Abstract

We report on the current status of our work concerning the development of new optical sensors for the measurement of hydroxyl (OH) and nitric oxide (NO). Laser based sensors potentially fulfill all requirements to implement pollutant detection generated in combustion processes. Some of these requirements are high sensitivity, compactness, cost-efficiency, and the capability to make real-time measurements. The latter is particularly important, if these sensors are to be combined with combustion control systems. Sensors based on diode lasers operating in the near-infrared are most-common. However, absorption features in this spectral range are typically due to vibrational overtones which are weak compared to electronic transitions in the visible or ultraviolet (UV). In addition, background absorption from water limits the sensitivity in the near-infrared. A solution to these problems is to move to the aforementioned spectral region. However, it is difficult to develop usable UV laser systems that have the advantages of diode-laser based systems such as compactness and cost efficiency.

© 2002 Optical Society of America