Solar Laser Emission of Light Amplification by Stimulated Radiation Academia Quantum 2015 Light Amplification by Stimulated Emission of Radiation http://www.cefitec.fct.unl.pt/en/lasers

Solar Laser research team Professor Dawei Liang (Head of the research) Filipe Gonçalves (Master student) Cláudia Vistas (Post-Doc researcher) Dário Garcia (Master student) Rochdi Bouadjemine (PhD Student) Joana Almeida (PhD student) Mariana Oliveira (Master Student) Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

Lasers are everywhere… Medicine http://www.theglobeandmail.com/technology/a-healing-light-how-lasers-can-diagnose-and-treat-disease/article4238487/ Laser Guide Star http://eijournal.com/news/industry-insights-trends/laser-communication-provides-near-gigabit-transmission-of-imagery-from-space https://www.youtube.com/watch?v=ngFX_4_dUDE Space communication Military Industry CLEO/EQEC 2015 trade fair https://www.eso.org/public/images/dave-jones-10/ Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

Spectral irradiance (W/m2/µm) Light Amplification by Stimulated Emission of Radiation Fonte de bombeamento Active medium Active medium Solar spectrum 0.4 0.5 0.6 0.7 0.8 1600 1200 800 400 Spectral irradiance (W/m2/µm) Wavelength λ (µm) Absorption (cm-1) 8 6 4 2 Adapted from M. Weksler and J. Shwartz, IEEE J. Quantum Electron. 24(6) (1988) http://www.lasercomponents.com/us/news/ndylf-laser-rods-an-alternative-to-ndyag/ Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

Light Amplification by Stimulated Emission of Radiation Absorption E2 Spontaneous Emission Population Inversion - - - - - - E1 Active medium Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

Light Amplification by Stimulated Emission of Radiation Population Inversion - - - - - - E3 E3 E2 - E2 E1 - - - - - E1 Active medium Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

Light Amplification by Stimulated Emission of Radiation HR mirror (100%) PR mirror (<100%) LASER emission Non-excited state Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

Solar collection and concentration Laser head Heliostat Positioning system Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

Solar collection and concentration 1 MW solar furnace in PROMES-CRNS http://sfera.sollab.eu/index.php?page=access_promes http://www.promes.cnrs.fr/index.php?page=mega-watt-solar-furnace Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

Solar collection and concentration https://www.youtube.com/watch?v=z0_nuvPKIi8 http://www.promes.cnrs.fr/index.php?page=mssf-vertical Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

Solar laser operation Solar Laser / Academia Quantum 2015 https://www.youtube.com/watch?v=wADpzJ0XmH0 https://www.youtube.com/watch?v=F3I-VDAhELg Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

First solar pumped laser C. G. Young, Appl. Opt. 5(6) (1966) 1 W cw Nd:YAG laser Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

Solar laser schemes Solar Laser / Academia Quantum 2015 J. Almeida et al., Laser Phys. 23 (2013). J. Almeida et al., Laser Technol. 44(7) (2012) J. Almeida et al., Appl. Opt 54 (8) (2015) D. Liang et al., Sol. Energ. Mat. Sol. Cells 134 (2015) Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

End-pumping schemes 40 W cw Nd:YAG laser Laser beam Output coupler Concentrated solar radiation Water out Fused silica light-guide Conical cavity 5 mm Nd:YAG crystal HR for 1064 nm PR Resonant cavity (30 mm - 250 mm length) CPC output end Water in J. Almeida, et al., Laser Phys. 23 (2013). HR Nd:YAG crystal Conical cavity Light distribution at the focal spot Light distribution at D2 = 25 mm cross-section Conical light-guide 3D-CPC output end Cooling water Light distribution at the input face of the Nd:YAG rod 5 mm Solar pump light from the parabolic mirror 40 W cw Nd:YAG laser 13.9 W/m2 collection efficiency 2.8% slope efficiency 0.15W brightness figure of merit Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

End-pumping schemes July 2014 Solar Laser / Academia Quantum 2015 Parabolic mirror Power meter Output coupler Conical lens Nd:YAG rod Conical cavity Water outlet Water outlet J. Almeida et al., Appl. Opt 54 (8) (2015) 1.57 0.00 W/mm3 Absorbed pump flux distribution Pabs =208W Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

56 W cw Nd:YAG solar laser by a heliostat – parabolic mirror system End-pumping schemes 56 W cw Nd:YAG laser 21.1 W/m2 collection efficiency 4.9 % slope efficiency 0.028 W brightness figure of merit J. Almeida et al., Appl. Opt 54 (8) (2015) 56 W cw Nd:YAG solar laser by a heliostat – parabolic mirror system CLEO / EQEC 2015

Uniform absorbed pump distribution along the rod Sept. 2011 Rear mirror Nd:YAG laser head Water supply Pump cavity Output mirror Fused silica light guide Side-pumping schemes J. Almeida et al., Laser Technol. 44(7) (2012) Light-guide output end Concentrated solar radiation 22mm 14mm Pump light distribution Water-flooded 2D-CPC pump cavity 120mm Nd:YAG crystal light guide Uniform absorbed pump distribution along the rod 30mm 4mm Water-flooded 2D-CPC cavity Nd:YAG rod Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

(1.6 m away from the output mirror) Side-pumping schemes J. Almeida et al., Laser Technol. 44(7) (2012) 27 W cw Nd:YAG laser 14.6mm 13.8mm Laser beam profile (1.6 m away from the output mirror) 9.6 W/m2 collection efficiency 2.0% slope efficiency 0.29 W brightness figure of merit Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

4 W brightness figure of merit Side-pumping schemes Nd:YAG rod Water in Concentrated solar radiation Rectangular fused silica light guide Water out 2D-CPC concentrator V-shaped pump cavity D. Liang et al., Sol. Energ. Mat. Sol. Cells 134 (2015) 4 W brightness figure of merit Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

Solar lasers – Motivation and Applications Compared to electrically powered lasers, solar laser is simpler and more reliable due to the elimination of the electrical power generation and conditioning equipments. Solar energy is a natural choice in places where sun is abundant and other energy sources are scarce In Portugal… FCT-UNL Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

Deep space communication Solar lasers – Motivation and Applications http://eijournal.com/news/industry-insights-trends/laser-communication-provides-near-gigabit-transmission-of-imagery-from-space Space to earth power transmission Orbital space debris removal Deep space communication This technology is particularly attractive for space-based applications where extended run times are required and where compactness, reliability, and efficiency are critical. As solar energy is the main continuous energy source in space, it can be used to pump solid-state lasers Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

Magnesium – hydrogen renewable energy cycle Solar lasers – Motivation and Applications Solar-pumped laser H2 fuel cells H2 + ½ O2 (combustion) + 86 kcal + Mg Mg fuel cells Mg engines MgO 4000 K H O 2 + Magnesium – hydrogen renewable energy cycle Mg 850 K Mg Mg Mg resource in ocean: 1800 trillion tons T. Yabe et. al., Appl. Phys Lett. 90(26) (2007) Solar Laser / Academia Quantum 2015 http://www.cefitec.fct.unl.pt/en/lasers

I wish I had a solar-pumped laser You wish!! THANK YOU!!!