  Objects that are small compared to their thermal photon wavelengths violate
the assumptions underlying optical pyrometry and can show unusual coherence
effects. To investigate this regime we measure the absolute light intensity
from individual, incandescent multiwalled carbon nanotubes. The nanotube
filaments' physical dimensions and composition are determined using
transmission electron microscopy and their emissivities are calculated in terms
of bulk conductivities. A single-color pyrometric analysis then returns a
temperature value for each wavelength, polarization, and applied bias measured.
Compared to the more common multiwavelength analysis, single-color pyrometry
supports a more consistent and complete picture of the carbon nanotube lamps,
one that describes their emissivity, optical conductivity, and thermal
conductivity in the range 1600-2400 K.
