THE APPLICATION OF THIRD ORDER NONLINEAR OPTICAL TECHNIQUES TO THE DIAGNOSIS OF COMBUSTING MEDIA

摘要

Optical diagnostic probes are particularly well suited to gas diagnostic applications in their ability to provide quantitative information with a high degree of spatial and temporal resolution with minimal disturbance to the medium. In this report we briefly review spontaneous Raman scattering (SRS) and examine the relative merits of three nonlinear optical techniques for gas diagnostics. These techniques are: (1) coherent anti-Stokes Raman spectroscopy (CARS), (2) stimulated anti-Stokes Raman spectroscopy (SARS), and (3) the Raman induced Kerr effect (RIKE). Detection limits are placed on each of these techniques by examining a representative example of a trace density of nitrogen gas in a background mixture at one atmosphere, it is found that nonlinear techniques offer significant improvements over SRS in applications where discrimination against fluorescence, time resolution and spectral resolution are desired.