Precise calibration of zero-crossing temperature and drift of an ultralow expansion cavity with a clock transition spectrum

Liu Hui^{1, 2, 3}, Jiang Kun-Liang^{1, 2, 3}, Wang Jin-Qi^{1, 2, 3}, Xiong Zhuan-Xian^{1, 2}, He Ling-Xiang^{1, 2,}, Lü Bao-Long^{1, 2}

(color online) Schematic setup for zero-crossing temperature measurement. Normalized clock transition spectrum of clock transition (Lorentz fitting of the black dots) is derived according to fluorescence signal collected by the photo-multiplier (PMT) while sweeping continuously AOM driving frequency.