Laser-Based Multiphoton Excitation Processes in Combustion Diagnostics
Abstract
Light atomic species such as oxygen atoms (O) and hydrogen atoms (H) are fundamentally important in a wide variety of combustion related phenomena such as flame ignition, propagation, extinction, and in chemical flame reactions. Furthermore, they are difficult to detect by conventional laser based optical methods (laser induced fluorescence) in combustion environments because the necessary resonance excitation wavelengths fall far into the vacuum ultraviolet (vuv) and the requisite tunable laser sources are not generally available. However, recent developments in nonlinear spectroscopic techniques such as multiphoton induced emission (MPE) and multiphoton ionization (MPI) have made direct detection of these light atoms possible. We have utilized a number of laser multiphoton excitation schemes for their detection using tunable lasers in the 190-400 nm range. Similar diagnostic techniques were attempted for the detection of carbon (C) and nitrogen (N) atoms in flames. The effects of laser induced photochemical perturbations on species detection in flames were also investigated. Keywords: Atoms, Laser induced fluorescence, Multiphoton ionization, Optogalvanic, Flames, Fuel, Oxidizer, Laser, Dye laser.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1990
- Accession Number
- ADA226031
Entities
People
- Andrzej W. Miziolek
- Brad E. Forch
- Jeffrey B. Morris
Organizations
- Ballistic Research Laboratory