slide1 n.
Download
Skip this Video
Download Presentation
Selective, Sensitive Detection of Dipicolinic Acid and Other Molecules (NO, C 6 H 6 , C 2 H 2 ) Using CARS Techniques

Loading in 2 Seconds...

play fullscreen
1 / 50

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


  • 155 Views
  • Uploaded on

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

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Selective, Sensitive Detection of Dipicolinic Acid and Other Molecules (NO, C 6 H 6 , C 2 H 2 ) Using CARS Techniques' - maleah


Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1
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

slide2

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)
outline of the presentation
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
slide4

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.

slide8

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
ultraviolet resonant raman spectra
Ultraviolet Resonant Raman Spectra

3b: Calcium Dipicolinate

2b: Bacillus Cereus

1b: Bacillus Megaterium

slide10

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

slide11

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
slide12

ER CARS, Pump 1 = Pump 2

Druet and Taran

Prog Quant Elec

1979

slide27

CARS SusceptibilityNear Electronic Resonance

Raman resonance

Resonance

enhancement

“Normal” Raman

cross section

slide31

Acetylene Electronic Spectrum

Watson et al., J. Mol.

Spectrosc. 95, 101 (1982)

slide34

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
slide35

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

slide36

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
slide39

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
slide47

ER CARS, Pump 1 = Pump 2

Doerk et al.

Appl Phys B

1997