Solid State Lasers and Nonlinear Optics Sources for Remote Sensing and Imaging: Past, Present and Future OSA Topical Meeting Applications of Lasers for Sensing and Free Space Communications San Diego, CA February 3, 2010 Paper LSWE3 Kevin Wall Q-Peak, Inc.
Outline Sources for lidar Aerosol DIAL Wind-sensing Source for ladar Ranging 3-D imaging Future technologies Hybrid (fiber-bulk) lasers QCL-seeded OPOs Contributions from: Glen Rines, John Flint, Yelena Isyanova, Alex Dergachev, Kevin Wall and Peter Moulton
High-energy KTP OPO allows generation of eyesafe pulsed power for aerosol sensing Q-switched Nd:YAG Osc / Amp 1064 nm, 0-1.1 J, 10 ns, 10 Hz -or- Q-switched Nd:YLF 1053 nm, 0-240 mj, 10 ns, 10-50 Hz - or - 625 mj, 30 Hz KTP OPO OPO Signal Output Telescope Input Mirror Highest-energy, ns-opo ever? Output Mirror 1571-nm OPO Output 500 400 300 200 100 4.5 W average power 0 0.2 0.4 0.6 0.8 1 1.2 1064-nm Pump Energy (J)
Compact, ruggedized lamp-pumped laser (CLH) with internal OPO
Compact Field-Deployable Lidar System built at Los Alamos used Q-Peak CLH OPO system System Specifications Output wavelength 1550 nm Pulse length < 10 ns Output power > 7.2 Watts Repetition rate 0 to 50 Hz Telescope aperture 10" Telescope focal length f/10 Field-of-View 0.5 mrad Bandpass filter width 3 nm Detector efficiency 0.7 Total weight < 300 lbs
Application of CLEAR lidar to urban areas
Army biological standoff detection system (LR-BSDS) used Q-Peak high-power OPO
Development of large-aperture KTA crystals enables OPO operation at high average powers %T 100 80 60 40 20 0 T = 75% @ 3297nm T = 23% @ 3297nm KTA 2cm KTP 2cm 3000 3200 3400 3600 3800 4000 Wavelength (nm) Signal Power (Watts) 35 30 25 20 15 10 5 0 0 20 40 60 80 100 120 Pump Power (Watts) M.S. Webb et al. Opt.Lett. 23, 1161 (1998) Absorption of the idler (3297 nm) energy in KTP crystals causes unacceptable crystal heating at high OPO pulse rates. KTA crystals do not absorb the idler, and allow operation at virtually unlimited average powers.
Detail of LR-BSDS system mounted in UH-60 Use of a 7 diameter transmit telescope allows eyesafe operation at the aperture, even with system having a 30-W average-power transmitter
Outline Sources for lidar Aerosol DIAL Wind-sensing Source for ladar Ranging 3-D imaging Future technologies Hybrid (fiber-bulk) lasers QCL-seeded OPOs
Laser-pumped, high-energy, ns Ti:sapphire laser Pump #1 Ti:sapphire crystals Output Prisms Pump #2 GRM 10-20-ns pulse duration diffraction-limited HR 500 450 Developed with NASA Langley, DARPA support, 1986-1992 Ti:sapphire output energy (mj) 400 350 300 250 200 150 100 790 nm 727 nm 911 nm 960 nm 50 0 0 200 400 600 800 1000 1200 1400 Green pump energy (mj)
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
Harmonic conversion of Ti:sapphire lasers for species sensing Harmonic 4th NO 3rd Benzene Toluene Ozone Cl2 Hg SO2 2nd NO2 700 750 800 850 900 950 Wavelength (nm)
Performance of third-harmonic converter to 300-nm region for ozone (NASA funded) 35.00 50.0 Output - unseeded THG Output Energy (mj) 30.00 25.00 20.00 15.00 10.00 45.0 40.0 35.0 30.0 25.0 20.0 15.0 Efficiency (%) Output - seeded Efficiency - unseeded Efficiency - seeded 5.00 10.0 5.0 0.00 0.0 0 20 40 60 80 100 Input Energy (mj)
Facility for Airborne Atmospheric Measurements (FAAM) (UK) BAE 146-301 Large Atmospheric Research Aircraft G-LUXE
