ABSTRACT
Quantitative imaging of nitric oxide (NO) concentrations with laser-induced fluorescence (LIF) has attracted significant interest in recent years for optimizing combustion efficiency and minimizing pollutant formation as well as for validating combustion chemistry models [ 1 -5 ] . At high pressures, however, NO-LIF spectroscopy is faced with a number of problems that complicate quantification. Fluorescence interference occurs from 02-LIF in high pressure high-temperature fuel-lean environments [6] . The interpretation of NO-LIF signals is influenced by temperature in many respects, since not only ground state population distribution, but also line shapes and fluorescence-quenching cross-sections are temperature-
dependent. The quenching rates depend on local gas composition, which also varies with temperature. In the < 250 nm range used for NO diagnostics, strong absorption of laser and signal light by combustion products such as H20 and CO2 must be considered [7], and this absorption strongly depends on temperature. Finally reliable calibration techniques are re quired [2,8] . These influences are discussed in more detail in a related paper from the same authors [9] .
