Research

Optical & Laser Diagnostic Techniques at ODIL (“Laser Diagnostics Toolkit”):

Laser-Induced Fluorescence (LIF)**
Laser-Induced Breakdown Spectroscopy (LIBS)
Coherent Anti-Stokes Raman Scattering (CARS)
Polarization Spectroscopy & Wave-Mixing Techniques
Optical Emission Spectroscopy (OES) & High-Speed Chemiluminescence Imaging
Rayleigh Scattering
Digital Inline Holography (DIH)
Particle Image Velocimetry (PIV)
Laser-Induced Incandescence (LII)
High-Speed Shadowgraphy & Digital Particle Tracking
Schlieren Imaging (including Self-Aligned Focusing Schlieren-SAFS)
Other: Absorption Spectroscopy, Femtosecond-Laser Electronic Excitation Tagging (FLEET), Raman Scattering,…

Laser-Induced Fluorescence (LIF):

Why LIF? “Laser-induced fluorescence (LIF) is a spectroscopic technique that involves the excitation of a molecular target by a beam of laser radiation followed by the detection of the subsequent emission of radiation from the target. LIF detection has several advantages over absorption spectroscopy. First, LIF has excellent detection sensitivity because a signal is observed against a dark background. Second, the emitted radiation can be collected at various angles with respect to the incoming laser beam, making it possible to obtain two- and three-dimensional images because the fluorescence is emitted in all directions. Third, by dispersing the fluorescence, it is also possible to learn about the transitions from the state excited to the various lower levels of the target species. Finally, because of the delay between the excitation and detection events, it is also possible to learn about what processes the excited target undergoes in the intervening time.” Richard N. Zare 2012: “My Life with LIF: A Personal Account of Developing Laser-Induced Fluorescence,” Annu. Rev. Anal. Chem. 2012. 5:1–14 (DOI: 10.1146/annurev-anchem-062011-143148).

Why Two-Photon LIF? “I had a busy job in Washington at the time when various groups were trying to make the earliest lasers. But I was also supervising graduate students at Columbia University who were trying to make continuously pumped infrared lasers. Shortly after the ruby laser came out I advised them to stop this work and instead capitalize on the power of the new ruby laser to do an experiment on two-photon excitation of atoms. This was one of the early experiments in nonlinear optics, and two-photon excitation is now widely used to study atoms and molecules.” Charles H. Townes 2003: “The first laser, Charles H. Townes,” from A Century of Nature: Twenty One Discoveries that Changed Science and the World, Laura Garwin and Tim Lincoln, editors, Chicago University Press. 2003.

Why Femtosecond Two-Photon LIF?

Outcomes of Laser Diagnostics Toolkit:

Non-intrusive measurement in reacting and non-reacting flows and extreme events:

Physical Properties → Temperature, Pressure, Velocity, Density, Heat Release, Flow Structures/Mixing, Turbulence/Vorticity,…..
Chemical Properties → Chemical Species Imaging (H, O, N, C, Kr, Xe, OH, CH, NO, NH, CO, CH2O, C2H2, NH3, …..)
Particles → Size, Shape, Velocity/Acceleration, Momentum, Chemical Speciation,…..

Research Thrust A: Fundamentals of Laser-Matter Interactions & Diagnostics Development: S&T (Select Examples):

Research Thrust B: Laser Diagnostics Applications: S&T and R&D (Select Examples):

ODIL Equipment & Facilities:

Amplified femtosecond lasers and frequency-conversion units
Nd:YAG lasers and dye lasers
High-power CW lasers
KHz–MHz-rate pulse burst laser
High-speed CMOS cameras and image intensifiers
Intensified CCD (ICCD) cameras
High-resolution dual-frame PIV camera
High-resolution spectrometers
Fiber-coupled spectrometers
High-bandwidth digital oscilloscope
High-pressure, low-pressure modular burner
High-pressure gas cell
Calibration burners (Hencken, McKenna, Bunsen burners)
Turbulent Jet burner
Piloted liquid-spray burner.
Numerous optics, optical components, and imaging systems
Various electronics and diagnostic hardware

TAMU Collaborator Facilities & Centers:

Collaborators & Co-Authors from External Institutions:

Air Force Research Laboratory (AFRL), Aerospace Systems Directorate
Argonne National Laboratory (ANL), Chemical Sciences and Engineering Division
Complexe de Recherche Interprofessionnel en Aérothermochimie (CORIA), France
Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Italy
Los Alamos National Laboratory (LANL), Non-Destructive Testing & Evaluation Branch
Sandia National Laboratories (SNL), Combustion Research Facility (CRF)
University of California, Berkley, USA, Dept. of Mechanical Eng.
University of Duisburg-Essen, Germany, Institute for Energy and Materials Processes
University of Lille-CNRS, France, PC2A
University of Michigan, USA, Dept. of Mechanical Eng.
University of Texas at El Paso, Dept. of Metallurgical, Materials and Biomedical Eng.
University of Tokyo, Japan, Mechanical Eng.

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