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Quantitative concentrations measurements using time-resolved laser-induced fluorescence have been demonstrated for nitric oxide (NO) in flame. Fluorescence lifetimes measured using a picosecond Nd:YAG laser and optical parametric amplifier system have been used to directly compensate the measured signal for collisional quenching and evaluate NO concentration. The full evaluation also includes the spectral overlap between the ∼15 cm⁻¹ broad laser pulse and multiple NO absorption lines as well as the populations of the probed energy levels. Effective fluorescence lifetimes of 1.2 and 1.5 ns were measured in prepared NO/N₂/O₂ mixtures at ambient pressure and temperature and in a premixed NH₃-seeded CH₄/N₂/O₂ flame, respectively. Concentrations evaluated from measurements in NO/N₂/O₂ mixtures with NO concentrations of 100–600 ppm were in agreement with set values within 3% at higher concentrations. An accuracy of 13% was estimated by analysis of experimental uncertainties. An NO profile measured in the flame showed concentrations of ∼1000 ppm in the post-flame region and is in good agreement with NO concentrations predicted by a chemical mechanism for NH₃ combustion. An accuracy of 16% was estimated for the flame measurements. The direct concentration evaluation from time-resolved fluorescence allows for quantitative measurements in flames where the composition of major species and their collisional quenching on the probed species is unknown. In particular, this is valid for non-stationary turbulent combustion and implementation of the presented approach for measurements under such conditions is discussed.

We present a compact TW-class OPCPA system operating at 800 nm. Broadband seed pulses are generated and pre-amplified to 25 μJ in a white light continuum seeded femtosecond NOPA. Amplification of the seed pulses to 35 mJ at a repetition rate of 10 Hz and compression to 9 fs is demonstrated.

The influcence of the pulse duration on the emission characteristics of nearly debris-free laser-induced plasmas in the soft x-ray region (λ ≈1-5 nm) was investigated, using six different target gases from a pulsed jet. Compared to ns pulses of the same energy, a ps laser generates a smaller, more strongly ionized plasma, being about 10 times brighter than the ns laser plasma. Moreover, the spectra are considerably shifted towards shorter wavelengths. Electron temperatures and densities of the plasma are obtained by comparing the spectra with model calculations using a magneto-hydrodynamic code.