Optical emission spectroscopy of plasma in waveguide-supplied nozzleless microwave source

Recently, microwave plasma sources (MPSs) operated at atmospheric pressure have been developed [1]. Such devices were used in spectroscopy, technological processes like surface treatment, carbon nanotubes synthesis and sterilization. They also found applications in the processing of various gases. Destruction of Freon HFC-134a [2] and production of hydrogen via methane conversion [3] in microwave atmospheric pressure plasmas were reported by us. Optical emission spectroscopy (OES) is a very useful, powerful and valuable tool in the study of plasma properties (densities of electrons and heavy species, gas temperature, etc), contributing significantly to the development of microwave plasma technology and its applications.