Patterned Border Template 1 Purdue University School of Mechanical Engineering 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 2003 TAMU/DARPA/ONR Workshop on Quantum Optics, Jackson Hole, WY, July 7-11, 2003

Patterned Border Template 2 Purdue University School of Mechanical Engineering 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)

Patterned Border Template 3 Purdue University School of Mechanical Engineering 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 C 2 H 2 CARS Detection of Solid DPA Conclusions and Future Work

Patterned Border Template 4 Purdue University School of Mechanical Engineering Triple-pump CARS measurements performed in laminar hydrogen/air diffusion flame. Simultaneous acquisition of single-shot H 2 /N 2 and H 2 /O 2 spectra demonstrated. CARS Experiments in Flames

Patterned Border Template 5 Purdue University School of Mechanical Engineering Dual-Pump CO 2 /N 2 CARS Performed in Exhaust of JP8- Fueled Combustor at WPAFB

Patterned Border Template 6 Purdue University School of Mechanical Engineering Dual-Pump CARS of N 2 /CO 2

Patterned Border Template 7 Purdue University School of Mechanical Engineering Dual-Pump CARS Spectrum of N 2 /CO 2 from Hencken Burner N2N2 CO 2

Patterned Border Template 8 Purdue University School of Mechanical Engineering 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

Patterned Border Template 9 Purdue University School of Mechanical Engineering Ultraviolet Resonant Raman Spectra 3b: Calcium Dipicolinate 2b: Bacillus Cereus 1b: Bacillus Megaterium

Patterned Border Template 10 Purdue University School of Mechanical Engineering Research Roadmap “Ordinary” CARSERE CARS Benzene CARS Liquid, 992 cm -1 DPA CARS Powder Polycrystalline 998 cm -1 NO CARS Gas Phase C 2 H 2 CARS Gas Phase DPA, Benzene CARS DPA in Spores

Patterned Border Template 11 Purdue University School of Mechanical Engineering 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

Patterned Border Template 12 Purdue University School of Mechanical Engineering Druet and Taran Prog Quant Elec 1979 ER CARS, Pump 1 = Pump 2

Patterned Border Template 13 Purdue University School of Mechanical Engineering Electronic Resonance CARS of NO

Patterned Border Template 14 Purdue University School of Mechanical Engineering Electronic Resonance CARS Detection of NO

Patterned Border Template 15 Purdue University School of Mechanical Engineering ERCARS Beam Geometry

Patterned Border Template 16 Purdue University School of Mechanical Engineering Stokes Scan, Fixed Pump 2

Patterned Border Template 17 Purdue University School of Mechanical Engineering NO CARS Spectrum: Theory

Patterned Border Template 18 Purdue University School of Mechanical Engineering CARS Detection of NO

Patterned Border Template 19 Purdue University School of Mechanical Engineering Electronic Resonance CARS Detection of NO

Patterned Border Template 20 Purdue University School of Mechanical Engineering Electronic Resonance CARS Detection of NO

Patterned Border Template 21 Purdue University School of Mechanical Engineering Polarization Suppression of Nonresonant Background

Patterned Border Template 22 Purdue University School of Mechanical Engineering NO Electronic Resonance CARS with Background Suppression

Patterned Border Template 23 Purdue University School of Mechanical Engineering Stokes Scan, Comparison of Theory and Experiment

Patterned Border Template 24 Purdue University School of Mechanical Engineering Pump 2 Scan, Fixed Stokes

Patterned Border Template 25 Purdue University School of Mechanical Engineering UV Pump Scan, Comparison of Theory and Experiment

Patterned Border Template 26 Purdue University School of Mechanical Engineering Energy Level Diagram

Patterned Border Template 27 Purdue University School of Mechanical Engineering CARS Susceptibility Near Electronic Resonance Resonance enhancement “Normal” Raman cross section Raman resonance

Patterned Border Template 28 Purdue University School of Mechanical Engineering Detailed Energy Level Diagram

Patterned Border Template 29 Purdue University School of Mechanical Engineering Acetylene ERE CARS Spectrum

Patterned Border Template 30 Purdue University School of Mechanical Engineering Theoretical Acetylene CARS Spectrum

Patterned Border Template 31 Purdue University School of Mechanical Engineering Acetylene Electronic Spectrum Watson et al., J. Mol. Spectrosc. 95, 101 (1982)

Patterned Border Template 32 Purdue University School of Mechanical Engineering DPA, Benzene CARS System

Patterned Border Template 33 Purdue University School of Mechanical Engineering DPA, Benzene CARS Spectra

Patterned Border Template 34 Purdue University School of Mechanical Engineering 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 C 2 H 2 demonstrated, significant resonant enhancement observed Very strong CARS signal from DPA demonstrated, narrow spectral feature at 998 cm -1 observed

Patterned Border Template 35 Purdue University School of Mechanical Engineering Research Roadmap “Ordinary” CARSERE CARS Benzene CARS Liquid, 992 cm -1 DPA CARS Powder Polycrystalline 998 cm -1 NO CARS Gas Phase C 2 H 2 CARS Gas Phase DPA, Benzene CARS DPA in Spores

Patterned Border Template 36 Purdue University School of Mechanical Engineering 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: (  1,  2 visible,  3 ultraviolet) or (  1,  2 ultraviolet,  3 =  1 ) Work towards ERE CARS microscopy, focus UV beam(s) to less than 10 microns

Patterned Border Template 37 Purdue University School of Mechanical Engineering ERE CARS of DPA

Patterned Border Template 38 Purdue University School of Mechanical Engineering ERE CARS of DPA

Patterned Border Template 39 Purdue University School of Mechanical Engineering 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

Patterned Border Template 40 Purdue University School of Mechanical Engineering Electronic Resonance Enhancement Factor 0 = 532 nm

Patterned Border Template 41 Purdue University School of Mechanical Engineering Electronic Resonance Enhancement Factor – Saturated  3

Patterned Border Template 42 Purdue University School of Mechanical Engineering Theoretical Acetylene CARS Spectrum

Patterned Border Template 43 Purdue University School of Mechanical Engineering Single-Shot Dual-Pump CO 2 /N 2 CARS Spectrum from JP8-Fueled Combustor

Patterned Border Template 44 Purdue University School of Mechanical Engineering Third-order Perturbation Theory Result for CARS Susceptibility

Patterned Border Template 45 Purdue University School of Mechanical Engineering NO Electronic Resonance CARS with Background Suppression

Patterned Border Template 46 Purdue University School of Mechanical Engineering Third-order CARS Susceptibility Near Electronic Resonance ~0

Patterned Border Template 47 Purdue University School of Mechanical Engineering ER CARS, Pump 1 = Pump 2 Doerk et al. Appl Phys B 1997

Patterned Border Template 48 Purdue University School of Mechanical Engineering Pump 2 Scan, Comparison of Theory and Experiment

Patterned Border Template 49 Purdue University School of Mechanical Engineering NO Electronic Spectroscopy J = N + S

Patterned Border Template 50 Purdue University School of Mechanical Engineering NO Electronic Spectroscopy J = N - S