OxyFog analysis:
Optical emission and photos

In this section, we analyze optical emission from AAPlasma’s open-source OxyFog system and supply photographs of plasma for visual verification of a fully-functional electrode. We use an optical emission spectrometer (Avantes Starline AvaSpec-ULS2048CL-EVO-RS) with a 1-meter optical fiber (Avantes FC-UVIR400-1) and a collimating lens (Avantes COL-90-UV/VIS). All are available on the Avantes website.

As shown in the photographs below, we remove the press-fit 1/4” tube adapter from the center of the chamber and use the remaining 0.5” hole to feed the fiberoptic cable through. The collimating lens is kept 1” away from the plasma-generating electrode surface by a homemade plywood spacer.

The Avantes setup that we are working with—especially the fiber and lens—absorbs emissions below 300nm, as is evident from the observed emission lines. Clearly, water present in the room’s air is enough to provide us with OH emission, making both spectra virtually identical (with or without water fog).

However, water fog presents a significant barrier for photographing plasma, so the photographs below are only done in room air, at different exposures and distances.

Questions or comments should be directed to greg@aaplasma.com.