dual wavelength lasers
DESCRIPTION
Presented at the Laser Physics Workshop - Barcelona, Spain (July 13 - 17, 2009)Publication Reference: B.M. Walsh, “Dual Walelength Lasers”, Laser Physics, 20, 622-634 (2010).TRANSCRIPT
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
Brian M. WalshNorman P. Barnes
NASA Langley Research CenterHampton, VA 23681 USA
Dual Wavelength Lasers
Laser Physics Workshop - Barcelona, Spain (July 13 - 17, 2009)
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
• Dual wavelength concept• I. Two Wavelength Oscillation (TWO)
- Er:Tm:Ho:YAG (2.0 and 2.9 µm)
• II. Synchronous Tunable Optical Pulses (STOP)- Nd:YAG (1.0xx and 1.3xx µm)
• IIa. Non-linear optics- SHG, sum frequency techniques
• III. Other dual-λ lasers- Er:Nd:YAG (2.9 µm and 1 µm)- Ho:Nd:YAG (3 µm and 1 µm)
• Summary
Outline
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
Dual Wavelength Concept
• Dual wavelength lasing on separate dopant ions:- Energy transfer dynamics between the ions- Lifetimes of the upper laser manifolds- Duration of the pump pulse
• Dual wavelength lasing on same dopant ion:- System design (e.g., prisms, mirrors, resonator design)- Laser transition cross section
• Advantages- Can produce widely or closely separated wavelengths- Sum frequency, difference frequency readily implemented- One laser serves dual purpose (efficient & cost effective)- Medicine, remote sensing, surveillance, machining
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
I. Er:Tm:Ho dual-λ laser
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
TWO Laser schematic
Laser
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
1.)2.)3.)4.)5.)
R. Balda, et. al., Optics Express, 17, 8788 (2009)
Er:Tm Energy Transfer
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
Er:Tm:Ho Energy Transfer
0
5000
10000
15000
En
erg
y (
cm-1
)
Tm3 + YAG Ho3 + YAG
4I15/2
4I13/2
3F4
5I8
5I7
3H6
Er3 + YAG
4I11/2
(! = 100 µs)
(! = 9 ms)
(! = 14 ms)(! = 8 ms)
4I9/2
3H55I6
23
1
2
4
2.9 µm
2.1 µm34
Short pump pulse - 2.9 µm Er lasing Long pump pulse - 2.1 µm Ho lasing Intermediate pump pulse - Er and Ho
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
Pump Pulse Wavelength Tuning
Time
2.9 µm
Time
2.9 µm 2.1 µm
Time
2.1 µm
Short, high intensity Long, low intensity
Moderate length, mid-intensity
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
Er Lifetime Quenching
0.0
0.2
0.4
0.6
0.8
1.0
0 50 100 150 200 250 300
Time (µs)
Norm
aliz
ed I
nte
nsi
ty
Er 4!11/2 Manifold Lifetime"2.9 µm upper laser level"
30%, 50%,60% Er YAG
10% Er 1% Ho
10% Er 4% Tm
10% Er 4% Tm 0.5% Ho
10% Er 5% Tm 1.0% Ho
4I11/2
Lifetime
90 µsec
80 µsec
50 µsec
40 µsec
35 µsec
Sample
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
Er:Tm:Ho pulse switched lasing
0.0
0.20
0.40
0.60
0.80
1.0
1.2
0 50 100 150 200
Er 2.9 µm, 100 µs pump pulse, 0.90R OC
Ho 2.1 µm, 1 ms pump pulse, 0.95R OC
Las
er E
ner
gy
(J)
Electrical energy (J)
Cr(1)Er(35)Tm(0.7)Ho(0.35) YAG6x122 mm laser rod
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
Er:Tm:Ho Simultaneous lasing
0
50
100
150
200
250
300
350
50 100 150 200
2.1 micron (0.95R)2.9 micron (0.85R)
Las
er E
ner
gy (
mJ)
Electrical energy (J)
1 ms 100 µs
0
50
100
150
200
250
300
350
10 20 30 40 50 60 70 80 90
2.1 micron (0.95R)2.9 micron (0.85R)
Las
er E
ner
gy (
mJ)
Electrical energy (J)
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
II. Nd:YAG dual-λ laser
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
STOP laser schematic
Output
Mirror
Nd:YAG diode
Pumped HeadQ-Switch
Quartz
Prisms
1.0xx µm
HR mirror
1.3xx µm
HR mirror
Synchronous
laser pulses
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
Dispersive Tuning in Nd:YAGL( m) e(10-20 cm2) (cm-1) EETH(J) s
1.0520 9.62 5.7 4.93 0.0123 1.0614 20.62 4.8 2.60 0.0184 1.0641 27.74 6.0 1.99 0.0193 1.0737 15.15 5.2 3.62 0.0139 1.0779 6.26 9.9 7.63 0.0095 1.1120 3.97 12.1 10.28 0.0113 1.1160 3.95 14.4 11.48 0.0104 1.1225 3.97 11.4 11.26 0.0112
L( m) e(10-20 cm2) (cm-1) EETH(J) s 1.3187 8.92 4.5 6.64 0.0127 1.3336 4.03 3.7 11.82 0.0104 1.3381 9.57 5.0 6.53 0.0131 1.3564 7.35 6.6 8.42 0.0107
4F3/2 → 4I13/2 Parameters
4F3/2 → 4I11/2Parameters
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
Synchronous Pulses
5000
0
1000
4000
3000
2000
12000
11000
Nd3+:YAG
4F3/2
4I9/2
4I11/2
4I13/2
852
0
133
199
312
11506
11421
3925
3932
4035
4050
4494
?
