Two-photon-excited fluorescence measurement of hydrogen atoms in flames

Abstract

We report the first two-photon-excited hydrogen-atom fluorescence measurements in flames made to our knowledge. The n = 3 level of the H atom was excited by 205.1-nm radiation generated by Raman shifting a 224-nm beam produced by frequency mixing. Fluorescence was observed at 656.3 nm as a result of radiative decay from n = 3 to n = 2, the Balmer-alpha transition. A novel technique, photoionization-controlled loss spectroscopy, is proposed to eliminate the quenching dependence of the fluorescence signal.

Simultaneous spatially resolved NO and NO_2 measurements using one- and two-photon laser-induced fluorescence

“…This work was followed shortly by flame detection of 0 (Ref. 7) and H. 8 , 9 The combination of imaging and multiphoton absorption LIF experiments was also recently report- In this Letter we describe the simultaneous detection of NO and NO 2 by using one laser pulse at 452 nm. This wavelength induces a two-photon transition in the -y band at 226 nm of NO with subsequent fluorescence in the UV spectral region.…”

Comparison of Three Schemes of Two-Photon Laser-Induced Fluorescence for CO Detection in Flames

“…1,[3][4][5][6] Many investigations have been done to measure important parameters that affect the different processes that the CO molecule will undergo in two-photon LIF, e.g., absorption and excitation cross section, 7 spectral broadening, 8 collisional quenching, 9,10 photoionization, 11 and fluorescence lift times. 12,13 For two-photon CO LIF in combustion systems, the most common excitation wavelength is 230.1 nm, matching the…”

Triple Quadrupole Mass Spectrometry Diagnostics of Propellant-Like Flames

“…Laser-induced fluorescence (LIF) and multiphoton techniques such as resonance-enhanced multiphoton ionization (REMPI) have yielded measurements with a good degree of selectivity and spatial resolution (Lucht et al 1983, Alden et al 1982, Goldsmith 1983). More intrusive techniques for gas sampling that use gas-liquid chromatography (GC) or mass spectrometry (MS) as detectors have also been used (Eltenton 1947, Serry and Zabielski 1989, Biordi et al 1974, Greene and Pust 1958, Fristrom and Westenberg 1965, Banna 1979.…”