Two-wavelength differential thermometry for microscopic extended source

Sample temperature may theoretically be determined if we know or measure four quantities (two radiances at two specific wavelengths). We performed differential, continuous two-wavelength thermometry on a micro-surface element of the coiled coil filament used in tungsten lamp with a spectrometer. Results indicate that differential, continuous thermometry using a spectrometer measures temperature distribution along a short line. This method significantly enhances the capability of this established technique to new applications.