Globar

A Globar is used as thermal light source for infrared spectroscopy. It is a silicon carbide rod of 5 to 10 mm width and 20 to 50 mm length which is electrically heated up to 1,000 to 1,650 °C (1,830 to 3,000 °F). When combined with a downstream variable interference filter, it emits radiation from 4 to 15 micrometres wavelength. Globars are used as thermal light sources for infrared spectroscopy because their spectral behaviour corresponds approximately to that of a Planck radiator (i.e. a black body). Alternative middle-infrared luminous sources are Nernst lamps, coils of chrome-nickel alloy or high-pressure mercury lamps.