Detailed block diagram of FAAM lidar source for ozone and water-vapor DIAL 25-Hz pulse rate, 5 pulses each a new wavelength, repeat Master Control Seed Laser Control/Drive Pump Laser Lamp Drivers Wavemeter Computer ECDL SEED ECDL SEED ECDL SEED ECDL SEED ECDL SEED Wavemeter Pulsed Ti:sapphire Laser CLH Pump Laser Harmonic Generation Ramp /Lock Electronics UV Output 297-319 nm NIR Output 942-942 nm Lasers Cooling Switch Optical bench Electronics rack Optical Electrical Coolant
Final box design for FAAM lidar
High-energy, 1-kHz, diode-pumped Nd:YLF MOPA (driver for OPO-based ozone DIAL system) 30-W Fiber-coupled diode laser Single-frequency, passively Q-switched Nd:YLF Oscillator, 1 mj Pre-amplifier 2 15 mj Pre-amplifier 1 5 mj Double Isolator h Quasi-CW pumping h 1 khz pulse rate h 500-μsec pump pulses h 50% duty cycle W/2x60 W diodes Pre-amplifier 3 24 mj W/2x90 W diodes W/2x40 W diodes Final amplifier 55 mj W / 285 W nlight Cascade Laser hend- & side-pumping hsimple relay-imaging hsingle frequency h10-nsec pulses h55 mj per pulse
Outline Sources for lidar Aerosol DIAL Wind-sensing Source for ladar Ranging 3-D imaging Future technologies Hybrid (fiber-bulk) lasers QCL-seeded OPOs
SALTS 2-micron coherent lidar source built for Lockheed for wind profiling off ships OUTPUT M1 AO Q-SWITCH M4 COLLIMATING LENS M3 M2 PUMP FOCUSING LENS TE COOLER LASER CRYSTAL FIBER-COUPLED 15 WATT LASER DIODE BIFURCATED FIBER 1-W single-frequency unidirectional ring
4 mj, 1 khz PRR single-frequency source at 349 nm for incoherent-detection wind-sensing 1 2 3 Optical Isolator 1 Amplifier Gain Module w/ 90-W Lightstone diodes 1 1 UV-Contoller Photodetector SLM Seed Laser 10 11 5 9 4 7 12 12 13, 14 1 17 349-nm output 1047-nm output 8 Seeder Electronics Photodetector Oscillator Gain Module w/ 40-W diodes 6 1 15 NCPM LBO CPM LBO (SHG) crystal (THG) crystal 16 Beam dump G-5398
Outline Sources for lidar Aerosol DIAL Wind-sensing Source for ladar Ranging 3-D imaging Future technologies Hybrid (fiber-bulk) lasers QCL-seeded OPOs
SLR2000 transmitter for precision satellite ranging based on amplified microchip Nd:YVO 4 Multipass Amplifier Cylindrical lens HR Mirror SHG Nd:YAG/Cr:YAG Microlaser 532-nm beam Fiber Design: MPV-amplified microchip laser Pulse duration: 200-300 ps Pulse energy: 200 uj at 532 nm Pulse rate: 2 khz λ/2 plate Isolator λ/2 plate Telescope Diode laser Photograph of hardware designed for remote, autonomous operation
MPS short-pulse technology, 1 khz rate, for satellite-ground ranging Short-pulse Nd:YLF laser (1.5 mj, 7.5 ns) Laser diode Fiber bundle Nd:YLF Amplifier Imaging telescope Nd:YLF crystal HR/HT coating Lens AR coating Q-switch Output coupler HR Mirror Complete system (10.5 mj, 1 khz) 1047-nm output Cylindrical lens Spherical lens Nd:YLF Laser λ/2 plate Isolator
Outline Sources for lidar Aerosol DIAL Wind-sensing Source for ladar Ranging 3-D imaging Future technologies Hybrid (fiber-bulk) lasers QCL-seeded OPOs
Nd:YVO 4 laser head and pump assembly design for autonomous munitions testing Semi-Tactical Pump Assembly 10 W @ 1 μm RS-232 Ext. Trigger 28 V 28 V Temperature Controller Temp. Set Micro-Controller Current Set Current Sense 0-28 V Temp. Sense Diode Temp. RF Control 28 V TE Coolers Q-Switch Driver Diode Laser RF Output Coupler Q-Switch Schematic of system 10-W average power 30-100 khz 6-10 ns pulses TEMoo 28 V Diode-Laser Current Source 0-40 Amp. Laser Crystal Optical Fiber Laser Head Photograph of system flown in helicopters and jet aircraft Used 2-D scanner, range sensing to build 3-D image
