Rawlins W T, Oakes D B, Davis S J
Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810, USA.
J Phys Chem A. 2007 Jul 26;111(29):6860-9. doi: 10.1021/jp071786r. Epub 2007 May 23.
This paper presents results from investigations of chemically reacting flowfields and optical gain profiles in HF chemical laser media by infrared hyperspectral imaging. Subsonic and supersonic chemiluminescent F+H2 reacting flowfields, produced in high-fluence microwave-driven reactors, were imaged at a series of wavelengths, 2.6-3.1 microm, by a low-order, spectrally scanning Fabry-Perot interferometer mated to an infrared camera. The resulting hyperspectral data cubes define the spectral and spatial distributions of the emission. Spectrally resolved images at high spatial resolution were processed to determine spatial distributions of the excited-state concentrations of the product HF(v, J) molecules, as well as spatial distributions of small-signal gain on specific laser transitions. Additional high-resolution Fourier transform spectroscopy and spectral fitting analysis determined detailed excited-state distributions in the reacting flowfields. The measurements showed that energetic HF(v, J) state distributions were generated by both the supersonic and fast-flow subsonic mixing schemes. In particular, the subsonic reactor produced a spatially distributed field of inverted, near-nascent state populations, with small-signal gains near 2-3%/cm.
本文介绍了通过红外高光谱成像对HF化学激光介质中的化学反应流场和光学增益分布进行研究的结果。在高通量微波驱动反应器中产生的亚音速和超音速化学发光F+H2反应流场，由与红外相机配合使用的低阶光谱扫描法布里-珀罗干涉仪在2.6-3.1微米的一系列波长下成像。所得的高光谱数据立方体定义了发射的光谱和空间分布。对高空间分辨率的光谱分辨图像进行处理，以确定产物HF(v, J)分子激发态浓度的空间分布，以及特定激光跃迁上小信号增益的空间分布。额外的高分辨率傅里叶变换光谱和光谱拟合分析确定了反应流场中详细的激发态分布。测量结果表明，超音速和快速流亚音速混合方案均能产生高能HF(v, J)态分布。特别是，亚音速反应器产生了一个空间分布的反转近初生态粒子场，小信号增益接近2-3%/cm。
