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TRANSCRIPT
Laser Development at Q-Peak for Remote Sensing
Peter MoultonQ-Peak, Inc.
MRS Spring MeetingMarch 29, 2005
Paper FF1.1
Outline
• Introduction to Q-Peak• Early systems: lamp-pumped (mostly)
– High-energy Ti:sapphire lasers– High-energy eyesafe parametric oscillators
• Recent systems: diode-pumped– Basic lasers– Parametric oscillators for IR coverage– Amplified microchip laser for precision ranging– Single-frequency UV laser for direct-detection wind
sensing• Under development:
– High-energy pump for ozone lidar– QCL-seeded IR parametric oscillator– Fiber-laser-pumped Ho:YLF/ZGP OPO
Q-Peak History
• Previously Research Division of SEO, founded 1985– Established to provide SEO with the latest in solid state laser technology, leveraging
outside funding as much as possible– Conducted Government, commercial and internally funded R&D– Developed multi-wavelength, lamp-pumped lasers and Ti:sapphire lasers as scientific
and OEM products– SBIR’s (> 22 Phase II programs) a large component– Developed key technology for BSDS $40 million Government contract in Orlando– Developed high-power, diode-pumped solid state laser as basis for new product line– Accumulated contract R&D sales through 1998: > $25 million
• Spun out as Q-Peak, July 1, 1998, a subsidiary of SEO– Continued Government and commercial Contract R&D work and further developed a
commercial business in diode-pumped lasers
• Acquired by Physical Sciences Inc. (Andover, MA) on October 15, 2001– Continuing contract R&D work, custom product sales, limited production and
developing partners for large-scale production of commercial lasers– Establishing synergies with PSI in photonics areas
High-Energy Ti:sapphire Lasers
Ti:sapphire laser is pumped with blue-green wavelengths and lases in near-IR
400 500 600 700 800 900 1,0000
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WAVELENGTH (nm)
AB
SOR
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IEN
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rb. u
nits
)
FLU
OR
ESC
ENC
E IN
TESI
TY (a
rb. u
nits
)
Fluorescence and gain in Ti:sapphire spans a large wavelength region
600 700 800 900 1000
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WAVELENGTH (nm)
INTE
NSI
TY (a
rb. u
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GAIN
PI
SIGMA
Laser-pumped, high-energy Ti:sapphire laser design uses unstable resonator
Pump #1
Pump #2
Output
GRM
HR
Ti:sapphirecrystals
Prisms
Developed with NASA Langley, DARPA support, 1986-1992Continuing to build systems for specialized sensing
applications in the near-IR and UV
Pulsed Ti:sapphire input-output, 727-960 nm
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50
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250
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450
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0 200 400 600 800 1000 1200 1400
Green pump energy (mJ)
Ti:s
apph
ire
outp
ut e
nerg
y (m
J)
790 nm727 nm911 nm960 nm
LASE system with Ti:sapphire laser has measured global water-vapor profiles
•The seed source is a single-frequency diode laser operating around 815 nm
•The pump laser produces two pulses spaced less than a msec apart, to provide on-line, off-line data for a “frozen” atmosphere
•LASE has flown > 30 times on an ER-2 and on a P-3 aircraft since 1995. Now being adapted for DC-8
DARPA/ONR SLC Ti:sapphire achieved 250 mJ, 455-nm, narrow-linewidth power
But, program cancelled
Harmonic conversion of Ti:sapphire lasers: applied to DIAL, fluorescence lidar
700 750 800 850 900 950Wavelength (nm)
NO2
Benzene
Hg
Toluene Ozone
NO
SO2
Cl2
2nd
3rd
4th
Harmonic
50 mJ at 253 nm, 28 MHz linewidth source for Hg resonance filter
Frequency-doubled,Flash lamp-pumped,
Nd:YAG laser
Pulsed Ti:sapphirelaser
Ti:sapphireseed laser
Ramp & Lock electronics
10HzMaster clock
High voltageOp-amp
Photo-diode PZT
FlashlampTrigger
Pulses from seeded lasers
50 mJ, 290-nm source used solid state green laser to pump cw Ti:sapphire seed laser
Pulsed Ti:Sapphire LaserTHG Module SHG Module
SHG Module
Lamp DriverCooler Pump LaserNd:YLF
Isolator
532-nm CW Pump Laser CW Ti:Sapphire Laser
Output
290 nm50 mJ 200 mJ, 870 nm
1 J, two beam lines
BBO crystals
1.75 J, two beam lines
900 mW, 870 nm5 W, 532 nm
Ozone lidar transmitter for NASA Langley used diode-laser seed sources
Double-PulseLamp Driver
SLM Diode Laser -On-Line Seeder
Isolator
Passive SHGModule
Passive THGModule
Double-Pulse UV Output
SLM Diode Laser -Off-Line Seeder
DichroicMirror
CLH Nd:YLF Pump Laser
Pulsed Ti:sapphire Unstable-Resonator
LaserBBO- orLBO-based
1996, Phase II NASA SBIR
THG efficiency and energy exceeded 45% and 30 mJ
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Input Energy (mJ)
THG
Effi
cien
cy
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THG
Out
put E
nerg
y (m
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Photo of NASA ozone Ti:sapphire system
Facility for Airborne Atmospheric Measurements (FAAM)
BAE 146-301 Large Atmospheric Research Aircraft G-LUXE
FAAM is the result of a collaboration between the Met Office(TM) and the Natural Environment Research Council (NERC) to provide an aircraft measurement platform for use by all the UK atmospheric research community. The aircraft is owned by BAE Systems and operated for them by Directflight. The Home Base is at Cranfield University, Bedfordshire.
