Non-intrusive, quantitative, calibration-free optical diagnostics methods for most molecular gases such as carbon dioxide and carbon monoxide do not exist. This limits the ability to understand and to develop predictive combustion models that describe the oxidation of gaseous, liquid, and solid fuels that are being considered in next-generation engines. This project will develop a new diagnostic tool for quantitative imaging of gas temperature and composition in combustion flames. The results will help improve understanding of how fuels burn and will help engineers design and manufacture new engines for aircraft and automobiles that offer improved performance and efficiency with new fuels. The primary goals of this work are: (1) develop the first quantitative and calibration-free gaseous species and temperature imaging diagnostics for CO, CO2, and, if possible, CH4 and C2H4 and (2) validate the accuracy of these imaging diagnostics in canonical flames, heated jets, and shock-tube experiments. This will be done using wavelength-modulated infrared planar laser-induced fluorescence techniques that were invented by the principal investigator. In this technique two infrared lasers with a time-varying wavelength are used to excite molecular vibrational modes at a specific frequency and the time-varying fluorescence is imaged with an infrared camera to determine the local gas temperature and concentration of a specific chemical species. The intellectual significance of this work