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 5(2)P(1/2) → 6(2)S(1/2) 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.
- indium hyperfine
Hult, J., Burns, I. S., & Kaminski, C. F. (2004). Measurements of the indium hyperfine structure in an atmospheric-pressure flame by use of diode-laser-induced fluorescence. Optics Letters, 29(8), 827-829. https://doi.org/10.1364/OL.29.000827