Dual Wavelength Lasers

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Presented at the Laser Physics Workshop - Barcelona, Spain (July 13 - 17, 2009)

Publication Reference: B.M. Walsh, “Dual Walelength Lasers”, Laser Physics, 20, 622-634 (2010).

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  • Light and its nature have caused a lot of ink to flow during these last decades. Its dual behavior is partly explained by (1)Double-slit experiment of Thomas Young - who represents the photon’s motion as a wave - and also by (2)the Photoelectric effect in which the photon is considered as a particle. A Revolution: SALEH THEORY solves this ambiguity and this difficulty presenting a three-dimensional trajectory for the photon's motion and a new formula to calculate its energy. More information on https://youtu.be/mLtpARXuMbM
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Dual Wavelength Lasers

  1. 1. Dual Wavelength Lasers Brian M. Walsh Norman P. Barnes NASA Langley Research Center Hampton, VA 23681 USA Laser Physics Workshop - Barcelona, Spain (July 13 - 17, 2009) National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  2. 2. Outline • Dual wavelength concept • I. Two Wavelength Oscillation (TWO) - Er:Tm:Ho:YAG (2.0 and 2.9 µm) • II. Synchronous Tunable Optical Pulses (STOP) - Nd:YAG (1.0xx and 1.3xx µm) • IIa. Non-linear optics - SHG, sum frequency techniques • III. Other dual-λ lasers - Er:Nd:YAG (2.9 µm and 1 µm) - Ho:Nd:YAG (3 µm and 1 µm) • Summary National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  3. 3. Dual Wavelength Concept • Dual wavelength lasing on separate dopant ions: - Energy transfer dynamics between the ions - Lifetimes of the upper laser manifolds - Duration of the pump pulse • Dual wavelength lasing on same dopant ion: - System design (e.g., prisms, mirrors, resonator design) - Laser transition cross section • Advantages - Can produce widely or closely separated wavelengths - Sum frequency, difference frequency readily implemented - One laser serves dual purpose (efficient & cost effective) - Medicine, remote sensing, surveillance, machining National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  4. 4. I. Er:Tm:Ho dual-λ laser National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  5. 5. TWO Laser schematic Laser National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  6. 6. Er:Tm Energy Transfer 1.) 2.) 3.) 4.) 5.) R. Balda, et. al., Optics Express, 17, 8788 (2009) National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  7. 7. Er:Tm:Ho Energy Transfer 15000 Short pump pulse - 2.9 µm Er lasing 4I Long pump pulse - 2.1 µm Ho lasing 9/2 Intermediate pump pulse - Er and Ho 1 4I 11/2 10000 (! = 100 µs) 2.9 µm Energy (cm -1) 3H 5I 5 6 4I 13/2 (! = 9 ms) 3F 4 5I 5000 (! = 14 ms) 7 (! = 8 ms) 2 2 3 3 2.1 µm 4 4 4I 3H 5I 15/2 0 6 8 Er3 + YAG Tm3 + YAG Ho3 + YAG National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  8. 8. Pump Pulse Wavelength Tuning Short, high intensity Long, low intensity 2.9 µm 2.1 µm Time Time Moderate length, mid-intensity 2.9 µm 2.1 µm Time National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  9. 9. Er Lifetime Quenching 1.0 Er 4!11/2 Manifold Lifetime "2.9 µm upper laser level" 0.8 4I11/2 Normalized Intensity Sample Lifetime 0.6 30%, 50%,60% Er YAG 90 µsec 10% Er 1% Ho 80 µsec 0.4 10% Er 4% Tm 50 µsec 10% Er 4% Tm 0.5% Ho 40 µsec 0.2 10% Er 5% Tm 1.0% Ho 35 µsec 0.0 0 50 100 150 200 250 300 Time (µs) National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  10. 10. Er:Tm:Ho pulse switched lasing 1.2 Er 2.9 µm, 100 µs pump pulse, 0.90R OC Ho 2.1 µm, 1 ms pump pulse, 0.95R OC 1.0 Cr(1)Er(35)Tm(0.7)Ho(0.35) YAG 6x122 mm laser rod 0.80 Laser Energy (J) 0.60 0.40 0.20 0.0 0 50 100 150 200 Electrical energy (J) National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  11. 11. Er:Tm:Ho Simultaneous lasing 1 ms 100 µs 350 350 2.1 micron (0.95R) 2.1 micron (0.95R) 2.9 micron (0.85R) 2.9 micron (0.85R) 300 300 250 250 Laser Energy (mJ) Laser Energy (mJ) 200 200 150 150 100 100 50 50 0 0 50 100 150 200 10 20 30 40 50 60 70 80 90 Electrical energy (J) Electrical energy (J) National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  12. 