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) Frequency variations with time of the ULE cavity at controlled temperatures of (a) 32 °C, (b) 33 °C, and (c) 34 °C, respectively. The insets show frequency drifts with the linear drifts removed.