4432
2003
2029
2111
2146
2515
2462
Z5
Z1
Z2
Z3
Z4
Y1
Y2
Y3
Y6Y5
Y4
X1
X2
X3
X4
X7
X5
X6
R2R1 • Synchronous pulses require equal
pulse evolution time intervals- Different emission cross sections- Resonator lengths adjustable- Output losses adjustable (output coupling)
1
!c
"c
2lc
ln RMRL( ) + 2# e
l$c
2lc
%
&'(
)*EEP+ E
LTH( ),
-.
/
01
-1 0 1 2 3 4
Time (µs)
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
STOP light laser performance
0.0
0.10
0.20
0.30
0.40
0.50
0.60
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
1.052
1.319
Inv
erse
of
pu
lse
evo
luti
on
in
terv
al
( µs-1
)
Electrical energy (J)
0
5
10
15
20
25
30
35
0.6 0.8 1.0 1.2 1.4 1.6
1.052 QS1.319 QSBoth QS
La
ser
En
erg
y (
mJ
)
Electrical Energy (J)
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
IIa. Non-linear optics
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
Non-linear Conversion
Red Orange Green~ 0.660 mm ~ 0.585 mm ~ 0.526 mm
SHG sum frequency SHG
SynchronousTunableOpticalPulses
BBO
Crystal
waveplate
1/2 waveat 0.59 µm
BBO
Crystal
VIS UV
Synchronous
laser pulses
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
One dual laser - 172 wavelengths
2B3BB+2A4B
A+B2AA+2B3A2(A+B)4A
1.00 1.05 1.10 1.15 1.20 1.25 1.30 1.35 1.40
Wavelength ( µm)
0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70
Wavelength ( µm)
A
B3F3/2 → 4I11/2
3F3/2 → 4I13/2
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
III. Other dual-λ lasers
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
0
2000
4000
6000
8000
10000
12000
En
erg
y (
cm-1
)
Er:YAG
4I15/2
4I13/24I15/2
4F3/2
Nd:YAG
4I11/2
(! = 100 µs)
(! = 9 ms)
(! = 240 µs)
4I13/2
4I11/2
4I9/2
4I9/2
1.06 µm2.9 µm1
1 2
2
3
Nd:Er:YAG
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
0
2000
4000
6000
8000
10000
12000
En
erg
y (
cm-1
)
Ho:YAG
5I8
5I6
4I15/2
4F3/2
Nd:YAG
5I5
(! = 50 µs)
(! = 1 µs)(! = 240 µs)
4I13/2
4I11/2
4I9/2
5I7
(! = 8 ms)
1.06 µm
3.0 µm
1
1 2
Nd:Ho:YAG
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
• Dual-λ lasers discussed and demonstrated- Er:Tm:Ho:YAG (TWO laser)- Nd:YAG (STOP laser)
• Physics & engineering criteria- energy transfer, lifetime, transition cross section- Optics, resonator design, pumping schemes
• Non-linear techniques- SHG and sum frequency techniques- Multitude of harmonic wavelengths realized
• Future work- What new potential dual- λ lasers exist?- Driven by application needs, multiple solutions
Summary
National Aeronautics andSpace Administration
Laser Physics WorkshopBarcelona, Spain (July 13-17, 2009)
Brian M. WalshLaser Remote Sensing BranchEmail: [email protected]: 757 864-7112
NASA LangleyResearch Center