Diode-Pumped Er,Yb:glass Micro-Laser ⢠Lightweight ... - Kigre, Inc.
Diode-Pumped Er,Yb:glass Micro-Laser ⢠Lightweight ... - Kigre, Inc.
Diode-Pumped Er,Yb:glass Micro-Laser ⢠Lightweight ... - Kigre, Inc.
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LASE 2004 Presentation<br />
Conference 5332 Solid State <strong>Laser</strong>s XIII: Technology and Devices<br />
Presentation 5332-14<br />
<strong>Diode</strong>-<strong>Pumped</strong> <strong>Er</strong>,<strong>Yb</strong>:<strong>glass</strong> <strong>Micro</strong>-<strong>Laser</strong><br />
C. Ward Trussell<br />
Vernon King<br />
Alan D. Hays<br />
Night Vision & Electronic Sensors Directorate, US Army RDECOM<br />
Scott J. Hamlin<br />
MegaWatt <strong>Laser</strong>s, <strong>Inc</strong>.<br />
PO Box 24190<br />
Hilton Head Island, SC 29925-4190<br />
scott.hamlin@megawattlasers.com<br />
MegaWatt <strong>Laser</strong>s<br />
Eyesafe <strong>Laser</strong> Rangefinder<br />
Transmitters Requirements<br />
• <strong>Lightweight</strong><br />
•Small<br />
• Low cost<br />
• Operation over temperature<br />
• Battery operated, low power consumption<br />
• Single shot up to 10 pulses/sec.<br />
• Energy : ~ 100 µJ<br />
• Pulse width: < 5 nsec<br />
MegaWatt <strong>Laser</strong>s
Ytterbium-<strong>Er</strong>bium Kinetics<br />
<strong>Yb</strong> 3+ , <strong>Er</strong> 3+ :Phosphate Glass System<br />
20<br />
Energy [X 10 3 cm -1 ]<br />
15<br />
10<br />
5<br />
Pump<br />
4 F 9/2<br />
4 I 9/2<br />
4 I 11/2<br />
4 I 13/2<br />
Lasing<br />
2 F 5/2<br />
<strong>Yb</strong> 3+ <strong>Er</strong> 3+<br />
4 I 15/2<br />
0<br />
2 F 7/2<br />
MegaWatt <strong>Laser</strong>s<br />
<strong>Yb</strong> 3+ Absorption with Temperature<br />
Shift of Pump <strong>Laser</strong> Wavelength<br />
8E-20<br />
Absorption Cross-Section [cm 2 ]<br />
7E-20<br />
6E-20<br />
5E-20<br />
4E-20<br />
3E-20<br />
2E-20<br />
1E-20<br />
-40 C to +50 C<br />
<strong>Laser</strong> <strong>Diode</strong> Temp Bandwidth<br />
0<br />
850 900 950 1000 1050<br />
Wavelength [nm]<br />
MegaWatt <strong>Laser</strong>s
<strong>Micro</strong> Eyesafe Solid State <strong>Laser</strong><br />
<strong>Diode</strong>-<strong>Pumped</strong> <strong>Er</strong>,<strong>Yb</strong>:<strong>glass</strong> Approach<br />
Top View<br />
Q<br />
Switch<br />
<strong>Laser</strong><br />
<strong>Diode</strong><br />
<strong>Diode</strong><br />
Optics<br />
<strong>Er</strong>,<strong>Yb</strong>:<br />
Glass<br />
Output<br />
Coupler<br />
1.5 micron<br />
pulses<br />
Side View<br />
End <strong>Pumped</strong> <strong>Laser</strong><br />
•Good pump/laser mode overlap<br />
•Long pump absorption length<br />
•Wide Temp range for laser diode<br />
•High Efficiency<br />
<strong>Er</strong>,<strong>Yb</strong>:<strong>glass</strong><br />
•Direct 1.5 micron output (no OPO)<br />
•Long fluorescence Lifetime(20x Nd:YAG)<br />
•Single stripe pump laser diode<br />
•Low cost material<br />
Performance Results:<br />
Single laser diode: 3 watts at 925nm, 3 milliseconds pump time, 9 mJ pump energy<br />
Energy Output at 1.54 microns: 90 to 120 micro-joules, 2 ns pulse, 10 Hz.<br />
Peak Power: ~ 50 kW<br />
Electrical input: 20 mJ/pulse at 10 Hz = 200 mW<br />
MegaWatt <strong>Laser</strong>s<br />
<strong>Diode</strong> Pump Optics Design<br />
using ZEMAX<br />
Unit #2 Design<br />
New design with more<br />
uniform pump beam<br />
ZEMAX model by Jerry Franck (NVESD)<br />
MegaWatt <strong>Laser</strong>s
