Inverse Photoacoustice Pyrometer

A~pyrometer~is a type of non-contacting thermometer which intercepts and measures thermal radiation. When an infrared active gas is periodically exposed to a body at low temperature, the emission of radiation from the gas causes an acoustic signal to be generated. This phenomenon, known as the ``inverse'' photoacoustic effect, can be explained by consideration of a gas of harmonic oscillators in an enclosure where the blackbody energy density is perturbed. Here, we describe a pyrometer based on inverse photoatoustic effect.