The response of thin sputtered thermocouples to interrupted radiation of low frequency has been studied and corroboration with the theory obtained. The anomalous behavior of bismuth-tellurium couples has been observed. These couples when used in conjunction with a low frequency amplifier are more sensitive than wire thermocouples used with the most sensitive galvanometers, but without "multipliers."
LOUIS HARRIS and ALVIN C. SCHOLP, "The Response of Sputtered Thermocouples to Interrupted Radiation," J. Opt. Soc. Am. 30, 519-522 (1940)