Research on combustion diagnostics and sensor development is focused on a wide range of techniques to study combustion processes in-cylinder, as well as, in related systems such as engine aftertreatment systems. Diagnostic techniques include 2-D, line-of-sight, and point measurement techniques with measuring frequencies ranging from a few Hz up to 1 MHz. Diagnostics utilize pulsed and CW lasers with widely varying power levels, in addition to non-laser-based techniques utilizing broadband light sources or more conventional transducers. Quantities of interest for measurement include temperature, species concentrations, pressure, and velocity. The development of sensors based on various diagnostic techniques that are applicable for measurement and control of real systems is another important area of research in the center.