Reichardt T A, Giancola W C, Lucht R P
Department of Mechanical and Industrial Engineering, University of Illinois, 1206 West Green Street, Urbana, Illinois 61801, USA.
Appl Opt. 2000 Apr 20;39(12):2002-8. doi: 10.1364/ao.39.002002.
Polarization-spectroscopy (PS) line shapes and signal intensities are measured in well-characterized hydrogen-air flames operated over a wide range of equivalence ratios. We use both low (perturbative) and high (saturating) pump beam intensities in the counterpropagating pump-probe geometry. The effects of saturation on the line-center signal intensity and the resonance linewidth are investigated. The PS signal intensities are used to measure relative OH number densities in a series of near-adiabatic flames at equivalence ratios (phi) ranging from 0.5 to 1.5. The use of saturating pump intensities minimizes the effect of pump beam absorption, providing more accurate number density measurements. When calibrated to the calculated OH concentration in the phi = 0.6 flame, the saturated PS number density measurements probing the P(1)(2) transition are in excellent agreement with OH absorption measurements, equilibrium calculations of OH number density, and previous saturated degenerate four-wave mixing OH number density measurements.
在一系列当量比范围很宽的、特性明确的氢 - 空气火焰中测量了偏振光谱（PS）线形状和信号强度。在反向泵浦 - 探测几何结构中，我们使用了低（微扰）和高（饱和）泵浦光束强度。研究了饱和对谱线中心信号强度和共振线宽的影响。PS信号强度用于测量一系列当量比（φ）在0.5至1.5之间的近绝热火焰中的相对OH数密度。使用饱和泵浦强度可将泵浦光束吸收的影响降至最低，从而提供更精确的数密度测量。当根据φ = 0.6火焰中计算出的OH浓度进行校准时，探测P(1)(2)跃迁的饱和PS数密度测量结果与OH吸收测量、OH数密度的平衡计算以及先前的饱和简并四波混频OH数密度测量结果高度一致。