Ruggedized laser for advanced ladar Power supply DC-DC converter RS-232 controlled Laser head: Nd:YLF 1047 nm 30 W Pave, TEMoo 3-9 khz, 8-15 ns pulses Used linear array, vehicle motion to build 3-D image
Transmitter for LANL RULLI System HR HR HR λ/2 PBS ROT ISO λ/2 SHG OSC DM HR DM FCL MPV BD Output HR System stage Parameter Value Master Wavelength 1064 nm Oscillator: Linewidth < 0.1 nm Beam quality TEM 00 Osc diode current: 1.0-2.0 A Nominal 2.5 A Maximum Pulsewidth ~0.9 ns Repetition rate range 20-200 khz Nominal Power 0.52 W Nominal Amplifier: Amp diode current: 30 A Nominal 34 A Maximum Power (2-pass) 10 W Nominal 12 W Maximum SHG: Wavelength 532 nm Pulsewidth ~0.8 ns Power 5.0 W Nominal 7.5W Maximum
Outline Sources for lidar Aerosol DIAL Wind-sensing Source for ladar Ranging 3-D imaging Future technologies Hybrid (fiber-bulk) lasers QCL-seeded OPOs
Motivation for hybrid system Development of a 2050-nm laser source: High-energy (> 200 mj) High repetition rate (200-1000 Hz) High beam quality (TEM 00 ) CW 1940 nm >200 mj 2050 nm Tm:fiber laser Ho:YLF OSC Ho:YLF AMPs Immediate applications: 200 Hz - 1000 Hz Pump source for OPOs (IR DIAL and long-path sensing) Long-range 2D and 3D imaging, coherent systems for Doppler and vibrometry sensing
2050-nm Ho:YLF MOPA Tm-pump #1 ~120 W at 1940 nm Osc/ Amp #1 Ho-stage/ Regime CW 100 Hz 500 Hz Tm-pump #2 ~120 W at 1940 nm Tm-pump #3 ~120 W at 1940 nm Amp #2 Amp #3 Osc/Amp #1 39 W 55 mj 50 mj Amp#2 76 W 110 mj 95 mj Amp#3 115 W 170 mj 140 mj Tm-fiber laser TLR-100-1940 IPG Photonics www.ipgphotonics.com Operation regime Beam Profile Output power Wavelength Polarization Linewidth CW TEMoo 120 W 1940 nm Random 2 nm
> 1 kw of power output at 2045 nm from Tm:fiber laser 1200 1000 Signal Power (W) 800 600 400 53.2% slope 200 0 0 500 1000 1500 2000 Pump Power (W)
Outline Sources for lidar Aerosol DIAL Wind-sensing Source for ladar Ranging 3-D imaging Future technologies Hybrid (fiber-bulk) lasers QCL-seeded OPOs
MWIR OPOs nanosecond pulse, high beam quality 9 Tuning curve of ZGP OPO pump at 2050 nm covers entire MWIR band RISTRA OPO (with Sandia collaboration) provides high beam quality Signal, idler wavelengths (um) 8 7 6 5 4 3 2 51 52 53 54 55 56 57 58 Angle (degrees) 10-W average power, 3400 nm at 500 Hz OPO-OPA design produces high energy 35 30 OPA output DM3 DM4 Ho-MOPA DM1 OPA ZGP 10 mm DM2 BS Ch. 1 <60 mj Ristra OPO ZGP 10 mm HR HR OPA output (mj) Signal seed ~10 mj 25 Signal seed ~9 mj 20 Signal seed ~9 mj 15 10 5 0 0 20 40 60 80 100 120 Ho-pump energy (mj) 100 Hz 300 Hz 500 Hz
Quantum-cascade-laser (QCL) seed provides wavelength control and narrow linewidth 2050-nm pump laser QCL seeder MIR OPO 2.2 to 4.0 um signal output 4.0 to 22 um idler output Design goal: 200 mj/pulse >50-Hz PRR pump laser Photograph of ZGP OPO demonstration
Summary Solid state lasers (fixed wavelength or tunable) combined with nonlinear optics provide: Conversion of non-eyesafe to eyesafe wavelengths, for aerosol detection Power tunable to absorption lines of atmospheric species, for DIAL systems Short-pulses at high rates for range-and 3-D imaging Single-frequency, narrow-linewidth power for wind and vibration sensing Emergence of diode-pumping technology favors use of higher pulse rates and lower pulse energies, if averaging is possible Hybrid (fiber-bulk) systems combine high efficiency of cw fiber lasers with high pulse energies of bulk materials QCLs (and variants) combined with OPOs provide a new, narrowlinewidth, high-peak-power source for DIAL and other sensing