12. II. Nd:YAG dual-λ laser National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  13. 13. STOP laser schematic Output Nd:YAG diode Q-Switch Synchronous Mirror Pumped Head laser pulses Quartz Prisms 1.0xx µm HR mirror 1.3xx µm HR mirror National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  14. 14. Dispersive Tuning in Nd:YAG -20 L( m) e(10 cm2) (cm-1) EETH(J) s 1.0520 9.62 5.7 4.93 0.0123 1.0614 20.62 4.8 2.60 0.0184 4F → 4I11/2 3/2 1.0641 27.74 6.0 1.99 0.0193 Parameters 1.0737 15.15 5.2 3.62 0.0139 1.0779 6.26 9.9 7.63 0.0095 1.1120 3.97 12.1 10.28 0.0113 1.1160 3.95 14.4 11.48 0.0104 1.1225 3.97 11.4 11.26 0.0112 -20 L( m) e(10 cm2) (cm-1) EETH(J) s 1.3187 8.92 4.5 6.64 0.0127 4F → 3/2 4I 13/2 1.3336 4.03 3.7 11.82 0.0104 Parameters 1.3381 9.57 5.0 6.53 0.0131 1.3564 7.35 6.6 8.42 0.0107 National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  15. 15. Synchronous Pulses 12000 4F R2 11506 3/2 R1 11421 • Synchronous pulses require equal 11000 pulse evolution time intervals - Different emission cross sections 5000 X7 4494 - Resonator lengths adjustable X6 4432 5X ? 4I 13/2 X4 X3 4050 4035 - Output losses adjustable (output coupling) 4000 X2 3932 X1 3925 1 , c % c ( / " . ln ( R M R L ) + 2# el$ ' * ( E EP + E LTH ) 1 ! c - 2lc & 2lc ) 3000 Y6 Y5 2515 0 2462 4I 11/2 Y4 2146 Y3 2111 Y2 2000 Y1 2029 2003 1000 Z5 852 4I 9/2 Z4 312 Z3 199 Z2 133 0 Z1 0 -1 0 1 2 3 4 Nd3+:YAG Time (µs) National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  16. 16. STOP light laser performance 0.60 35 1.052 QS Inverse of pulse evolution interval (µs-1) 1.052 1.319 30 1.319 QS 0.50 Both QS 25 0.40 Laser Energy (mJ) 20 0.30 15 0.20 10 0.10 5 0.0 0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 0.6 0.8 1.0 1.2 1.4 1.6 Electrical energy (J) Electrical Energy (J) National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  17. 17. IIa. Non-linear optics National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  18. 18. Non-linear Conversion VIS UV Synchronous Synchronous Tunable laser pulses BBO waveplate BBO Optical Crystal 1/2 wave Crystal at 0.59 µm Pulses SHG sum frequency SHG ~ 0.660 mm ~ 0.585 mm ~ 0.526 mm Red Orange Green National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  19. 19. One dual laser - 172 wavelengths A 3F 3/2 → 4I13/2 3F 3/2 → 4I11/2 B 1.00 1.05 1.10 1.15 1.20 1.25 1.30 1.35 1.40 Wavelength ( µm) 4A 2(A+B) 3A A+2B 2A A+B 4B B+2A 3B 2B 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 Wavelength ( µm) National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  20. 20. III. Other dual-λ lasers National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  21. 21. Nd:Er:YAG 4F 4I 3/2 9/2 12000 (! = 240 µs) 3 4I 11/2 10000 (! = 100 µs) 1 1.06 µm 2 2.9 µm 8000 Energy (cm -1) 4I 4I 13/2 15/2 (! = 9 ms) 6000 4I 13/2 4000 1 2 4I 11/2 2000 4I 4I 9/2 15/2 0 Nd:YAG Er:YAG National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  22. 22. Nd:Ho:YAG 12000 4F 5I 3/2 5 (! = 240 µs) (! = 1 µs) 10000 1 2 5I 1 6 1.06 µm (! = 50 µs) 8000 3.0 µm Energy (cm -1) 4I 6000 15/2 5I 7 (! = 8 ms) 4I 4000 13/2 4I 2000 11/2 4I 5I 9/2 8 0 Nd:YAG Ho:YAG National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  23. 23. Summary • Dual-λ lasers discussed and demonstrated - Er:Tm:Ho:YAG (TWO laser) - Nd:YAG (STOP laser) • Physics & engineering criteria - energy transfer, lifetime, transition cross section - Optics, resonator design, pumping schemes • Non-linear techniques - SHG and sum frequency techniques - Multitude of harmonic wavelengths realized • Future work - What new potential dual- λ lasers exist? - Driven by application needs, multiple solutions National Aeronautics and Laser Physics Workshop Space Administration Barcelona, Spain (July 13-17, 2009)
  24. 24. NASA Langley Brian M. Walsh Research Center Laser Remote Sensing Branch National Aeronautics and Laser Physics Workshop Email: brian.m.walsh@nasa.gov Space Administration Barcelona, Spain (July 13-17, 2009) Phone: 757 864-7112

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