Sulfur lamp

Sulfur lamp inside a Faraday cage, which is necessary to prevent microwave radiation leakage from the magnetron which would cause radio interference

The sulfur lamp (also sulphur lamp) is a highly efficient full-spectrum electrodeless lighting system whose light is generated by sulfur plasma that has been excited by microwave radiation. They are a particular type of plasma lamp, and one of the most modern. The technology was developed in the early 1990s and appeared promising, but was not a commercial success by the late 1990s. Since 2005, lamps are again being manufactured for commercial use.