|
Code:
WOA
|
Time Slot/Poster Number:
10:30 - 11:00 am
|
Session:
Coherent Raman II
|
Real-time Detection of Bacterial Spores and Food Contaminants Using Coherent Anti-Stokes Raman Spectroscopy
|
| Marlan Scully2; P. Cremer1; P. Hemmer1; R. Nevels1; T. Phillips1; S. Scully1; T. Siebert1; A. Sokolov1; A. Traverso1; G.R. Welch1; K. Wang1; X. Wang1; H. Xia2; W. Yang1
|
1Texas A&M University, College Park, TX; 2Princeton University, Princeton, NJ
|
|
| View Abstract PDF |
| Summary |
Using a variant on coherent Raman spectroscopy which we call FAST CARS (Femtosecond Adaptive Spectroscopic Techniques for Coherent Anti-Stokes Raman Spectroscopy) we have perfected a realistic method of detecting anthrax-type spores in real-time. Specifically we demonstrate that coherent Raman scattering can be used to accurately identify spores with high selectivity in a few nanoseconds. In another application of this technique we have been studying the rapid identification of myotoxin contaminants, e.g., aflatoxin B1. The present paper proposes and analyses ways in which these techniques can be used to identify selected molecules such as aflatoxin rapidly and economically.
|
|
Code:
WOA
|
Time Slot/Poster Number:
11:00 - 11:30 am
|
Session:
Coherent Raman II
|
Nonlinear Raman Spectroscopy with Shaped Femtosecond Laser Pulses
|
| Marcus Motzkus
|
Universität Heidelberg, Heidelberg, Germany
|
|
| View Abstract PDF |
| Summary |
With the availability of high intensity pulsed laser sources, nonlinear optical phenomena like coherent anti-Stokes Raman Scattering (CARS) have become usable for new approaches in spectroscopic analytics and microscopy. The typical drawback of such experiments is their experimental complexity. However using femtosecond pulse shaping techniques, nonlinear spectroscopy can be performed in an integrated approach, which implements different optical functions in respectively designed pulse shapes. A successful example is single-beam CARS. Here, pulse shaping is used to create multi-colour pulse sequences at defined temporal delays performing truly femtosecond time-resolved vibrational spectroscopy, and also to integrate a local oscillator for interferometric detection.
|
|
Code:
WOA
|
Time Slot/Poster Number:
11:30 am - 12:00 pm
|
Session:
Coherent Raman II
|
Pulse Shaping Strategies for Single-beam CARS
|
| Paul Wrzesinski1; Vadim Lozovoy1; Dmitry Pestov1; Sukesh Roy3; Marcos Dantus1; James Gord2
|
1Department of Chemistry, East Lansing, MI; 2Propulsion Directorate, Air Force Research Labs, Wright Patterson AFB, Ohio; 3Spectral Energies LLC, Dayton , Ohio
|
|
| View Abstract PDF |
| Summary |
Single-beam CARS is a powerful technique that is ideal for chemical-species selective imaging. Our group has been exploring a number of strategies involving phase, amplitude and polarization shaping aimed at selective mode excitation or at acquisition of multiplexed signals with minimum background. Results from both of these approaches and their application in gas, liquid and solid phases will be shown, including applications for the imaging of reacting flow species for combustion diagnostics.
|
|
Code:
WOA
|
Time Slot/Poster Number:
12:00 - 12:20 pm
|
Session:
Coherent Raman II
|
Interferometric Coherent Raman Micro-Spectroscopy with a Low Coherence Supercontinuum Source
|
| Bradley Littleton
|
King's College London, London, United Kingdom
|
|
| View Abstract PDF |
| Summary |
We report on a CARS microscopy system based on a comparatively low cost, commercially available, ultra-broadband supercontinuum source. Despite the low first order coherence of the laser, it was found to still be suitable for CARS microscopy. A simple interferometric method was developed (using only standard polarisation optics) to give spectra of the imaginary component of $\chi^{(3)}$, and suppress the non-resonant background.
|