A-X(0,1) excitation is a promising new approach for NO laser-induced fluorescence (LIF) diagnostics at elevated pressures and temperatures. We present what to our knowledge are the first detailed spectroscopic investigations within this excitation band using wavelength-resolved LIF measurements in premixed methane/air flames at pressures between 1 and 60 bar and a range of fuel/air ratios. Interference from O_(2) LIF is a significant problem in lean flames for NO LIF measurements, and pressure broadening and quenching lead to increased interference with increased pressure. Three different excitation schemes are identified that maximize NO/O_(2) LIF signal ratios, thereby minimizing the O_(2) interference. The NO LIF signal strength, interference by hot molecular oxygen, and temperature dependence of the three schemes are investigated.
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