A method of calculating and describing transmission characteristics of light guides is developed and applied to rods of synthetic sapphire. The total transmission is shown to be an inadequate measure of the extent to which a calibration curve relating relative signal to temperature is possible for a light guide radiation pyrometer. The angular field of view of synthetic sapphire rod is presented in terms of fractional emergent power per five degree angular increment. It is concluded that the transmission properties presented here, in combination with data for a single point, permit the simple, individual calibration of commercially available light guide radiation pyrometers.
J. VOLLMER, G. C. REIN, and J. A. DUKE, "Light Guide Radiation Pyrometry," J. Opt. Soc. Am. 49, 75-75 (1959)