Sensing combustion intermediates by femtosecond filament excitation.

Simultaneous monitoring of multiple combustion intermediates using femtosecond filament-induced nonlinear spectroscopy is demonstrated. Clean fluorescence emissions from free radicals CH, CN, NH, OH, and C(2), as well as atomic C and H, are observed when a femtosecond filament is formed in the laminar ethanol/air flame on an alcohol burner. The fluorescence signals of these species are found to vary as functions of the position of interaction of the filament with the flame along the vertical axis of the central combusting flow, opening up a possibility for remote combustion diagnostic in engines by the excitation of femtosecond laser filament.

[1]  J. Wolf,et al.  Laser filaments generated and transmitted in highly turbulent air. , 2006, Optics letters.

[2]  A. G. Gaydon,et al.  The identification of molecular spectra , 1950 .

[3]  D. Mishra,et al.  Flame structure of LPG-air Inverse Diffusion Flame in a backstep burner , 2010 .

[4]  G. Roy,et al.  Simultaneous detection and identification of multigas pollutants using filament-induced nonlinear spectroscopy , 2007 .

[5]  Yong‐Lai Zhang,et al.  Designable 3D nanofabrication by femtosecond laser direct writing , 2010 .

[6]  See Leang Chin,et al.  Femtosecond Laser Filamentation for Atmospheric Sensing , 2010, Sensors.

[7]  N. Spinelli,et al.  Detection of fluorescent nanoparticles in flame with femtosecond laser-induced fluorescence anisotropy. , 2008, Optics express.

[8]  Sune Svanberg,et al.  Atomic and Molecular Spectroscopy , 2022, Graduate Texts in Physics.

[9]  G. Roy,et al.  Filament-induced breakdown remote spectroscopy in a polar environment , 2012 .

[10]  J. Biegert,et al.  Pulse self-compression to the single-cycle limit by filamentation in a gas with a pressure gradient. , 2005, Optics letters.

[11]  Xin Yu,et al.  Plasma-assisted combustion of methane using a femtosecond laser. , 2011, Optics letters.

[12]  Johannes Kiefer,et al.  Laser-induced breakdown flame thermometry , 2012 .

[13]  Stelios Couris,et al.  Femtosecond laser induced breakdown for combustion diagnostics , 2012 .

[14]  See Leang Chin,et al.  Femtosecond Laser Filamentation , 2009 .

[15]  Sukesh Roy,et al.  Laser-induced fluorescence detection of hydroxyl (OH) radical by femtosecond excitation. , 2011, Optics letters.

[16]  A. Eckbreth.  Laser Diagnostics for Combustion Temperature and Species , 1988 .