 300 words)
The demands for infrared laser which shows a good water absorption have been
increased continuously in the field of medical area. The purpose of this project is
development of the excitation system and optical delivery for Er:YAG laser.
Therefore, we are trying to optimize the excitation spectrum of flashlamp to match
the absorption spectrum of laser material well. More than 500mJ of pulse energy has
been obtained with an excitation diffusive chamber. We investigated several
parameters of laser transmission with 7 knuckles articulated arm.
Subject Keywords(About 10 words)
laser, excitation, spectrum, flashlamp, infrared