Multiplex Degenerate Four Wave Mixing Thermometry of the C2 Radical

Abstract

In recent years an increasing use has been made of laser based techniques for non-intrusive temperature measurements and analysis of combustion and other hostile environments. Degenerate four-wave mixing (DFWM) is a single photon resonant process producing a collimated signal which enables spatial discrimination of background and scattered light. Scanning DFWM has been used for detection of several radical species including OH [1] and C2[2] and for thermometry [3]. Of particular use for diagnostics, however, are single-shot temperature measurements, especially for studying rapidly varying environments. The feasibility of single-shot multiplex DFWM thermometry of the hydroxyl radical has been demonstrated[4,5].