Trace gas detection of chemical species
Tittel, Frank K.
Master of Science
The theory of continuous wave difference frequency generation (DFG) is studied for a mixing of two waves in a nonlinear medium, the absorption effect of the material is included and optimization conditions are studied. Trace concentrations of nitric oxide were observed in a mixture of ambient air using a DFG source with periodically poled lithium niobate (PPLN) as the nonlinear medium. A sensitivity of 300 ppb was achieved. The design and development of a fiber-coupled DFG sensor are reported. This sensor applied to the observation of carbon monoxide.
Physical chemistry; Electronics; Electrical engineering; Optics