Detailed block diagram of NIR/UV Lidar source for FAAM
Pulsed Ti:sapphire Laser
HarmonicGeneration
Ramp /LockElectronics
Pump LaserLamp Drivers
Lasers Cooling
WavemeterWavemeterComputer
NIROutput
Optical bench
Electronics rackElectrical CoolantOptical
ECDLSEED
ECDLSEED
ECDLSEED
ECDLSEED
ECDLSEED
Switch
Seed LaserControl/Drive
MasterControl
Big SkyPump Lasers
UVOutput
Toptica DL100 ECDL seed source with Laserscope accessory
High-energy eyesafe parametric oscillators
Test system for high-energy KTP OPO
KTP OPO
InputMirror
OutputMirror
Q-switched Nd:YLF1053 nm, 0-240 mJ,
10 ns, 10-50 Hz- or -
625 mJ, 30 Hz
Q-switched Nd:YAGOsc / Amp
1064 nm, 0-1.1 J,10 ns, 10 Hz
-or-
Telescope
OPOSignalOutput
OPO resonator designs
pump
signalRING
pump signal
HT pump HR signal
PR signal HR pump
20 mm KTPSTANDING-WAVE M1
pump
450 mJ, 10 Hz41% conversionLimits: M1 damagePump feedback
TIR prism
4, 10-mm KTP
240 mJ, 30 Hz34% conversionNo feedbackNo damage atfull power
(with KTA330 mJ, 100 Hz>30% conversion)
Compact, ruggedized lamp-pumped laser with internal OPO
Complete OPO-based lidar system built for NASA Langley
Complete CLEAR lidar system at UCLA used Q-Peak eyesafe OPO transmitter
Application of CLEAR lidar to urban areas
Army biological standoff detection system (LR-BSDS) used Q-Peak high-power OPO
Plot of KTP and KTA IR transmission
3000 3200 3400 3600 3800 40000
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40
60
80
100T = 75% @ 3297nm
T = 23% @ 3297nm
KTA 2cm KTP 2cm
Wavelength (nm)
%T
Design for high-power KTA OPO
signal out
pump in
pump& idler out
CaF2prism
KTA x-cut
Four KTA Crystals 1 x 1 x 2 cm each
0 20 40 60 80 100 1200
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Pump Power (Watts)
Sign
al P
ower
(Wat
ts)
M.S. Webb et al. Opt.Lett. 23, 1161 (1998)
Detail of BSDS system mounted in UH-60
Recent systems: diode-pumped
Basic lasers
SALTS 2-micron coherent lidar source built for for wind profiling off ships
Inside of SALTS hermetic-sealed laser head – mirrors aligned and then hard-mounted
Q-Peak’s DPSSL design obtains high efficiency and high beam quality with side-pumping
Diode laser
Diode laser
Laser crystal
Cylinder lens Laser beam
Pump beam
Multi-Pass Slab (MPS)US Patent 5,774,489
“Gain Module”Applied to Nd:YLF, Nd:YVO4 , Nd:YAG Yb:S-FAP, Yb:YAG, Tm:YLF, Er:YLF, Cr:LiSAF
MPS Tm:YLF cw laser operation provides tunable IR output
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1900 1920 1940 1960 1980 2000 2020 2040 2060 2080
Wavelength, nm
Out
put p
ower
, W
T=3 %T=13%
Wavelength tuning of Tm:YLF laser with a 2-plate birefringent filter (TEMoo operation) for two values of output coupler transmission.