<strong>Diode</strong> <strong>Pumped</strong> <strong>Er</strong>:<strong>Yb</strong>:<strong>glass</strong> <strong>Micro</strong>-laser<br />
Packaged in TO3 can<br />
MegaWatt <strong>Laser</strong>s<br />
<strong>Er</strong>,<strong>Yb</strong>:<strong>glass</strong> micro-laser packaging design<br />
by Alan Hays (NVESD)<br />
MegaWatt <strong>Laser</strong>s
Assembly and Test<br />
Facility<br />
MegaWatt <strong>Laser</strong>s<br />
<strong>Diode</strong> <strong>Pumped</strong> <strong>Er</strong>:<strong>Yb</strong>:<strong>glass</strong> <strong>Micro</strong>-laser<br />
Recent results with TO3 package<br />
<strong>Micro</strong>-laser in TO3 package and<br />
<strong>Diode</strong> drive circuit for use with L123<br />
Battery.<br />
Oscilloscope traces showing diode pump current<br />
for 8 milliseconds and 7 q-switched pulses with<br />
approximately 80 micro-joules/pulse. Pulses are<br />
stretched for display. Actual pulse width is 2 ns.<br />
MegaWatt <strong>Laser</strong>s
Eye-Safe <strong>Laser</strong> Output Pulse<br />
MegaWatt <strong>Laser</strong>s<br />
Beam Quality<br />
Beam Quality < 2.6 mm-mrad<br />
MegaWatt <strong>Laser</strong>s
Time to Q-switch Q<br />
vs. laser diode power<br />
NV01 <strong>glass</strong><br />
Q/S Build Up Time-vs-Pump Power<br />
NV-01, 80% OC, 94%T Q/S (MO176), 2.8mm lens-lens, 1.6 mm vv200-<strong>glass</strong><br />
Turn-on Time (mS)<br />
9<br />
8<br />
7<br />
6<br />
5<br />
4<br />
3<br />
2<br />
1<br />
0<br />
2 2.2 2.4 2.6 2.8 3 3.2 3.4<br />
Power (Watts)<br />
MegaWatt <strong>Laser</strong>s<br />
Eye-Safe <strong>Laser</strong> Environmental Test<br />
5<br />
<strong>Er</strong>bium <strong>Laser</strong> Performance<br />
over Temperature 03/06/03<br />
4<br />
Buildup Time, msec<br />
3<br />
2<br />
1<br />
0<br />
-50 -40 -30 -20 -10 0 10 20 30 40 50 60 70<br />
Temperature, C<br />
MegaWatt <strong>Laser</strong>s
Pulse Timing Jitter<br />
MegaWatt <strong>Laser</strong>s<br />
Intended Application: OICW / Land Warrior<br />
MegaWatt <strong>Laser</strong>s
New Applications: LIBS<br />
Class 1<br />
<strong>Er</strong>:Glass <strong>Laser</strong><br />
MegaWatt <strong>Laser</strong>s<br />
LIBS Spectrum of Pb<br />
Using <strong>Er</strong>:Glass <strong>Micro</strong>laser<br />
45000<br />
Pb I<br />
40000<br />
35000<br />
30000<br />
Intensity<br />
25000<br />
20000<br />
Pb I<br />
15000<br />
Pb I<br />
Pb I<br />
Pb II<br />
10000<br />
5000<br />
Pb II<br />
0<br />
200 300 400 500 600 700 800<br />
Wavelength (nm)<br />
MegaWatt <strong>Laser</strong>s
Butterfly Package<br />
MegaWatt <strong>Laser</strong>s<br />
Butterfly Package Pinout<br />
MegaWatt <strong>Laser</strong>s
PRO-E E Model of NVL Rangefinder<br />
Early tests using a 30 mm aperture saw ranges in<br />
Excess of 2 km.<br />
MegaWatt <strong>Laser</strong>s<br />
<strong>Diode</strong> <strong>Pumped</strong> <strong>Er</strong>,<strong>Yb</strong>:<strong>glass</strong> <strong>Micro</strong>-<strong>Laser</strong><br />
Summary<br />
• <strong>Lightweight</strong> Eyesafe <strong>Micro</strong>-<strong>Laser</strong> developed for<br />
Rangefinder Applications: 12 gm<br />
• Wavelength: 1.54 µm for eyesafety<br />
• Energy: 80 to 120 µJ<br />
• Pulse Width: 2.0 nsec<br />
• Peak Power: ~ 50 kW<br />
• PRF: 1 to 20 Hz<br />
• Beam Quality < 2.4 mm-mrad, 1.2 x D.L.<br />
• Tested to 4 x 10 6 with No Degradation @ 60 ºC<br />
• Low cost projected<br />
MegaWatt <strong>Laser</strong>s
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