We report on what we believe is the first demonstration of laser-induced fluorescence (LIF) in flames by use of diode lasers. Indium atoms seeded into an atmospheric-pressure flame at trace concentrations are excited by a blue GaN laser operating near 410 nm. The laser is mounted in an external-cavity configuration, and the hyperfine spectrum of the 52P1/2→62S1/2 transition is captured at high resolution in single-wavelength sweeps lasting less than one tenth of a second. The research demonstrates the potential of diode-based LIF for practical diagnostics of high-temperature reactive flows.
© 2004 Optical Society of America
(020.2930) Atomic and molecular physics : Hyperfine structure
(120.1740) Instrumentation, measurement, and metrology : Combustion diagnostics
(300.2530) Spectroscopy : Fluorescence, laser-induced
(300.6260) Spectroscopy : Spectroscopy, diode lasers
Johan Hult, Iain Stewart Burns, and Clemens Friedrich Kaminski, "Measurements of the indium hyperfine structure in an atmospheric-pressure flame by use of diode-laser-induced fluorescence," Opt. Lett. 29, 827-829 (2004)