In situ laser diagnostics of solar chemical reactions using coherent anti-Stokes Raman spectroscopy (CARS)

A laser based temperature metrology method, coherent anti-Stokes raman spectroscopy (CARS), has been used to measure temperatures and to study gas phase chemical reactions in a high temperature solar reactor. The solar chemical reactor was a cavity type receiver and placed in the focus of the solar concentrator at the Paul Scherrer Institute. The receiver was designed for CARS spectroscopy and temperature metrology. The feasibility of measuring the CARS spectrum of nitrogen, ammonia and hydrogen in an operating solar reactor was demonstrated in this work. We found that the severe environment existing in the solar reactor did not present any insurmountable problems for the temperature measurements.