CLRC07

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Lidar Technology Developments for ESAs Earth
Observation Missions
Yannig Durand European Space Agency yannig.durand
_at_ esa.int
CLRC XIV Snowmass, CO, 10 July 2007
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Earth Observation Missions involving Lidars
EarthCARE - 2013
ADM-Aeolus - 2009
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Measurement techniques and applications

• Altimetry Lidar
• Vegetation canopy height
• Topography
• Backscatter Lidar
• Cloud vertical profile
• Aerosol vertical profile
• Doppler Lidar
• Wind vectors
• Differential Absorption Lidar
• Trace gases concentration

A-SCOPE Altimetry ATLID ALADIN A-SCOPE
Water Vapor
Range cDt/2
Time
IT
Extinction IR/IT
IR
Time
Velocity l/2Df
Frequency
IT
IR
Concentration Log(I(lon)/I(loff))
lon
loff
Wavelength
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Lidar Technology Roadmap

• ESAs overall technology development effort for
  Earth Observation includes
• TRP (Technology Research Programme, 3 years
  budget),
• GSTP (General Support Technology Programme, 3
  years budget)
• EOEP (Earth Observation Envelope Programme, 5
  years budget)
• ESA Technology Strategy and Long-Term Plan
  provides key directions up to 2015
• Generic Lidar technology activities introduced in
  the TRP plans since 2003
• Following evolution of instrument concepts,
  activities are tailored

GSTP
EOEP
TRP
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Lidar Technology Developments Areas

• Transmitter
• Sub-System Laser sources at 935 nm, 1 and 2
  microns
• Component
• High-Power Laser Diodes at 808 nm,
• Mixed Garnet Crystals for direct pumping at 935
  nm (NdYGG) and 942 nm (NdGSAG),
• Hollow Waveguide,
• Photonic Crystal Fibers,
• Phase Conjugation Mirrors
• Tunable frequency stabilisation schemes
• Laser Induced Damage Mitigation
• Contamination Test Programme
• Receiver
• Sub-system Lightweight Large Aperture Telescope,
  Optical filtering chain, Acquisition chain
• Component High-Resolution Optical Filters,
  Detectors in UV and NIR
• Instrument demonstrator
• ALADIN Airborne Instrument

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Transmitter sub-systems overview
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Transmitter sub-system (1/3)
ATLID Transmitter LASer breadboards Performance
achievements
M2 7.5 W in IR
21 o-o in IR
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Transmitter Developments systems
Transmitter sub-system (2/3)
ATLID Transmitter LASer breadboards
Environmental tests
Irradiation tests for new material 60 MeV Proton
Fluences 2, 4 and 20109 p/cm2
Vibration tests for FM like components Random
16.6 g rms 100-2000 Hz 0.4 g2/Hz
BIBO crystal Transmission variation at 532 nm 10
min after radiation vs. dose Grin Lenses No
change in transmission and focal length
Laser Diode Assembly and Crystal Assembly No
change in the oscillator electro-optical
performance after vibration
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Transmitter Developments systems
Transmitter sub-system (3/3)
Feasibility of a frequency converter unit for
Pulsed Laser in NIR Combination of Optical
Parametric Oscillators and Amplifiers compact and
versatile to produce laser emission at any
wavelength in the NIR at high energy and very
high spectral stability and purity
Pump Laser SLM Nd YAG (30 Hz, 15 ns)
1.064 µm
110 mJ
wp
10 mJ
1 mJ
Tunable source
OPA amplifiers

• 2.051 µm
• for CO2 line

ws
wi
ws
Type II ppLN Dual-cavity OPO
Type 0 ppLN Pre-amplifier
Type II KTPs amplifier stages
2.2112 µm

• 40 mJ, 10 ns, 30 Hz
• w Stability
• 1.5 MHz within 10 s
• Spectral purity
• 99.98 within 1 GHz

1.064 µm
2.2112 µm
Wavelength Purity Control (Photo acoustic cell
/ Fizeau interferometry)
Control Electronics
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Transmitter components (1/2)

• High-Power Laser Diodes at 808 nm
• ADM-Aeolus
• CW and QCW Laser Diodes assessment
• 840 W, 45 e-o efficiency, 3 Gshots
  demonstrated.
• EarthCARE
• QCW Stacks developments
• 700 W and 50 e-o efficiency after 10 Gshots
• Advanced developments
• 1200 W, 2.5 nm spectral width, 65 e-o
  efficiency after 12 Gshots
• 2 contracts started in May 2007

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Transmitter components (2/2)

• Development and Assessment of High-Power Laser
  Diode Arrays 2 contracts
• Failure Mode and Effect Analysis,
  Thermo-mechanical Analysis
• Design fully revisited
• Bar acceptance procedure hardened
• Manufacturing Process optimised
• Burn-in and screening tuned on reliability

6 bars, 1.8 Gshots 0 dead emitter
Aging conditions QCW 200µs, 100Hz, 25C ,
80W/bar, 100W/bar, 115W/bar,125W/bar
Stack efficiency for different bar cavity lengths
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Receiver Sub-systems (1/2)

• ADM-Aeolus
• ALADIN Pre Development Model
• EM of the ALADIN receiver
• Validate the technology planed for the FM design
• Verify the instrument performance

• Ligthweigth Large Aperture Telescope Technology
  Development
• 9 m2 with lightweight design
• active control wavefront error by arrays of
  actuator
• Electrostatic locking

Optical bench on the vibration shaker seen from
the Mie spectrometer side (Fizeau)
Vibration tests of the Electrostatic locking
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Receiver Sub-systems (2/2)

• EarthCARE filtering and acquisition stages
• Backgroud rejection and FP etalons
• Narrow bandwith interference filter and
  background rejection tunable FP and HSR tunable
  FP

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Receiver components UV Detection Chain
ADM Accumulation CCD On-chip accumulation before
read-out EarthCARE Low Light Level CCD
(Electron Multiplication CCD) at high sampling
rate EarthCARE Advanced PMT Detection
efficiency 30 2 chains to increase Dynamic range
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Receiver components NIR Detectors

• A-SCOPE NIR detectors
• Type II/InAlAs superlattice structure
• InAs

C-V data _at_RT from circular mesa devices
PL data _at_10K
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Instrument Demonstrator
ALADIN Airborne Instrument

• PDM and laser breadboards are refurbished in an
  airborne instrument
• Goal provide realistic atmospheric data in
• a down looking configuration to
• Validate the predicted instrument performance
• Validate the ground processing algorithms

sf 313 kHz
Heterodyne single-shot measurements of frequency
stability in flight
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Conclusion
This work has been carried out by many European
academic and industrial partners Within ESA it
has been supported by Alain Culoma, Jean-Loup
Bézy, Arnaud Hélière, Roland Meynart (EO) Errico
Armandillo, Michael Jost, Nick Nelms, Igor Zayer,
(Technology) For further information, please
visit us atwww.esa.int