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Selective, Sensitive Detection of Dipicolinic Acid and Other Molecules (NO, C 6 H 6 , C 2 H 2 ) Using CARS Techniques

Selective, Sensitive Detection of Dipicolinic Acid and Other Molecules (NO, C 6 H 6 , C 2 H 2 ) Using CARS Techniques. Prof. Robert P. Lucht School of Mechanical Engineering, Purdue University, W. Lafayette, IN Institute for Quantum Studies, Texas A&M University, College Station, TX

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Selective, Sensitive Detection of Dipicolinic Acid and Other Molecules (NO, C 6 H 6 , C 2 H 2 ) Using CARS Techniques

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  1. Selective, Sensitive Detection of Dipicolinic Acid and Other Molecules (NO, C6H6, C2H2) Using CARS Techniques Prof. Robert P. Lucht School of Mechanical Engineering, Purdue University, W. Lafayette, IN Institute for Quantum Studies, Texas A&M University, College Station, TX 2003 TAMU/DARPA/ONR Workshop on Quantum Optics, Jackson Hole, WY, July 7-11, 2003

  2. Acknowledgments • Funding Support from DARPA, DOE Office of Basic Energy Sciences, ARO • Experiments: Sherif Hanna, Waruna Kulatilaka, Jonathan DuBois (Texas A&M MEEN graduate students), Dr. Zane Arp (now at Los Alamos) • Modeling: Joel Kuehner (Univ. Illinois) • Prof. Marlan Scully (Physics), Dr. Tomas Opatrny (Physics),Prof. Phil Hemmer (EE)

  3. Outline of the Presentation • Introduction and Motivation • Laser Diagnostics in Combustion: Dual-Pump CARS • Electronic-Resonance-Enhanced CARS of NO: Experiments and Modeling • Electronic Resonance CARS of C2H2 • CARS Detection of Solid DPA • Conclusions and Future Work

  4. CARS Experiments in Flames Triple-pump CARS measurements performed in laminar hydrogen/air diffusion flame. Simultaneous acquisition of single-shot H2/N2 and H2/O2 spectra demonstrated.

  5. Dual-Pump CO2/N2 CARS Performed in Exhaust of JP8-Fueled Combustor at WPAFB

  6. Dual-Pump CARS of N2/CO2

  7. Dual-Pump CARS Spectrum of N2/CO2 from Hencken Burner N2 CO2 CO2

  8. Anthrax Spore Detection • Weaponized anthrax mailed to Senate offices, National Enquirer offices Fall 2001 • Anthrax difficult to detect in short period of time • Anthrax spores can remain dangerous for years • Anthrax diagnosis must be rapid to prevent severe damage or death

  9. Ultraviolet Resonant Raman Spectra 3b: Calcium Dipicolinate 2b: Bacillus Cereus 1b: Bacillus Megaterium

  10. Research Roadmap “Ordinary” CARS ERE CARS NO CARS Gas Phase Benzene CARS Liquid, 992 cm-1 C2H2 CARS Gas Phase DPA CARS Powder Polycrystalline 998 cm-1 DPA, Benzene CARS DPA in Spores

  11. Electronic-Resonance-Enhanced Coherent Anti-Stokes Raman Scattering (ERE CARS) • ERE CARS was explored as a combustion diagnostic technique by Taran, Attal-Tretout and co-workers from the late 1970s to early 1990s • Technique was complicated both experimentally and theoretically because only two laser frequencies were used, both electronically resonant • Our ERE CARS approach is a variant on the dual-pump CARS technique, demonstrated on NO in gas cell to gain understanding of the physics

  12. ER CARS, Pump 1 = Pump 2 Druet and Taran Prog Quant Elec 1979

  13. Electronic Resonance CARS of NO

  14. Electronic Resonance CARS Detection of NO

  15. ERCARS Beam Geometry

  16. Stokes Scan, Fixed Pump 2

  17. NO CARS Spectrum: Theory

  18. CARS Detection of NO

  19. Electronic Resonance CARS Detection of NO

  20. Electronic Resonance CARS Detection of NO

  21. Polarization Suppression of Nonresonant Background

  22. NO Electronic Resonance CARS with Background Suppression

  23. Stokes Scan, Comparison of Theory and Experiment

  24. Pump 2 Scan, Fixed Stokes

  25. UV Pump Scan, Comparison of Theory and Experiment

  26. Energy Level Diagram

  27. CARS SusceptibilityNear Electronic Resonance Raman resonance Resonance enhancement “Normal” Raman cross section

  28. Detailed Energy Level Diagram

  29. Acetylene ERE CARS Spectrum

  30. Theoretical Acetylene CARS Spectrum

  31. Acetylene Electronic Spectrum Watson et al., J. Mol. Spectrosc. 95, 101 (1982)

  32. DPA, Benzene CARS System

  33. DPA, Benzene CARS Spectra

  34. Conclusions • NO detected by electronic resonance CARS, spectrum observed clearly for 100 ppm NO • Sensitive, selective detection of minority species demonstrated, good agreement between model and experiment • ERE CARS of C2H2 demonstrated, significant resonant enhancement observed • Very strong CARS signal from DPA demonstrated, narrow spectral feature at 998 cm-1 observed

  35. Research Roadmap “Ordinary” CARS ERE CARS NO CARS Gas Phase Benzene CARS Liquid, 992 cm-1 C2H2 CARS Gas Phase DPA CARS Powder Polycrystalline 998 cm-1 DPA, Benzene CARS DPA in Spores

  36. Future Work • Experimental measurements of dissolved DPA and/or solid DPA particles and benzene by ERE CARS • Study two different ERE CARS schemes for DPA: (w1, w2 visible, w3 ultraviolet) or (w1, w2 ultraviolet, w3 = w1) • Work towards ERE CARS microscopy, focus UV beam(s) to less than 10 microns

  37. ERE CARS of DPA

  38. ERE CARS of DPA

  39. Multi-Pump CARS Measurements in Combustion Systems • Electronic resonance CARS technique demonstrated in this work is a variant of the technique of dual-pump CARS • Dual-pump CARS developed for simultaneous measurement of two species in flames

  40. Electronic Resonance Enhancement Factor l0 = 532 nm

  41. Electronic Resonance Enhancement Factor – Saturated w3

  42. Theoretical Acetylene CARS Spectrum

  43. Single-Shot Dual-Pump CO2/N2 CARS Spectrum from JP8-Fueled Combustor

  44. Third-order Perturbation TheoryResult for CARS Susceptibility

  45. NO Electronic Resonance CARS with Background Suppression

  46. Third-order CARS SusceptibilityNear Electronic Resonance ~0 ~0

  47. ER CARS, Pump 1 = Pump 2 Doerk et al. Appl Phys B 1997

  48. Pump 2 Scan, Comparison of Theory and Experiment

  49. NO Electronic Spectroscopy J = N + S

  50. NO Electronic Spectroscopy J = N - S

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