Development of Mid-infrared Solid-State Lasers

Transcription

1 Development of Mid-infrared Solid-State Lasers M. J. Daniel Esser Team members: C. Jacobs, W. Koen, H. Strauss, D. Preussler, L. R. Botha O. J. P. Collett and C. Bollig Laser Sources Group CSIR National Laser Centre 4 May CSIR 2010 Slide 1

2 Outline of presentation Introduction to diode-pumped solid-state lasers Applications of Mid-infrared solid-state lasers What? Approach to obtain mid-infrared laser output Ho:YLF gain medium High Power Diode Lasers Tm 3+ doped gain media Ho 3+ doped amplifier How? Tm:GdVO 4 laser Tm:YLF slab laser Ho:YLF ring laser Ho:YLF slab amplifier Optically pumped molecular laser Heat load: high Thermal management: optimal Beam quality: low Heat load: high Thermal management: good Beam quality: sufficient Heat load: low Thermal management: good Beam quality: good Lab demonstration Slide 2 Next Phase

3 Diode-pumped Solid-state Lasers Gas lasers Liquid (Dye) lasers Solid-state lasers Semiconductor (diode) Fibre Slide 3

4 Applications of mid-infrared lasers Spectral window in atmosphere Free-space optical communication Defence: protection against heat-seeking missiles Spectral fingerprint of molecular gasses Remote detection of gasses Eye-safe Industrial laser processing Water 1.9 µm Laser surgery without bleeding Slide 4 Depth-selective scalpel

5 DIRCM: Directed Infra-Red Counter Measure MAWS Controller Atmosphere Divergence Target Laser Pointing system Distance ~1-5 km Slide 5 Mode (Continuous / single shot) Power / Energy Beam Quality Wavelength(s)

6 Laser Sources for DIRCM: Directed Infra-Red Counter Measure Jamming Low Average Power Laser ~ 1 Watt Modulation of signal Jamming codes Confuse tracking algorithm Reticule seekers Imaging seekers Multiple threats Damaging/Hard-kill High Energy Laser Joule-level energy Destroy / permanent blinding of seeker No Jamming codes needed Reticule seekers Imaging seekers Multiple threats Dazzling High Average Power Laser ~ 10 Watts Saturation / temporary blinding of seeker Can add Jamming codes Reticule seekers (only with added Jam code) Imaging seekers Multiple threats? Slide 6

7 DIRCM: Directed Infra-Red Counter Measure Application Areas Air Land Sea Anti Aircraft Missiles Anti Tank Guided Missiles IR Anti Ship Missiles Slide 7

8 Laser Sources for DIRCM: Directed Infra-Red Counter Measure Jamming Damaging/Hard-kill Dazzling Low Average Power Laser ~ 1 Watt High Energy Laser Joule-level energy High Average Power Laser ~ 10 Watts Demonstrator Lab demonstration Next phase Solid-state technology 1 µm laser + converters Fieldable system Airborne jamming Jamming codes Pulsed high-energy lasers 2 µm laser + converter Lab demonstrator Destroy detector material World leading Full multi-spectral system 2 µm lasers + converters Portable evaluation tool Demonstrate dazzling Route to industrialisation Slide 8

9 traditional diode-pumped solid-state laser 0.8 µm µm OPO 1 OPO 2 Non-linear conversion 27% 4.0 um 73% 54% 1.45 um 46% 2.3 um 1.9 um Laser Diode Nd 3+ doped solid-state laser CSIR 2010 Slide 9 M. J. D. Esser, et al, International Aerospace Symposium of South Africa (IASSA) (2009)

10 Diode laser 1.9 µm Tm 3+ Laser Ho 3+ 2 µm 3 H 4 2 µm Oscillator 0.8 µm 1.9 µm 2.1 µm 3 F 4 5 I 7 3 H 6 5 I 8 Laser Diode Tm 3+ doped solid-state laser Ho 3+ doped solid-state laser E. H. Bernhardi, et al, 17th International Laser Physics Workshop (LPHYS 08) (invited) (2008) Slide 10

11 Absorption cross section [10 Emission cross section [10-20 cm 2 ] Long upper laser level lifetime (~14 ms), Small quantum defect 1.6 p 1.4 s -20 cm 2 ] Tm:YLF Ho:YLF gain medium Very weak thermal lens on the σ-polarisation, Naturally birefringent Tm:GdVO nm Tm:fibre 1940nm 2064nm Amplify Slide Wavelength [nm] W. Koen, et al, Applied Physics B 99 (1-2) (April 2010) M. J. D. Esser, et al. Appl. Phys. B. 97 (2), (Special Issue) (Sep 2009)