Technology of efficient diode-pumped, conduction-cooled Nd:YLF rod laser
Design concept CAD model
I/O curve for conduction-cooled rod laser
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0 0.2 0.4 0.6 0.8 1 1.2 1.4Pump Energy (J)
Out
put E
nerg
y (J
)
R = 70%
R = 60%
No Pockels cell or polarizer in the resonator, cavity length 15 cm, rep rate 10Hz, pump pulsewidth 400ms
40% slope efficiency
Q-switched results: 110 mJ/pulse in double-pulse format
Recent systems:
Parametric oscillators for IR coverage
Amplified microchip laser for precision ranging
Single-frequency UV laser for direct-detection wind sensing
Tuning curve for MPS-driven KTA OPO
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Wavelength (um)
Pow
er (W
)
Tandem OPO scheme
Nd-doped,Q-switched laser KTA OPO CdSe OPO
IR seed source
IR seed source
Nd-dopedseed laser
1.5 - 3.6 m
3.3 - 11 m
Or: PPLN, other KTP isomorphs
Or: AgGaSe2 ZnGeP2
Angle-tuned Pump-tuned, NCPM
Tandem OPO tuning with x- and y-cut KTA
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KTA Phasematch angle (degrees)
Wav
elen
gth
(um
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y-cut KTA
x-cut KTACdSe signal and idler
KTA signal and idler
Overall design of SBCCOM, rapidly tunable, 1-kHz PRR Tandem OPO
Legend:Laser diode currentMPL control (current settings, burst mode)AOBD control (RF, burst mode)Rotation control (angle)Trigger pulseBurst pulse
AOBD
MPL RF Synthesizer(rapid tuning)
Rotation control(slow tuning)
OSC AMP 3AMP 2
PC 2
Mid IR output
Rotary stages
External burst
PC 1
AMP 1
Legend:Laser diode currentMPL control (current settings, burst mode)AOBD control (RF, burst mode)Rotation control (angle)Trigger pulseBurst pulse
AOBD
MPL RF Synthesizer(rapid tuning)
Rotation control(slow tuning)
OSC AMP 3AMP 2
PC 2
Mid IR output
Rotary stages
External burst
PC 1
AMP 1
Microchip laser schematic and performance
Pump optics
Dielectric coatingHR laserHT pump
Fiber-coupled diode laser
Nd:YAG(laser)
Cr:YAG(Q-switch)
Dielectric coatingPR laser
Microchip laser output
1.5 mm
0.7 W pump power at 809.0 nm 440 ps pulse duration
SLR2000 transmitter for precision satellite ranging based on amplified microchip
Fiber
Nd:YAG/Cr:YAG Microlaser
TelescopeIsolatorplate
Cylindrical lens
HR Mirror
Nd:YVO4 Multipass Amplifier
/2 plate
SHG
Diode laser
532-nmbeam
Design: MPV-amplified microchip laserPulse duration: 200-300 psPulse energy: 200 uJ at 532 nmPulse rate: 2 kHz
Photograph of hardwaredesigned for remote, autonomous operation
4 mJ, 1 kHz PRR single-frequency source at 349 nm for incoherent-detection wind-sensing
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11
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79
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13, 14
Amplifier Gain Modulew/ 90-W Lightstone diodes
NCPM LBO(SHG) crystal
15 CPM LBO(THG) crystal
17
16
1047-nmoutput
349-nmoutput
Beamdump
SLM
Seed
Lase
r
Seeder ElectronicsPhotodetector
Optical Isolator
Oscillator Gain Modulew/ 40-W diodes
UV-ContollerPhotodetector
6
G-5398
Under Development
100 W, 1-kHz IR source for ozone lidar
Nd:YLF oscillator1-1.5 mJ, 6-9 ns
1 kHzTandem optical
isolatorDouble-passpreamplifierRetro-mirror
14-18 mJ
Final stageamplifier
Pre-finalamplifier
100 mJ, 6-9 ns1 kHz
Required Pump Laser Parameter Units Wavelength 1047 nm Linewidth <500 MHz SLM (no multimode
permitted) Average Power 100 W combined Main leg Secondary leg ** after OPO isolator
70 W 30 W **
Pulse width 6-8 ns (critical not to exceed) Beam diameter < 2 mm 1/e^2 points Beam quality M^2 < 1.3 in both axis Beam shape Near circular > 90% Pulse shape >95 % gaussian , no after pulsing
Results to date: 28 mJ at 1 kHzfrom a single crystal
Quantum-cascade-laser (QCL) seeded OPO for atmospheric sensing
MIROPO
QCLseeder
2.05-umpump laser
2.2 to 4.0 umsignal output
4.0 to 22 umidler output
Design goal:200 mJ/pulse>50-Hz PRRpump laser
Photograph of Phase IZGP OPO demonstration
Scale-up of Ho:YLF-driven ZGP OPO will use 350 W of Tm-fiber-laser pumping
HR
OC AOM
Ho:YLF
Tm-fiber laser
DM DM
Ho:YLF
PBS
/2
Results to date: 40 W of cw power 40 mJ of Q-switched energy in 17-ns pulse
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Total Tm-pump power, W
Ho:
YLF
ener
gy p
er p
ulse
, mJ
1000 Hz400 Hz200 Hz
Tuning curve for Ho:YLF-pumped ZGP OPO
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Angle (degrees)
Sign
al, i
dler
wav
elen
gths
(um
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ZGP OPO operation – pulse energy at 3200 nm
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Pump pulse energy, mJ
OPO
pul
se e
nerg
y, m
J
50 Hz200 Hz400 Hz
Slope efficiency:50 Hz 60%200 Hz 56%400 Hz 63%
Conclusions
• Advances in solid state laser and nonlinear optical materials have allowed development of new sources for active remote sensing
• Tunable Ti:sapphire lasers with nonlinear conversion generate tunable IR, visible and UV wavelengths for a variety of species detection
• Large-aperture KTP and KTA crystals can shift the output of Nd- doped lasers into the eyesafe wavelength region, for ground- based aerosol sensing
• Diode-pumped laser extend the performance of solid state lasers and provide the basis for satellite-based active remote sensors
• Nonlinear optics based on improved nonlinear crystals provide extended, tunable wavelength coverage from LWIR to the UV