The main characteristics of laser-induced fluorescence are high sensitivity and molecule-specific selectivity. One special advantage of the technique is the possibility of measuring two-dimensional distributions using single-pulse technology. This method is therefore preferred for structural analysis of flames (with OH, CH, NO or H2CO as indicator molecules), for characterising the mixture in reactive flows (fuel distribution) and for determining minority species and 2D temperature distributions with the OH radical. Mobile LIF measurement systems are operated at the Institute in order to perform investigations on technical combustion devices. Potential applications range from industrial premix burners and engine test rigs to combustion chambers of aircraft engines.