12 Peak Output Power [W] Output Power [W] Tm:GdVO 4 laser End mirror Output Coupler ms, 5 Hz, R = 95 %, 1915 nm 10 ms, 5 Hz, R = 28 %, 1818 nm 20 ms, 5 Hz, R = 28 %, 1818 nm Slope efficiency 28% 10 Optical damage! Slope efficiency 22% 6 QCW CW QCW Slope efficiency 28% Optical dama Thermal fracture! CW lasing, thermal fracture! Slide 12 CSIR 2010 Incident Laser Diode Peak Power [W] Incident Laser Diode Power [W]

13 Tm:YLF slab laser 300 W 792 nm cylindrical lenses r = 300 mm cylindrical lenses 300 W 792 nm Tm:YLF flat R = 95% Tm:YLF laser output Slide M. J. 13D. Esser, et al, 4 th EPS-QEOD Europhoton, WeP29, (2010)

14 Slide 14 Tm:fibre Ho:YLF ring laser

15 Slide 15 Tm:fibre Ho:YLF ring laser

16 Slide 16 Tm:fibre Ho:YLF ring laser

17 Slide 17 Tm:fibre Ho:YLF ring laser

18 Slide 18 Tm:fibre Ho:YLF ring laser

19 Slide 19 Tm:fibre Ho:YLF ring laser

20 Slide 20 Tm:fibre Ho:YLF ring laser Ho:YLF pre-amp

21 Slide 21 Tm:fibre Ho:YLF ring laser Ho:YLF pre-amp

22 Tm:fibre Ho:YLF ring laser Ho:YLF pre-amp Highest energy from a Ho 3+ laser, pumped with one Tm:fibre laser (1 x 80 W) Highest single-frequency singly-doped Ho:YLF laser C. Bollig, M. J. D. Esser, et al, Middle-Infrared Coherent Sources, Mo3 (invited) (2009). Slide 22

23 4um Output Energy [mj] Ho:YLF ring laser molecular gas laser 80W Tm:fibre Laser 2 µm Ring Oscillator & Pre-Amplifier HBr molecules 4 µm E out = xE in Highest energy from an optically pumped HBr laser um Input Energy [mj] L. R. Botha, et al, Optics Express, 17 (22) (Oct 2009). Slide 23

24 Ho:YLF Tm:YLF slab laser Ho:YLF slab amplifier 80W Tm:Fibre Laser 1.9 µm PM R95% PM M3 Amplifier M3 R99% 1.9 µm L6 M1 Tm:YLF Slab Laser 1892 nm 2.1 µm L1 M4 2 µm Laser Ring Oscillator & Pre-Amplifier M4 L2 L3 Amplifier Output λ/2 M3 PM H. Strauss, et al, ASSP (Feb 2011). Slide 24

25 Ho:YLF amplifier molecular gas laser & amplifier M. J. D. Esser, et al, CLEO Europe (May 2011). Slide 25 Highest energy for Optically Pumped Molecular Laser technology First wavelength tuned Optically Pumped HBr laser system

26 Lab demonstration of detector damage InSb material Other detector material Wikipedia: Details not supplied. Indium antimonide is a semiconductor material used in infrared detectors, including thermal imaging cameras, FLIR systems, infrared homing missile guidance systems, and in infrared astronomy. The detectors are sensitive between 1 5 µm wavelengths and is a very common detector in thermal imaging systems. Slide 26

27 Tm laser power [W] Power & Energy scaling of mid-infrared laser technology Page 27 Technology steps / time Ho laser energy 100 [mj] 50 0

28 Next phase High average power Visible 2µm band 3-5µm band 8-12µm band Full multi-spectral system 2 µm lasers + converters Portable evaluation tool Demonstrate dazzling Route to industrialisation Slide 28

29 Thank you for your attention! CSIR 2010 Slide 29

30 DIRCM: Directed Infra-Red Counter Measure Atmosphere Wavelength: Band 2: From 2.2 to 2.4 m Jam code Band 4: From 3.9 to 4.1 m Divergence From 2 to 5 mrad (at 1/e 2 ) Target Active unit Pointing system Distance ~ 3 km Slide 30