Optical–optical double resonance LIF detection of in high pressure gas discharges

An optical?optical double resonance (OODR) laser induced fluorescence (LIF) for the detection of the metastable is described. OODR employs the double laser excitation of A?B and B?C nitrogen transitions. Here it is proposed as a sensitive approach to detect in high-pressure discharges. We have tested its sensitivity with respect to conventional single photon LIF by an excitation/detection scheme in which the two wavelengths required are generated by a provisional single laser setup. Other single laser configurations that might allow a sensitivity close to two orders of magnitude larger than that of conventional LIF are proposed. Such gain can be particularly useful for the detection of in non-equilibrium, high-pressure discharges.